Seagate Fibre Channel Interface, 77767496 User Manual

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Fibre Channel Interface

Publication number: 77767496, Rev. D

February 2004

Seagate and Seagate Technology are registered trademarks of Seagate Technology LLC. SeaTools, SeaFONE, SeaBOARD, SeaTDD, and the Wave logo are either registered trademarks or trademarks of Seagate Technology LLC. Other product names are registered trademarks or trademarks of their owners.

Seagate reserves the right to change, without notice, product offerings or specifications. No

part of this publication may be reproduced in any form without written permission of Seagate

Technology LLC.

Revision status summary sheet

Revision Date Sheets Affected

A 03/21/1997 L. Newman/J. Coomes and W. Whittington All B 08/01/2000 L. Newman/J. Coomes All C 01/03/2003 L. Newman No change except for new Seagate logo.

D 02/05/2004 K. Schweiss/J. Coomes and W. Paulsen All

Sheets Affected

Document migration/conversion only.

Contents

1.0 Publication overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 How to use this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 General interface description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2.0 Introduction to Fibre Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.2 Channels vs. networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.3 The advantages of Fibre Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.0 Fibre Channel standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.1.1 Description of Fibre Channel levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.1.1.1 FC-0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.1.1.2 FC-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.1.1.3 FC-1.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.1.1.4 FC-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.1.1.5 FC-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.1.1.6 FC-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.1.2 Relationship between the levels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.1.3 Topology standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.1.4 FC Implementation Guide (FC-IG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4.0 Introduction to topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.1 Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.2 Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.3 Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.4 Arbitrated loop topology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.5 Topology and port login . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.6 Port bypass circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

5.0 Data encoding (FC-1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.1 Encoding and decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.2 Buffer-to-buffer data transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5.3 Data hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.3.1 Transmission words . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.3.1.1 Data characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.3.1.2 Special characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.4 Ordered sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.4.1 Primitive signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.4.1.1 Primitive signals used as frame delimiters. . . . . . . . . . . . . . . . . . . . . . 16

5.4.1.2 Primitive signals custom made for arbitrated loop topologies . . . . . . . 18

5.4.2 Primitive sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

5.4.2.1 Primitive sequences custom made for Arbitrated Loop topologies . . . 20

6.0 Framing protocol (FC-2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

6.1 Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

6.1.1 Frame structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

6.1.1.1 Start-of-frame (SOF) delimiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.1.1.2 Frame header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.1.1.3 Data field (payload) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

6.1.1.4 CRC field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

6.1.1.5 End-of-frame (EOF) delimiter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

6.2 Frame sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Fibre Channel Interface Manual, Rev. D v

6.3 Exchanges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

6.4 Credit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.0 Classes of service (FC-2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.1 Class 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.2 Class 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.3 Class 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.3.1 Class 3 flow control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.4 Classes 4 and 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

8.0 FC Arbitrated Loop concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

8.1 Arbitrated Loop physical address (AL_PA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

8.2 Loop initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

8.2.1 Loop initialization state machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

8.2.2 Loop reinitialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

8.3 Accessing another L_Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

8.3.1 Access fairness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

8.3.2 Access unfairness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

8.3.3 Clock skew management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

8.4 Loop ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

8.4.1 Maximum number of NL_Ports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

8.4.2 Blocking switch emulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

8.4.3 Non-meshed environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

8.4.4 Assigned AL_PA values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

9.0 Fibre Channel link services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

9.1 Basic link services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

9.1.1 Abort Sequence (ABTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

9.1.2 Basic Accept (BA_ACC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

9.1.3 Basic Reject (BA_RJT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

9.2 Extended link services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

9.2.1 Port Login (PLOGI) (02x) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

9.2.2 Port Logout (PLOGO) (03x) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

9.2.3 Fabric Login (FLOGI) (04) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

9.2.4 Process Login (PRLI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

9.2.5 Process Logout (PRLO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

9.2.6 Third Party Process Logout (TPRLO). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

9.2.7 Read Link Error Status Block (RLS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

9.2.8 Reinstate Recovery Qualifier (RRQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

9.2.9 Port Discovery (PDISC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

9.2.10 Discover Address (ADISC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

9.2.11 Report Node Capabilities (RNC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

9.2.12 Link Service Reject (LS_RJT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

9.3 FC common transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

9.3.1 Register FC-4 Types Name Service (RFT_ID). . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

10.0 Enclosure services interface (ESI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

10.1 Discovery process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

10.2 8045 mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

10.2.1 8045 ESI pinouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

10.3 8067 mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

10.3.1 8067 ESI command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

10.3.2 8067 ESI interface pinouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

10.3.3 8067 information format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

10.4 ESI command transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

10.4.1 ESI read transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

vi Fibre Channel Interface Manual, Rev. D

10.4.2 ESI write transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

10.5 Enclosure-initiated ESI transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

10.5.1 EIE Discovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

10.5.2 EIE operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

10.5.3 Enclosure requested information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

10.5.3.1 Device Standard Inquiry Data page . . . . . . . . . . . . . . . . . . . . . . . . . 113

10.5.3.2 Device Address page. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

10.5.3.3 Loop Position Map page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

10.5.3.4 Device Identification page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

10.5.3.5 Device Temperature page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

10.5.3.6 Port Parameters page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

10.5.3.7 Link Status page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

10.5.3.8 Spin-Down Control Action Specific Bits . . . . . . . . . . . . . . . . . . . . . . 123

10.5.3.9 ESI data validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

11.0 SCSI operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

11.1 SCSI-FCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

11.1.1 FC-4 mapping layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

11.2 FCP CMND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

11.2.1 Command Descriptor Block (CDB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

11.2.1.1 Operation Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

11.2.1.2 Logical block address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

11.2.1.3 Operation code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

11.2.1.4 Relative address bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

11.2.1.5 Transfer length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

11.2.1.6 Control byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

11.3 FCP XFER RDY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

11.4 FCP DATA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

11.5 FCP RSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

11.5.1 Extended Sense Data format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

11.5.1.1 Sense Key Specific Valid (SKSV) and Sense Key Specific . . . . . . . . 147

11.5.1.2 Current and deferred errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

11.6 Parameter rounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

12.0 Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

12.1 Change Definition command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

12.2 Compare command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

12.3 Copy command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

12.4 Copy and Verify command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

12.5 Format Unit command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

12.5.1 Format Unit parameter list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

12.5.1.1 Defect List header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

12.5.1.2 Initialization Pattern descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

12.6 Inquiry command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

12.6.1 Vital product data pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

12.6.2 Unit Serial Number page (80h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

12.6.3 Implemented Operating Definition page (81h) . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

12.6.4 Device Identification page (83h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

12.6.5 Firmware Numbers page (C0h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

12.6.6 Date Code page (C1h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

12.6.7 Jumper Settings page (C2h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

12.6.8 Device Behavior page (C3h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

12.7 Lock-Unlock Cache (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

12.8 Lock-Unlock Cache (16) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

12.9 Log Select command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

12.10 Log Sense command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

Fibre Channel Interface Manual, Rev. D vii

12.10.1 Error Counter pages, Write, Read, Read Reverse, and Verify (code 02, 03, 04, and 05h) 196

12.10.2 Non-Medium Error page (code 06h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

12.10.3 Temperature page (code 0Dh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

12.10.4 Device Self-Test Results Log page (code 10h) . . . . . . . . . . . . . . . . . . . . . . . . . . 201

12.10.5 Cache Statistics page (code 37h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

12.10.6 Factory Log page (code 3Eh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

12.11 Mode Select (6) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

12.12 Mode Select (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

12.13 Mode Sense (6) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

12.13.1 Unit Attention page (00h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

12.13.2 Error Recovery page (01h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

12.13.3 Disconnect/Reconnect Control page (02h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

12.13.4 Format Parameters page (03h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

12.13.5 Rigid Disc Drive Geometry Parameters page (04h) . . . . . . . . . . . . . . . . . . . . . . . 226

12.13.6 Verify Error Recovery page (07h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228

12.13.7 Caching Parameters page (08h) for Mode Sense/Mode Select . . . . . . . . . . . . . . 230

12.13.8 Mode Sense/Mode Select Control Mode page (0Ah) . . . . . . . . . . . . . . . . . . . . . . 233

12.13.9 Notch page (0Ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

12.13.10 XOR Control Mode page (10h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

12.13.11 Fibre Channel Interface Control page (19h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

12.13.12 Power Condition page (1Ah) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

12.13.13 Informational Exceptions Control page (1Ch). . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

12.14 Mode Sense (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246

12.15 Move Medium command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

12.16 Persistent Reserve In command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

12.16.1 Persistent Reserve In parameter data for read keys . . . . . . . . . . . . . . . . . . . . . . 250

12.16.2 Persistent Reserve In parameter data for read reservation . . . . . . . . . . . . . . . . . 251

12.17 Persistent Reserve Out command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

12.17.1 Persistent Reserve Out parameter list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256

12.18 Prefetch (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

12.19 Prefetch (16) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

12.20 Prevent/Allow Medium Removal command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

12.21 Read (6) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262

12.22 Read (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

12.23 Read (12) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

12.24 Read (16) command (88h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

12.25 Read Buffer command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270

12.25.1 Read Combined Descriptor Header and Data mode (000b) . . . . . . . . . . . . . . . . 271

12.25.2 Read Data mode (010b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

12.25.3 Read Buffer descriptor mode (011b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

12.26 Read Capacity (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

12.27 Read Capacity (16) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

12.28 Read Defect Data (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

12.29 Read Defect Data (12) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

12.30 Read Element Status command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

12.31 Read Long command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

12.32 Reassign Blocks command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

12.33 Receive Diagnostic Results command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

12.34 Release (6) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

12.35 Release (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

12.36 Report Device Identifier command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

12.37 Report LUNs command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

12.38 Request Sense command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

12.39 Reserve (6) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

viii Fibre Channel Interface Manual, Rev. D

12.40 Reserve (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

12.40.1 Logical unit reservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

12.40.2 Third-party reservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

12.40.3 Superseding reservations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

12.40.4 Parameter list format for third-party addressing. . . . . . . . . . . . . . . . . . . . . . . . . . 301

12.41 Rezero Unit command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

12.42 Search Data Equal command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

12.43 Search Data High command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

12.44 Search Data Low command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

12.45 Seek (6) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

12.46 Seek (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

12.47 Send Diagnostic command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304

12.47.1 Supported Diagnostic page–Send Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . 307

12.47.2 Translate Address page–Send Diagnostic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308

12.47.3 Diagnostic page–Send Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

12.48 Set Device Identifier command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

12.49 Set Limits command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312

12.50 Start/Stop Unit command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313

12.51 Synchronize Cache (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314

12.52 Synchronize Cache (16) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315

12.53 Test Unit Ready command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316

12.54 Verify (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317

12.55 Verify (12) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318

12.56 Verify (16) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320

12.57 Write (6) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322

12.58 Write (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324

12.59 Write (12) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

12.60 Write (16) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

12.61 Write and Verify (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

12.62 Write and Verify (12) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331

12.63 Write and Verify (16) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

12.64 Write Buffer command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335

12.64.1 Combined Header and Data mode (000b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337

12.64.2 Write Data Only mode (010b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337

12.64.3 Download Microcode and Save mode (101b) . . . . . . . . . . . . . . . . . . . . . . . . . . . 337

12.64.4 Download Microcode with Offsets and Save mode (111b) . . . . . . . . . . . . . . . . . 338

12.65 Write Long command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339

12.66 Write Same (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340

12.67 Write Same (16) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

12.68 XDRead (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

12.69 XDRead (32) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

12.70 XDWrite (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345

12.71 XDWrite (32) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347

12.72 XDWriteRead (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

12.73 XDWriteRead (32) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350

12.74 XPWrite (10) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352

12.75 XPWrite (32) command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

13.0 Drive features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

13.1 Self-Monitoring Analysis and Reporting Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

13.2 Self-test operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

13.2.1 Default self-test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

13.2.2 Short and extended device self-tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

13.2.3 Device self-test modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356

13.2.3.1 Foreground mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356

Fibre Channel Interface Manual, Rev. D ix

13.2.3.2 Background mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356

13.2.3.3 Elements common to foreground and background self-test modes. . 357

14.0 Seagate Technology support services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363

x Fibre Channel Interface Manual, Rev. D

List of Figures

Figure 1. Fibre Channel standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 2. Arbitrated loop topology (dual port private loop) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 3. Port bypass circuit physical interconnect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 4. Decimal value translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 5. Serialization process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Figure 6. FC data hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Figure 7. Relationship between frames, sequences, and exchanges. . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 8. Frame structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 9. FC–SCSI exchanges, command and response transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 10. Loop initialization sequences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 11. Loop initialization state machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Figure 12. Loop state machine (simplified) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Figure 13. Discovery process flow diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Figure 14. ESI transfer phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Figure 15. ESI command transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Figure 16. ESI reads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Figure 17. ESI writes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Figure 18. Enclosure Initiated ESI Request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Figure 19. Prepare for Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Figure 20. EIE Operation Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Fibre Channel Interface Manual, Rev. D xi

xii Fibre Channel Interface Manual, Rev. D

1.0 Publication overview

This publication provides some general information about Fibre Channel as well as detailed information about how Seagate disc drives implement Fibre Channel Arbitrated Loop technology.

This publication will continue to be revised as Fibre Channel technology advances and as Seagate Fibre Channel drives change to meet data storage needs.

You will observe that many references are made to SCSI throughout this publication. This is because Fibre Channel transports the SCSI command set. This concept is discussed in more detail throughout this publication beginning in Chapter 2.

1.1 Acknowledgements

The information contained in this publication was gathered from many sources. Portions of the text used to explain general Fibre Channel concepts were adapted in various forms, with permission, from Ancot Corporation’s Fibre Channel, Volume 1: The Basics written by Gary R. Stephens and Jan V. Dedek. Additional information was contributed by Canadian Valley Vocational-Technical instructor Chuck Chalupa.

1.2 How to use this manual

This publication provides a universal detailed description of the Fibre Channel interface for Seagate disc drives. You may read it from front-to-back, or turn directly to the sections that interest you the most. A glossary is provided in the back (see Appendix A) which you may find useful as you read this manual.

Note. Volume 1 Product Manuals have tables that specify which SCSI features are implemented in each

specific drive model, what the default parameters are for the various features they implement, and which parameters are changeable and which are not.

No method exists at present to inform an initiator if a target supports SCSI-3 features as opposed to only SCSI2 features. A few SCSI-3 features are supported by Seagate drives, but no attempt has been made herein to differentiate between SCSI-2 and SCSI-3 features. Therefore, when an Inquiry command reports what the ANSI-approved version of the drive is, it reports SCSI-2, where SCSI-2 means SCSI-2 features plus some SCSI-3 features.

No attempt is made in this universal specification to specify which descriptions or tables apply to SCSI-2 or SCSI-3. The combination of this general specification with the details in the individual drive’s Product Manual, Volume 1, provides a description of the individual drive implementation of the SCSI interface.

This interface manual is not intended to be a stand-alone publication about Fibre Channel’s features. You should reference the individual drive’s Product Manual to determine the specific features supported by each drive model.

This specification is Volume 2 of a set of manuals that is made up of a separate drive Product Manual, Volume 1, and this manual. This Volume 2 manual is referenced by the Volume 1 Product Manual for Seagate Fibre Channel disc drives.

Fibre Channel Interface Manual, Rev. D 1

1.3 General interface description

This manual describes the Seagate Technology LLC Fibre Channel/SCSI (Small Computer Systems Interface) as implemented on Seagate Fibre Channel (FC) disc drives.

The disc drives covered by this manual are classified as intelligent peripherals.

The interface supports multiple initiators, self-configuring host software, automatic features that relieve the host from the necessity of knowing the physical architecture of the target (logical block addressing is used), and some other miscellaneous features.

The physical interface uses differential drivers and receivers for the Fibre Channel serial connections. The single channel transfer rate is 106 MB/second (commonly called 1 gigabit/sec) or 212 MB/second (commonly called 2 gigabit/sec). See the Volume 1 Product Manual for a definition of the electrical characteristics of the interface.

2 Fibre Channel Interface Manual, Rev. D

2.0 Introduction to Fibre Channel

Fibre Channel is an American National Standards Institute (ANSI) interface that acts as a general transport vehicle to simultaneously deliver the command sets of several existing interface protocols including SCSI-3, IPI-3, HIPPI-FP, IP, and ATM/AAL5. Proprietary and other command sets may also use and share the Fibre Channel, but these are not yet defined as part of the Fibre Channel standard.

Fibre Channel Arbitrated Loop (FC-AL) is one topology used to connect two or more devices within the guidelines set by the ANSI standards. This topology is discussed in detail throughout this manual. Other topologies do exist and are discussed briefly in this manual to give you some idea of how these topologies can coexist and interact.

2.1 General information

Fibre Channel supports both large and small data transfers. This makes it effective in transferring a wide variety of data and can be used in systems ranging from supercomputers to individual workstations. Fibre Channel peripherals can include devices such as, but not limited to, disc drives, tape units, high-bandwidth graphics terminals, and laser printers.

To accommodate all of these device types with various command sets, Fibre Channel separates the physical I/ O interface from the I/O operations. This makes it possible to use the multiple command sets simultaneously. This also allows new speeds and new functions to be added without making all previous investment in existing components obsolete.

Another benefit of Fibre Channel is that it supports both channel and network peripheral protocols for device communication. This means that channel and network protocols can share the same physical medium.

Fibre Channel does not have its own native I/O command set protocol. It simply lets other protocols superimpose their command sets onto itself and then transports this information. Fibre Channel has a command set that it uses to manage the links between the various participating devices using Fibre Channel. Fibre Channel calls these link level functions “link services.”

Since multiple command sets may use Fibre Channel, it identifies the information by command set type. This allows the receiving port to distinguish among the protocols and make processing decisions. Each Fibre Channel frame has a field in the frame header to identify the protocol associated with that frame. Additional information about frames is available in Section 6.0 beginning on page 23.

2.2 Channels vs. networks

As mentioned above, Fibre Channel supports both channel and network communications.

Channels

Traditional disc drive communications occur in a channel environment where the host controls the devices attached to it. The primary requirement for channel environments is to provide error-free delivery, with transfer delays being a secondary consideration.

Fibre Channel Interface Manual, Rev. D 3

Networks

Networks allow many devices to communicate with each other at will. This is usually accompanied by software support to route transactions to the correct provider and to verify access permission. Networks are used for transferring data with “error-free delivery” and voice and video where “delivery on time” is the primary requirement with error-free delivery being a secondary consideration. For example, when transferring video, it is more important to provide on-time delivery of data to prevent loss of video frames than to lose one or two pixels in a video frame.

2.3 The advantages of Fibre Channel

In addition to the channel/network support, Fibre Channel:

• Supports multiple physical interface types.

• Provides a means to interconnect physical interface types.

• Provides high-speed data transfer rates much faster than parallel SCSI.

• Separates the logical protocol being transported from the physical interface—this allows multiple protocols to be transported over a common physical interface.

• Allows increased cable lengths. You can have 30 meters between each device when using twisted pair copper media. Note that this 30 meters is between each device, not the total length (multiply the number of devices by 30m to obtain total allowable length). Fiber optic media extended this even further by allowing distances of 10km between each device.

• Increases the potential number of devices connected. Just one private arbitrated loop can have up to 125 devices attached. Even more can be attached in non-participating mode. Also, multiple loops can be attached to fabrics to significantly increase the number of devices attached.

• Uses asynchronous transmission to fully utilize the available bandwidth.

• Allows flexibility in transfer rates, distances, media types, and protocols.

4 Fibre Channel Interface Manual, Rev. D

3.0 Fibre Channel standards

Figure 1 shows the various documents involved in the ANSI set of standards relating to Fibre Channel. This model is not static—it is growing as others areas of interest are developed.

FC-SB

Mapping of Single-Byte

Command Code Sets

FC-ATM

Mapping of

ATM

FC-AE

Avionics

Environment

FC-FP

Mapping of

HIPPI-FP

Fibre Channel Enhanced Physical

Fibre Channel Physical Interface

FC-IG Fibre Channel Implementation Guide

FC-LE

Link

Encapsulation

FC-PH-n

FC-PH

X3.230-1994

SCSI-FCP

SCSI-FC

Protocol

SCSI-GPP

Generic

Packetized

Protocol

FC-I3

Revision to

IPI-3 Disk std

Arbitrated Loop

Switch Fabric

FC-FG

General Fabric

Requirements

FC-I3

Revision to

IPI-3 Tape std

FC-AL-n

FC-SW

FC-GS

Generic Services

Figure 1. Fibre Channel standards

The interface is compatible with a subset of the ANSI standards listed below:

• SCSI-2 Standard and the Common Command Set (CCS) document, Revision 4.B

• SCSI Parallel Interface-3 (SPI-3)

• SCSI Enclosure Services (SES) Command Set, X3T10 NCITS, 305-199x

• Fibre Channel Physical and Signaling, Revision 4.3 (FC-PH)

• Fibre Channel Physical and Signaling, Revision 7.4 (FC-PH-2)

• Fibre Channel Physical and Signaling, Revision 9.4 (FC-PH-3)

• SCSI Fibre Channel Protocol, Revision 12 (SCSI-FCP)

• Fibre Channel Arbitrated Loop, Revision 4.5 (FC-AL)

• Fibre Channel Arbitrated Loop Direct Attach SCSI Technical Report

• Fibre Channel Fabric Loop Attach Technical Report

Fibre Channel Interface Manual, Rev. D 5

Copies of ANSI documents relating to Fibre Channel can be purchased from:

Global Engineering 15 Inverness Way East Englewood, CO 80112-5704 (800) 854-7179 or (303) 792-2181 Fax: (303) 792-2192

3.1 General information

The FC-PH standard is the foundation upon which all others are based. Each topology, command set, and protocol has its own standard. These are all separate to allow future growth and to allow designers to more easily use only those parts that affect their products. It is important for system designers to consider the requirements of the set of protocols to be supported because different protocols require different subsets of the functions permitted in a Fibre Channel port.

3.1.1 Description of Fibre Channel levels

The Fibre Channel levels are listed below:

• Physical (FC-0)

• 8B/10B encoding/decoding (FC-1)

• FC-AL (FC-1.5)

• Framing protocol (FC-2)

• Common services (FC-3)

• Interface mapping (FC-4)

3.1.1.1 FC-0

FC-0 defines the physical portions of the Fibre Channel. This includes the fibre, connectors, and optical and electrical parameters for a variety of data rates and physical media. Coax, twinax, and twisted pair versions are defined for limited distance applications. FC-0 also provides the point-to-point physical portion of the Fibre Channel.

3.1.1.2 FC-1

FC-1 defines the transmission protocol which includes the serial encoding, decoding, and error control.

3.1.1.3 FC-1.5

FC-1.5 defines the topology involved with Fibre Channel Arbitrated Loop (FC-AL) configurations.

3.1.1.4 FC-2

FC-2 defines the signaling protocol which includes the frame structure and byte sequences.

3.1.1.5 FC-3

FC-3 defines a set of services which are common across multiple ports of a node.

6 Fibre Channel Interface Manual, Rev. D

3.1.1.6 FC-4

FC-4 defines the interface mapping between the lower levels of the Fibre Channel and the various command sets. These various command sets are known as upper layer protocols (ULPs). Examples of upper layer protocols include SCSI, IPI, HIPPI, and IP.

3.1.2 Relationship between the levels

FC-0, FC-1, and FC-2 are integrated into the FC-PH document. The other documents are separate so that each implementation may use the technology best suited to the environment in which it will be used.

3.1.3 Topology standards

Each topology has its own standard. This is done so that designers can concentrate on documents that apply to the technology suited to their specific area of interest.

The following topology standards are available:

• FC-FG (Fibre Channel Fabric Generic)

• FC-SW (Fibre Channel Cross-point switch)

• FC-AL (Fibre Channel Arbitrated Loop)

The FC-FG and FC-AL documents are of the most interest for Seagate disc drive interconnection.

3.1.4 FC Implementation Guide (FC-IG)

FC-IG provides some implementation guidance for all Fibre Channel systems.

Fibre Channel Interface Manual, Rev. D 7

8 Fibre Channel Interface Manual, Rev. D

4.0 Introduction to topologies

Topologies include all the elements necessary to successfully connect two or more nodes (also known as devices). See Section 4.1. There are several topologies available with Fibre Channel, but all of them have certain common components: nodes, ports, and links. These components are discussed in this section.

The ANSI Fibre Channel standard defines three topologies:

1. Arbitrated loop (Fibre Channel Arbitrated Loop, FC-AL)

2. Fabric

3. Point-to-point

Seagate supports arbitrated loop and fabric as the primary topologies for disc drive connections.

Note. Some brief discussions about items not directly associated with arbitrated loop and fabric topolo-

gies are included to make you aware that other topologies exist within the constructs of the ANSI Fibre Channel standard.

The fabric topology permits dynamic interconnections between nodes through ports connected to a fabric. This fabric is similar to a switch or router and is often compared to a telephone system because of its redundant rerouting capabilities. The fabric topology also allows multiple connections simultaneously, unlike FC-AL which results in a single circuit being established between only two ports at any one particular time. Fabric and arbitrated loop topologies may be combined in one system to provide a wide variety of services and performance levels to the nodes.

Point-to-point topologies are used only to connect two ports without any routing capabilities.

4.1 Nodes

Fibre Channel devices are called nodes. This is a generic term describing any device (workstation, printer, disc drive, scanner, etc.) connected to a Fibre Channel topology. Each node has at least one port, called an N_Port to provide access to other nodes. The “N” in N_Port stands for node. As you will see later, ports used in a Fibre Channel Arbitrated Loop topology are called NL_Ports where the “NL” stands for node loop.

The components that connect two or more node ports together are what are collectively called a topology. Nodes work within the provided topology to communicate with all other nodes.

4.2 Ports

Ports are the link to the outside world for a Fibre Channel node. See Figure 2. As stated above, each node has at least one port to provide access to other nodes. Each Seagate Fibre Channel drive has two ports.

Each port uses a pair of fibers—one to carry information into the port and one to carry information out of the port. This pair of fibers (actually copper wire) is called a “link” and is part of each topology. The Fibre Channel ANSI specification also supports fibers made of optical strands as a medium for data transfer.

Fibre Channel Interface Manual, Rev. D 9

As stated above, ports used in a FC-AL topology are called node loop ports (NL_Ports). Other port types exist as documented in the following table.

Table 1: Fibre Channel port types

Port type Location Associated topology

N_Port Node Point-to-point or Fabric

NL_Port Node in N_Port mode—Point-to-point or Fabric

F_Port Fabric Fabric

FL_Port Fabric in F_Port mode—Fabric

E_Port Fabric Internal Fabric Expansion

G_Port Fabric in F_Port mode—Fabric

GL_Port Fabric in F_Port mode—Fabric

NL_Ports and FL_Ports discover their mode of operation dynamically during the initialization procedure.

Note. You may hear the term “L_Port” when discussing Fibre Channel. This term is often used as a

“catch-all” term meaning NL_Port or FL_Port when it is not important to specifically distinguish between the two. Therefore, when you read the term L_Port, you should think of NL_Port when the discussion is about Arbitrated Loop or Point-to-Point topologies, and you should think of FL_Port when the discussion is about the Fabric topology.

in NL_Port mode—Arbitrated Loop

in FL_Port mode—Arbitrated Loop

in E_Port mode—Internal fabric expansion

in FL_Port mode—Arbitrated Loop in E_Port mode—Internal fabric expansion

An L_Port discovers its environment and works properly, without outside intervention, with an F_Port, N_Port, or with other L_Ports.

Arbitrated loops can have up to 126 active NL_Ports, but only one active FL_Port attached to the same arbitrated loop. The NL_Ports discover whether there is a fabric present by discovering whether there is an FL_Port present. If there isn’t an FL_Port present, the loop is called a private loop. If there is an FL_Port present, the loop is called a public loop and the FL_Port is considered the manager of the loop.

The most commonly used ports are the NL_Port and FL_Port. With these two types, you can easily migrate nodes from one topology to another.

Each NL_Port is attached to one link. Information flows in one direction only.

4.3 Links

Each port is comprised of two fibers, one carries information into the port and is called a receiver. The other carries information out of the port and is appropriately called a transmitter. Fibre Channel supports two types of fibers—electrical wires (most commonly copper) and optical strands. This pair of wires is called a link. See Figure 2.

Links carry the data frames between nodes. Each link can handle multiple frame types; therefore, frame multiplexing is possible. For example, a frame containing SCSI information may be followed by a frame containing TCP/IP followed by a frame containing yet another protocol’s information.

4.4 Arbitrated loop topology

Fibre Channel Arbitrated Loops (FC-AL) attach multiple nodes in a loop without hubs and switches. The node ports use arbitration to establish a point-to-point circuit. FC-AL is a distributed topology where each L_Port includes the minimum necessary function to establish the circuit.

10 Fibre Channel Interface Manual, Rev. D

The arbitrated loop topology is used to connect from two to 126 node ports. See Figure 2.

NL_Port 6

(Fibre A)

Node A

NL_Port 6

(Fibre B)

NL_Port 5

(Fibre A)

Node F

NL_Port 5

(Fibre B)

NL_Port 4

(Fibre A)

Node E

NL_Port 4

(Fibre B)

Figure 2. Arbitrated loop topology (dual port private loop)

NL_Port 1

(Fibre A)

Node B

NL_Port 1

(Fibre B)

NL_Port 2

(Fibre A)

Node C

NL_Port 2

(Fibre B)

NL_Port 3

(Fibre A)

Node D

NL_Port 3

(Fibre B)

The ports in an arbitrated loop topology are called NL_Ports (Node Loop Ports). Each of the NL_Ports has an input and output connection. Seagate Fibre Channel drives support dual ports (specified with a “1” in byte 6, bit 4 of the disc drive inquiry data). The actual ports are located on the host’s backpanel, not on the disc drive. Dual ports are provided for redundancy so that if one loop fails, the other one can fulfill the loop duties. Each drive has one FC SCA (single connector attachment) connector.

The arbitrated loop protocol is a token acquisition protocol. This means each port on the same arbitrated loop sees all messages, but passes all messages that are addressed to other ports.

4.5 Topology and port login

Each NL_Port must sign in with the other ports on the loop. Each port first attempts to locate an FL_Port. If it finds an FL_Port, it knows it is a part of a public loop connected to a fabric. If the port does not locate an FL_Port, it knows it is a part of a private loop with other NL_Ports only.

There can be up to 126 active NL_Ports and up to one active FL_Port attached to the same arbitrated loop. If an NL_Port does not attempt to discover an FL_Port and there is an FL_Port present, the NL_Port is only allowed to access other NL_Ports on the same loop.

4.6 Port bypass circuits

So far, we’ve discussed links, ports, nodes, and topology logins. All’s fine with this model as long as the loop is intact. What happens, then, if a device is disconnected from the loop. Doesn’t this break the loop? The answer is no. Fibre Channel provides port bypass circuitry which bypasses the drive if it is removed, incapable of providing loop services, unable to obtain a valid address, or otherwise incapable of providing loop services. These port bypass circuits (PBCs) are located external to the drive or other FC-AL device. Figure 3 shows the relationship between the PBC and drive.

Fibre Channel Interface Manual, Rev. D 11

Port Bypass

From Previous

Drive

Port Bypass

Circuit N–1

Drive N–1

Figure 3. Port bypass circuit physical interconnect

Circuit

MUX

Select

SerialInSerial

Out

Drive N

To Next

Drive

Port Bypass

Circuit N+1

Drive N+1

12 Fibre Channel Interface Manual, Rev. D

5.0 Data encoding (FC-1)

Fibre Channel devices don’t transmit 8-bit bytes. If this were to occur, the receiving node would not understand the transmitter’s intentions. To fix this situation, the data is encoded prior to transmission. Encoding allows the creation of special transmission code characters with unique bit patterns for data management and word alignment so the receiving node will know what to do with the bytes. Encoding also improves the transmission characteristics across a fibre and increases the likelihood of detecting errors.

5.1 Encoding and decoding

An unencoded data byte is represented in FC-1 as HGFEDCBA where H is the most significant bit. The hex to FC-1 decimal value translation is accomplished as shown below:

Kxx.y

y = the decimal value of the most significant 3 bits (HGF)

xx = the decimal value of the least significant 5 bits (EDCBA)

y xx

Example: BCh = 10111100 (binary) = 101 11100 (binary grouped)

K28.5

Figure 4. Decimal value translation

A decimal value is assigned to each bit combination with the range of 0 to 31 for xx and 0 to 7 for y. This means the range of valid data characters using the FC-1 naming convention is D00.0 through D31.7.

FC serial transmission delivers 10-bit characters which represent encoded data. Of the 1,024 characters possible with the 10-bit space, 256 8-bit byte data characters are mapped, along with 1 control character. This mapping process is called 8B/10B encoding. This encoding method involves selecting encoded 10-bit characters to maintain a run-length-limited serial stream of bits. To prevent too many ones or zeros on the serial interface from causing a DC electrical shift of the serial media, the encoder monitors the number of ones in the encoded character and selects the option of the 10-bit encode character that will shift to balance the total number of zeros and ones. This balancing is called running disparity.

A 10-bit character is actually made up of 6- and 4-bit sub-blocks. The 6-bit sub-block shifts out first followed by the 4-bit sub-block. Running disparity is set positive at the end of the sub-block as follows:

• If the number of ones in a sub-block is greater that the number of zeros, the 6-bit sub-block is 000111b, or the 4-bit sub-block is 0011b. Running disparity is set positive at the end of the sub-block.

• If the number of zeros in a sub-block is greater than the number of ones, the 6-bit sub-block is 111000b, or the 4-bit sub-block is 1100b. Running disparity is set negative at the end of the sub-block.

5 28 (decimal values)

Fibre Channel Interface Manual, Rev. D 13

• If the number of ones and zeros in a sub-block are equal, running disparity is neutral and the value of running disparity at the end of the sub-block remains the same as the preceding character even if it is separated by neutral characters.

Note. The rules of running disparity prohibit consecutive positive or consecutive negative characters even

if they are separated by neutral disparity characters. In other words, the negative and positive disparity characters must alternate, even if separated by a neutral disparity character. See Table 2.

Table 2: Running disparity examples

Sub-blocks

Val id?12345

+N–+– Yes

+N+ No

++ No

–– No

5.2 Buffer-to-buffer data transfers

Fibre Channel devices transfer information from an output buffer in the transmitting node to an input buffer of the receiving node. This is called a buffer-to-buffer transfer. Each node may have from 1 to n buffers. The number of buffers in each node does not have to be equal. Each buffer is the size a frame may transfer in its payload. The Fibre Channel standard does not define the actual length of the buffer or the method used to store the bytes in the buffer. Figure 5 shows how data is sent from the transmit buffer and received by the receive buffer.

Transmit

Buffer

8-bit

byte

8-bit character 10-bit character

byte

8-bit byte

8B/10B

Encoder

Serializer

Serial transfer

10-bit character

Deserializer

8B/10B

Decoder

Receive

Buffer

8-bit

byte

8-bit character

8-bit byte

Figure 5. Serialization process

The bytes being transmitted are sent in increasing displacement.1

The basic unit of transfer for the contents of a buffer-to-buffer data transfer is the frame.

This means that if byte 0 is sent first, bytes 1, 2, 3, and 4 are then transmitted in that order. If byte 100 is sent first, bytes

101, 102, 103, and 104 are then transmitted in that order.

14 Fibre Channel Interface Manual, Rev. D

5.3 Data hierarchy

A hierarchy of data types is presented in Figure 6.

Transmission word (40 bits — 4 10-bit encoded bytes)

8B/10B encoded byte 1 (10 bits)

Byte (8 bits)

Bit Bit Bit Bit Bit

Figure 6. FC data hierarchy

• • •

Bit Bit Bit Bit Bit Bit Bit Bit Bit Bit

8B/10B encoded byte 4 (10 bits)

Byte (8 bits)

Bit Bit Bit Bit Bit

5.3.1 Transmission words

Transmission words are the lowest level of control on Fibre Channel other than the control character used to provide character synchronization.

A transmission word is defined as four contiguous 8B/10B encoded transmission characters (10 bits each) treated as a unit. This unit is 40 bits in length (4 characters x 10 bits each) and is the smallest unit of transmission in Fibre Channel.

5.3.1.1 Data characters

A data character is a 8B/10B encoded transmission character with a data byte equated by the transmission code as one of the 256 possible data characters.

5.3.1.2 Special characters

The 8B/10B encoding scheme allows for all 256 data byte values, plus several others that can be used for special signaling. These other values are called special characters. Special characters include any transmission character considered valid by the transmission code but not equated to a valid data byte.

5.4 Ordered sets

An ordered set is a four-character combination of data and special transmissions characters. There are three primary categories of ordered sets:

• Primitive signals

• Primitive sequences

• Frame delimiters

The K28.5 special character is the first character of all ordered sets.

5.4.1 Primitive signals

Primitive signals are ordered sets that perform a control function. Primitive signals are recognized when one ordered set is detected. Table 3 lists the defined primitive signals. There must be a minimum of six primitive signals (Idles and R_RDYs) at the N_Port transmitter between frames to properly maintain clock skew.

Fibre Channel Interface Manual, Rev. D 15

Table 3: Primitive signals

Beginning running

Primitive signal Signal

Idle IDLE Negative K28.5 D21.4 D21.5 D21.5 BC 95 B5 B5

Receiver_Ready R_RDY Negative K28.5 D21.4 D10.2 D10.2 BC 95 4A 4A

disparity Ordered set (FC-1) Ordered set (hex)

Idle (IDLE)

An Idle is transmitted on the loop to indicate the node is operational and ready for frame transmission and reception. Idles are transmitted when frames, R_RDY, or primitive sequences are not being transmitted. This maintains word synchronization and minimum spacing between frames.

Receiver ready (R_RDY)

R_RDY indicates that a frame was received and that the interface buffer that received the frame is ready for another frame. R_RDY is preceded and followed by a minimum of two Idles. R_RDY establishes buffer-tobuffer credit during data transmissions between an initiator and target.

5.4.1.1 Primitive signals used as frame delimiters

Primitive signals can also be frame delimiters. A frame is an indivisible information unit that may contain data to record on disc or control information such as a SCSI command.

Note. All ordered sets (except for the End-of-frame delimiter, EOF) require the running disparity from the

previous word to be negative. The second character of an ordered set (except EOF) will be positive and the third and fourth characters are neutral.

Frame delimiters mark the beginning and end of frames. There are several frame delimiters available in Fibre Channel. There are nine Start-of-frame (SOF) delimiters and six End-of-frame (EOF) delimiters as listed in Table 4.

Start-of-frame (SOF) delimiters:

• mark the beginning of a frame,

• indicate whether this is the first frame of the sequence, and

• indicate the class of service for the frame.

End-of-frame (EOF) delimiters:

• mark the end of a frame, and

• indicate whether this frame is the last frame of the sequence.

The second character of EOF delimiters differentiates between normal and invalid frames. The EOF delimiter also ensures that negative running disparity results after processing the set by assigning the appropriate second character.

The third and fourth characters of the delimiter functions (SOF and EOF) are repeated to ensure that an error affecting a single character will not result in the recognition of an ordered set other than the one transmitted. See Table 4 below.

16 Fibre Channel Interface Manual, Rev. D

Seagate disc drives use only those listed in bold type (Seagate Fibre Channel disc drives are Class 3 devices and use only Class 3 delimiters).

Table 4: Frame delimiters

Beginning running

Delimiter function Delimiter

SOF Connect Class 1 SOFc1 Negative K28.5 D21.5 D23.0 D23.0 BC B5 17 17

SOF Initiate Class 1 SOFi1 Negative K28.5 D21.5 D23.2 D23.2 BC B5 57 57

SOF Normal Class 1 SOFn1 Negative K28.5 D21.5 D23.1 D23.1 BC B5 37 37

SOF Initiate Class 2 SOFi2 Negative K28.5 D21.5 D21.2 D21.2 BC B5 55 55

SOF Normal Class 2 SOFn2 Negative K28.5 D21.5 D21.1 D21.1 BC B5 35 35

SOF Initiate Class 3 SOFi3 Negative K28.5 D21.5 D22.2 D22.2 BC B5 56 56

SOF Normal Class 3 SOFn3 Negative K28.5 D21.5 D22.1 D22.1 BC B5 36 36

SOF Initialize Loop SOFil Negative K28.5 D21.5 D22.2 D22.2 BC B5 56 56

SOF Activate Class 4 SOFc4 Negative K28.5 D21.5 D25.0 D25.0 BC B5 19 19

SOF Initiate Class 4 SOFi4 Negative K28.5 D21.5 D25.2 D25.2 BC B5 59 59

SOF Normal Class 4 SOFn4 Negative K28.5 D21.5 D25.1 D25.1 BC B5 39 39

disparity Ordered set (FC-1) Ordered set (hex)

SOF Fabric SOFf Negative K28.5 D21.5 D24.2 D24.2 BC B5 58 58

EOF Terminate EOFt Negative

Positive

EOF DisconnectTe r m in a t e

EOF Abort EOFa Negative

EOF Normal EOFn Negative

EOF DisconnectTerminate-Invalid

EOF Normal-Invalid EOFni Negative

EOFdt Negative

Positive

EOFdti Negative

Positive

K28.5 D21.4 D21.3 D21.3 K28.5 D21.5 D21.3 D21.3

K28.5 D21.4 D21.4 D21.4 K28.5 D21.5 D21.4 D21.4

K28.5 D21.4 D21.7 D21.7 K28.5 D21.5 D21.7 D21.7

K28.5 D21.4 D21.6 D21.6 K28.5 D21.5 D21.6 D21.6

K28.5 D10.4 D21.4 D21.4 K28.5 D10.5 D21.4 D21.4

K28.5 D10.4 D21.6 D21.6 K28.5 D10.5 D21.6 D21.6

BC 95 75 75 BC B5 75 75

BC 95 95 95 BC B5 95 95

BC 95 F5 F5 BC B5 F5 F5

BC 95 D5 D5

BC B5 D5 D5

BC 8A 95 95 BC AA 95 95

BC 8A D5 D5 BC AA D5 D5

Notes.

1. EOF primitives come in two forms—one is used when the beginning running disparity is positive and the other is used if the beginning running disparity is negative. Regardless of which form is used, each EOF delimiter is defined so that negative current running disparity results after processing the final (rightmost) character of the ordered set.

2. Ordered sets associated with SOF delimiters, primitive signals, and primitive sequences are always transmitted with negative beginning running disparity. As a result, primitive signals, primitive sequences, and SOF delimiters are only defined for the negative beginning running disparity case.

3. Frames that end with any other EOF type are discarded by the drive.

Fibre Channel Interface Manual, Rev. D 17

Start-of-frame Initiate Class 3 (SOFi3)

SOFi3 indicates the beginning of the first frame of a sequence of frames (an exchange). (This includes all single frame sequences, commands, link services, transfer readys, and response frames.) SOFi3 is also used in the first data frame of a sequence.

Start-of-frame Normal Class 3 (SOFn3)

SOFn3 indicates the beginning of any frame other than the first frame of an exchange (see SOFi3 above).

Start-of-frame Initialize Loop (SOFil)

SOFil is the same as SOFi3, but is renamed for use in Loop Initialization to remove the class of service distinction from the initialization process.

End-of-frame Normal (EOFn)

EOFn indicates the end of any frame other than the last frame of an exchange or sequence.

End-of-frame Terminate (EOFt)

EOFt marks the end of the last frame of all sequences. It can also indicate the end of the last frame of an exchange. For example, the single frame sequences, commands, link services, transfer readys, and response frames.

5.4.1.2 Primitive signals custom made for arbitrated loop topologies

There are eight primitive signals used exclusively within arbitrated loop (FC-AL) topologies. These primitives are listed in Table 5 and defined in text following the table.

Table 5: FC-AL primitive signals

Beginning running

FC-AL primitive signal Signal

Arbitrate ARBx Negative K28.5 D20.4 AL_PA AL_PA BC 94 AL_PA AL_PA

Arbitrate (F0) ARB(F0) Negative K28.5 D20.4 D16.7 D16.7 BC 94 F0 F0

Open full-duplex OPNyx Negative K28.5 D17.4 AL_PD AL_PS BC 91 AL_PD AL_PS

Open half-duplex OPNyy Negative K28.5 D17.4 AL_PD AL_PD BC 91 AL_PD AL_PD

Open broadcast replicate OPNfr Negative K28.5 D17.4 D31.7 D31.7 BC 91 FF FF

Open selective replicate OPNyr Negative K28.5 D17.4 AL_PD D31.7 BC 91 AL_PD FF

Close CLS Negative K28.5 D5.4 D21.5 D21.5 BC 85 B5 B5

Dynamic Half Duplex DHD Negative K28.5 D10.4 D21.5 D21.5 BC 8A B5 B5

Mark MRKtx Negative K28.5 D31.2 MK_TP AL_PS BC 5F MK_TP AL_PS

disparity Ordered set (FC-1) Ordered set (hex)

Arbitrate (ARBx)

ARBx is transmitted to request access to the loop. Each ARBx contains the Physical (port) Address (AL_PA) of the requestor.

Arbitrate (ARB(F0))

ARB(F0) is transmitted to manage access fairness (see Section 8.3.1 on page 47). It is also used to assign a loop master during initialization.

18 Fibre Channel Interface Manual, Rev. D

Open full-duplex (OPNyx)

After successful arbitration, the transmitting port (x) opens the receiving port (y) for control and data frame transmission and reception. Any FC port can transmit or receive an OPN.

Open half-duplex (OPNyy)

After successful arbitration, the initiator opens the target (y) for control and data frame transmission and reception of control frames. Data frame transmission from the target is not allowed.

Open broadcast replicate (OPNfr)—Not supported by Seagate drives

OPNfr is used by the open port to communicate with all ports in the loop. When received by the targets (the opened ports), they are not allowed to generate any transmission words (except fill words). They must replicate and retransmit all received words until a CLS is detected. Both ‘ f ’ and ‘ r ’ are FFh (D31.7 in FC-1 transmission code).

Open selective replicate (OPNyr)—Not supported by Seagate drives

Similar to OPNfr (see definition above), with the exception that the initiator can communicate with a subset of the targets on the loop. The target at AL_PA ‘ y ’ is a member of the subset.

Close (CLS)

Close indicates that the CLS originator is prepared to or has ended the current loop circuit.

Dynamic Half Duplex (DHD)

DHD indicates the open L_Port is relinquishing control of when the current loop circuit is closed. Support of DHD is discovered during Port Login.

Mark (MRKtx)—Not supported by Seagate drives

Mark may be used for synchronization within the loop (for example, spindle sync in a RAID application). The third character of the ordered set ‘ t ’ (MK_TP) is a vendor-unique sync code. Seagate drives pass through this primitive signal without responding to it.

5.4.2 Primitive sequences

Primitive sequences are ordered sets that perform control functions. These primitive sequences are listed in Table 6. Primitive sequences differ from primitive signals in the requirement for detection. Primitive sequences must have at least three consecutive ordered sets to be detected. Primitive sequences are transmitted repeatedly.

All of these primitive sequences are defined in Fibre Channel, but are not recognized by the drive. The Loop Initialization Primitive (LIP) sequence is used in arbitrated loop configurations to reset all attached ports to a known state. Refer to Section 8.2 on page 35 for additional information about LIPs.

Fibre Channel Interface Manual, Rev. D 19

Table 6: Primitive sequences

Beginning running

Primitive sequences Sequence

Offline OLS Negative K28.5 D21.1 D10.4 D21.2 BC 35 8A 55

Not_Operational NOS Negative K28.5 D21.2 D31.5 D5.2 BC 55 BF 45

Link_Reset LR Negative K28.5 D9.2 D31.5 D9.2 BC 49 BF 49

Link_Reset_Response LRR Negative K28.5 D21.1 D31.5 D9.2 BC 35 BF 49

disparity Ordered set (FC-1) Ordered set (hex)

Offline (OLS)

Offline is transmitted to indicate that the port is initiating the initialization protocol prior to going offline. The sequence will be transmitted for a minimum of 5 msec before further action is taken.

Not_Operational (NOS)

Not_Operational is transmitted to indicate that the port has detected a loop failure or is offline.

Link_Reset (LR)

Link_Reset is transmitted by a port to initiate the Link Reset protocol following a Link Timeout. This brings the port back to a stable synchronized state.

Link_Reset_Response (LRR)

Link_Reset_Response is transmitted to indicate that the port is receiving and recognizes the Link_Reset (LR) primitive sequence.

5.4.2.1 Primitive sequences custom made for Arbitrated Loop topologies

There are eight primitive sequences used exclusively within arbitrated loop (FC-AL) topologies. These primitives are listed in Table 7 and defined in text following the table.

Table 7: FC-AL primitive sequences

Beginning running

FC-AL primitive sequence Sequence

Loop initialization, no valid AL_PA

Loop initialization, loop failure, no valid AL_PA

Loop initialization, valid AL_PA

Loop initialization, loop failure, valid AL_PA

Loop initialization reset LIP Negative K28.5 D21.0 AL_PD AL_PS BC 15 AL_PD AL_PS

Loop initialization reset all LIP Negative K28.5 D21.0 D31.7 AL_PS BC 15 FF AL_PS

Loop port enable LPEyx Negative K28.5 D5.0 AL_PD AL_PS BC 05 AL_PD AL_PS

Loop port enable all LPEfx Negative K28.5 D5.0 D31.7 AL_PS BC 05 FF AL_PS

Loop port bypass LPByx Negative K28.5 D9.0 AL_PD AL_PS BC 09 AL_PD AL_PS

Loop port bypass all LPBfx Negative K28.5 D9.0 D31.7 AL_PS BC 09 FF AL_PS

LIP Negative K28.5 D21.0 D23.7 D23.7 BC 15 F7 F7

LIP Negative K28.5 D21.0 D24.7 D23.7 BC 15 F8 F7

LIP Negative K28.5 D21.0 D23.7 AL_PS BC 15 F7 AL_PS

LIP Negative K28.5 D21.0 D24.7 AL_PS BC 15 F8 AL_PS

disparity

Ordered set (FC-1)

Ordered set (hex)

20 Fibre Channel Interface Manual, Rev. D

Note. There are six sequences that invoke loop initialization. There is no operational difference between

them except that bytes 3 and 4 identify the reason for the loop initialization.

Loop initialization, no valid AL_PA (LIP)

The L_Port is attempting to acquire an AL_PA.

Loop initialization, loop failure, no valid AL_PA (LIP)

The transmitting L_Port detects a loop failure at its receiver. Since it has not completed initialization, it uses ‘F7’ (D23.7) rather than a valid AL_PA.

Loop initialization, valid AL_PA (LIP)

The L_Port is attempting to reinitialize the loop to a known state after recognizing a problem (performance degradation).

Loop initialization, loop failure, valid AL_PA (LIP)

The transmitting L_Port detects a loop failure at its receiver.

Loop initialization reset (LIP)

If the rightmost two bytes consist of a valid destination and source address, the source is requesting the target to perform a device reset.

Loop initialization reset all (LIP)

If byte 3 is FFh and byte 4 is a valid source address, the source is requesting all receiving targets to perform a device reset.

Loop port enable (LPEyx)

LPEyx resets the bypass circuit and enables a previously-bypassed L_Port.

Loop port enable all (LPEfx)

LPEfx resets the bypass circuits on all L_Ports on the loop.

Loop port bypass (LPByx)

LPByx activates the port bypass circuit and prevents the L_Port from actively participating on the loop.

Loop port bypass all (LPBfx)

LPBfx activates the port bypass circuit for all L_Ports on the loop with bypass circuits except for the source of the LPBfx.

Fibre Channel Interface Manual, Rev. D 21

22 Fibre Channel Interface Manual, Rev. D

6.0 Framing protocol (FC-2)

The entire responsibility of moving frames between N_Ports is assigned to the Fibre Channel layer called the framing protocol (FC-2). This protocol is primarily concerned with constructing and managing frames, sequences, and exchanges.

Navigation assistance

The field descriptions that are provided for most tables have sidebar labels which identify the table they are associated with. This helps orient you when nested tables occur within a section.

Sidebar example

Tab le

6.1 Frames

Field definitions (listed alphabetically)

number

Field name

The sidebar (black background with reversed text) identifies this field as being associated with Table 1.

Frames transfer all information between nodes. The frames are normally constructed by the transmitting node’s N_Port. A frame is the smallest unit of information transfer across a link. A sequence is one or more frames. An exchange is one or more sequences. See Figure 7 below.

It is possible, but not common, for a sequence to have only one frame and for an exchange to have only one sequence. Again, this isn’t common, but possible. Most sequences have more than one frame, and most exchanges have more than one sequence.

Frame 1 Frame 2

Figure 7. Relationship between frames, sequences, and exchanges

Frame... Frame n Frame 1 Frame 2

Sequence 1

Frame... Frame n Frame 1 Frame 2

Sequence 2

Exchange 1 Exchange 2...

Frame... Frame n

Sequence n

6.1.1 Frame structure

A frame is a string of transmission words containing data bytes. Every frame is prefixed by a start-of-field (SOF) delimiter and suffixed by an end-of-field (EOF) delimiter. There are never any primitive signals or primitive sequences in a frame.

Fibre Channel Interface Manual, Rev. D 23

All frames also have a header and a Cyclic Redundancy Check (CRC) field. The payload data field is optional (but normally present) with the size and contents determined by the type of frame.

Bytes

Words

Transmission

Words

Fill

4 24 0 to 2112 4 4 24

Frame Header Payload Data Field CRCFill Bytes EOF

SOF

1 6 0 to 528 1 1 6

Fill

Words

Figure 8. Frame structure

6.1.1.1 Start-of-frame (SOF) delimiter

Start-of-frame (SOF) delimiters signal the beginning of a frame. See “Frame delimiters” on page 17. This referenced page contains a list of the various types of SOF delimiters.

6.1.1.2 Frame header

The frame header is 24 bytes long and is present in all frames. It is used to control link operation, control device protocol transfers, and to detect missing frames or frames that are out of order.

Table 8: Frame header format

Byte Word

0R_CTL D_ID

1 Reserved S_ID

2Type F_CTL

3 SEQ_ID DF_CTL SEQ_CNT

(bits 31 - 24)

(bits 23 - 16)

(bits 15 - 08)

(bits 07 - 00)

4 OX_ID RX_ID

Tab le

Field definitions (listed alphabetically)

number

DF_CTL (Data Field Control)

Offset

Specifies the presence of optional headers in the payload of the frame. The drive does not support optional headers. 00h The drive sets this field to 00h for all frames it originates (sends), and should also be 00h for all frames sent to the

drive.

D_ID (Destination Identifier)

The 3-byte N_Port address to which the frame is being sent.

24 Fibre Channel Interface Manual, Rev. D

F_CTL (Frame Control)

This 3-byte (24-bit) field contains control information relating to the frame content as defined below.

Table 9: Frame Control (F_CTL) bit definitions

Bit Definition Description

Exchange context 0 = Frame is from the exchange originator.

Sequence context 0 = Initiator

First sequence 0 = Not the first sequence of the exchange.

Last sequence 0 = Not the last sequence of the exchange.

End of sequence 0 = Not the last frame of the sequence.

End connection

Chained sequence

Sequence initiative 0 = Hold sequence initiative.

X_ID reassigned

Invalid X_ID

Reserved

13 12 11 10

Retransmitted

sequence

Unidirectional

transmit

Continue sequence

condition

Abort sequence

condition

Relative offset

present

Reserved

Fill data bytes End of data field fill bytes

1 0

1 = Frame is from the exchange responder.

1 = Recipient

1 = First sequence of the exchange.

1 = Last sequence of the exchange.

1 = Last frame of the sequence.

Not supported.

1 = Transfer sequence initiative.

Not supported.

0 = Parameter field not meaningful. 1 = Parameter field equals relative offset.

00 = 0 bytes of fill. 01 = 1 byte of fill (last byte of data field). 02 = 2 bytes of fill (last 2 bytes of data field). 03 = 3 bytes of fill (last 3 bytes of data field).

Offset

This 4-byte field is used in data frames to define the relative offset (displacement) of the first byte of the payload from the base address of the command. When the relative offset is present, bit 3 of F_CTL is set to indicate that relative offset is valid.

The drive uses the SEQ_CNT value to verify that frames are being received in order. The drive does not use relative offset in frames it receives. The drive sends relative offset information in data frames it originates.

Fibre Channel Interface Manual, Rev. D 25

OX_ID (Originator Exchange Identifier)

This 2-byte field is assigned by the originator of an exchange. For SCSI FCP frames, this value is analogous to the Queue Tag used in Parallel SCSI and must be unique for an initiator/drive pair.

R_CTL (Routing Control)

This one-byte field provides routing bits and information bits to categorize the frame function. The high order bits (bits 31-28) indicate the frame type as indicated below:

0000 = FC-4 Device_Data frame 0010 = Extended Link_Data frame 0011 = FC-4 Link_Data frame 0100 = Video_Data frame 1000 = Basic Link_Data frame 1100 = Link_Control frame Others = Reserved

The low order bits (bits 27-24) contain the Information field values. This is dependent on the value of the high order bits (31-

28). If the high order bit value = 1000, the Information field contains a basic link service. For all other high order bit values, the Information field specifies the Common Information Categories specified in the table below.

Table 10: Routing Control values

High order bits Low order bits Use

Type 08h, SCSI FCP, Device Data frames

0000 Uncategorized Not supported

0001 Solicited Data Read and write data

0010 Unsolicited Control Not supported

0011 Solicited control Not supported

0000

0100 Unsolicited data Not supported

0101 Data descriptor Transfer ready

0110 Unsolicited command Command

0111 Command status Response

Type 01h, Extended link service

0000 Uncategorized Not supported

0001 Solicited data Not supported

0010 Unsolicited control Request

0011 Solicited control Reply

0010

0100 Unsolicited data Not supported

0101 Data descriptor Not supported

0110 Unsolicited command Not supported

0111 Command status Not supported

Type 00h, Basic link service

26 Fibre Channel Interface Manual, Rev. D

Table 10: Routing Control values (Continued)

High order bits Low order bits Use

0000 No operation Not supported

0001 Abort sequence (ABTS) Request

0010 Remove connection Not supported

1000

0011 Reserved Not supported

0100 Basic_Accept (BA_ACC) Reply

0101 Basic_Reject (BA_RJT) Reply

01100111

RX_ID (Responder Exchange Identifier)

Reserved Not supported

This 2-byte identifier is a unique identifier generated by the responder for an exchange established by an originator and identified by an OX_ID.

With Class 3 devices such as this drive, the responder of the exchange assigns a unique value for RX_ID other than FFFFh if RX_ID is being used in an ACK to a data frame in the first sequence transmitted as a sequence initiator.

The drive returns FFFFh in this field to indicate the RX_ID is not being used.

SEQ_CNT (Sequence Count)

This 2-byte field identifies the sequential order of frames within a sequence or multiple sequences of the same exchange. The SEQ_CNT value for each frame of a sequence has to be unique. The field range limits the number of frames per sequence to a maximum of 65,536.

For SCSI FCP write data transfers that require more than one sequence to transfer the data, the first frame of each sequence starts with a SEQ_CNT of 0000h. The transfer of sequence initiative between write data sequences and the XFR_RDY sent by the drive give the sequence originator (the SCSI Initiator) verification that the previous sequence is closed.

For SCSI FCP read data transfers that require more than one sequence to transfer the data, the SEQ_CNT does not reset to 0000h for each new sequence. The SEQ_CNT increments sequentially across the sequence boundaries. The SEQ_CNT is still allowed to increment through all 65,536 possible values for each sequence. This is required as there is no verification in Class 3 that all the frames of previous sequences have been delivered.

SEQ_ID (Sequence Identifier)

This field uniquely identifies frames in a non-streamed sequence or when only one sequence is open.

S_ID (Source Identifier)

The 3-byte address of the N_Port or F_Port originating the frame.

Type (Data Structure Type)

This 1-byte field identifies the protocol of the frame contents as described below:

Table 11: Data type codes

R_CTL (4 highest order bits)

1000 00 Basic Link Service

0010 01 Extended Link Service

0000 08 SCSI FCP

Type code Description

Fibre Channel Interface Manual, Rev. D 27

6.1.1.3 Data field (payload)

The data field, also known as the payload, is aligned on word boundaries. The payload length must be an integer multiple of four bytes and is limited to 2,112 bytes. If the data field is not an integer multiple of four bytes, valid fill bytes are inserted to meet the requirement. F_CTL bits 0 and 1 indicate how many fill bytes are used. Fill bytes are only permitted in the last frame of a sequence. These fill bytes can be any valid byte value.

The contents of the frame payload is specified by the type of frame. Refer to Section 9.0 for link service information.

6.1.1.4 CRC field

The Cyclic Redundancy Check (CRC) is a 4-byte field that follows the payload field. The CRC is used to verify the integrity of the frame header and payload fields. This helps detect errors in a frame. The SOF and EOF frame delimiters are not included in the CRC calculation.

The algorithm used to calculate the CRC field value is the same as that used in the Fiber Distributed Data Interface (FDDI) standard. The polynomial for the CRC is:

+ x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1

6.1.1.5 End-of-frame (EOF) delimiter

End-of-frame (EOF) delimiters signal the end of a frame. See “Frame delimiters” on page 17. This page contains a list of the various types of EOF delimiters.

6.2 Frame sequences

Since the data field has a maximum length of 2,112 bytes (528 transmission words), larger amounts of data must be split into several frames.

Frame sequences always contain at least one frame. The frame header subfields in the F_CTL field are used to identify the beginning, middle, and end of a frame sequence. The SEQ_ID and SEQ_CNT fields are used to identify the order of the frames for reassembly in the event they arrive out of order at the destination when participating in a fabric topology.

The OX_ID and RX_ID fields identify the larger context (the exchange) of which this frame sequence is a part.

The frame sequence itself may be part of an exchange and is identified by the SEQ_ID field in the frame header. The R_CTL field of the frame header identifies the category of information in all the frames of the sequence. All of the frames within the same sequence are required to have the same category.

6.3 Exchanges

Exchanges are an additional layer that controls operations across Fibre Channel. An exchange provides a control environment for the transfer of information between two N_Ports. You can think of exchanges as an operating system that controls communications between nodes when two or more sequences are required to transmit data or commands. Exchanges even keep track of operations that occur in opposite directions (sender to receiver and receiver to sender). Here’s a short explanation of how this occurs:

One of the N_Ports establishes an exchange by sending a sequence to the other N_Port with at least one frame in it. The originator names its resources using the OX_ID field in the frame header of each frame of the exchange.

The responder of the exchange also allocates resources after it receives the first frame of the first sequence. It names its resources using the RX_ID field.

28 Fibre Channel Interface Manual, Rev. D

These two independent fields (OX_ID and RX_ID) allow each N_Port to identify the resources needed to manage a frame or sequence as it arrives. Each N_Port involved with the exchange can use a link service request to view the contents of the control information in the other port in the exchange; however, no other N_Ports are allowed to request information for the exchange since they are not involved with that particular exchange.

Command

Write Data

Exchange

Write Data

SCSI Write

Initiator

Command Transfer

Initiator

Target

Arb

Transfer Ready

Optional Transfer Ready’s

Response

Target

Command

Exchange

Response Transfer

Initiator

Arb

SCSI Read

Target

Read Data

Optional Read Data

Response

Target

OPN

RDY/s

Command

CLS

Figure 9. FC–SCSI exchanges, command and response transfers

OPN

RDY/s

Response

CLS

6.4 Credit

The framing protocol must be concerned about how many frames one source N_Port can send to another without overflowing the buffers in the receiving N_Port. To address this problem, there are two types of credit:

1. Buffer-to-buffer credit (BB_Credit). This type of credit is associated only with the immediate fiber exiting the transmitter to the next receiver (F_Port or N_Port). This credit is managed by the R_RDY primitive signal on a link.

2. End-to-end credit (EE_Credit). This type of credit is negotiated between a source N_Port and a destination N_Port. This credit is managed using an acknowledgment (ACK) frame sent from the destination back to

Fibre Channel Interface Manual, Rev. D 29

the source N_Port. This type of credit is not used in Class 3 therefore it is not applicable to Seagate drives.

30 Fibre Channel Interface Manual, Rev. D

7.0 Classes of service (FC-2)

There are five classes of service currently available or being defined. Classes of service are simply different communication methods used between nodes. Seagate drives use only Class 3; however, brief explanations of the other classes are provided as well.

7.1 Class 1

Class 1 is like a direct face-to-face meeting with no interruptions or delays. It is a dedicated full-bandwidth connection between two nodes.

Other Class 1 attributes

• Guaranteed delivery

• Frames are received in the order they are transmitted

• Usually uses the least overall bandwidth

• Very little software interaction

7.2 Class 2

Class 2 is like an electronic mail transaction where each message has an acknowledgment message sent from the receiver to signal that the message was received successfully. This class of service allows one N_Port to transmit consecutive frames to multiple destinations without establishing a dedicated connection with any specific N_Port and also allows one N_Port to receive consecutive frames from one or more N_Ports without having established dedicated connections with any of them.

Other Class 2 attributes

• Confirmed delivery (the receiver sends an acknowledgment on receipt)

• Frames are not always guaranteed to be received in the order they are transmitted

• Can potentially use more bandwidth than Class 1 and latency may increase by waiting for acknowledgments

7.3 Class 3

Class 3 service multiplexes frames at frame boundaries to or from one or more N_Ports without acknowledgment of receipt.

Seagate drives use Class 3 exclusively. Class 3 reduces the complexity of the ports and provides better performance for disc applications.

Other Class 3 attributes

• Full duplex transfers may be used between two ports using Class 3; however, Class 3 operation does not

require half duplex operation.

• Acknowledge (ACK) buffer not required (no waiting for ACKs)

Fibre Channel Interface Manual, Rev. D 31

• EE_Credit not required

• Busy and Reject not needed due to alternate credit model

• Errors are recovered at the exchange level

7.3.1 Class 3 flow control

Class 3 flow control is a simple model which does not require EE_Credits. With Class 3, there is only buffer-tobuffer flow control in one direction and there are no link level responses to Class 3 frames.

7.4 Classes 4 and 5

Classes 4 and 5 are being defined by Fibre Channel committees to aid audio and video applications.

Class 4 is similar to Class 1 in that a dedicated connection is established; however, with Class 4, the full bandwidth is not available. Connections for other nodes connected may be assigned portions of the bandwidth.

Class 5 provides isochronous service through a fabric. A Class 5 node is guaranteed access through a fabric at established time intervals.

32 Fibre Channel Interface Manual, Rev. D

8.0 FC Arbitrated Loop concepts

This section describes some basic Fibre Channel Arbitrated Loop (FC-AL) concepts. Seagate disc drives support FC-AL as the topology for connectivity in Fibre Channel environments.

Fibre Channel is a serial data channel that provides logical point-to-point service to two communicating devices. With FC-AL, you can have a maximum of one point-to-point circuit at any one time. When this circuit is active, only two L_Ports are communicating, but up to 127 devices may be attached to and participating on the same loop. All of the L_Ports that are on the loop but that are not one of the two communicating L_Ports “see” all data transferred across the loop and retransmit this information so that the data reaches its intended destination.

8.1 Arbitrated Loop physical address (AL_PA)

Each device communicating on an arbitrated loop must have an Arbitrated Loop Physical Address (AL_PA). The AL_PA is an 8-bit (1-byte) 8B/10B encoded value that is a valid data character. This 8-bit character, when encoded to 10 bits, must have an equal number of 1’s and 0’s in the address to maintain neutral running disparity. Neutral running disparity is required so that the AL_PA data character does not change the current running disparity of the current transmission word. There are 134 characters that result in neutral disparity. See Table 12. Seven of the 134 neutral disparity characters are reserved (see Table 13 on page 35). This leaves 127 valid addresses.

Table 12: 8B/10B characters with neutral disparity

D xx.y y

xx 01234567

* * * 00, 80, E0

* * * 01, 81, E1

* * * 02, 82, E2

* * * * * 23, 43, 63, A3, C3

* * * 04, 84, E4

* * * * * 25, 45, 65, A5, C5

* * * * * 26, 46, 66, A6, C6

* * * * * 27, 47, 67, A7, C7

* * * 08, 88, E8

* * * * * 29, 49, 69, A9, C9

Hex value

Fibre Channel Interface Manual, Rev. D 33

Table 12: 8B/10B characters with neutral disparity

D xx.y y

xx 01234567

* * * * * 2A, 4A, 6A, AA, CA

* * * * * 2B, 4B, 6B, AB, CB

* * * * * 2C, 4C, 6C, AC, CC

* * * * * 2E, 4E, 6E, AE, CE

* * * 0F, 8F, EF

* * * 10, 90, F0

* * * * * 31, 51, 71, B1, D1

* * * * * 32, 52, 72, B2, D2

* * * * * 33, 53, 73, B3, D3

* * * * * 34, 54, 74, B4, D4

* * * * * 35, 55, 75, B5, D5

* * * * * 36, 56, 76, B6, D6

* * * 17, 97, F7

* * * 18, 98, F8

Hex value

To t al

* * * * * 39, 59, 79, B9, D9

* * * * * 3A, 5A, 7A, BA, DA

* * * 1B, 9B, FB

* * * * * 3C, 5C, 7C, BC, DC

***1D, 9D, FD

* * * 1E, 9E, FE

* * * 1F, 9F, FF

13 19 19 19 13 19 19 13

134

* character with neutral disparity.

Reserved (see Table 13 on page 35).

Of the 134 neutral disparity characters, seven are reserved. This leaves 127 valid non-reserved addresses. 126 of these addresses may be used by NL_Ports and one (00) may be used by a FL_Port (if present).

34 Fibre Channel Interface Manual, Rev. D

Table 13: AL_PA addressing

Values (hex) Use

00 Reserved for the FL_Port (if present)

01-EF Contains 127 valid addresses

F0 Reserved for fairness

F1-F6 These values do not have neutral running disparity

F7-F8 Reserved for loop initialization

FB, FD, and FE Reserved for future use

FF Reserved to address all ports in broadcast mode

In the parallel SCSI world, the higher the bus address, the higher the priority the device has. The opposite is true with FC-AL. See Table 14.

Table 14: AL_PA value priorities

AL_PA value Priority

00 Highest priority (assigned to the FL_Port if present)

01 Highest priority NL_Port (on a public loop)

EF Lowest priority NL_Port address

F0 Used only by the fairness algorithm and has no priority

During loop initialization, each NL_Port interested in participating on the loop is assigned one of the 126 AL_PA values. If an NL_Port is offline because its node is powered off, the port is considered a non-participating NL_Port.

One more reason exists for an L_Port being in non-participating mode; you can place more than 127 L_Ports on a loop, and, if this occurs, loop initialization permits only the first 126 NL_Ports and the first FL_Port to acquire a valid AL_PA. The remaining L_Ports must wait for a position to open up to obtain a valid AL_PA.

An L_Port can get a valid AL_PA in four ways:

1. Assigned by the fabric (if present)

2. Use the previously-assigned address

3. Hard assigned by the backpanel

4. Soft assigned and acquired through the loop initialization process

The most common method that disc drives use is to have the backpanel provide a hard assigned address. This is similar to setting a SCSI ID on a drive, but with Fibre Channel, the ID is set on the backpanel rather than the drive. If, for some reason, a duplicate address is encountered when hard-assigned addresses are processed, the drive will revert to acquiring a soft-assigned AL_PA during initialization. This insures that every node gets a unique AL_PA.

A more detailed explanation of loop initialization is provided in the following section.

8.2 Loop initialization

Loop initialization is the process used to obtain or verify AL_PAs. Loop initialization occurs at power-up, when a new node is inserted in the loop, or for error recovery.

During loop initialization, each NL_Port discovers that it is connected in an arbitrated loop topology and that there may be multiple NL_Ports on the arbitrated loop. The procedure used for this discovery is called the loop port state machine (LPSM). The FC-2 protocol is also used.

Fibre Channel Interface Manual, Rev. D 35

A buffer on the drive receives each of the following loop initialization frames: LISM, LIFA, LIPA, LIHA, LISA, LIRP, and LILP. All other frames may be discarded if the L_Port’s buffer is full.

If the NL_Ports finds that there are not any more NL_Ports attached, but that there is only an F_Port or N_Port attached, the NL_Port configures itself to operate as an N_Port by going into N_Port mode.

An L_Port begins the loop initialization procedure in the initializing state at the request of the node. In most cases, the backpanel will be set to provide a hard assigned physical address which will not be changed by the initialization process, unless duplicate hard assigned physical addresses are found. The AL_PA of the one FL_Port (if present) is always 00h. All other AL_PA values will range from 01h - EFh.

Start_of_Frame delimiter (4 bytes)

SOFil

Frame_Header (24 bytes)

22xxxxxx

where ‘xxxxxx’ is hex ‘000000’ for an FL_Port and hex ‘0000EF’ for an NL_Port.

Payload (12, 20, or 132 bytes)

Loop Initialization Identifier*

*The loop initialization identifier is one of the following:

11010000h = LISM — Select master based on 8-byte Port_Name (12-byte payload with an 8-byte Port_Name)

11020000h = LIFA — Fabric Assigned AL_PA bit map (20-byte payload with a 16-byte AL_PA bit map)

11030000h = LIPA — Previously-acquired AL_PA bit map (20-byte payload with a 16-byte AL_PA bit map)

11040000h = LIHA — Hard Assigned AL_PA bit map (20-byte payload with a 16-byte AL_PA bit map)

11050000h = LISA — Soft Assigned AL_PA bit map (20-byte payload with a 16-byte AL_PA bit map)**

11060000h = LIRP — Report AL_PA position map (132-byte payload with a 128-byte AL_PA position map)

11070000h = LILP — Loop AL_PA position map (132-byte payload with a 128-byte AL_PA position map)

00xxxxxx 01380000

8-byte Port_Name

16-byte AL_PA bit map

128-byte AL_PA position map (1-byte offset followed by up to 127 AL_PAs)

LIFA is used to gather all fabric-assigned AL_PAs.

LIPA is used to gather all previously-acquired AL_PAs.

LIHA is used to gather all hard assigned AL_PAs (usually set with configuration jumpers on the host backpanel).

LISA is used to assign any remaining AL_PA bits.

LIRP is used to record the relative positions of all L_Ports on the loop.

LILP is used to inform all L_Ports of their relative positions on the loop from the perspective of the loop master.

00000000 FFFFFFFF 00000000

**LISA contains the AL_PA mapping field in byte 2 (01h) to indicate that all L_Ports are able to enter their position into the LIRP AL_PA position map. The 01h value in byte 2 may be changed to 00h to bypass the LIRP and LILP sequences.

Cyclic Redundancy Check (4 bytes)

CRC

End_of_Frame delimiter (4 bytes)

EOFt

Figure 10. Loop initialization sequences

36 Fibre Channel Interface Manual, Rev. D

The loop initialization process begins when any NL_Port forces the loop into the INITIALIZING state. See Figure 11. This initializing port begins transmitting loop initialization primitive sequences (LIPs). Any NL_Port can cause this by sending any of the LIPS listed in Table 15. All LIPs cause the 4-step initialization process to occur. A loss of signal will also force the loop to initialize.

There are five Loop Initialization Primitive (LIP) sequences:

Table 15: Loop Initialization Primitive (LIP) sequences

LIP Reason Code Use Description

F7, F7 Initializing LIP Used when an L_Port wants to acquire an AL_PA.

F8, AL_PS Loop failure The originating L_Port has detected an input failure. The

AL_PS is the AL_PA of the L_Port.

F8, F7 Loop failure The originating L_Port has detected an input failure but the

L_Port does not have an AL_PA.

F7, AL_PS Performance degradation The originating L_Port has detected poor loop performance.

Example: The L_Port is unable to win arbitration.

AL_PD, AL_PS Selective reset The source L_Port (AL_PS) wants to reset the destination

port (AL_PD). All L_Ports complete loop initialization. The selected L_Port performs a reset after loop initialization.

FF, AL_PS Reset all The source L_Port (AL_PS) wants to reset all other L_Ports

supporting LIP reset on the loop. All L_Ports complete initialization. The L_Ports supporting LIP reset all (generally only the targets in a storage implementation) perform a reset after loop initialization.

The next L_Port in the loop receives the LIPs and transitions to the OPEN_INIT state and transmits LIPs to the next L_Port on the loop. This cycle continues until the port that started the initialization process receives the LIPs. It then also transitions to the OPEN_INIT state. This means all L_Ports on the loop are in the OPEN_INIT state at this point.

Each port transmits a minimum of 12 LIPs and then transmits Idles for the AL_TIME (15 msecs). The L_Port then transmit Loop Initialization Select Master (LISM) frames to select a loop master who will then control the initialization process.

Loop initialization steps

There are four primary steps involved in initializing the loop.

1. Select a loop master based on the 8-byte port name (Loop Initialization Select Master—LISM).

2. Assign each port an arbitrated loop physical address (AL_PA). There are four ways a port can acquire an AL_PA. These are listed below.

• Fabric assigned (Loop Initialization Fabric Assigned—LIFA)

• Previously acquired (Loop Initialization Previously Acquired—LIPA)

• Hard assigned (Loop Initialization Hardware Assigned—LIHA)

• Soft assigned (Loop Initialization Soft Assigned—LISA)

3. Generate AL_PA position map (Loop Initialization Report Position—LIRP).

4. Transmit completed AL_PA position map around the loop (Loop Initialization Loop Position—LILP).

Fibre Channel Interface Manual, Rev. D 37

Loop Initialization Select Master (LISM)

12-byte payload

11010000 8-byte port name

The loop master is determined as follows:

• Each NL_Port selects an initial AL_PA of ‘EF’. The FL_Port (if present) selects an AL_PA of ‘0’.

• Each port transmits LISM with the D_ID and S_ID fields of the header set to its AL_PA. The payload is set to the port name which includes the world wide name (WWN).

• Each port examines the payload in the inbound LISM. If it is greater than its own, the port transmits a new LISM with its own port name in the payload. If it is less than its own, the port retransmits the received LISM. If it is the same as its own, it becomes the loop master.

• The loop master sends ARB(F0) to purge the loop and to inform all other ports that a master has been selected. When the master receives ARB(F0) on the inbound fibre, initialization proceeds to LIFA.

Loop Initialization Fabric Assigned (LIFA)

20-byte payload

11020000 16-byte bit map of AL_PAs

The loop master primes the bit map with zeroes (0) then sends the bit map around the loop in the LIFA payload.

Example

The loop master places zeroes in the bit map corresponding to each bit position.

Bit position

AL_PA positions -- 00 01 02 04 08 0F 10 17 ... EF

Switch address -- 7E 7D 7C 7B 7A 79 78 77 ... 00

Bit map content

012345678...128

L00000000...0

Any port which has an AL_PA assigned by the fabric will set a ‘1’ in the bit map at the position corresponding to its AL_PA. If a ‘1’ already exists, no map entry is made.

38 Fibre Channel Interface Manual, Rev. D

Loop Initialization Previously Assigned (LIPA)

20-byte payload

11030000 16-byte bit map of AL_PAs

The loop master transmits the bit map resulting from the LIFA.

The L_Port checks to see if the bit that corresponds to its previously acquired AL_PA is set. If not, the L_Port sets it to ‘1’. If the L_Port’s bit has already been set by another port, it will attempt to assume a soft-assigned AL_PA (LISA).

Example

The L_Port had a previously assigned AL_PA of 4 which was not already set by another port, so it set the bit at position 4 to ‘1’.

Bit position

AL_PA positions -- 00 01 02 04 08 0F 10 17 ... EF

Switch address -- 7E 7D 7C 7B 7A 79 78 77 ... 00

Bit map content

012345678...128

L00010000...0

The L_Port at AL_PA 4 claims its’ previously assigned address.

The L_Port then retransmits the LIPA frame.

Loop Initialization Hard Assigned (LIHA)

20-byte payload

11040000 16-byte bit map of AL_PAs

The loop master transmits the bit map resulting from the LIPA.

The L_Port checks to see if the bit that corresponds to its hard address is set (usually using switches or jumpers). If not, the L_Port sets it to ‘1’. If the L_Port’s bit has already been set by another port, it will attempt to assume a soft-assigned AL_PA (LISA).

Example

The L_Port had a hard address set by switch or jumper at AL_PA 8 which was not already set by another port, so it set the bit at position 8 to ‘1’.

Bit position

AL_PA positions -- 00 01 02 04 08 0F 10 17 ... EF

Switch address -- 7E 7D 7C 7B 7A 79 78 77 ... 00

Bit map content

012345678...128

L00010001...0

The L_Port at AL_PA 8 claims its’ preferred (hard-assigned) address.

The L_Port then retransmits the LIHA frame.

Fibre Channel Interface Manual, Rev. D 39

Loop Initialization Soft Assigned (LISA)

20-byte payload

11050100 16-byte bit map of AL_PAs

The loop master transmits the bit map resulting from the LIHA.

The L_Port checks to see if there are any free addresses left in the bit map by checking for the first available ‘0’. The L_Port sets it to ‘1’. If there are no zeroes in the bit map, all 126 NL_Port addresses have been taken and the port is not allowed to actively participate in the loop.

Example

The L_Port saw that the first ‘0’ occurred in bit position 1, so it changed that bit to a ‘1’ to effectively select ‘1’ as it’s AL_PA.

Bit position

AL_PA positions -- 00 01 02 04 08 0F 10 17 ... EF

Switch address -- 7E 7D 7C 7B 7A 79 78 77 ... 00

Bit map content

012345678...128

L10010001...0

First available ‘0’ changed to ‘1’.

The L_Port then retransmits the LISA frame.

Loop Initialization Report Position (LIRP)

132-byte payload

11060000 128-byte map of AL_PA physical positions

The LIRP and LILP sequences build a mapping between AL_PA values and participating L_Port positions. This allows all L_Ports to know where all of the other AL_PA addresses are physically located on the loop.

To build this address map, the loop master primes the 128-byte position map with ‘FF’ in each position. The loop master then sets byte 0 (the “counter” byte) of the position map to ‘01’ and places its own AL_PA in byte 1 and then sends the position map around the loop.

Each port increments the position counter (byte 0) by one and places its AL_PA at the map position indicated by the counter. For example, the second device on the loop (with the loop master counted as the first device) increments byte 0 by one to make byte 0 have a value of ‘2’ and then places its AL_PA in position 2 of the position map.

Each port retransmits the LIPA frame until the map completes its journey to each of the devices on the loop and gets back to the loop master. At this point, the LIRP process results in a position map containing the physical location and AL_PA of every device on the loop.

Example

This example position map shows that there are 6 ports on the loop. The loop master has AL_PA ‘E8’. The first port after the master on the outbound fibre has AL_PA ‘D6’ and the last port on the loop before getting back to the master has AL_PA ‘08’.

Byte map content

06 E8 D6 E2 6A 5F 08 FF ... FF

40 Fibre Channel Interface Manual, Rev. D

Loop Initialization Loop Position (LILP)

132-byte payload

11070000 128-byte map of AL_PA physical positions

When the loop master gets the LIRP frame back from the loop, it contains the AL_PAs and physical location of each participating port on the loop. The loop master retransmits the completed position map (now called the LILP) to the next port on the loop. This informs all ports of the loop’s physical make-up and also makes it possible for each port to make a copy of the map before retransmitting it to the next port.

When the loop master gets the LILP back from the loop, it sends a CLS followed by Idles. All of the other ports retransmit the CLS and transition to the Monitoring state. When the loop master gets the CLS back from the loop, it removes it and then transitions to the Monitoring state. This signals the end of the initialization process.

Example

This example LILP map shows that there are 6 ports on the loop. The hex values of the AL_PAs are in the appropriate positions indicating the physical order of the ports on the loop.

Byte map content

06 E8 D6 E2 6A 5F 08 FF ... FF

Detailed loop initialization explanation

1. Select initial AL_PA Each FL_Port selects an AL_PA hex value of ‘00’. Each NL_Port selects an AL_PA hex value of ‘EF’.

2. Select the loop master Each L_Port continuously

transmits a LISM loop initialization sequence with the D_ID and S_ID fields set to hex ‘0000xx’ (where ‘xx’ is its initial AL_PA) and its Port_Name in the payload. Each L_Port monitors its receiver and proceeds as follows:

a. If the L_Port receives a LISM loop initialization sequence that is the same as the one it transmits, it

becomes the loop master and continues at step 3.

b. If the L_Port received a LISM loop initialization sequence that is not the same as the one it transmits,

the L_Ports checks the D_ID and payload as follows: i. If the L_Port is an FL_Port and the received D_ID = hex ‘000000’, the loop initialization sequence

is from another FL_Port. If its Port_Name is algebraically:

- lower than the Port_Name in the payload, the FL_Port transmits a LISM loop initialization sequence with the payload containing its own Port_Name.

- higher than the Port_name in the payload, the FL_Port retransmits the same LISM that it received and goes to the MONITORING state in nonparticipating mode (another FL_Port won the role of loop master).

ii. If the L_Port is an FL_Port and the received D_ID is not equal to hex ‘000000’, the FL_Port dis-

cards the received sequence. This allows an FL_Port to become the loop master.

iii. If the L_Port is a NL_Port and the received D_ID equals hex ‘000000’, the NL_Port retransmits the

received Loop Initialization Sequence. This allows an FL_Port to become the loop master.

iv. If the L_Port is an NL_Port and the received D_ID is not equal to hex ‘000000’, the Loop Initializa-

tion Sequence is from another NL_Port. If its Port_Name is algebraically:

Frames are sent continuously because they may be discarded by any L_Port that does not have a receive buffer available

(flow control is not used during initialization).

Fibre Channel Interface Manual, Rev. D 41

- lower than the Port_Name in the payload, the NL_Port transmits a LISM loop initialization sequence with the payload containing its Port_Name.

- higher than the Port_name in the payload, the NL_Port retransmits the received Loop Initialization Sequence.

Each L_Port continues with steps 2a through 2d. c. If the L_Port receives an ARB(F0), it continues at step 4. d. If it receives anything else, the value is discarded and the port continues with steps 2a to 2d.

3. Loop master — transmit remaining Loop Initialization Sequences a. The loop master continuously transmits ARB(F0)s until its receives its own ARBx (ARB(F0)). b. The L_Port transmits the LIFA, LIPA, LIHA, and LISA loop initialization sequences. These sequences

contain a 16-byte AL_PA bit map in the payload. Each bit represents one AL_PA. See figure 10 and tables 12 and 16.

Table 16: Loop initialization sequence AL_PA bit map

Bits

Word

3322 1098

L000 0000 0000 0000 0000 0000 0000 0000

0000 0000 0000 0000 0000 0000 0000 0000

2222 7654

2222 3210

1111 9876

1111 5432111098 7654 3210

Except for the L_bit, each bit in table Table 16 represents a valid AL_PA. The L_bit is set by the FL_Port or F/NL_Port to indicate that the configuration has changed. Setting the L_bit implicitly logs out all NL_Ports. Private NL_Ports are implicitly logged out since the public NL_Ports with which they may have been communicating, may have a new AL_PA.

The loop master transmits the four loop initialization sequences that contain the 16-byte AL_PA bit maps as follows:

LIFA

The L_Port primes the AL_PA bit map with binary zero (0) and sets the bit that corresponds to its Fabric Assigned AL_PA to one (1). If the L_Port is an FL_Port, it sets the bit associated with AL_PA 00h. The L_bit is set if this is the first initialization attempt of an FL_Port or of an NL_Port that has assumed the role of an F/NL_Port.

LIPA

The L_Port primes the AL_PA bit map with the AL_PA bit map of the previous LIFA loop initialization sequence. The L_Port checks to see if the bit that corresponds to its previously acquired AL_PA is set. If it is not set to 1, the L_Port sets the bit (unless a bit was set in LIFA); if the bit is already set to 1, the L_Port assumes a soft assigned AL_PA.

LIHA

The L_Port primes the AL_PA bit map with the AL_PA bit map of the previous LIPA loop initialization sequence. The L_Port checks to see if the bit that corresponds to its hard assigned AL_PA is set. If it is not set to 1, the L_Port sets the bit (unless a bit was set in LIFA or LIPA); if the bit is already set to 1, the L_Port assumes a soft assigned AL_PA.

If ESI activity is underway when the request for the hard address is received, the drive shall use the last known value of the hard address before the current ESI activity started. For more information on ESI, refer to Section 10.5.

42 Fibre Channel Interface Manual, Rev. D

LISA

The L_Port primes the AL_PA bit map with the AL_PA bit map of the previous LIHA loop initialization sequence. The L_Port sets the first available bit to 1 (unless a bit was set in LIFA, LIPA, or LIHA) which corresponds to its soft assigned AL_PA. If a bit was available, the L_Port adjusts its AL_PA according to which bit it set. If no bits are available, the L_Port remains in the nonparticipating mode; the L_Port may attempt to re-initialize at the request of the node. If the L_Port does not support the AL_PA position mapping loop initialization sequences, it sets byte 2 of the loop initialization identifier to 00h.

c. When the loop master receives the LISA sequence, it checks the loop initialization identifier value. If

the value is 11050100h, the loop master transmits two additional loop initialization sequences as follows:

LIRP

The L_Port sets the AL_PA position map to all hex ‘FF’, enters an offset of 01h followed by its AL_PA. For example, if AL_PA = 05h, the AL_PA position map contains 0105FFFFFF...FFh.

LILP

The L_Port transmits the AL_PA position map of the previous LIRP loop initialization sequence.

d. When the last loop initialization sequence (identifier = LISA or LILP) is returned, the loop master trans-

mits CLS to place all L_Ports into Monitoring state. When the loop master received CLS, the L_Port makes the transition to the Monitoring state and relinquishes its loop master role. At this time, all possible AL_PA values have been assigned for the number of L_Ports and every L_Port that has a valid AL_PA is in participating mode.

If any frame is received that is not formatted according to figure 10, the frame is discarded and the loop master restarts initialization at step 3b.

The loop master uses the E_D_TOV timer to wait for each of the above loop initialization sequences and the CLS. If the timer expires before each transmitted loop initialization sequence of CLS is received, the L_Port goes to the Initializing state.

The L_Port continues at step 5.

4. Non loop master L_Port—select unique AL_PA

A non loop master L_Port retransmits any received ARB(F0)s and prepares to receive (e.g. empties its receive buffers) and retransmits the following LIFA, LIPA, LIHA, LISA, LIRP, and LILP loop initialization sequences followed by CLS. The loop initialization sequences contain a 16-byte AL_PA bit map in the payload. Each bit represents one AL_PA (see figure 10 and tables 16 and 13).

LIFA

The L_Port checks to see if the bit that corresponds to its fabric-assigned AL_PA is set. If it is not set to 1, the L_Port sets the bit; if the bit is already set to 1, the L_Port assumes a soft-assigned AL_PA. The L_Port retransmits the loop initialization sequence.

LIPA

The L_Port checks to see if the bit that corresponds to its previously-acquired AL_PA is set. If it is not set to 1, the L_Port sets the bit; if the bit is already set to 1, the L_Port assumes a soft-assigned AL_PA. The L_Port retransmits the loop initialization sequence.

LIHA

The L_Port checks to see if the bit that corresponds to its hard-assigned AL_PA is set. If it is not set to 1, the L_Port sets the bit (unless a bit was set in LIFA or LIPA); if the bit is already set to 1, the L_Port assumes a soft-assigned AL_PA. The L_Port retransmits the loop initialization sequence. To get the hard address, the drive must abort all Enclosure Services Interface (ESI) activity that may be in process. Both ESI initiated by a receive or send diagnostic command and Enclosure Initiated ESI will be aborted. Refer to Section 10.0 for more information on ESI.

LISA

The L_Port sets the first available bit to 1 (unless a bit was set in LIFA, LIPA, or LIHA above) that corresponds to its soft-assigned AL_PA. If a bit was available, the L_Port adjusts its AL_PA according to which bit was set. If no bits are available, the L_Port remains in nonparticipating mode; the L_Port may attempt to

Fibre Channel Interface Manual, Rev. D 43

reinitialize at 10.3 at the request of the node. If the L_Port does not support the AL_PA position mapping loop initialization sequences, it sets byte 2 of the loop initialization identifier to 00h. The L_Port retransmits the loop initialization sequence.

LIRP

If LIRP is received, the L_Port reads the left-most byte (offset), increment it by one, store the offset, and store its AL_PA into the offset position. The L_Port retransmits the loop initialization sequence.

LILP

If LILP is received, the L_Port may use the AL_PA position map to save the relative positions of all L_Ports on the loop. This information may be useful for error recovery. The L_Port retransmits the loop initialization sequence. If any frame is received that is not formatted according to figure 10 and as specified in step 3 on page 42, the frame is discarded. If a LIRP or LILP frame is received by an L_Port which does not support the AL_PA position map, the frame is discarded. Each L_Port uses the E_D_TOV timer to wait for each of the above loop initialization sequences and the CLS. If the timer expires before each loop initialization sequence of CLS is received, the L_Port goes to the Initializing state. One possible reason for this is that the loop master was removed from the loop. When CLS is received, the L_Port retransmits CLS and goes to the Monitoring state in participating mode (if it acquired a valid AL_PA). The L_Port continues at step 5.

5. Select final AL_PA and exit initialization a. If an FL_Port is in participating mode, it has completed initialization with an AL_PA of 00h and exits the

loop initialization.

b. If a private NL_Port is in participating mode, the NL_Port has completed initialization with an AL_PA in

the range of 01h - EFh and exits loop initialization. If during initialization, the NL_Port detected that the L_bit (Login required) was set to 1, it implicitly logs out with all other NL_Ports.

c. If a public NL_Port is in participating mode, the NL_Port has discovered an AL_PA in the range of 01h

- EFh. If one of the following occurred, the NL_Ports implicitly logout with all ports and attempt a fabric login to the address FFFFFEh - AL_PA 00h:

• the NL_Port detected that the L_bit (login required) was set to 1 in a LIFA, LIPA, LIHA, or LISA loop initialization sequence;

• the NL_Port was unable to set to 1 its fabric-assigned AL_PA bit or its previously-acquired AL_PA bit in the LIFA or LIPA loop initialization sequence (i.e., another NL_Port is using the AL_PA);

• the NL_Port has not previously executed a fabric login.

Normal responses to a fabric login request are:

• the transmitted OPN(00,AL_PS) and login extended link service sequence are returned to the NL_Port. No L_Port on the loop has accepted this request. The NL_Port sets its native address identifier to 0000xxh (where xx is its AL_PA).

If the NL_Port is capable of providing fabric services in the absence of an FL_Port (i.e., it recognizes the well-known alias address FFFFFEh as well as its own native address identifier), this NL_Port (also known as an F/NL_Port) recognizes OPN(00,x) in addition to its own AL_PA. If this is the first time that the NL_Port is assuming the responsibility of an F/NL_Port, to ensure that all previous login requests are reset, the F/NL_Port goes to the Initializing state (REQ(initialize)) and sets the L_bit (login required) to 1 in the LIFA loop initialization sequence.

Note. To prevent another L_Port from winning arbitration, this F/NL_Port should not relinquish control of

the loop until it is prepared to receive OPN(00,AL_PS).

If the NL_Port is not capable of becoming an F/NL_Port, the NL_Port exits loop initialization.

• the NL_Port receives an Accept (ACC) link service sequence. The NL_Port uses the D_ID in the ACC sequence as its native address identifier and bits 7 - 0 of the D_ID as its fabric-assigned AL_PA. The NL_Port compares the fabric-assigned AL_PA in the ACC sequence with the AL_PA acquired prior to step 5. If they are equal, the NL_Port exits loop initialization. If they are not equal, the NL_Port goes to the Initializing state (REQ(initialize)) to re-initialize and acquire the fabric-assigned AL_PA value.

44 Fibre Channel Interface Manual, Rev. D

8.2.1 Loop initialization state machine

Start

* Exit

OLD-PORT

State

LISM rcvd = LISM xmit

LIP or LP_TOV

timeout occurred between

events

Notes:

* Not supported by drives covered by this manual.

** The L_Port must set the appropriate AL_PA bit before transmitting the Loop Initialization Sequences.

< > implies that these are

optional.

Initializing

Send LIPs

LIP Received OPEN-INIT: Transmit received LIPs

Step (1)

Select

Initial AL_PA

LISM rcvd > LISM xmit

Select Loop Master

Transmit LISM

Receive LISM/ARB

Compare LISMs

Loop Master

Transmit ARB(F0)

Receive ARB(F0)

Step (3)

**Transmit LIFA

Receive LIFA

**Transmit LIPA

Receive LIPA

**Transmit LIHA

Receive LIHA

**Transmit LISA

Recive LISA

Transmit CLS

Receive CLS

CLS received CLS transmitted

AL_PA no AL_PA

Step (5)

EXIT

NL_Port:

Step (2)

LIP received

after AL_TIME

LISM rcvd < LISM xmit

Wait Master

Retransmit all

received frames

Step (4)

Receive LIFA

**Transmit LIFA

Receive LIPA

**Transmit LIPA

Receive LIHA

**Transmit LIHA

Receive LISA

**Transmit LISA

Receive CLS

Transmit CLS

No AL_PA was

available.

WAIT and retry

Retry

LIP or LP_TOV

timeout

occurred

before ARB(F0)

rcvd

LIP or LP_TOV

timeout occurred between

events

Figure 11. Loop initialization state machine

The loop initialization process is used whenever any unusual event occurs on the loop. One such event would be inserting a new NL_Port into the loop. Invoking the loop initialization process permits the new NL_Port to acquire an AL_PA so it can begin operations.

Fibre Channel Interface Manual, Rev. D 45

8.2.2 Loop reinitialization

Loop reinitialization occurs when an L_Port is added to the loop, removed from the loop, or for error recovery.

ENTER HERE REQ(initialize)

REQ(arbritrate as x)

ARBITRATING

Rcvd my ARBx

ARBITRATION

WON

Transmit OPNy|OPNr

Received CLS

MONITORING

ARB_PEN = 1

Transmit CLS

REQ(old-port)

TRANSFER

OLD-PORTINITIALIZATION

REQ(bypass L_Port)

REQ(monitor) (when allowed)

XMITTED

Transmit CLS

OPEN OPENED

Rcvd CLS

ARB_PEND = 1

RECEIVED

Received CLS

Received OPNy

Figure 12. Loop state machine (simplified)

8.3 Accessing another L_Port

Each port has its own private arbitration primitive (ARBx) signal. Each port uses this ARBx signal to arbitrate for and win access rights to the loop. This must be done before communicating with another port.

When an L_Port is not communicating with another port, it is in a monitoring state to see if some other L_Port is trying to communicate with it. The L_Port is also retransmitting the stream of transmission words it is receiving. If a port needs to communicate, it sends out its arbitration primitive signal by replacing the fill words between frames. If the arbitration primitive signal (ARBx) travels completely around the loop without being

Fill words may be Idles, ARBx’s, or ARB(F0)’s. Fill words are transmitted between frames and may be deleted for clock

skew management purposes.

46 Fibre Channel Interface Manual, Rev. D

replaced, that port has won arbitration of the loop and is free to open the loop between its receiver and transmitter and is also free to stop retransmitting received transmission words. This means the NL_Port is no longer in repeat mode and all words transmitted on its outbound fiber are generated by the NL_Port.

When operating in full duplex mode, the port that wins arbitration sends out a special primitive signal called OPNyx to select a destination port on the loop and to identify the port sending the OPNyx primitive signal. The “y” value of OPNyx is the arbitrated loop physical address of the destination device (AL_PD). If a port receives an OPNyx and recognizes its AL_PD, the L_Port opens the loop at its L_Port. This L_Port and the one that sent the OPNyx begin normal FC-2 protocols.

When the port that won arbitration and sent the OPNyx to initiate communication between itself and another L_Port wants to close communication with the port, it uses another primitive signal called close (CLS) to signal the other port of its intent to close the loop. The receiving L_Port finishes its work and then transmits a CLS back to the originating L_Port. At this point, the two ports return to the monitoring state, and other L_Ports can start communicating.

When operating in half duplex mode, OPNyy only identifies the destination port; therefore, the sending port cannot be determined.

8.3.1 Access fairness

So what happens when two or more ports happen to request access to the loop at exactly the same time? Or what happens when one port has already won access to the loop and others then want to arbitrate to win access? The answers lie in the access fairness algorithm that most NL_Ports on a loop use. This access fairness algorithm ensures that all participating NL_Ports will have equal access to the loop. NL_Ports that use the access fairness algorithm are called “fair” NL_Ports. Seagate Fibre Channel drives fully implement the access fairness algorithm.

Remember that each L_Port can continuously arbitrate to access the loop. Each L_Port has a priority assigned to it based on its’ Arbitrated Loop Physical Address (AL_PA). AL_PA “01” has the highest priority for an NL_Port and AL_PA “EF” has the lowest priority (except for the special arbitration primitive signal ARB(F0) discussed below). See section 8.1 for additional information about AL_PAs. The access fairness algorithm creates an access window in which all L_Ports are given an opportunity to arbitrate and win access to the loop regardless of its’ assigned priority. After all L_Ports have had an opportunity to win access to the loop, a new access window is started; however, all L_Ports don’t have to actually choose to win access, they just have to be given the opportunity to win access in each access window.

When a fair L_Port has arbitrated for and won access to the loop, that L_Port will not arbitrate again until it receives at least one Idle. The time between the first L_Port to win arbitration and transmitting an Idle is an access window. A special arbitration Primitive Signal (ARB(F0)) prevents the access window from being reset too early.

When a fair NL_Port has arbitrated for and won access to the loop and does not detect that another L_Port is arbitrating, it may keep the existing circuit open indefinitely or close the circuit and retain control of the loop (without rearbitrating) to open another L_Port on the loop.

How does the open NL_Port know when another port is arbitrating? The open NL_Port transmits ARB(F0) primitive sequences and monitors to see if its ARB(F0) is replaced by a higher priority address. Since xF0 is the lowest-priority address, any other NL_Port that is arbitrating will replace the ARB(F0) with its’ own ARBx (which will always be higher-priority than ARB(F0)) and the highest priority arbitrating L_Port will win arbitration. If the OPEN L_port receives the ARB(F0) back it knows that no other NL_Port is arbitrating for the loop.

Once an L_Port has won access to the loop, it may retain control of the loop indefinitely; however, if access is denied longer than the Error Detect Timeout Value (E_D_TOV), the offended L_Port can reset the access window to force arbitration. When a Seagate drive is operating as a target, it closes the loop when it has transmitted all of the frames it needed to send. Seagate drives do not hold the loop open to monitor the input stream for ARBs.

Fibre Channel Interface Manual, Rev. D 47

When a fair NL_Port has arbitrated for and won access to the loop and does detect that another L_Port is arbitrating, the NL_Port closes the loop at the earliest possible time and arbitrates again in the next access window before opening a different L_Port.

8.3.2 Access unfairness

Some loops may require that certain NL_Ports have more access to the loop than just one access per access window. Examples of this situation include an NL_Port for a subsystem controller or file server. Any NL_Port can be initialized to not use the fairness algorithm. If this occurs, the NL_Port is called an “unfair” NL_Port. An NL_Port can also be configured to be temporarily unfair.

When an unfair L_Port has arbitrated for and won access to the loop and does not detect that another L_Port is arbitrating, that L_Port may keep the existing circuit open indefinitely or close that circuit and retain ownership of the loop without re-arbitrating to open another L_Port on the loop.

When an unfair NL_Port controls the loops and detects that another L_Port is arbitrating, the unfair NL_Port may close the loop at the earliest possible time.

If you have a public loop connected to a fabric, the participating FL_Port is always the highest priority L_Port on the loop based on its AL_PA value of 00h (see Section 8.1).

Note. There can be only one participating FL_Port on any one loop. Additional FL_Ports can be present,

but they will be in nonparticipating mode.

The FL_Port doesn’t use the access fairness algorithm because it must control communications with the attached fabric. This means the FL_Port will always win arbitration.

8.3.3 Clock skew management

Each loop port receives an input stream from the port upstream that is based on the clock frequency of that upstream device. The clock frequency of the upstream device may be slightly faster or slower than the frequency the loop port is using to transmit data. Each loop port captures data using the receive clock frequency and retimes it to its own transmit clock before forwarding the data. Over time, if the receive clock frequency is faster than the transmit frequency, data will start backing up in the port. If the receive clock frequency is slower than the transmit frequency, the port may run out of data.

To compensate for this difference in clock frequencies, each loop port contains an Elasticity (smooting) FIFO (First In, First Out) buffer that allows words to be inserted or deleted as necessary to account for this difference in clock frequencies. Only fill words such as Idles or ARB’s may be inserted or deleted during times when frames or R_RDYs are not being transmitted. Each port originating frames is required to transmit at least six fill words between frames. This gives all monitoring loop ports an opportunity to insert or delete the fill words. A minimum of two fill words must be left between frames when it arrives at its destination.

8.4 Loop ports

A loop port (L_Port) is a port designed specifically to operate in a Fibre Channel Arbitrated Loop topology. NL_Ports have special additional functions which permit them to operate in the arbitrated loop topology as well as in the point-to-point physical topology when attached to an N_Port or an F_Port. N_Ports are designed for point-to-point physical topologies, and F_Ports are designed for fabric topologies.

8.4.1 Maximum number of NL_Ports

Up to 126 NL_Ports may be participating on a single arbitrated loop. There can be more than 126 NL_Ports attached to the loop, but only 126 will be able to obtain a valid arbitrated loop physical address (AL_PA). Only one (rare) or two NL_Ports communicate at any one time, except during loop initialization. Only one NL_Port can send frames but several NL_Ports may copy that frame into their buffer.

48 Fibre Channel Interface Manual, Rev. D

8.4.2 Blocking switch emulation

When two NL_Ports open communication with each other (see the OPNyx discussion in Section 8.3), communication between other devices is effectively blocked (other than to retransmit frames or insert fill words). This is known as a blocking environment since the two communicating ports block operation between any other L_Ports.

8.4.3 Non-meshed environment

FC-AL is called a non-meshed environment due to the fact that there is only one route to any other port. A meshed environment (like a fabric) is like a telephone system in which there are many routes possible between two communicating entities.

Fibre Channel Interface Manual, Rev. D 49

8.4.4 Assigned AL_PA values

All AL_PAs that are used in the loop protocol are listed in table 12. The AL_PAs are assigned to the 16-byte AL_PA bit maps of table 16 as shown in table 17.

Table 17: AL_PA mapped to bit maps

AL_PA

(hex)

-- 031 3C 131 73 231 B3 331

00 0 30 43 1 30 74 2 30 B4 3 30

01 0 29 45 1 29 75 2 29 B5 3 29

02 0 28 46 1 28 76 2 28 B6 3 28

04 0 27 47 1 27 79 2 27 B9 3 27

08 0 26 49 1 26 7A 2 26 BA 3 26

0F 0 25 4A 1 25 7C 2 25 BC 3 25

10 0 24 4B 1 24 80 2 24 C3 3 24

17 0 23 4C 1 23 81 2 23 C5 3 23

18 0 22 4D 1 22 82 2 22 C6 3 22

1B 0 21 4E 1 21 84 2 21 C7 3 21

1D 0 20 51 1 20 88 2 20 C9 3 20

1E 0 19 52 1 19 8F 2 19 CA 3 19

1F 0 18 53 1 18 90 2 18 CB 3 18

23 0 17 54 1 17 97 2 17 CC 3 17

25 0 16 55 1 16 98 2 16 CD 3 16

26 0 15 56 1 15 9B 2 15 CE 3 15

27 0 14 59 1 14 9D 2 14 D1 3 14

29 0 13 5A 1 13 9E 2 13 D2 3 13

2A 0 12 5C 1 12 9F 2 12 D3 3 12

2B 011 63 111 A3 211 D4 311

2C 010 65 110 A5 210 D5 310

2D 09 66 19 A6 29 D6 39

2E 08 67 18 A7 28 D9 38

31 07 69 17 A9 27 DA 37

32 06 6A 16 AA 26 DC 36

33 05 6B 15 AB 25 E0 35

34 04 6C 14 AC 24 E1 34

35 03 6D 13 AD 23 E2 33

36 02 6E 12 AE 22 E4 32

39 01 71 11 B1 21 E8 31

3A 00 72 10 B2 20 EF 30

Notes: ‘--’ is reserved for the L-bit (login required) AL_PA = ‘00’ is reserved for the FL_Port.

Bit map

Word Bit

AL_PA

(hex)

Bit map

Word Bit

AL_PA

(hex)

Bit map

Word Bit

AL_PA

(hex)

Bit map

Word Bit

50 Fibre Channel Interface Manual, Rev. D

9.0 Fibre Channel link services

Link service frames are used to perform functions at the Fibre Channel layer. They are used to establish the operating parameters, perform channel level error recovery, and check the status of the physical link between two devices. Link service frames are divided into two groups, Basic and Extended.

Navigation assistance

The field descriptions that are provided for most tables have sidebar labels which identify the table they are associated with. This helps orient you when nested tables occur within a section.

Sidebar example

Tab le

Field definitions (listed alphabetically)

number

Field name

The sidebar (black background with reversed text) identifies this field as being associated with Table 1.

Fibre Channel Interface Manual, Rev. D 51

9.1 Basic link services

The drive supports the Abort Sequence (ABTS) and two basic services replies, Basic Accept (BA_ACC) and Basic Reject (BA_RJT). All other basic link services are discarded by the drive. Basic link service functions are identified by the R_CTL field of the header.

Table 18: Basic link services header

Bit

76543210

Byte

R_CTL

1 (MSB)

D_ID2

3 (LSB)

400000000

Reserved

5 (MSB)

S_ID6

7 (LSB)

800000000

Ty pe

9 (MSB)

F_CTL10

11 (LSB)

SEQ_ID

1300000000

DF_CTL

14 (MSB)

SEQ_CNT

15 (LSB)

16 (MSB)

OX_ ID

17 (LSB)

1811111111

1911111111

RX_ID

20 (MSB)

Parameter

23 (LSB)

Tab le

Field definitions (listed alphabetically)

number

D_ID (Destination Identifier)

The address of the drive for ABTS. This value must match the current address of the drive. For the basic link service replies, the D_ID is the address of the initiator.

52 Fibre Channel Interface Manual, Rev. D

DF_CTL (Data Field Control)

Set to 00h to indicate no optional Fibre Channel headers are used.

F_CTL (Frame Control)

Set to 090000h for the ABTS. This indicates the ABTS is from the originator of the exchange, this is the last frame of the sequence, and sequence initiative is transferred for the drive to send the reply back.

For the reply frames, the drive sets the F_CTL to 990000h. This indicates the frame is from the responder, this is the last sequence, this is the last frame of the sequence, and sequence initiative is returned to the initiator.

OX_ID (Originator Exchange Identifier)

The OX_ID for the sequence being identified by the basic link service.

Parameter

Not used for basic link services.

R_CTL (Routing Control)

The basic link service frame. See the description of each basic link service below for the R_CTL value.

RX_ID (Responder Identifier)

Not used by the drive. The value of FFFFh indicates the RX_ID is not being used.

S_ID (Source Identifier)

The address of the initiator that sent the frame for ABTS. For the basic link service replies, the S_ID contains the address of the drive.

SEQ_CNT (Sequence Count)

Set to 0000h to indicate this is the first frame of the Fibre Channel sequence.

SEQ_ID (Sequence Identifier)

Contains the last used SEQ_ID for the exchange for ABTS. The drive does not check the SEQ_ID as the entire exchange (command) is aborted by the error recovery process. The drive returns the same SEQ_ID in the reply frame as received from the initiator in the ABTS.

Type

00h Used for all basic link services frames.

9.1.1 Abort Sequence (ABTS)

The Abort Sequence (ABTS) is sent by the initiator to abort a single SCSI exchange (command) or FC exchange (one of the link service operations). The ABTS frame does not have a payload. All the information is included in the header.

The R_CTL is 81h.

Fibre Channel Interface Manual, Rev. D 53

9.1.2 Basic Accept (BA_ACC)

BA_ACC is sent by the drive in response to all correctly structured ABTS. If the ABTS identifies an exchange in execution or buffered for execution, the drive will discard the exchange.

The R_CTL is 84h.

Table 19: BA_ACC Payload

Bit

76543210

Byte

SEQ_ID Valid

Last SEQ_ID

2 (MSB)

3 (LSB)

4 (MSB)

5 (LSB)

6 (MSB)

7 (LSB)

8 (MSB)

9 (LSB)

10 (MSB)

11 (LSB)

Tab le

Field definitions (listed alphabetically)

number

Highest SEQ_CNT (Highest Sequence Count)

FFFFh.

Reserved

OX_ID Aborted

RX_ID Aborted

Lowest SEQ_CNT

Highest SEQ_CNT

Last SEQ_ID (Last Sequence Identifier)

Not used.

Lowest SEQ_CNT (Lowest Sequence Count)

OX_ID Aborted (Originator Exchange Identifier Aborted)

The same value as received in the ABTS.

RX_ID Aborted (Responder Identifier Aborted)

FFFFh.

SEQ_ID Valid (Sequence Identifier Valid)

00h Marks the Last SEQ_ID field as invalid. The SEQ_ID is not used because the error recovery procedure requires the

entire exchange (command) to be aborted.

54 Fibre Channel Interface Manual, Rev. D

9.1.3 Basic Reject (BA_RJT)

BA_RJT is sent by the drive in response to an ABTS with a RX_ID not set to FFFFh.

The R_CTL is 85h.

Table 20: BA_RJT Payload

Bit

76543210

Byte

0 Reserved

1 Reason Code

2 Reason Explanation

3 Vendor Unique

Tab le

Field definitions (listed alphabetically)

number

Reason Code

03h (Logical Error) is the only Reason code sent by the drive if the RX_ID sent with the ABTS is not FFFFh.

Reason Explanation

03h No Additional Explanation. This is the only Reason Explanation code sent by the drive.

Vendor Unique

Not supported by the drives described in this manual.

Fibre Channel Interface Manual, Rev. D 55

9.2 Extended link services

The type of extended link service is identified by the LS Command Code in the first word of the payload. The R_CTL field of the frame header identifies whether the extended link service is a request or a reply to a request. The accept for extended link services varies with the function. A description of the accept for each request is included with the description of the request.

Table 21: Extended link services header

Bit Byte

00010001X

1 (MSB)

3 (LSB)

400000000

5 (MSB) S_ID

7 (LSB)

800000001

9 (MSB)

11 (LSB)

1300000000

76543210

R_CTL

D_ID2

Reserved

Ty pe

F_CTL10

SEQ_ID

DF_CTL

14 (MSB)

15 (LSB)

16 (MSB) OX_ID

17 (LSB)

1811111111

1911111111

20 (MSB)

23 (LSB)

SEQ_CNT

RX_ID

Parameter

56 Fibre Channel Interface Manual, Rev. D

Field definitions (listed alphabetically)

Tab le

number

D_ID (Destination Identifier)

Frame destination address.

DF_CTL (Data Field Control)

Set to 00 to indicate no optional Fibre Channel headers are used.

F_CTL (Frame Control)

Set to 290000h for extended link service requests. This indicates the frame is from the originator of the exchange, this is the last frame of the sequence, and sequence initiative is transferred for the responder to send the reply back.

For the reply frames, the F_CTL is set to 990000h. This indicates the frame is from the responder, this is the last sequence, this is the last frame of the sequence, and sequence initiative is returned to the originator.

OX_ID (Originator Exchange Identifier)

The drive sends 0000 to the OX_ID field in extended link services requests it originates. For extended link services replies, the drive uses the OX_ID value received from the initiator.

Parameter

Not used for extended link services.

R_CTL (Routing Control)

22h Extended link services and unsolicited control for extended link service request, PLOGI, PRLI, RLS, RRQ, and

PDISC.

23h Extended link services and solicited control for replies, ACC and LS_RJT.

RX_ID (Responder Identifier)

Not used by the drive. The value of FFFFh indicates the RX_ID is not being used.

S_ID (Source Identifier)

The address of the originator of the frame. This address is used by the destination to return any responses that may be required by the operation.

SEQ_CNT (Sequence Count)

Not checked by the drive. For extended link services replies and requests sent by the drive, SEQ_CNT equals 0000.

SEQ_ID (Sequence Identifier)

Not checked by the drive. For extended link services replies, the drive uses the SEQ_ID value received from the initiator. The drive sends SEQ_ID equal to FFh for extended link services requests it originates.

Type

01h All extended link services frames.

Fibre Channel Interface Manual, Rev. D 57

9.2.1 Port Login (PLOGI) (02x)

Port Login (PLOGI) is sent by the initiator to a drive to establish the Fibre Channel operating parameters. The PLOGI causes any open exchanges (commands) the initiator may have queued in the drive to be discarded.

Table 22: PLOGI Payload

Bit

76543210

Byte

000000011

100000000

200000000

300000000

LS Command Code

4-19

20-27

28-35

36-51

52-67

68-83

84-99

100-115

Tab le

Field definitions (listed alphabetically)

number

Class 1 and 2 Service Parameters

N_Port Common Service Parameters

Port Name

Node Name

Class 1 Service Parameters

Class 2 Service Parameters

Class 3 Service Parameters

Reserved

Vendor Version

May be present in the PLOGI frame. The drive checks only for class 3 service parameters.

Class 3 Service Parameters

Required by the drive. See Table 26 on page 62.

LS Command Code (Link Services Command Code)

03h PLOGI payload.

N_Port Common Service Parameters

See Table 24 on page 60.

Port Name and Node Name

Used to identify the device. The device may have multiple Fibre Channel ports with each having a unique Port Name. The drive is a dual-ported device.

The Port and Node Names in the PLOGI identify the initiator. The drive saves the Port Name of the initiator with the login parameters. If a change of the Port Name/AL_PA address association is detected during a Port Discovery (PDISC), an implicit logout occurs (any queued commands for the previous Port Name/AL_PA are discarded, the previous login is cleared) and a LS_RJT is returned to the initiator.

The Port and Node Names in the Port Login Accept (PLOGI ACC) identify the drive. The drive uses a format for the Port and Node Names defined as the IEEE extended address. See Table 23.

58 Fibre Channel Interface Manual, Rev. D

Table 23: Port/Node Name format

Bit

76543210

Byte

00010(MSB

Network Address ID N_Port Identifier

1 (LSB)

2 (MSB)

Company Identifier Assigned by IEEE3

4 (LSB)

5 (MSB)

Unique Drive Identifier Assigned by Seagate6

7 (LSB)

Company Identifier Assigned by IEEE

This Seagate-unique value is registered with the IEEE.

N_Port Identifier

Used by the drive to identify the name of a specific port or node. 000h Drive Node Name 100h Port A 200h Port B

Network Address ID

2h Defines the name as the IEEE extended format.

Unique Drive Identifier Assigned by Seagate

Assigned by Seagate. Uniquely assigned to each disc drive.

Vendor Version

Vendor-unique.

Fibre Channel Interface Manual, Rev. D 59

Table 24: N_Port Common Service Parameters

Bit

76543210

Byte

Highest ANSI FC-PH Version

Lowest ANSI FC-PH Version

2 (MSB)

Buffer to Buffer Credit

3 (LSB)

4 Contin

Increasing

Offset

Random

Relative

Offset

Val id Vendor Version

F_Port Alternate

Credit Model

E_D_TOV

Resolution0Reserved0Reserved

Common Features

500000Dynamic

Reserved

Half Duplex

Continuous

Increase

SEQ_CNT

60000(MSB)

Reserved Receive Data Field Size

7 (LSB)

Reserved

9 (MSB) Total Concurrent Sequences (LSB)

10 (MSB)

Relative Offset by Info Category

11 (LSB)

Payload

Length

12 (MSB)

E_D_TOV (Pt to Pt)

15 (LSB)

Tab le

Field definitions (listed alphabetically)

number

Buffer to Buffer Credit

Not checked by the drive. The drive requires the Alternate Credit Model and assumes a Buffer to Buffer Credit of zero. When the drive opens a device on the loop, it waits until it receives a R_RDY or a Close. The drive returns 0000 in the accept.

60 Fibre Channel Interface Manual, Rev. D

Common Features

This is a bit significant field which requests options that are used in all classes of service by initiator login. Below is a list of the features and the drive requirements. The drive returns an LS_RJT to PLOGI requests that do not satisfy the requirements.

Table 25: Common Features bits

Feature Drive requirement

Continuously Increasing Offset Must be a one (1).

Random Relative Offset Not checked. Port Login Accept returns a value of zero (0). Not supported.

Valid Vendor Version X

F_Port (Fabric Port) Must be a zero (0) to denote a N_Port.

Alternate Credit Model Must be a one (1).

E_D_TOV Resolution Not checked. Port Login ACC returns 0.

Dynamic Half Duplex Not checked. Port Login ACC returns 0.

Continuous Increase SEQ_CNT

Not checked. Port Login ACC returns 0.

Payload Length Not checked. Port Login ACC returns 0.

E_D_TOV (Pt to Pt) (Error Detect Time Out Value)

This field is only for point-to-point connections and is not valid for loop operation.

Highest ANSI FC-PH Version and Lowest ANSI FC-PH Version

The highest and lowest version of the ANSI Fibre Channel Physical and Signaling standards supported by the drive. A version level of 09h is defined for FC-PH, Rev. 4.3. A version level of 20h is defined for FC-PH-3, Rev. 9.4. Earlier drives supported by this manual require 09h in the highest and lowest version fields. An LS_RJT will be returned in

response to any PLOGI that does not satisfy this requirement. Later drives do not check the version fields in PLOGI and return 20h in the PLOGI ACC. The version fields are not considered an accurate indicator of functionality. Reference the drive product manual for specific behavior.

Receive Data Field Size

In the common and class 3 service parameters. Current drives check this field for the range 256 < fs < 2112 and a multiple of four bytes. For multiple frame sequences, all frames but the last frame of the sequence must be this size. The drive uses the receive buffer field size in the class 3 parameters when it sends frames. The drive returns the receive buffer field size in the class 3 parameters from the initiator in the PLOGI ACC.

Relative Offset by Info Category

Indicates on a bit position basis which categories (e.g., solicited control, data descriptor) support the relative offset in the FC header. The drive does not require relative offset and does not check this field in the PLOGI. The drive sends Relative Offset in FCP Data frames (it sets 02h, bit 1 set, in the accept to indicate Relative Offset is supported for solicited data, category 0001b).

Total Concurrent Sequences

Number of concurrent sequences across all classes of service. Sequences are concurrent if they are open and delivery verification has not been received. It is the initiator’s responsibility to not issue commands to the drive that will exceed the initiator’s capabilities for concurrent sequences.

The drive returns FFh in Concurrent Sequences field of the PLOGI ACC payload.

Fibre Channel Interface Manual, Rev. D 61

Table 26: Class Service Parameters

Bit

76543210

Byte

0 Class

Val id

Intermix

Mode

Stacked Connect

Request

Sequence

Delivery0Reserved0Reserved0Reserved

Service Options

Reserved

X_ID Reassignment

Initial Process

Associator

ACK_0

Capable

ACK_N

Capable

Reserved0Reserved

Initiator Control

Reserved

4ACK_0

Capable

ACK_N

Capable

X_ID

Interlock

Error Policy

Reserved

Categories per Sequence

Recipient Control

Reserved

60000(MSB)

Reserved Receive Data Field Size

7 (LSB)

Reserved

9 (MSB) Concurrent Sequences (LSB)

10 0 (MSB)

11 (LSB)

Reserved

13 (MSB) Open Sequences per Exchange (LSB)

Tab le

Field definitions (listed alphabetically)

number

Concurrent Sequences

Reserved

Must be greater than 0. The drive returns FFh in the PLOGI ACC.

N_Port End to End Credit

62 Fibre Channel Interface Manual, Rev. D

Initiator Control

The transmit capabilities of the initiator in the PLOGI. The drive returns an LS_RJT to PLOGI requests that do not satisfy the drive’s requirements. The Initiator Control bits in the PLOGI ACC indicate the capabilities of the drive. The drive returns zero (0) for all bits that are not applicable for class 3 services and for all reserved bits.

Table 27: Initiator Control fields

Option Drive requirement

X_ID (Exchange Identifier) Reassignment Not applicable. Not valid for class 3.

00 Initial Process Associator not supported. 01 Initial Process Associator supported.

Initial Process Associator

ACK_0 (Acknowledge 0) Capable Not applicable. Not valid for class 3.

ACK_N (Acknowledge N) Capable Not applicable. Not valid for class 3.

N_Port End to End Credit

Not valid for class 3.

Open Sequences per Exchange

Must be greater than zero (0). The drive returns 01h in the PLOGI ACC. The PLOGI ACC returns the drive’s parameters to the initiator. The PLOGI ACC Payload has the same definition as the

PLOGI Payload except the LS Command Code.

10 Reserved. 11 Initial Process Associator Values of 10 or 11 cause the Login to be rejected. Other values are accepted.

Receive Data Field Size

A class 3 service parameter. Current drives check this field for the range 256 < fs < 2112 and a multiple of four bytes. For multiple frame sequences, all frames but the last frame of the sequence must be this size. The drive uses the receive buffer field size in the class 3 parameters when it sends frames. The drive returns the receive buffer field size in the class 3 parameters from the initiator in the PLOGI ACC.

Recipient Control

Indicates the receive capabilities of the initiator in the PLOGI. The Recipient Control bits in the PLOGI ACC indicate the capabilities of the drive. The drive returns zero (0) for all bits that are not applicable for class 3 services and for all reserved bits.

Table 28: Recipient Control fields

Option Drive requirement

ACK_0 (Acknowledge 0) Capable Not applicable. Not valid for class 3.

ACK_N (Acknowledge N) Capable Not applicable. Not valid for class 3.

X_ID (Exchange Identifier) Interlock Not applicable. Not valid for class 3.

00 Only discard supported. 01 Reserved. 10 Discard and process supported.

Error Policy

11 Reserved. The drive supports only the discard error policy. It does not check the Error Policy bits in the PLOGI as all FC devices are required to support the discard policy. The drive returns 00 in the PLOGI ACC.

Fibre Channel Interface Manual, Rev. D 63

Table 28: Recipient Control fields

Option Drive requirement

The drive does not check the Categories per Sequence bits in the PLOGI. The

Categories per Sequence

drive originates only one category per sequence. The drive returns 00 in the PLOGI ACC to indicate it only supports receiving one category per sequence.

Service Options

These bits are only checked for class 3 service parameters. The drive returns an LS_RJT to PLOGI requests that do not satisfy the drive’s requirement.

Table 29: Service Option fields

Option Drive requirement

Class Valid Must be a one (1).

Intermix Mode Not applicable. Not valid for class 3.

Stacked Connect Request Not applicable. Not valid for class 3.

Sequence Delivery Not applicable. Valid only for Fabric login.

64 Fibre Channel Interface Manual, Rev. D

Table 30: Port Login Accept Payload (PLOGI ACC)

Bit

76543210

Byte

000000010

100000000

200000000

300000000

LS Command Code

4-19

20-27

28-35

36-51

52-67

68-83

84-99

100-115

Tab le

Field definitions (listed alphabetically)

number

Class 1 and 2 Service Parameters

N_Port Common Service Parameters

Port Name

Node Name

Class 1 Service Parameters

Class 2 Service Parameters

Class 3 Service Parameters

Reserved

Vendor Version

May be present in the PLOGI frame. The drive returns only class 3 service parameters. Class parameters for all other classes of service are set to all zeros.

Class 3 Service Parameters

Sent by the drive. See Table 26 for details.

LS Command Code (Link Services Command Code)

02h PLOGI ACC.

N_Port Common Service Parameters

See Table 24.

Port Name and Node Name

Used to identify the device. The device may have multiple Fibre Channel ports with each having a unique Port Name. The drive is a dual-ported device.

The Port and Node Names in the PLOGI ACC identify the drive. The drive uses a format for the Port and Node Names defined as the IEEE extended address. The format is in Table 23.

Vendor Version

Vendor-unique. Not supported.

Fibre Channel Interface Manual, Rev. D 65

9.2.2 Port Logout (PLOGO) (03x)

Port Logout (PLOGO) is sent by the target in response to any frame from an initiator that has not completed N_Port Login. PLOGO may also be sent by an initiator when it has no further need for a target.

Table 31: LOGO Payload

Bit

76543210

Byte

000000101

100000000

200000000

300000000

Reserved

N_Port Identifier

Port Name

Tab le

Field definitions (listed alphabetically)

number

LS Command Code (Link Services Command Code)

05h PLOGO Payload.

LS Command Code

N_Port Identifier

The three-byte address used in the D_ID and S_ID fields of the frame headers.

Port Name

The unique eight-byte address assigned to the port.

Table 32: PLOGO Accept

Bit Byte

000000010

100000000

200000000

300000000

Tab le

Field definitions (listed alphabetically)

number

LS Command Code (Link Services Command Code)

02h PLOGO Accept.

76543210

LS Command Code

66 Fibre Channel Interface Manual, Rev. D

9.2.3 Fabric Login (FLOGI) (04)

Fabric Login (FLOGI) is sent by the drive to the fabric to establish the Fibre Channel operating parameters in a public loop environment. When the drive sends FLOGI, any open exchanges (commands) queued in the drive are discarded.

Table 33: FLOGI Payload

Bit

76543210

Byte

000000100

100000000

200000000

300000000

LS Command Code

4-19

20-27

28-35

36-51

52-67

68-83

84-99

100-115

Tab le

Field definitions (listed alphabetically)

number

Class 1 and 2 Service Parameters

N_Port Common Service Parameters

Port Name

Node Name

Class 1 Service Parameters

Class 2 Service Parameters

Class 3 Service Parameters

Reserved

Vendor Version

The drive supports only class 3 service parameters. The drive sends all zeros for all other classes of service.

Class 3 Service Parameters

Sent by the drive. See Table 36 on page 70.

LS Command Code (Link Services Command Code)

04h FLOGI payload.

N_Port Common Service Parameters

See Table 34 on page 68.

Port Name and Node Name

Used to identify the device. The drive is a dual-ported device. The Port and Node Names in the FLOGI uniquely identify the drive and the port sending the FLOGI. The drive uses a format for the Port and Node Names defined as the IEEE extended address. See Table 23.

Vendor Version

Vendor-unique. Not supported.

Fibre Channel Interface Manual, Rev. D 67

Table 34: F_Port Common Service Parameters

Bit

76543210

Byte

Highest ANSI FC-PH Version

Lowest ANSI FC-PH Version

2 (MSB)

Buffer to Buffer Credit

3 (LSB)

4 Contin

Increasing

Offset

Random

Relative

Offset

Val id Vendor Version

F_Port Alternate

Credit Model

E_D_TOV

Resolution

Multicast Broadcast

Common Features

5 Hunt

Groups

Dedicated

Simplex

0 0 0 Dynamic

Reserved

Half Duplex

Continuous

Increase

SEQ_CNT

60000(MSB)

Reserved Receive Data Field Size

7 (LSB)

8 (MSB)

: Reserved

15 (LSB)

Payload

Length

Tab le

Field definitions (listed alphabetically)

number

Buffer to Buffer Credit

The drive sets the Alternate Credit Model and sets the Buffer to Buffer Credit to zero.

68 Fibre Channel Interface Manual, Rev. D

Common Features

This is a bit significant field which indicates the options that are supported by the drive. Below is a list of the features. The drive returns an LS_RJT to FLOGI ACC for requests that do not satisfy the drive’s requirements.

Table 35: Common Features bits

Feature

Drive

Support (FLOGI) Requirement (FLOGI ACC)

Continuously Increasing Offset 1 Must = 1

Random Relative Offset 0 Not checked

Valid Vendor Version 0 Not checked

F_Port (Fabric Port) 0 Must = 1

Alternate Credit Model 1 Must = 1

E_D_TOV Resolution 0 Not checked. Not valid for loop operation.

Multicast 0 Not checked

Broadcast 0 Not checked

Hunt Groups 0 Not checked

Dedicated Simplex 0 Not checked

Dynamic Half Duplex 0 Not checked

Payload Length 0 Not checked

Highest ANSI FC-PH Version and Lowest ANSI FC-PH Version

The highest and lowest version of the ANSI Fibre Channel Physical and Signaling standards supported by Public loop drives is FC-PH-3 Rev. 9.4

A version level of 20h is defined for FC-PH-3 Rev. 9.4.

Receive Data Field Size

The drive sends a receive buffer size of 2112 bytes.

Fibre Channel Interface Manual, Rev. D 69

Table 36: Class 3 Service Parameters

Bit Byte

0 Class

76543210

Val id

Intermix

Mode

Stacked Connect

Request

Sequence

Delivery

Dedicated

Simplex

Camp-on Buffered

Class 1

Service Options

0000000

Priority

Reserved

Tab le

Field definitions (listed alphabetically)

number

Service Options

The following class 3 service parameters are sent by the drive.

Table 37: Service Option Class 3 fields

Option

Class Valid 1 Must = 1

Intermix Mode 0, not applicable or valid for class 3. Not checked

Stacked Connect Request 00, not applicable or valid for class 3. Not checked

Sequence Delivery 1 Must = 1

Dedicated Simplex 0, Not applicable or valid for class 3 Not checked

Camp-on 0, not applicable or valid for class 3. Not checked

Buffered Class 1 0, not applicable or valid for class 3 Not checked

Priority 0, not applicable or valid for class 3 Not checked

Support (FLOGI) Requirement (FLOGI ACC)

Drive

70 Fibre Channel Interface Manual, Rev. D

Table 38: Fabric Login Accept Payload (FLOGI ACC)

Bit

76543210

Byte

000000010

100000000

200000000

300000000

LS Command Code

4-19

20-27

28-35

36-51

52-67

68-83

84-99

100-115

Tab le

Field definitions (listed alphabetically)

number

Class 1 and 2 Service Parameters

F_Port Common Service Parameters

Port Name

Node Name

Class 1 Service Parameters

Class 2 Service Parameters

Class 3 Service Parameters

Reserved

Vendor Version

May be present in the FLOGI ACC frame. The drive returns only class 3 service parameters. Class parameters for all other classes of service are set to all zeros.

Class 3 Service Parameters

Sent by the drive. See Table 37 for details.

F_Port Common Service Parameters

See Table 24.

LS Command Code (Link Services Command Code)

02h FLOGI ACC.

Port Name and Node Name

Used to identify the fabric. The device may have multiple Fibre Channel ports with each having a unique Port Name. The Port and Node Names in the FLOGI ACC identify the fabric. The drive saves the Port Name of the fabric with the login

parameters. If a change of the Port Name is detected during loop initialization, an implicit logout occurs (any queued commands for the previous Port Name/AL_PA are discarded, the previous login is cleared).

Vendor Version

Vendor-unique. Not supported.

Fibre Channel Interface Manual, Rev. D 71

9.2.4 Process Login (PRLI)

Process Login (PRLI) is sent by the initiator to a target to establish the SCSI FCP operating features.

Table 39: PRLI Payload

Bit

76543210

Byte

000100000

LS Command Code

100010000

Page Length

200000000

300010100

Payload Length

400001000

Type Code

500000000

Type Code Extension

Orig Proc

Assc Valid

Reserved

Resp Proc

Assc Valid

Est Image

Pair

000

Reserved

8 (MSB)

Originator Process Associator

11 (LSB)

12 (MSB)

Responder Process Associator

15 (LSB)

19 0

Reserved

Data

Overlay

Allow

Initiator

Function

Ta rg e t

Function

Command/

Data

Mix

Data/

Response

Mix

RD XFR

RDY

Disable

Service Parameters

Tab le

Field definitions (listed alphabetically)

number

Command/Data Mixed Allowed

1 The initiator sends data in the same sequence as the command. The drive does not support Command/Data Mixed.

It will accept a PRLI with the Allow bit set, but will return a 0 in the accept to indicate the function cannot be used.

72 Fibre Channel Interface Manual, Rev. D

WR XFR

RDY

Disable

Data Overlay Allow

Not supported by the drive. The Data Overlay Allowed bit is not checked.

Data/Response Mix Allowed

1 Allows the drive to send the FCP RSP in the same sequence as the data. The drive does not support the Data/

Response Mix. It will accept a PRLI with the Allow bit set, but will return zero (0) in the accept to indicate the function cannot be used.

Establish Image Pair

1 The drive establishes a SCSI login for the initiator. 0 The PRLI is only an inquiry of the drive’s support of the process. The accept is still returned, but the login is not

retained.

Initiator Function

Must be set to one (1) for the drive to accept the login request.

LS Command Code (Link Services Command Code)

20h PRLI Payload.

Orig Proc Assc Valid (Originator Process Associator Valid)

Not supported by the drive. Not checked by the drive.

Page Length

Length of the service parameter page (in bytes). For a SCSI FCP service page, the length is 10h.

Payload Length

Length of PRLI payload (in bytes). The count includes the LS Command Code. The drive supports one service parameter page per PRLI.

The Payload Length must be 14h (20 decimal).

RD XFR RDY Disable (Read Transfer Ready Disable)

1 FCP_XFR_RDY will not be sent before read data. The drive requires this bit to be set to one (1).

Resp Proc Assc Valid (Responder Process Associator Valid)

Not supported by the drive. Not checked by the drive.

Target Function

May be set in addition to the Initiator Function bit. The drive does not check this bit.

Type Code

08h SCSI FCP process as included in the frame header for FCP frames.

Type Code Extension

0 Not defined for SCSI FCP and must be set to zero (0).

WR XFR RDY Disable (Write Transfer Ready Disable)

0 The drive requires this bit to be set to zero (0). The drive also requires the use of the WR_XFR_RDY bit.

Fibre Channel Interface Manual, Rev. D 73

The PRLI recipient returns a PRLI Accept or a LS_RJT to a PRLI request. The PRLI Accept may indicate success or failure of the process login request in the Response Code field. A LS_RJT is returned to a PRLI with a basic format error, e.g. page length error, payload length, and type code.

Table 40: PRLI Accept Payload

Bit

76543210

Byte

000000010

LS Command Code

100010000

Page Length

200000000

300010100

Payload Length

400001000

Type Code

500000000

Type Code Extension

Orig Proc

Assc Valid

Reserved

Resp Proc

Assc Valid

Est Image

Pair

Reserved Response Code

8 (MSB)

Originator Process Associator

11 (LSB)

12 (MSB)

Responder Process Associator

15 (LSB)

19 0

Reserved

Data

Overlay

Allow

Initiator

Function

Ta rg e t

Function

Command/

Data

Mix

Data/

Response

Mix

RD XFR

RDY

Disable

Service Parameters

Tab le

Field definitions (listed alphabetically)

number

Command/Data Mixed Allowed

1 The initiator sends data in the same sequence as the command. The drive does not support Command/Data Mixed.

It will accept a PRLI with the Allow bit set, but will return a 0 in the accept to indicate the function cannot be used.

WR XFR

RDY

Disable

74 Fibre Channel Interface Manual, Rev. D

Data Overlay Allow

Not supported by the drive. The Data Overlay Allowed bit is not checked.

Data/Response Allowed

1 Allows the drive to send the FCP RSP in the same sequence as the data. The drive does not support the Data/

Response Mix. It will accept a PRLI with the Allow bit set, but will return a 0 in the accept to indicate the function cannot be used.

Establish Image Pair

1 The drive establishes a SCSI login for the initiator. 0 The PRLI is only an inquiry of the drive’s support of the process. The accept is still returned, but the login is not

retained.

Initiator Function

Must be set to one (1) for the drive to accept the login request.

LS Command Code (Link Services Command Code)

02h PRLI Accept Payload.

Orig Proc Assc Valid (Originator Process Associator Valid)

Not supported by the drive. Not checked by the drive. Must be set to zero (0).

Page Length

Length of the service parameter page (in bytes). For a SCSI FCP service page, the length is 10h.

Payload Length

Length of PRLI payload (in bytes). The count includes the LS Command Code. The drive supports one service parameter page per PRLI.

The Payload length must be 14h (20 decimal).

Rd XFR RDY Disable (Read Transfer Ready Disable)

1 FCP_XFR_RDY will not be sent before read data. The drive requires this bit to be set to one (1).

Resp Proc Assc Valid (Responder Process Associator Valid)

Not supported by the drive. Not checked by the drive. Must be set to zero (0).

Response Code

The result of the PRLI request. Only codes 1 and 7 are supported by the drive.

0 Reserved. 1 Request executed. 2 The target has no resources available for establishing the login. 3 Initialization is not complete. The PRLI may be retried. 4 The Image Pair does not exist. 5 The Image Pair cannot be established due to a predefined configuration. 6 Request executed conditionally. Some of the parameters were not able to be set to their requested state. 7 The destination port is unable to process multiple page PRLI request. The PRLI request may be retried as a single

page request.

Target Function

May be set in addition to the Initiator Function bit. The drive does not check this bit.

Fibre Channel Interface Manual, Rev. D 75

Type Code

08h SCSI FCP process as included in the frame header for FCP frames.

Type Code Extension

0 Not defined for SCSI FCP and must be set to zero (0).

Wr XFR RDY Disable (Write Transfer Ready Disable)

1 FCP_XFR_RDY will not be sent to request write data. 0 The drive requires this bit to be set to zero (0). The drive also requires the use of the WR_XFR_RDY bit.

76 Fibre Channel Interface Manual, Rev. D

9.2.5 Process Logout (PRLO)

Process Logout (PRLO) is sent by the initiator to a target to remove an existing SCSI login. This frees target resources for use by other initiators.

Table 41: PRLO Payload

Bit

76543210

Byte

000100001

LS Command Code

100010000

Page Length

200000000

300010100

Payload Length

400001000

Type Code

500000000

Type Code Extension

6Orig Proc

Assc Valid

Reserved

Resp Proc

Assc Valid

0 0 0 0

Reserved

8 (MSB)

Originator Process Associator

11 (LSB)

12 (MSB)

Responder Process Associator

15 (LSB)

Reserved

Tab le

Field definitions (listed alphabetically)

number

LS Command Code (Link Services Command Code)

21h PRLO Payload.

Page Length

Length of the service parameter page in bytes. For a SCSI FCP service page, the length is 10h.

Fibre Channel Interface Manual, Rev. D 77

Payload Length

Length of PRLO payload (in bytes). The count includes the LS Command Code. The drive supports one service parameter page per PRLO. The Payload Length must be 14h (20 decimal).

Process Associators

Not supported by the drive. The process associator fields are not checked by the drive.

Type Code

00h All FC-4 processes between the initiator and target are removed. The drive treats 08h and 00h the same. 08h The SCSI-FCP process will be removed.

Type Code Extension

Not defined for SCSI-FCP and must be zero (0).

78 Fibre Channel Interface Manual, Rev. D

Table 42: PRLO Accept Payload

Bit

76543210

Byte

000000010

LS Command Code

100010000

Page Length

200000000

300010100

Payload Length

Reserved

6Orig Proc

Assc Valid

Reserved

Resp Proc

Assc Valid0Reserved0Reserved

Response Code

8 (MSB)

Originator Process Associator

11 (LSB)

12 (MSB)

Responder Process Associator

15 (LSB)

Reserved

Tab le

Field definitions (listed alphabetically)

number

LS Command Code (Link Services Command Code)

02h PRLO Accept Payload.

Page Length

Length of the service parameter page in bytes. For a SCSI FCP service page, the length is 10h.

Payload Length

Length of PRLO payload (in bytes). The count includes the LS Command Code. The drive supports one service parameter page per PRLO. The Payload Length must be 14h (20 decimal).

Process Associators

Not supported by the drive. The originator and responder process associator valid bits must be set to zero (0). The process associator fields are not checked by the drive.

Fibre Channel Interface Manual, Rev. D 79

Response Code

The result of the PRLO request. Codes 1, 4, and 7 are supported by the drive. 0 Reserved. 1 Request executed. 2 Reserved. 3 Reserved. 4 The Image Pair does not exist. 5 Reserved. 6 Reserved 7 The destination port is unable to process a multiple page PRLO request. The PRLO request may be retried as a sin-

gle page request.

80 Fibre Channel Interface Manual, Rev. D

9.2.6 Third Party Process Logout (TPRLO)

Third Party Process Logout (TPRLO) is sent by the initiator to a target to remove an existing SCSI login. This frees target resources for use by other initiators.

Table 43: TPRLO Payload

Bit

76543210

Byte

000100100

LS Command Code

100010000

Page Length

200000000

300010100

Payload Length

400001000

Type Code

500000000

Type Code Extension

6Third Party

Orig Proc

Assc Valid

Reserved

Third Party

Resp Proc

Assc Valid

Third Party

Orig N_Port

ID Validity

Global

Process

Logout

0 0 0 0

Reserved

8 (MSB)

Third Party Originator Process Associator

11 (LSB)

12 (MSB)

Third Party Responder Process Associator

15 (LSB)

16 Reserved

17 (MSB

18 Third Party Originator N_Port ID

19 (LSB)

Tab le

Field definitions (listed alphabetically)

number

Global Process Logout

00h Only the process login for the port identified in the N_Port ID field and type code is removed. 01h All process logins for the specified type code are removed.

LS Command Code (Link Services Command Code)

24h TPRLO Payload.

Fibre Channel Interface Manual, Rev. D 81

Page Length

The length must be in the range of 10h to 14h.

Payload Length

Length of TPRLO payload (in bytes). The count includes the LS Command Code. The drive supports one service parameter page per TPRLO. The Payload Length must be in the range of 14h to 18h.

Process Associators

Not supported by the drive. The originator and responder process associator valid bits must be set to zero (0). The process associator fields are not checked by the drive.

Third Party Originator N_Port ID

This field specifies the N_Port address associated with the process login to be removed.

Third Party Originator N_Port ID Validity

00h Third Party Originator N_Port ID field is not valid. 01h Third Party Originator N_Port ID field is valid.

Type Code

00h All FC-4 processes between the initiator and target are removed. The drive treats 08h and 00h the same. 08h The SCSI-FCP process will be removed.

Type Code Extension

Not defined for SCSI-FCP and must be zero (0).

82 Fibre Channel Interface Manual, Rev. D

Table 44: TPRLO Accept Payload

Bit

76543210

Byte

000000010

LS Command Code

100010000

Page Length

200000000

300010100

Payload Length

Reserved

6Third Party

Orig Proc

Assc Valid

Reserved

Third Party

Resp Proc

Assc Valid

Third Party

Orig N_Port

ID Validity

Global

Process

Logout

Reserved

8 (MSB)

Third Party Originator Process Associator

11 (LSB)

12 (MSB)

Third Party Responder Process Associator

15 (LSB)

16 Reserved

17 (MSB)

18 Third Party Originator N_Port ID

19 (LSB)

Tab le

Field definitions (listed alphabetically)

number

Global Process Logout

00h Only the process login for the port identified in the N_Port ID field and type code is removed. 01h All process logins for the specified type code are removed.

LS Command Code (Link Services Command Code)

02h TPRLO Accept Payload.

Page Length

Length of the service parameter page in bytes. For a SCSI FCP service page, the length is 10h.

Payload Length

Length of TPRLO payload (in bytes). The count includes the LS Command Code. The drive supports one service parameter page per TPRLO. The Payload Length must be 14h (20 decimal).

Fibre Channel Interface Manual, Rev. D 83

Process Associators

Not supported by the drive. The process associator fields are not checked by the drive.

Response Code

The result of the TPRLO request. Codes 1, 4, and 7 are supported by the drive. 0 Reserved. 1 Request executed. 2 Reserved. 3 Reserved. 4 The Image Pair does not exist. 5 Reserved. 6 Reserved 7 The destination port is unable to process a multiple page TPRLO request. The TPRLO request may be retried as a

single page request.

Third Party Originator N_Port ID

This field specifies the N_Port address associated with the process login to be removed.

Third Party Originator N_Port ID Validity

00h Third Party Originator N_Port ID field is not valid. 01h Third Party Originator N_Port ID field is valid.

84 Fibre Channel Interface Manual, Rev. D

9.2.7 Read Link Error Status Block (RLS)

Read Link Error Status Block (RLS) is sent by the initiator to request the drive to return the Fibre Channel link error information. The error information is contained in the Link Error Status Block (LESB) that is returned in the accept to the RLS. The drive maintains a separate LESB for each port.

Table 45: RLS Payload

Bit

76543210

Byte

000001111

100000000

200000000

300000000

LS Command Code

Reserved

Port Identifier6

Tab le

Field definitions (listed alphabetically)

number

LS Command Code (Link Services Command Code)

0Fh RLS Payload.

Port Identifier

This field is interpreted to determine whether to return the Link Error Status Block for port A or B. 0 Return the LESB for the port the RLS was received on. 1 Return the LESB for port A. 2 Return the LESB for port B. Others LS_RJT is returned with Invalid N_Port Identifier.

Fibre Channel Interface Manual, Rev. D 85

The RLS Accept includes the LS Command Code and the LESB. The LESB counts are not cleared by a reset. There is no protocol for clearing the counts. The requester must compare the current values with those read previously.

Table 46: RLS Accept Payload

Bit

76543210

Byte

000000010

100000000

200000000

300000000

LS Command Code

4 (MSB)

Link Failure Count

7 (LSB)

8 (MSB)

Loss of Synchronization Count

11 (LSB)

12 (MSB)

Loss of Signal Count

15 (LSB)

16 (MSB)

Primitive Sequence Protocol Error

19 (LSB)

20 (MSB)

Invalid Transmission Word

23 (LSB)

24 (MSB)

Invalid CRC Count

27 (LSB)

Tab le

Field definitions (listed alphabetically)

number

Invalid CRC Count

Number of frames discarded due to CRC errors while the drive is in an “open” state. Reference the specific drive product manual to determine if this field is supported.

86 Fibre Channel Interface Manual, Rev. D

Seagate Fibre Channel Interface, 77767496 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1.0 Publication overview

1.1 Acknowledgements

1.2 How to use this manual

1.3 General interface description

2.0 Introduction to Fibre Channel

2.1 General information

2.2 Channels vs. networks

2.3 The advantages of Fibre Channel

3.0 Fibre Channel standards

3.1 General information

3.1.1 Description of Fibre Channel levels

3.1.1.1 FC-0

3.1.1.2 FC-1

3.1.1.3 FC-1.5

3.1.1.4 FC-2

3.1.1.5 FC-3

3.1.1.6 FC-4

3.1.2 Relationship between the levels

3.1.3 Topology standards

3.1.4 FC Implementation Guide (FC-IG)

4.0 Introduction to topologies

4.1 Nodes

4.2 Ports

4.3 Links

4.4 Arbitrated loop topology

4.5 Topology and port login

4.6 Port bypass circuits

5.0 Data encoding (FC-1)

5.1 Encoding and decoding

5.2 Buffer-to-buffer data transfers

5.3 Data hierarchy

5.3.1 Transmission words

5.3.1.1 Data characters

5.3.1.2 Special characters

5.4 Ordered sets

5.4.1 Primitive signals

5.4.1.1 Primitive signals used as frame delimiters

5.4.1.2 Primitive signals custom made for arbitrated loop topologies

5.4.2 Primitive sequences

5.4.2.1 Primitive sequences custom made for Arbitrated Loop topologies

6.0 Framing protocol (FC-2)

6.1 Frames

6.1.1 Frame structure

6.1.1.1 Start-of-frame (SOF) delimiter

6.1.1.2 Frame header

6.1.1.3 Data field (payload)

6.1.1.4 CRC field

6.1.1.5 End-of-frame (EOF) delimiter

6.2 Frame sequences

6.3 Exchanges

6.4 Credit

7.0 Classes of service (FC-2)

7.1 Class 1

7.2 Class 2

7.3 Class 3

7.3.1 Class 3 flow control

7.4 Classes 4 and 5

8.0 FC Arbitrated Loop concepts

8.1 Arbitrated Loop physical address (AL_PA)

8.2 Loop initialization

8.2.1 Loop initialization state machine

8.2.2 Loop reinitialization

8.3 Accessing another L_Port

8.3.1 Access fairness

8.3.2 Access unfairness

8.3.3 Clock skew management

8.4 Loop ports

8.4.1 Maximum number of NL_Ports

8.4.2 Blocking switch emulation

8.4.3 Non-meshed environment

8.4.4 Assigned AL_PA values

9.0 Fibre Channel link services

9.1 Basic link services

9.1.1 Abort Sequence (ABTS)

9.1.2 Basic Accept (BA_ACC)

9.1.3 Basic Reject (BA_RJT)