Nokia 7210 SAS-K 2F4T6C User Manual

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide7210 SAS M, T, X, R6, R12, Mxp,
Sx MPLS Configuration Guide

7210 SERVICE ACCESS SWITCH

7210 SAS OS 7210 SAS-K 2F4T6C MPLS
Guide
Release 9.0.R8

3HE12059AAAETQZZA

Issue: 01

September 2017

Nokia — Proprietary and confidential.
Use pursuant to applicable agreements.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS

Guide

Nokia is a registered trademark of Nokia Corporation. Other products and company
names mentioned herein may be trademarks or trade names of their respective
owners.

The information presented is subject to change without notice. No responsibility is
assumed for inaccuracies contained herein.

© 2017 Nokia.

Contains proprietary/trade secret information which is the property of Nokia and must
not be made available to, or copied or used by anyone outside Nokia without its
written authorization. Not to be used or disclosed except in accordance with
applicable agreements.

2

3HE12059AAAETQZZA Issue: 01

TABLE OF CONTENTS

Preface

About This Guide 11

Audience 11
List of Technical Publications 12

Getting Started

In This Chapter 15

Nokia 7210 SAS-K 2F4T6C Router Configuration Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

MPLS and RSVP

In This Chapter 17

MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

MPLS Label Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Label Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Label Switching Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

LSP Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

MPLS Facility Bypass Method of MPLS Fast Re-Route (FRR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Manual Bypass LSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

RSVP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Using RSVP for MPLS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

RSVP Traffic Engineering Extensions for MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Reservation Styles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

RSVP Message Pacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

RSVP Overhead Refresh Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Configuring Implicit Null . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

MPLS Traffic Engineering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

TE Metric (IS-IS and OSPF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Advanced MPLS/RSVP Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

LSP Path Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Manual LSP Path Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Make-Before-Break (MBB) Procedures for LSP/Path Parameter Configuration Change . . . . . . . . . . .37

Shared Risk Link Groups. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Enabling Disjoint Backup Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Static Configurations of SRLG Memberships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

TE Graceful Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

MPLS/RSVP Configuration Process Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Configuration Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

Configuring MPLS and RSVP with CLI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

MPLS Configuration Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46

LSPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46

Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46

Router Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Choosing the Signaling Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Basic MPLS Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 3

Table of Contents

Common Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

Configuring MPLS Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50

Configuring Global MPLS Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50

Configuring an MPLS Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Configuring MPLS Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

Configuring an MPLS LSP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Configuring a Static LSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

Configuring Manual Bypass Tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Configuring RSVP Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

Configuring RSVP Message Pacing Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

Configuring Graceful Shutdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

MPLS Configuration Management Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

Modifying MPLS Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

Modifying an MPLS LSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61

Modifying MPLS Path Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62

Modifying MPLS Static LSP Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63

Deleting an MPLS Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64

RSVP Configuration Management Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65

Modifying RSVP Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65

Modifying RSVP Message Pacing Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66

Deleting an Interface from RSVP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66

MPLS/RSVP Command Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67

Command Hierarchies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67

MPLS Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68

MPLS LSP Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68

MPLS Path Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70

RSVP Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70

Show Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71

Tools Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72

Clear Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72

Debug Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73

Label Distribution Protocol

In This Chapter 153

Label Distribution Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154

LDP and MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154

LDP Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155

Subsystem Interrelationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156

Memory Manager and LDP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157

Label Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157

LDP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157

Logger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157

Service Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157

Execution Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158

Initialization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158

Session Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158

Label Exchange. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160

Page 4 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Table of Contents

Other Reasons for Label Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160

Cleanup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160

Configuring Implicit Null Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160

LDP Fast-Reroute for IS-IS and OSPF Prefixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .162

LDP FRR Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .162

LDP FRR Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164

IS-IS and OSPF Support for Loop-Free Alternate Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . .166

Multi-Area and Multi-Instance Extensions to LDP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .172

LDP Process Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173

Configuring LDP with CLI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175

LDP Configuration Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .176

Basic LDP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177

Common Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .178

Enabling LDP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .178

Configuring Graceful-Restart Helper Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179

Applying Export and Import Policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .180

Targeted Session Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .181

Interface Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182

Session Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183

LDP Signaling and Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184

LDP Configuration Management Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185

Disabling LDP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185

Modifying Targeted Session Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186

Modifying Interface Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187

LDP Command Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189

Command Hierarchies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189

LDP Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189

Show Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .190

Clear Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .191

Debug Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .192

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 5

Table of Contents

Page 6 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

LIST OF TABLES

Preface

Table 1: Configuration Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

MPLS and RSVP

Table 2: Packet/Label Field Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Label Distribution Protocol

Table 3: FEC Originate Output Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .221

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 7

List of Tables

Page 8 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

LIST OF FIGURES

MPLS and RSVP

Figure 1: Label Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Figure 2: Label Packet Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Figure 3: Bypass Tunnel Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Figure 4: FRR Node-Protection Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Figure 5: Establishing LSPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Figure 6: LSP Using RSVP Path Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Figure 7: Shared Risk Link Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Figure 8: MPLS and RSVP Configuration and Implementation Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Label Distribution Protocol

Figure 9: Subsystem Interrelationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156

Figure 10: Topology with Primary and LFA Routes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .167

Figure 11: Example Topology with Broadcast Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168

Figure 12: LDP Configuration and Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 9

List of Figures

Page 10 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

About This Guide

This guide describes the services and protocol support provided by the 7210 SAS-K2F4T6C
Series and presents examples to configure and implement MPLS, RSVP, and LDP protocols. This
document is organized into functional chapters and provides concepts and descriptions of the
implementation flow, as well as Command Line Interface (CLI) syntax and command usage.

NOTES:

• 7210 SAS-K5 stands for 7210 SAS-K 2F2T1C and 7210 SAS-K12 stands for 7210 SAS­K 2F4T6C platforms.

• 7210 SAS-E, 7210 SAS-D, and 7210 SAS-K 2F2T1C operate in access-uplink mode by
default. There is no need of an explicit user configuration needed for this.
7210 SAS-K 2F4T6C operates in Access-uplink mode and Network mode. There is no
explicit BOF configuration required for it.

Preface

Audience

This manual is intended for network administrators responsible for configuring the 7210 SAS
Series routers. It is assumed that the network administrators have an understanding of networking
principles and configurations. Protocols and concepts described in this manual include the
following:

• Multi protocol Label Switching (MPLS)

• Resource Reservation Protocol (RSVP)

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 11

Preface

List of Technical Publications

The 7210- D, 7210 SAS-E, 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C documentation set is
composed of the following books:

• 7210- D, 7210 SAS-E, 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C Basic System
Configuration Guide

This guide describes basic system configurations and operations.

• 7210- D, 7210 SAS-E, 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C System
Management Guide

This guide describes system security and access configurations as well as event
logging and accounting logs.

• 7210- D, 7210 SAS-E, 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C Interface
Configuration Guide

This guide describes card, Media Dependent Adapter (MDA), and port provisioning.

• 7210- D, 7210 SAS-E, 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C OS Router
Configuration Guide

This guide describes logical IP routing interfaces and associated attributes such as an
IP address, port, link aggregation group (LAG) as well as IP and MAC-based filtering.

• 7210- D and 7210 SAS-E OS Services Guide

This guide describes how to configure service parameters such as customer
information and user services.

• 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C OS Services Guide

This guide describes how to configure service parameters such as customer
information and user services.

• 7210- D, 7210 SAS-E, 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C OAM and
Diagnostic Guide

This guide describes how to configure features such as service mirroring and
Operations, Administration and Management (OAM) tools.

• 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C Quality of Service Guide

This guide describes how to configure Quality of Service (QoS) policy management.

• 7210 SAS-K 2F4T6C OS MPLS Guide

This guide describes how to configure Multiprotocol Label Switching (MPLS) and Label
Distribution Protocol (LDP).

• 7210 SAS-K 2F2T1C and 7210 SAS-K 2F4T6C OS Routing Protocols Guide
This guide provides an overview of routing concepts and provides configuration examples
for OSPF, IS-IS and route policies.

Page 12 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

GETTING STARTED

In This Chapter

This chapter provides process flow information to configure MPLS, RSVP, and LDP protocols.

Nokia 7210 SAS-K 2F4T6C Router Configuration Process

Table 1 lists the tasks necessary to configure MPLS applications functions.

This guide is presented in an overall logical configuration flow. Each section describes a software
area and provides CLI syntax and command usage to configure parameters for a functional area.

Table 1: Configuration Process

Area Task Chapter

Protocol configuration Configure MPLS protocols:

• MPLS MPLS on page 18

• RSVP RSVP on page 28

• LDP Label Distribution Protocol on page 153

Reference List of IEEE, IETF, and other

proprietary entities.

Standards and Protocol Support on page 239

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 15

Getting Started

Page 16 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

In This Chapter

This chapter provides information to configure MPLS and RSVP.

• MPLS on page 18

→ MPLS Label Stack on page 18

→ Label Switching Routers on page 21

→ Using RSVP for MPLS on page 29

→ Reservation Styles on page 31

MPLS and RSVP

• MPLS Traffic Engineering on page 34

• Advanced MPLS/RSVP Features on page 36

→ Shared Risk Link Groups on page 37

→ TE Graceful Shutdown on page 41

• MPLS/RSVP Configuration Process Overview on page 42

• MPLS/RSVP Configuration Process Overview on page 42

• Configuration Notes on page 43

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 17

MPLS Label Stack

MPLS

Multiprotocol Label Switching (MPLS) is a label switching technology that provides the ability to
set up connection-oriented paths over a connection less IP network. MPLS facilitates network
traffic flow and provides a mechanism to engineer network traffic patterns independently from
routing tables. MPLS sets up a specific path for a sequence of packets. The packets are identified
by a label inserted into each packet. MPLS is not enabled by default and must be explicitly
enabled.

MPLS is independent of any routing protocol but is considered multiprotocol because it works
with the Internet Protocol (IP) and frame relay network protocols.

The 7210 SAS routers enable service providers to deliver virtual private networks (VPNs) and
Internet access using MPLS tunnels, with Ethernet interfaces.

On the 7210 SAS-K 2F4T6C, is designed to fit into a network using the principles of seamless
MPLS architecture which enable access devices with smaller IP routing scale (both control-plane
RIB and FIB) and smaller MPLS scale (both control-plane and FIB) to be used to deploy MPLS
end-to-end and benefit from the traffic engineering and resiliency mechanism that MPLS provides.
The MPLS features and capabilities available on 7210 SAS-K2F4T6C is described in this user
guide.

MPLS Label Stack

MPLS requires a set of procedures to enhance network layer packets with label stacks which
thereby turns them into labeled packets. Routers that support MPLS are known as Label Switching
Routers (LSRs). In order to transmit a labeled packet on a particular data link, an LSR must
support the encoding technique which, when given a label stack and a network layer packet,
produces a labeled packet.

In MPLS, packets can carry not just one label, but a set of labels in a stack. An LSR can swap the
label at the top of the stack, pop the stack, or swap the label and push one or more labels into the
stack. The processing of a labeled packet is completely independent of the level of hierarchy. The
processing is always based on the top label, without regard for the possibility that some number of
other labels may have been above it in the past, or that some number of other labels may be below
it at present.

As described in RFC 3032, MPLS Label Stack Encoding, the label stack is represented as a
sequence of label stack entries. Each label stack entry is represented by 4 octets. Figure 1 displays
the label placement in a packet.

Page 18 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

Figure 1: Label Placement

Table 2: Packet/Label Field Description

Field Description

Label This 20-bit field carries the actual value (unstructured) of the label.

Exp This 3-bit field is reserved for experimental use. It is currently used for Class of

Service (CoS).

S This bit is set to 1 for the last entry (bottom) in the label stack, and 0 for all

other label stack entries.

TTL This 8-bit field is used to encode a TTL value.

A stack can carry several labels, organized in a last in/first out order. The top of the label stack
appears first in the packet and the bottom of the stack appears last (Figure 2).

Layer 2 Header Top Label … Bottom Label Data Packet

OSSG014

Figure 2: Label Packet Placement

The label value at the top of the stack is looked up when a labeled packet is received. A successful
lookup reveals:

• The next hop where the packet is to be forwarded.

• The operation to be performed on the label stack before forwarding.

In addition, the lookup may reveal outgoing data link encapsulation and other information needed
to properly forward the packet.

An empty label stack can be thought of as an unlabeled packet. An empty label stack has zero (0)
depth. The label at the bottom of the stack is referred to as the Level 1 label. The label above it (if
it exists) is the Level 2 label, and so on. The label at the top of the stack is referred to as the Level
m label.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 19

MPLS Label Stack

Labeled packet processing is independent of the level of hierarchy. Processing is always based on
the top label in the stack which includes information about the operations to perform on the
packet's label stack.

Label Values

Packets travelling along an LSP (see Label Switching Routers on page 21) are identified by its
label, the 20-bit, unsigned integer. The range is 0 through 1,048,575. Label values 0-15 are
reserved and are defined below as follows:

• A value of 0 represents the IPv4 Explicit NULL Label. This Label value is legal only at
the bottom of the Label stack. It indicates that the Label stack must be popped, and the
packet forwarding must be based on the IPv4 header.

• A value of 1 represents the router alert Label. This Label value is legal anywhere in the
Label stack except at the bottom. When a received packet contains this Label value at the
top of the Label stack, it is delivered to a local software module for processing. The actual
packet forwarding is determined by the Label beneath it in the stack. However, if the
packet is further forwarded, the router alert Label should be pushed back onto the Label
stack before forwarding. The use of this Label is analogous to the use of the router alert
option in IP packets. Since this Label cannot occur at the bottom of the stack, it is not
associated with a particular network layer protocol.

• A value of 3 represents the Implicit NULL Label. This is a Label that a Label Switching
Router (LSR) can assign and distribute, but which never actually appears in the
encapsulation. When an LSR would otherwise replace the Label at the top of the stack
with a new Label, but the new Label is Implicit NULL, the LSR pops the stack instead of
doing the replacement. Although this value may never appear in the encapsulation, it
needs to be specified in the RSVP, so a value is reserved.

• Values 4-15 are reserved for future use.

7210 SAS devices uses labels for MPLS, RSVP-TE, and LDP, as well as packet-based services
such as VLL and VPLS.

Label values 16 through 1,048,575 are defined as follows:

• Label values 16 through 31 are reserved for future use.

• Label values 32 through 1,023 are available for static assignment.

• Label values 1,024 through 2,047 are reserved for future use.

• Label values 2,048 through 18,431 are statically assigned for services.

• Label values 32768through 131,071 are dynamically assigned for both MPLS and
services.

• Label values 131,072 through 1,048,575 are reserved for future use.

Page 20 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Label Switching Routers

LSRs perform the label switching function. LSRs perform different functions based on it’s
position in an LSP. Routers in an LSP do one of the following:

• The router at the beginning of an LSP is the ingress label edge router (ILER). The ingress
router can encapsulate packets with an MPLS header and forward it to the next router
along the path. An LSP can only have one ingress router.

• A Label Switching Router (LSR) can be any intermediate router in the LSP between the
ingress and egress routers. An LSR swaps the incoming label with the outgoing MPLS
label and forwards the MPLS packets it receives to the next router in the MPLS path
(LSP). An LSP can have 0-253 transit routers.

• The router at the end of an LSP is the egress label edge router (ELER). The egress router
strips the MPLS encapsulation which changes it from an MPLS packet to a data packet,
and then forwards the packet to its final destination using information in the forwarding
table. Each LSP can have only one egress router. The ingress and egress routers in an LSP
cannot be the same router.

MPLS and RSVP

LSP Types

A router in your network can act as an ingress, egress, or transit router for one or more LSPs,
depending on your network design.

An LSP is confined to one IGP area for LSPs using constrained-path. They cannot cross an
autonomous system (AS) boundary.

Static LSPs can cross AS boundaries. The intermediate hops are manually configured so the LSP
has no dependence on the IGP topology or a local forwarding table.

The following are LSP types:

• Static LSPs — A static LSP specifies a static path. All routers that the LSP traverses must
be configured manually with labels. No signaling such as RSVP or LDP is required.

• Signaled LSP — LSPs are set up using a signaling protocol such as RSVP-TE or LDP.
The signaling protocol allows labels to be assigned from an ingress router to the egress
router. Signaling is triggered by the ingress routers. Configuration is required only on the
ingress router and is not required on intermediate routers. Signaling also facilitates path
selection.

There are two signaled LSP types:

→ Explicit-path LSPs — MPLS uses RSVP-TE to set up explicit path LSPs. The hops

within the LSP are configured manually. The intermediate hops must be configured as
either strict or loose meaning that the LSP must take either a direct path from the

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 21

Label Switching Routers

→ Constrained-path LSPs — The intermediate hops of the LSP are dynamically

If fast reroute is configured, the ingress router signals the routers downstream. Each downstream
router sets up a detour for the LSP. If a downstream router does not support fast reroute, the
request is ignored and the router continues to support the LSP. This can cause some of the detours
to fail, but otherwise the LSP is not impacted.

No bandwidth is reserved for the rerouted path. If the user enters a value in the bandwidth
parameter in the config>router>mpls>lsp>fast-reroute context, it will have no effect on the LSP
backup LSP establishment.

previous hop router to this router (strict) or can traverse through other routers (loose).
You can control how the path is set up. They are similar to static LSPs but require less
configuration. See RSVP on page 28.

assigned. A constrained path LSP relies on the Constrained Shortest Path First (CSPF)
routing algorithm to find a path which satisfies the constraints for the LSP. In turn,
CSPF relies on the topology database provided by the extended IGP such as OSPF or
IS-IS.

Once the path is found by CSPF, RSVP uses the path to request the LSP set up. CSPF
calculates the shortest path based on the constraints provided such as bandwidth, class
of service, and specified hops.

Hop-limit parameters specifies the maximum number of hops that an LSP can traverse, including
the ingress and egress routers. An LSP is not set up if the hop limit is exceeded. The hop count is
set to 255 by default for the primary and secondary paths. It is set to 16 by default for a bypass or
detour LSP path.

7210 SAS-K2F4T6C supports the following functionality:

• MPLS LSR functionality.

• MPLS LER functionality with the following support:

→ Static LSPs.

→ RSVP signaled LSPs with support for both explicit-path LSP and constrained-path

LSPs.

→ LDP signaled LSPs are not supported.

• Support for FRR one-to-one and FRR facility bypass for RSVP signaled LSPs.

Page 22 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

MPLS Facility Bypass Method of MPLS Fast Re-Route (FRR)

The MPLS facility bypass method of MPLS Fast Re-Route (FRR) functionality is extended to the
ingress node.

The behavior of an LSP at an ingress LER with both fast reroute and a standby LSP path
configured is as follows:

• When a down stream detour becomes active at a point of local repair (PLR):

The ingress LER switches to the standby LSP path. If the primary LSP path is repaired
subsequently at the PLR, the LSP will switch back to the primary path. If the standby goes
down, the LSP is switched back to the primary, even though it is still on the detour at the
PLR. If the primary goes down at the ingress while the LSP is on the standby, the detour at
the ingress is cleaned up and for one-to-one detours a “path tear” is sent for the detour
path. In other words, the detour at the ingress does not protect the standby. If and when the
primary LSP is again successfully re-signaled, the ingress detour state machine will be
restarted.

• When the primary fails at the ingress:

The LSP switches to the detour path. If a standby is available then LSP would switch to
standby on expiration of hold-timer. If hold-timer is disabled then switchover to standby
would happen immediately. On successful global revert of primary path, the LSP would
switch back to the primary path.

• Admin groups are not taken into account when creating detours for LSPs.

Manual Bypass LSP

The 7210 SAS supports Manual bypass tunnels, on implementation of the Manual bypass feature a
LSP can be pre-configured from a PLR which is used exclusively for bypass protection. If a path
message for a new LSP requests for bypass protection, the node checks if a manual bypass tunnel
satisfying the path constraints exists. If a tunnel is found, it is selected. If no such tunnel exists by
default, the 7210 SAS dynamically signals a bypass LSP.

Users can disable the dynamic bypass creation on a per node basis using the CLI.

A maximum of 1000 associations of primary LSP paths can be made with a single manual bypass
at the PLR node. If dynamic bypass creation is disabled on the node, it is recommended to
configure additional manual bypass LSPs to handle the required number of associations.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 23

Label Switching Routers

ABEC

F

D

PLR Bypass LSP Selection Rules

Figure 3: Bypass Tunnel Nodes

The PLR uses the following rules to select a bypass LSP among multiple manual and dynamic
bypass LSP’s at the time of establishment of the primary LSP path or when searching for a bypass
for a protected LSP which does not have an association with a bypass tunnel:

1. The MPLS/RSVP task in the PLR node checks if an existing manual bypass satisfies the
constraints. If the path message for the primary LSP path indicated node protection
desired, which is the default LSP FRR setting at the head end node, MPLS/RSVP task
searches for a node-protect’ bypass LSP. If the path message for the primary LSP path
indicated link protection desired, then it searches for a link-protect bypass LSP.

2. If multiple manual bypass LSPs satisfying the path constraints exist, it will prefer a
manual-bypass terminating closer to the PLR over a manual bypass terminating further
away. If multiple manual bypass LSPs satisfying the path constraints terminate on the
same downstream node, it selects one with the lowest IGP path cost or if in a tie, picks the
first one available.

3. If none satisfies the constraints and dynamic bypass tunnels have not been disabled on
PLR node, then the MPLS/RSVP task in the PLR will check if any of the already
established dynamic bypasses of the requested type satisfies the constraints.

4. If none do, then the MPLS/RSVP task will ask CSPF to check if a new dynamic bypass of
the requested type, node-protect or link-protect, can be established.

5. If the path message for the primary LSP path indicated node protection desired, and no
manual bypass was found after Step 1, and/or no dynamic bypass LSP was found after 3
attempts of performing Step 3, the MPLS/RSVP task will repeat Steps 1-3 looking for a
suitable link-protect bypass LSP. If none are found, the primary LSP will have no
protection and the PLR node must clear the “local protection available” flag in the IPv4
address sub-object of the RRO starting in the next Resv refresh message it sends upstream.

6. If the path message for the primary LSP path indicated link protection desired, and no
manual bypass was found after step 1, and/or no dynamic bypass LSP was found after
performing Step 3, the primary LSP will have no protection and the PLR node must clear
the “local protection available” flag in the IPv4 address sub-object of the RRO starting in
the next RESV refresh message it sends upstream. The PLR will not search for a node­protect’ bypass LSP in this case.

Page 24 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

7. If the PLR node successfully makes an association, it must set the “local protection
available” flag in the IPv4 address sub-object of the RRO starting in the next RESV
refresh message it sends upstream.

8. For all primary LSP that requested FRR protection but are not currently associated with a
bypass tunnel, the PLR node on reception of RESV refresh on the primary LSP path
repeats Steps 1-7.

If the user disables dynamic-bypass tunnels on a node while dynamic bypass tunnels were
activated and were passing traffic, traffic loss will occur on the protected LSP. Furthermore, if no
manual bypass exist that satisfy the constraints of the protected LSP, the LSP will remain without
protection.

If the user configures a bypass tunnel on node B and dynamic bypass tunnels have been disabled,
LSPs which have been previously signaled and which were not associated with any manual bypass
tunnel, for example, none existed, will be associated with the manual bypass tunnel if suitable.
The node checks for the availability of a suitable bypass tunnel for each of the outstanding LSPs
every time a RESV message is received for these LSPs.

If the user configures a bypass tunnel on node B and dynamic bypass tunnels have not been
disabled, LSPs which have been previously signaled over dynamic bypass tunnels will not
automatically be switched into the manual bypass tunnel even if the manual bypass is a more
optimized path. The user will have to perform a make before break at the head end of these LSPs.

If the manual bypass goes into the down state in node B and dynamic bypass tunnels have been
disabled, node B (PLR) will clear the “protection available” flag in the RRO IPv4 sub-object in
the next RESV refresh message for each affected LSP. It will then try to associate each of these
LSPs with one of the manual bypass tunnels that are still up. If it finds one, it will make the
association and set again the “protection available” flag in the next RESV refresh message for
each of these LSPs. If it could not find one, it will keep checking for one every time a RESV
message is received for each of the remaining LSPs. When the manual bypass tunnel is back UP,
the LSPs which did not find a match will be associated back to this tunnel and the protection
available flag is set starting in the next RESV refresh message.

If the manual bypass goes into the down state in node B and dynamic bypass tunnels have not
been disabled, node B will automatically signal a dynamic bypass to protect the LSPs if a suitable
one does not exist. Similarly, if an LSP is signaled while the manual bypass is in the down state,
the node will only signal a dynamic bypass tunnel if the user has not disabled dynamic tunnels.
When the manual bypass tunnel is back into the UP state, the node will not switch the protected
LSPs from the dynamic bypass tunnel into the manual bypass tunnel.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 25

Label Switching Routers

P_5

PE_1

PE_3

P_1

P_3

P_2

P_4

PE_2

PE_4

FRR Node-Protection (Facility)

The MPLS Fast Re-Route (FRR) functionality enables PLRs to be aware of the missing node
protection and lets them regularly probe for a node-bypass. The following describes an LSP
scenario:

Figure 4: FRR Node-Protection Example

Where:

• LSP 1: between PE_1 to PE_2, with CSPF, FRR facility node-protect enabled.

• P_1 protects P_2 with bypass-nodes P_1 -P_3 - P_4 - PE_4 -PE_2.

• If P_4 fails, P_1 tries to establish the bypass-node three times.

• When the bypass-node creation fails, P_1 will protect link P_1-P_2.

• P_1 protects the link to P_2 through P_1 - P_5 - P_2.

• P_4 returns online.

Since LSP 1 had requested node protection, but due to lack of any available path, it could only
obtain link protection. Therefore, every 60 seconds the PLR for LSP 1 will search for a new path
that might be able to provide node protection. Once P_4 is back online and such a path is available,
A new bypass tunnel will be signaled and LSP 1 will get associated with this new bypass tunnel.

Uniform FRR Failover Time

The failover time during FRR consists of a detection time and a switchover time. The detection
time corresponds to the time it takes for the RSVP control plane protocol to detect that a network
IP interface is down or that a neighbor/next-hop over a network IP interface is down. The control
plane can be informed of an interface down event when event is due to a failure in a lower layer
such in the physical layer. The control plane can also detect the failure of a neighbor/next-hop on
its own by running a protocol such as Hello, Keep-Alive, or BFD.

Page 26 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

The switchover time is measured from the time the control plane detected the failure of the
interface or neighbor/next-hop to the time the IOM completed the reprogramming of all the
impacted ILM or service records in the data path. This includes the time it takes for the control
plane to send a down notification to all IOMs to request a switch to the backup NHLFE.

Uniform Fast-Reroute (FRR) failover enables the switchover of MPLS and service packets from
the outgoing interface of the primary LSP path to that of the FRR backup LSP within the same
amount of time regardless of the number of LSPs or service records. This is achieved by updating
Ingress Label Map (ILM) records and service records to point to the backup Next-Hop Label to
Forwarding Entry (NHLFE) in a single operation.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 27

Label Switching Routers

OSSG015

ILER

1

LSR

2

LSR

3

ELER

4

PATH

RESV

LSP

PATH PATH

RESV RESV

RSVP

The Resource Reservation Protocol (RSVP) is a network control protocol used by a host to request
specific qualities of service from the network for particular application data streams or flows.

RSVP is also used by routers to deliver quality of service (QoS) requests to all nodes along the
path(s) of the flows and to establish and maintain state to provide the requested service. RSVP
requests generally result in resources reserved in each node along the data path. MPLS leverages
this RSVP mechanism to set up traffic engineered LSPs. RSVP is not enabled by default and must
be explicitly enabled.

RSVP requests resources for simplex flows. It requests resources only in one direction
(unidirectional). Therefore, RSVP treats a sender as logically distinct from a receiver, although the
same application process may act as both a sender and a receiver at the same time. Duplex flows
require two LSPs, to carry traffic in each direction.

RSVP is not a routing protocol. RSVP operates with unicast and multicast routing protocols.
Routing protocols determine where packets are forwarded. RSVP consults local routing tables to
relay RSVP messages.

RSVP uses two message types to set up LSPs, PATH and RESV. Figure 5 depicts the process to
establish an LSP.

• The sender (the ingress LER (ILER)), sends PATH messages toward the receiver, (the
egress LER (ELER)) to indicate the FEC for which label bindings are desired. PATH
messages are used to signal and request label bindings required to establish the LSP from
ingress to egress. Each router along the path observes the traffic type.

PATH messages facilitate the routers along the path to make the necessary bandwidth
reservations and distribute the label binding to the router upstream.

• The ELER sends label binding information in the RESV messages in response to PATH
messages received.

• The LSP is considered operational when the ILER receives the label binding information.

Figure 5: Establishing LSPs

Page 28 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

SFO

10.10.10.1

SFO

10.10.10.1

PATH:30.30.30.1

1

RESV:10.10.10.1 RESV:10.10.10.1 RESV:10.10.10.1 RESV:10.10.10.1

label

100|push

1342

100 200 300

100|200|swap

PATH:30.30.30.1

label

200|300|swap

PATH:30.30.30.1

3

label

42

label

300|pop

NYC

30.30.30.1

NYC

30.30.30.1

OSSG016

Figure 6: LSP Using RSVP Path Set Up

Figure 6 displays an example of an LSP path set up using RSVP. The ingress label edge router

(ILER 1) transmits an RSVP path message (path: 30.30.30.1) downstream to the egress label edge
router (ELER 4). The path message contains a label request object that requests intermediate LSRs
and the ELER to provide a label binding for this path.

In addition to the label request object, an RSVP PATH message can also contain a number of
optional objects:

• Explicit route object (ERO) — When the ERO is present, the RSVP path message is
forced to follow the path specified by the ERO (independent of the IGP shortest path).

• Record route object (RRO) — Allows the ILER to receive a listing of the LSRs that the
LSP tunnel actually traverses.

• A session attribute object controls the path set up priority, holding priority, and local­rerouting features.

Upon receiving a path message containing a label request object, the ELER transmits a RESV
message that contains a label object. The label object contains the label binding that the
downstream LSR communicates to its upstream neighbor. The RESV message is sent upstream
towards the ILER, in a direction opposite to that followed by the path message. Each LSR that
processes the RESV message carrying a label object uses the received label for outgoing traffic
associated with the specific LSP. When the RESV message arrives at the ingress LSR, the LSP is
established.

Using RSVP for MPLS

Hosts and routers that support both MPLS and RSVP can associate labels with RSVP flows. When
MPLS and RSVP are combined, the definition of a flow can be made more flexible. Once an LSP
is established, the traffic through the path is defined by the label applied at the ingress node of the
LSP. The mapping of label to traffic can be accomplished using a variety of criteria. The set of

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 29

Using RSVP for MPLS

packets that are assigned the same label value by a specific node are considered to belong to the
same FEC which defines the RSVP flow.

For use with MPLS, RSVP already has the resource reservation component built-in which makes it
ideal to reserve resources for LSPs.

RSVP Traffic Engineering Extensions for MPLS

RSVP has been extended for MPLS to support automatic signaling of LSPs. To enhance the
scalability, latency, and reliability of RSVP signaling, several extensions have been defined.
Refresh messages are still transmitted but the volume of traffic, the amount of CPU utilization, and
response latency are reduced while reliability is supported. None of these extensions result in
backward compatibility problems with traditional RSVP implementations.

• Hello Protocol on page 30

• MD5 Authentication of RSVP Interface on page 30

Hello Protocol

The Hello protocol detects the loss of a neighbor node or the reset of a neighbor’s RSVP state
information. In standard RSVP, neighbor monitoring occurs as part of RSVP’s soft-state model.
The reservation state is maintained as cached information that is first installed and then
periodically refreshed by the ingress and egress LSRs. If the state is not refreshed within a
specified time interval, the LSR discards the state because it assumes that either the neighbor node
has been lost or its RSVP state information has been reset.

The Hello protocol extension is composed of a hello message, a hello request object and a hello
ACK object. Hello processing between two neighbors supports independent selection of failure
detection intervals. Each neighbor can automatically issue hello request objects. Each hello
request object is answered by a hello ACK object.

MD5 Authentication of RSVP Interface

When enabled on an RSVP interface, authentication of RSVP messages operates in both directions
of the interface.

A node maintains a security association with its neighbors for each authentication key. The
following items are stored in the context of this security association:

• The HMAC-MD5 authentication algorithm.

• Key used with the authentication algorithm.

Page 30 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

• Lifetime of the key. A key is user-generated key using a third party software/hardware and
enters the value as static string into CLI configuration of the RSVP interface. The key will
continue to be valid until it is removed from that RSVP interface.

• Source Address of the sending system.

• Latest sending sequence number used with this key identifier.

The RSVP sender transmits an authenticating digest of the RSVP message, computed using the
shared authentication key and a keyed-hash algorithm. The message digest is included in an
Integrity object which also contains a Flags field, a Key Identifier field, and a Sequence Number
field. The RSVP sender complies to the procedures for RSVP message generation in RFC 2747,
RSVP Cryptographic Authentication.

An RSVP receiver uses the key together with the authentication algorithm to process received
RSVP messages.

When a PLR node switches the path of the LSP to a bypass LSP, it does not send the Integrity
object in the RSVP messages over the bypass tunnel. If an integrity object is received from the MP
node, then the message is discarded since there is no security association with the next-next-hop
MP node.

The MD5 implementation does not support the authentication challenge procedures in RFC 2747.

Reservation Styles

LSPs can be signaled with explicit reservation styles. A reservation style is a set of control options
that specify a number of supported parameters. The style information is part of the LSP
configuration. SR OS supports two reservation styles:

Note that if FRR option is enabled for the LSP and selects the facility FRR method at the head-end
node, only the SE reservation style is allowed. Furthermore, if a PLR node receives a path
message with fast-reroute requested with facility method and the FF reservation style, it will reject
the reservation. The one-to-one detour method supports both FF and SE styles.

RSVP Message Pacing

When a flood of signaling messages arrive because of topology changes in the network, signaling
messages can be dropped which results in longer set up times for LSPs. RSVP message pacing
controls the transmission rate for RSVP messages, allowing the messages to be sent in timed
intervals. Pacing reduces the number of dropped messages that can occur from bursts of signaling
messages in large networks.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 31

RSVP Overhead Refresh Reduction

RSVP Overhead Refresh Reduction

The RSVP refresh reduction feature consists of the following capabilities implemented in
accordance to RFC 2961, RSVP Refresh Overhead Reduction Extensions:

• RSVP message bundling — This capability is intended to reduce overall message
handling load. The supports receipt and processing of bundled message only, but no
transmission of bundled messages.

• Reliable message delivery: — This capability consists of sending a message-id and
returning a message-ack for each RSVP message. It can be used to detect message loss
and support reliable RSVP message delivery on a per hop basis. It also helps reduce the
refresh rate since the delivery becomes more reliable.

• Summary refresh — This capability consists of refreshing multiples states with a single
message-id list and sending negative ACKs (NACKs) for a message_id which could not
be matched. The summary refresh capability reduce the amount of messaging exchanged
and the corresponding message processing between peers. It does not however reduce the
amount of soft state to be stored in the node.

These capabilities can be enabled on a per-RSVP-interface basis are referred to collectively as
“refresh overhead reduction extensions”. When the refresh-reduction is enabled on a RSVP
interface, the node indicates this to its peer by setting a refresh-reduction- capable bit in the flags
field of the common RSVP header. If both peers of an RSVP interface set this bit, all the above
three capabilities can be used. Furthermore, the node monitors the settings of this bit in received
RSVP messages from the peer on the interface. As soon as this bit is cleared, the node stops
sending summary refresh messages. If a peer did not set the “refresh-reduction-capable” bit, a
node does not attempt to send summary refresh messages.

Configuring Implicit Null

The implicit null label option allows a router egress LER to receive MPLS packets from the
previous hop without the outer LSP label. The operation of the previous hop is referred to as
penultimate hop popping (PHP).

This option is signaled by the egress LER to the previous hop during the LSP signaling with RSVP
control protocol. In addition, the egress LER can be configured to receive MPLS packet with the
implicit null label on a static LSP.

The user can configure your router to signal the implicit null label value over all RSVP interfaces
and for all RSVP LSPs for which this node is the egress LER using the implicit-null-label
command in the config>router>rsvp context. The user must shutdown RSVP before being able to
change the implicit null configuration option.

Page 32 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

All LSPs for which this node is the egress LER and for which the path message is received from
the previous hop node over this RSVP interface will signal the implicit null label. This means that
if the egress LER is also the merge-point (MP) node, then the incoming interface for the path
refresh message over the bypass dictates if the packet will use the implicit null label or not. The
same for a 1-to-1 detour LSP.

The implicit null label option is also supported on a static label LSP. The following commands can
be used to cause the node to push or to swap to an implicit null label on the MPLS packet:

config>router>mpls>static-lsp>push implicit-null-label nexthop ip-address
config>router>mpls>if>label-map>swap implicit-null-label nexthop ip-address

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 33

TE Metric (IS-IS and OSPF)

MPLS Traffic Engineering

Without traffic engineering, routers route traffic according to the SPF algorithm, disregarding
congestion or packet types.

With traffic engineering, network traffic is routed efficiently to maximize throughput and
minimize delay. Traffic engineering facilitates traffic flows to be mapped to the destination
through a different (less congested) path other than the one selected by the SPF algorithm.

MPLS directs a flow of IP packets along a label switched path (LSP). LSPs are simplex, meaning
that the traffic flows in one direction (unidirectional) from an ingress router to an egress router.
Two LSPs are required for duplex traffic. Each LSP carries traffic in a specific direction,
forwarding packets from one router to the next across the MPLS domain.

When an ingress router receives a packet, it adds an MPLS header to the packet and forwards it to
the next hop in the LSP. The labeled packet is forwarded along the LSP path until it reaches the
destination point. The MPLS header is removed and the packet is forwarded based on Layer 3
information such as the IP destination address. The physical path of the LSP is not constrained to
the shortest path that the IGP would choose to reach the destination IP address.

TE Metric (IS-IS and OSPF)

When the use of the TE metric is selected for an LSP, the shortest path computation after the TE
constraints are applied will select an LSP path based on the TE metric instead of the IGP metric.
The user configures the TE metric under the MPLS interface. Both the TE and IGP metrics are
advertised by OSPF and IS-IS for each link in the network. The TE metric is part of the traffic
engineering extensions of both IGP protocols.

A typical application of the TE metric is to allow CSPF to represent a dual TE topology for the
purpose of computing LSP paths.

An LSP dedicated for real-time and delay sensitive user and control traffic has its path computed
by CSPF using the TE metric. The user configures the TE metric to represent the delay figure, or a
combined delay/jitter figure, of the link. In this case, the shortest path satisfying the constraints of
the LSP path will effectively represent the shortest delay path.

An LSP dedicated for non delay sensitive user and control traffic has its path computed by CSPF
using the IGP metric. The IGP metric could represent the link bandwidth or some other figure as
required.

When the use of the TE metric is enabled for an LSP, CSPF will first prune all links in the network
topology that do not meet the constraints specified for the LSP path. These constraints include
bandwidth, admin-groups, and hop limit. CSPF will then run an SPF on the remaining links. The

Page 34 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

shortest path among the all SPF paths will be selected based on the TE metric instead of the IGP
metric used by default. The TE metric is only used in CSPF computations for MPLS paths and not
in the regular SPF computation for IP reachability.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 35

LSP Path Change

Advanced MPLS/RSVP Features

• LSP Path Change on page 36

• Manual LSP Path Switch on page 37

• Shared Risk Link Groups on page 37

• TE Graceful Shutdown on page 41

LSP Path Change

The tools perform router mpls update-path {lsp lsp-name path current-pathname
new-path new-path-name} command instructs MPLS to replace the path of the primary or second-

ary LSP.
The primary or secondary LSP path is indirectly identified via the current-path-name value. In ex­isting implementation, the same path name cannot be used more than once in a given LSP name.
This command is also supported on an SNMP interface.
This command applies to both CSPF LSP and to a non-CSPF LSP. However, it will only be honored
when the specified current-path-name has the adaptive option enabled. The adaptive option can be
enabled the LSP level or at the path level.
The new path must be first configured in CLI or provided via SNMP. The configure router mpls
path path-name CLI command is used to enter the path.
The command fails if any of the following conditions are satisfied:

• The specified current-path-name of this LSP does not have the adaptive option enabled.

• The specified new-path-name value does not correspond to a previously defined path.

• The specified new-path-name value exists but is being used by any path of the same LSP,
including this one.

When the command is executed, MPLS performs the following procedures:

• MPLS performs a single MBB attempt to move the LSP path to the new path.

• If the MBB is successful, MPLS updates the new path.

→ MPLS writes the corresponding NHLFE in the data path if this path is the current

backup path for the primary.

→ If the current path is the active LSP path, it will update the path, write the new

NHLFE in the data path, which will cause traffic to switch to the new path.

• If the MBB is not successful, the path retains it current value.

• The update-path MBB has the same priority as the manual re-signal MBB.

Page 36 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Manual LSP Path Switch

This feature provides a new command to move the path of an LSP from a standby secondary to an­other standby secondary.
The base version of the command allows the path of the LSP to move from a standby (or an active
secondary) to another standby of the same priority. If a new standby path with a higher priority or
a primary path comes up after the tools perform command is executed, the path re-evaluation com­mand runs and the path is moved to the path specified by the outcome of the re-evaluation.
The CLI command for the base version is:
tools perform router mpls switch-path lsp lsp-name path path-name
The sticky version of the command can be used to move from a standby path to any other standby
path regardless of priority. The LSP remains in the specified path until this path goes down or the
user performs the no form of the tools perform command.
The CLI commands for the sticky version are:

tools perform router mpls force-switch-path lsp lsp-name path path-name
tools perform router mpls no force-switch-path lsp lsp-name

MPLS and RSVP

Make-Before-Break (MBB) Procedures for LSP/Path Parameter Configuration Change

When an LSP is switched from an existing working path to a new path, it is desirable to perform
this in a hitless fashion. The Make-Before-Break (MBB) procedure consist of first signaling the
new path when it is up, and having the ingress LER move the traffic to the new path. Only then the
ingress LER tears down the original path.

MBB procedure is raised during the following operations:

1. Timer based and manual re-signal of an LSP path.

2. Fast-ReRoute (FRR) global revertive procedures.

3. Traffic-Engineering (TE) graceful shutdown procedures.

Shared Risk Link Groups

Shared Risk Link Groups (SRLGs) is a feature that allows the user to establish a backup secondary
LSP path or a FRR LSP path which is disjoint from the path of the primary LSP. Links that are
members of the same SRLG represent resources sharing the same risk, for example, fiber links
sharing the same conduit or multiple wavelengths sharing the same fiber.

When the SRLG option is enabled on a secondary path, CSPF includes the SRLG constraint in the
computation of the secondary LSP path. This requires that the primary LSP already be established

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 37

Shared Risk Link Groups

and up since the head-end LER needs the most current ERO computed by CSPF for the primary
path. CSPF would return the list of SRLG groups along with the ERO during primary path CSPF
computation. At a subsequent establishment of a secondary path with the SRLG constraint, the
MPLS/RSVP task will query again CSPF providing the list of SLRG group numbers to be
avoided. CSPF prunes all links with interfaces which belong to the same SRLGs as the interfaces
included in the ERO of the primary path. If CSPF finds a path, the secondary is setup. If not,
MPLS/RSVP will keep retrying the requests to CSPF.

When the SRLG option is enabled on FRR, CSPF includes the SRLG constraint in the
computation of a FRR detour or bypass for protecting the primary LSP path. CSPF prunes all links
with interfaces which belong to the same SRLG as the interface which is being protected, for
example, the outgoing interface at the PLR the primary path is using. If one or more paths are
found, the MPLS/RSVP task will select one based on best cost and will signal the bypass/detour. If
not and the user included the strict option, the bypass/detour is not setup and the MPLS/RSVP task
will keep retrying the request to CSPF. Otherwise, if a path exists which meets the other TE
constraints, other than the SRLG one, the bypass/detour is setup.

A bypass or a detour LSP path is not guaranteed to be SRLG disjoint from the primary path. This
is because only the SRLG constraint of the outgoing interface at the PLR that the primary path is
using is avoided.

Enabling Disjoint Backup Paths

A typical application of the SRLG feature is to provide for an automatic placement of secondary
backup LSPs or FRR bypass/detour LSPs that minimizes the probability of fate sharing with the
path of the primary LSP (Figure 7).

The following details the steps necessary to create shared risk link groups:

• For primary/standby SRLG disjoint configuration:

→ Create an SRLG-group similar to admin groups.

→ Link the SRLG-group to MPLS interfaces.

→ Configure primary and secondary LSP paths and enable SRLG on the secondary LSP

path. Note that the SRLG secondary LSP path(s) will always perform a strict CSPF
query. The srlg-frr command is irrelevant in this case (For more information, see srlg-

frr on page 77)

• For FRR detours/bypass SRLG disjoint configuration:

→ Create an SRLG group, similar to admin groups.

→ Link the SRLG group to MPLS interfaces.

→ Enable the srlg-frr (strict/non-strict) option, which is a system-wide parameter, and it

force every LSP path CSPF calculation, to take the configured SRLG membership(s)
(and propagated through the IGP opaque-te-database) into account.

Page 38 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

SRLG 1

SRLG 2

Primary Path (FRR, node protection)

Bypass tunnel taking SRLG into account

Secondary path taking SRLG into account

Fig_33

→ Configure primary FRR (one-to-one/facility) LSP path(s). Consider that each PLR

will create a detour/bypass that will only avoid the SRLG membership(s) configured
on the primary LSP path egress interface. In a one-to-one case, detour-detour merging
is out of the control of the PLR, thus the latter will not ensure that its detour will be
prohibited to merge with a colliding one. For facility bypass, with the presence of
several bypass type to bind to, the following priority rules will be followed:

1. Manual bypass disjoint

2. Manual bypass non-disjoint (eligible only if srlg-frr is non-strict)

3. Dynamic disjoint

4. Dynamic non-disjoint (eligible only if srlg-frr is non-strict)

Non-CSPF manual bypass is not considered.

Figure 7: Shared Risk Link Groups

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 39

Shared Risk Link Groups

This feature is supported on OSPF and IS-IS interfaces on which RSVP is enabled.

Static Configurations of SRLG Memberships

This feature provides operations with the ability to enter manually the link members of SRLG
groups for the entire network at any 7210 SAS node which will need to signal LSP paths (for
example, a head-end node).

The operator may explicitly enables the use by CSPF of the SRLG database. In that case, CSPF
will not query the TE database for IGP advertised interface SRLG information.

Note, however, that the SRLG secondary path computation and FRR bypass/detour path
computation remains unchanged.

There are deployments where the 7210 SAS will interpret with routers that do not implement the
SRLG membership advertisement through IGP SRLG TLV or sub-TLV.

In these situations, the user is provided with the ability to enter manually the link members of
SRLG groups for the entire network at any 7210 SAS node which will need to signal LSP paths,
for example, a head-end node.

The user enters the SRLG membership information for any link in the network by using the

interface ip-int-name srlg-group group-name command in the config>router>mpls> srlg­database>router-id context. An interface can be associated with up to 5 SRLG groups for each

execution of this command. The user can associate an interface with up to 64 SRLG groups by
executing the command multiple times. The user must also use this command to enter the local
interface SRLG membership into the user SRLG database. The user deletes a specific interface
entry in this database by executing the no form of this command.

The group-name must have been previously defined in the SRLG srlg-group group-name value
group-value command in the config>router>mpls. The maximum number of distinct SRLG
groups the user can configure on the system is 1024.

The parameter value for router-id must correspond to the router ID configured under the base
router instance, the base OSPF instance or the base IS-IS instance of a given node. Note however,
that a single user SLRG database is maintained per node regardless if the listed interfaces
participate in static routing, OSPF, IS-IS, or both routing protocols. The user can temporarily
disable the use by CSPF of all interface membership information of a specific router ID by
executing the shutdown command in the config>router>mpls> srlg-database> router-id
context. In this case, CSPF will assume these interfaces have no SRLG membership association.
The operator can delete all interface entries of a specific router ID entry in this database by
executing the no router-id router-address command in the config>router>mpls> srlg-database
context.

Page 40 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

CSPF will not use entered SRLG membership if an interface is not listed as part of a router ID in
the TE database. If an interface was not entered into the user SRLG database, it will be assumed
that it does not have any SRLG membership. CSPF will not query the TE database for IGP
advertised interface SRLG information.

The operator enables the use by CSPF of the user SRLG database by entering the user-srlg-db
enable command in the config>router>mpls context. When the MPLS module makes a request to
CSPF for the computation of an SRLG secondary path, CSPF will query the local SRLG and
computes a path after pruning links which are members of the SRLG IDs of the associated primary
path. Similarly, when MPLS makes a request to CSPF for a FRR bypass or detour path to associate
with the primary path, CSPF queries the user SRLG database and computes a path after pruning
links which are members of the SRLG IDs of the PLR outgoing interface.

The operator can disable the use of the user SRLG database by entering the user-srlg-db disable in
command in the config>router>mpls context. CSPF will then resumes queries into the TE
database for SRLG membership information. However, the user SRLG database is maintained

The operator can delete the entire SRLG database by entering the no srlg-database command in
the config>router>mpls context. In this case, CSPF will assume all interfaces have no SRLG
membership association if the user has not disabled the use of this database.

TE Graceful Shutdown

Graceful shutdown provides a method to bulk re-route transit LSPs away from the node during
software upgrade of a node. A solution is described in RFC 5817, Graceful Shutdown in MPLS
and Generalized MPLS Traffic Engineering Networks. This is achieved in this draft by using a
PathErr message with a specific error code Local Maintenance on TE link required flag. When a
LER gets this message, it performs a make-before-break on the LSP path to move the LSP away
from the links/nodes which IP addresses were indicated in the PathErr message.

Graceful shutdown can flag the affected link/node resources in the TE database so other routers
will signal LSPs using the affected resources only as a last resort. This is achieved by flooding an
IGP TE LSA/LSP containing link TLV for the links under graceful shutdown with the traffic
engineering metric set to 0xffffffff and 0 as unreserved bandwidth.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 41

TE Graceful Shutdown

RUN

START

ENABLE MPLS

CONFIGURE MPLS INTERFACE PARAMETERS

CONFIGURE LSP PARAMETERS

CONFIGURE PATH PARAMETERS

CONFIGURE LSP-PATH PARAMETERS

CONFIGURE RSVP INTERFACE PARAMETERS

MPLS/RSVP Configuration Process Overview

Figure 8 displays the process to configure MPLS and RSVP parameters.

Figure 8: MPLS and RSVP Configuration and Implementation Flow

Page 42 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Configuration Notes

This section describes MPLS and RSVP caveats.

• Interfaces must already be configured in the config>router>interface context

before they can be specified in MPLS and RSVP.

• A router interface must be specified in the config>router>mpls context in order to
apply it or modify parameters in the config>router>rsvp context.

• A system interface must be configured and specified in the config>router>mpls
context.

• Paths must be created before they can be applied to an LSP.

MPLS and RSVP

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 43

TE Graceful Shutdown

Page 44 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Configuring MPLS and RSVP with CLI

This section provides information to configure MPLS and RSVP using the command line
interface.

Topics in this section include:

• MPLS Configuration Overview on page 46

→ LSPs on page 46

→ Paths on page 46

→ Router Interface on page 47

→ Choosing the Signaling Protocol on page 47

• Basic MPLS Configuration on page 48

• Common Configuration Tasks on page 49

→ Configuring MPLS Components on page 50

MPLS and RSVP

→ Configuring Global MPLS Parameters on page 50

→ Configuring an MPLS Interface on page 51

→ Configuring MPLS Paths on page 52

→ Configuring an MPLS LSP on page 53

• Configuring RSVP Parameters on page 57

→ Configuring RSVP Message Pacing Parameters on page 58

• MPLS Configuration Management Tasks on page 60

• RSVP Configuration Management Tasks on page 65

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 45

LSPs

MPLS Configuration Overview

Multi protocol Label Switching (MPLS) enables routers to forward traffic based on a simple
label embedded into the packet header. A router examines the label to determine the next hop
for the packet, saving time for router address lookups to the next node when forwarding
packets. MPLS is not enabled by default and must be explicitly enabled.

In order to implement MPLS, the following entities must be configured:

• LSPs on page 46

• Paths on page 46

• Router Interface on page 47

LSPs

To configure MPLS-signaled label-switched paths (LSPs), an LSP must run from an ingress
router to an egress router. Configure only the ingress router and configure LSPs to allow the
software to make the forwarding decisions or statically configure some or all routers in the
path. The LSP is set up by Resource Reservation Protocol (RSVP), through RSVP signaling
messages. The automatically manages label values. Labels that are automatically assigned
have values ranging from 1,024 through 1,048,575 (see Label Values on page 20).

Paths

A static LSP is a manually set up LSP where the next hop IP address and the outgoing label
are explicitly specified.

To configure signaled LSPs, you must first create one or more named paths on the ingress
router. For each path, the transit routers (hops) in the path are specified.

Page 46 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Router Interface

At least one router interface and one system interface must be defined in the
config>router>interface context in order to configure MPLS on an interface.

Choosing the Signaling Protocol

If only static label switched paths are used in your configurations, then you must manually
define the paths through the MPLS network. Label mappings and actions configured at each
hop must be specified. You do not need to enable RSVP if you are configuring static LSPs.

If dynamic LSP signaling is implemented in your network, then RSVP must be specified.
Enable signaling protocols only on the links where the functionality is required.

In order to implement MPLS, the following entities must be enabled:

MPLS and RSVP

• MPLS must be enabled on all routers that are part of an LSP.

• RSVP must be enabled on the same routers.

When MPLS is enabled and either RSVP is also enabled, MPLS uses RSVP to set up the
configured LSPs. For example, when you configure an LSP with both MPLS and RSVP
running, RSVP initiates a session for the LSP. RSVP uses the local router as the RSVP session
sender and the LSP destination as the RSVP session receiver. When the RSVP session is
created, the LSP is set up on the path created by the session. If the session is not successfully
created, RSVP notifies MPLS, MPLS can then either initiate backup paths or retry the initial
path.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 47

Choosing the Signaling Protocol

Basic MPLS Configuration

This section provides information to configure MPLS and configuration examples of common
configuration tasks. To enable MPLS on routers, you must configure at least one MPLS
interface. The other MPLS configuration parameters are optional. This follow displays an
example of an MPLS configuration.

A:ALA-1>config>router>mpls# info

------------------------------------------

admin-group "green" 15
admin-group "yellow" 20
admin-group "red" 25
interface "system"
exit
interface "StaticLabelPop"
admin-group "green"
label-map 50
pop
no shutdown
exit
exit
interface "StaticLabelPop"
label-map 35
swap 36 nexthop 10.10.10.91
no shutdown
exit
exit
path "secondary-path"
no shutdown
exit
path "to-NYC"
hop 1 10.10.10.104 strict
no shutdown
exit
lsp "lsp-to-eastcoast"
to 10.10.10.104
from 10.10.10.103
fast-reroute one-to-one
exit
primary "to-NYC"
exit
secondary "secondary-path"
exit
no shutdown
exit
static-lsp "StaticLabelPush"
to 10.10.11.105
push 60 nexthop 10.10.11.105
no shutdown
exit
no shutdown

---------------------------------------------­A:ALA-1>config>router>mpls#

Page 48 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Common Configuration Tasks

This section provides a brief overview of the tasks to configure MPLS and provides the CLI
commands.

The following protocols must be enabled on each participating router.

•MPLS

• RSVP (for RSVP-signaled MPLS only)

•LDP

In order for MPLS to run, you must configure at least one MPLS interface in the
config>router>mpls context.

• An interface must be created in the config>router>interface context before it can be
applied to MPLS.

•In the config>router>mpls context, configure path parameters for configuring LSP
parameters. A path specifies some or all hops from ingress to egress. A path can be
used by multiple LSPs.

MPLS and RSVP

• When an LSP is created, the egress router must be specified in the to command and at
least one primary or secondary path must be specified. All other statements under the
LSP hierarchy are optional.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 49

Configuring MPLS Components

Configuring MPLS Components

Use the MPLS and RSVP CLI syntax displayed below for:

• Configuring Global MPLS Parameters on page 50

• Configuring an MPLS Interface on page 51

• Configuring MPLS Paths on page 52

• Configuring an MPLS LSP on page 53

• Configuring a Static LSP on page 54

• Configuring RSVP Parameters on page 57

• Configuring RSVP Message Pacing Parameters on page 58

Configuring Global MPLS Parameters

Admin groups can signify link colors, such as red, yellow, or green. MPLS interfaces
advertise the link colors it supports. CSPF uses the information when paths are computed for
constrained-based LSPs. CSPF must be enabled in order for admin groups to be relevant.

To configure MPLS admin-group parameters, enter the following commands:

CLI Syntax: mpls

admin-group group-name group-value
frr-object
resignal-timer minutes

The following displays an admin group configuration example:

A:ALA-1>config>router>mpls# info

---------------------------------------------­ resignal-timer 500
admin-group "green" 15
admin-group "yellow" 20
admin-group "red" 25
...

---------------------------------------------­A:ALA-1>config>router>mpls#

Page 50 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Configuring an MPLS Interface

Configure the label-map parameters if the interface is used in a static LSP.
To configure an MPLS interface on a router, enter the following commands:

CLI Syntax: config>router>mpls

interface

no shutdown
admin-group group-name [group-name...(up to 32 max)]
label-map

pop
swap

no shutdown
srlg-group group-name [group-name...(up to 5 max)]
te-metric value

The following displays an interface configuration example:

MPLS and RSVP

interface config

A:ALA-1>config>router>mpls# info

---------------------------------------------­...
interface "to-104"
admin-group "green"
admin-group "red"
admin-group "yellow"
label-map 35
swap 36 nexthop 10.10.10.91
no shutdown
exit
exit
no shutdown
...

---------------------------------------------­A:ALA-1>config>router>mpls#

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 51

Configuring MPLS Paths

Configuring MPLS Paths

Configure an LSP path to use in MPLS. When configuring an LSP, the IP address of the hops
that the LSP should traverse on its way to the egress router must be specified. The
intermediate hops must be configured as either strict or loose meaning that the LSP must take
either a direct path from the previous hop router to this router (strict) or can traverse through
other routers (loose).

Use the following CLI syntax to configure a path:

CLI Syntax: config>router> mpls

path path-name

pathconfig

The following displays a path configuration example:

A:ALA-1>config>router>mpls# info

-----------------------------------------­ interface "system"
exit
path "secondary-path"
hop 1 10.10.0.121 strict
hop 2 10.10.0.145 strict
hop 3 10.10.0.1 strict
no shutdown
exit
path "to-NYC"
hop 1 10.10.10.103 strict
hop 2 10.10.0.210 strict
hop 3 10.10.0.215 loose
exit

-----------------------------------------­A:ALA-1>config>router>mpls#

hop hop-index ip-address {strict|loose}
no shutdown

Page 52 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Configuring an MPLS LSP

Configure an LSP path for MPLS. When configuring an LSP, you must specify the IP address
of the egress router in the to statement. Specify the primary path to be used. Secondary paths
can be explicitly configured or signaled upon the failure of the primary path. All other
statements are optional.

MPLS and RSVP

lsp config

The following displays an MPLS LSP configuration:

A:ALA-1>config>router>mplp# info

---------------------------------------------­...
lsp "lsp-to-eastcoast"
to 192.168.200.41
rsvp-resv-style ff
cspf
include "red"
exclude "green"
adspec
fast-reroute one-to-one
exit
primary "to-NYC"
hop-limit 10
exit
secondary "secondary-path"
bandwidth 50000
exit
no shutdown
exit
no shutdown

---------------------------------------------­A:ALA-1>config>router>mpls#

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 53

Configuring an MPLS LSP

Configuring a Static LSP

An LSP can be explicitly (statically) configured. Static LSPs are configured on every node
along the path. The label’s forwarding information includes the address of the next hop router.

Use the following CLI syntax to configure a static LSP:

CLI Syntax: config>router>mpls

The following displays a static LSP configuration example:

A:ALA-1>config>router>mpls# info

---------------------------------------------­...
static-lsp "static-LSP"
to 10.10.10.124
push 60 nexthop 10.10.42.3
no shutdown
exit
...

---------------------------------------------­A:ALA-1>config>router>mpls#

static-lsp lsp-name

to ip-address
push out-label nexthop ip-addr
no shutdown

Page 54 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Configuring Manual Bypass Tunnels

A----B----C----D

| |

E----F

Consider the following network setup.

The user first configures the option to disable the dynamic bypass tunnels.

Listed below are the steps to configure the manual bypass tunnels:

1. Configure the option to disable the dynamic bypass tunnels on the 7210 SAS node B
(if required). The CLI for this configuration is:

config>router>mpls>dynamic-bypass [disable | enable]

The dynamic bypass tunnels are enabled by default.

MPLS and RSVP

2. Configure an LSP on node B, such as B-E-F-C which is used only as bypass. The user
specifies each hop in the path, for example, the bypass LSP has a strict path.

Note that including the bypass-only keyword disables the following options under the LSP
configuration:

• bandwidth

• fast-reroute

• secondary

The following LSP configuration options are allowed:

• adaptive

•adspec

• cspf

• exclude

• hop-limit

• include

•metric

The following example displays a bypass tunnel configuration:

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 55

Configuring Manual Bypass Tunnels

A:7210 SAS>config>router>mpls>path# info

------------------------------------------­ ...
path "BEFC"
hop 10 10.10.10.11 strict
hop 20 10.10.10.12 strict
hop 30 10.10.10.13 strict
no shutdown
exit

lsp "bypass-BC"
to 10.10.10.15
primary "BEFC"
exit
no shutdown
...

------------------------------------------­A:7210 SAS >config>router>mpls>path#

3. Configure an LSP from A to D and indicate fast-reroute bypass protection, select the
facility as “FRR method”. (Config>router>mpls>lsp>fast-reroute facility).

Observe if the following criterions apply:

→ If the LSP passes through B

→ A bypass is requested

→ The next hop is C

→ A manually configured bypass-only tunnel exists from B to C ( excluding link B

to C)

Result: Node B uses the manually configured bypass-only tunnel from B to C.

Page 56 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Configuring RSVP Parameters

RSVP is used to set up LSPs. RSVP must be enabled on the router interfaces that are
participating in signaled LSPs. The keep-multiplier and refresh-time default values can be
modified in the RSVP context.

Initially, interfaces are configured in the config>router>mpls>interface context. Only these
existing (MPLS) interfaces are available to modify in the config>router> rsvp context.
Interfaces cannot be directly added in the RSVP context.

The following example displays an RSVP configuration example:

MPLS and RSVP

rsvp config

A:ALA-1>config>router>rsvp# info

---------------------------------------------­interface "system"

no shutdown
exit
interface to-104
hello-interval 4000
no shutdown
exit
no shutdown

----------------------------------------------

A:ALA-1>config>router>rsvp#

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 57

Configuring RSVP Message Pacing Parameters

Configuring RSVP Message Pacing Parameters

RSVP message pacing maintains a count of the messages that were dropped because the
output queue for the egress interface was full.

Use the following CLI syntax to configure RSVP parameters:

CLI Syntax: config>router>rsvp

no shutdown
msg-pacing

period milli-seconds
max-burst number

The following example displays a RSVP message pacing configuration example:

msg pacing

A:ALA-1>config>router>rsvp# info

---------------------------------------------­ keep-multiplier 5
refresh-time 60
msg-pacing
period 400
max-burst 400
exit
interface "system"
no shutdown
exit
interface to-104
hello-interval 4000
no shutdown
exit
no shutdown

---------------------------------------------­A:ALA-1>config>router>rsvp#

Page 58 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Configuring Graceful Shutdown

Enable TE graceful shutdown on the maintenance interface using the
config>router>rsvp>interface>graceful-shutdown command.

Disable graceful shutdown by executing the no form of the command at the RSVP interface
level or at the RSVP level. This restores the user-configured TE parameters of the
maintenance links, and the 7210 SAS maintenance node floods them.

MPLS and RSVP

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 59

Modifying MPLS Parameters

MPLS Configuration Management Tasks

This section discusses the following MPLS configuration management tasks:

• Modifying MPLS Parameters on page 60

• Modifying MPLS Path Parameters on page 62

• Modifying MPLS Static LSP Parameters on page 63

• Deleting an MPLS Interface on page 64

Modifying MPLS Parameters

NOTE: You must shut down MPLS entities in order to modify parameters. Re-enable (no
shutdown) the entity for the change to take effect.

Page 60 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Modifying an MPLS LSP

Some MPLS LSP parameters such as primary and secondary, must be shut down before they
can be edited or deleted from the configuration.

The following displays a MPLS LSP configuration example. Refer to the LSP configuration
on page 53.

A:ALA-1>>config>router>mpls>lsp# info

----------------------------------------------

shutdown
to 10.10.10.104
from 10.10.10.103
rsvp-resv-style ff
include "red"
exclude "green"
fast-reroute one-to-one
exit
primary "to-NYC"
hop-limit 50
exit
secondary "secondary-path"
exit

----------------------------------------------

A:ALA-1>config>router>mpls#

MPLS and RSVP

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 61

Modifying MPLS Path Parameters

Modifying MPLS Path Parameters

In order to modify path parameters, the config>router>mpls>path context must be shut
down first.

The following displays a path configuration example. Refer to the LSP configuration on

page 52.

A:ALA-1>config>router>mpls# info
#-----------------------------------------­echo "MPLS"
#-----------------------------------------­...
path "secondary-path"
hop 1 10.10.0.111 strict
hop 2 10.10.0.222 strict
hop 3 10.10.0.123 strict
no shutdown
exit
path "to-NYC"
hop 1 10.10.10.104 strict
hop 2 10.10.0.210 strict
no shutdown
exit
...

---------------------------------------------­A:ALA-1>config>router>mpls#

Page 62 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Modifying MPLS Static LSP Parameters

In order to modify static LSP parameters, the config>router>mpls>path context must be shut
down first.

The following displays a static LSP configuration example. Refer to the static LSP
configuration on page 54.

A:ALA-1>config>router>mpls# info

----------------------------------------------

...
static-lsp "static-LSP"
to 10.10.10.234
push 102704 nexthop 10.10.8.114
no shutdown
exit
no shutdown

----------------------------------------------

A:ALA-1>config>router>mpls#

MPLS and RSVP

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 63

Deleting an MPLS Interface

Deleting an MPLS Interface

In order to delete an interface from the MPLS configuration, the interface must be shut down
first.

Use the following CLI syntax to delete an interface from the MPLS configuration:

CLI Syntax: mpls

[no] interface ip-int-name

shutdown

A:ALA-1>config>router>mpls# info

---------------------------------------------­...

admin-group "green" 15
admin-group "red" 25
admin-group "yellow" 20
interface "system"
exit
no shutdown

---------------------------------------------­A:ALA-1>config>router>mpls#

Page 64 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

RSVP Configuration Management Tasks

This section discusses the following RSVP configuration management tasks:

• Modifying RSVP Parameters on page 65

• Modifying RSVP Message Pacing Parameters on page 66

• Deleting an Interface from RSVP on page 66

Modifying RSVP Parameters

Only interfaces configured in the MPLS context can be modified in the RSVP context.

The no rsvp command deletes this RSVP protocol instance and removes all configuration
parameters for this RSVP instance.
The shutdown command suspends the execution and maintains the existing configuration.

MPLS and RSVP

The following example displays a modified RSVP configuration example:

A:ALA-1>config>router>rsvp# info

---------------------------------------------­ keep-multiplier 5
refresh-time 60
msg-pacing
period 400
max-burst 400
exit
interface "system"
exit
interface "test1"
hello-interval 5000
exit
no shutdown

---------------------------------------------­A:ALA-1>config>router>rsvp#

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 65

Modifying RSVP Message Pacing Parameters

Modifying RSVP Message Pacing Parameters

RSVP message pacing maintains a count of the messages that were dropped because the
output queue for the egress interface was full.

The following example displays command usage to modify RSVP parameters:

The following example displays a modified RSVP message pacing configuration example.
Refer to the RSVP message pacing configuration on page 57.

A:ALA-1>config>router>rsvp# info

---------------------------------------------­ keep-multiplier 5
refresh-time 60
msg-pacing
period 200
max-burst 200
exit
interface "system"
exit
interface "to-104"
exit
no shutdown

---------------------------------------------­A:ALA-1>config>router>rsvp#

Deleting an Interface from RSVP

Interfaces cannot be deleted directly from the RSVP configuration. An interface must have
been configured in the MPLS context and then the RSVP context. The interface must first be
deleted from the MPLS context. This removes the association from RSVP.

See Deleting an MPLS Interface on page 64 for information on deleting an MPLS interface.

Page 66 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS/RSVP Command Reference

Command Hierarchies

• MPLS Commands on page 67

• MPLS Path Commands on page 70

• RSVP Commands on page 70

• Show Commands on page 71

• Clear Commands on page 72

• Debug Commands on page 73

MPLS Commands

config

— router

— [no] mpls

— dynamic-bypass [enable | disable]
— [no] frr-object
— hold-timer seconds
—no hold-timer
— [no] interface ip-int-name

— [no] admin-group group-name [group-name...(up to 5 max)]
— label-map in-label
—no label-map in-label

—no pop
— pop
—no shutdown
— shutdown
— swap out-label nexthop ip-address
— swap implicit-null-label nexthop ip-address
—no swap

—no shutdown

— shutdown
—[no] srlg-group group-name [group-name...(up to 5 max)]

— te-metric metric
—no te-metric

— resignal-timer minutes
—no resignal-timer

[no] shutdown

—
— [no] srlg-database

— [no] router-id router-addr

— [no] interface ip-addr srlg-group group-name [group-name..(up

to 5 max)]

— [no] shutdown

— [no] srlg-frr [strict]

MPLS and RSVP

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 67

Command Hierarchies

MPLS LSP Commands

config

— router

—[no] static-lsp lsp-name

—[no] static-lsp-fast-retry seconds
— user-srlg-db [enable | disable]

— [no] mpls

— [no] lsp lsp-name [bypass-only

—no push label
— push label nexthop ip-address
—[no] shutdown
— to ip-address

— [no] adaptive
— [no] adspec
— bgp-transport-tunnel include | exclude
— [no] cspf [use-te-metric]
— [no] exclude group-name [group-name...(up to 5 max)]
— fast-reroute frr-method
—no fast-reroute

— bandwidth rate-in-mbps
—no bandwidth
— hop-limit number
—no hop-limit
— [no] node-protect

— from ip-address
— hop-limit number
—no hop-limit
— [no] include group-name [group-name...(up to 5 max)]
— [no] primary path-namex

— [no] adaptive
— bandwidth rate-in-mpbs
—no bandwidth
— [no] exclude group-name [group-name...(up to 5 max)]
— hop-limit number
—no hop-limit
— [no] include group-name [group-name...(up to 5 max)]
— [no] record
— [no] record-label
— [no] shutdown

— retry-limit number
—no retry-limit
— retry-timer seconds
—no retry-timer
— rsvp-resv-style [se | ff]
— [no] secondary path-name

— [no] adaptive
— bandwidth rate-in-mbps
—no bandwidth
— [no] exclude group-name [
— hop-limit number

group-name...(up to 5 max)]

Page 68 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

—no hop-limit
— [no] include group-name [group-name...(up to 5 max)]
—[no] path-preference
— [no] record
— [no] record-label
— [no] shutdown
— [no] srlg
— [no] standby

— [no] shutdown
— to ip-address

MPLS and RSVP

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 69

Command Hierarchies

MPLS Path Commands

config

— router

RSVP Commands

— [no] mpls

— [no] p2p-active-path-fast-retry

— [no] path path-name

— hop hop-index ip-address {strict | loose}
—no hop hop-index
— [no] shutdown

— [no] static-lsp lsp-name

— push label nexthop ip-address
—no push out-label
— to ip-addr
— [no] shutdown

config

— router

— [no] rsvp

— [no] implicit-null-label
— [no] interface ip-int-name

— keep-multiplier number
—no keep-multiplier
— [no] msg-pacing

— rapid-retransmit-time hundred-milliseconds
—no rapid-retransmit-time
— rapid-retry-limit number
—no rapid-retry-limit
— refresh-time seconds
—no refresh-time
— [no] shutdown

— authentication-key [authentication-key | hash-key] [hash | hash2]
—no authentication-key
— [no] bfd-enable
— [no] graceful-shutdown
— hello-interval milli-seconds
—no hello-interval
— [no] refresh-reduction

— [no] reliable-delivery

— [no] shutdown
— subscription percentage
—no subscription

— max-burst number
—no max-burst
— period milli-seconds

period

—no

Page 70 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Show Commands

show

— router

—mpls

MPLS and RSVP

— bypass-tunnel [to ip-address] [protected-lsp name] [dynamic | manual] [detail]
— interface [ip-int-name|ip-address] [label-map label]
— interface [ip-int-name|ip-address]
— label start-label [end-label | in-use | label-owner]
— label-range
— lsp [lsp-name] [status {up|down}] [from ip-address| to ip-address] [detail]
— lsp {transit | terminate} [status {up|down}] [from ip-address | to ip-address | lsp-

name] [detail]

name

— lsp count
— lsp lsp-name activepath
— lsp [lsp-name] path [path-name] [status {up | down}] [detail]
— srlg-database [router-id ip-address] [interface ip-address]
— static-lsp [lsp-name]
— static-lsp {transit | terminate}
— static-lsp count
— status

show

— router

—rsvp

— interface [interface [ip-int-name]] statistics [detail]
— neighbor [ip-address] [detail]
— session [session-type] [from ip-address| to ip-address| lsp-name name] [status

{up|down}][detail]

— statistics
— status

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 71

Command Hierarchies

Tools Commands

— perform

— router

—mpls

— cspf to ip-addr [from ip-addr] [bandwidth bandwidth] [include-bitmap

bitmap] [exclude-bitmap bitmap] [hop-limit limit] [exclude-address
excl-addr [excl-addr...(upto 8 max)]] [use-te-metric] [strict-srlg] [srlg-

group grp-id...(up to 8 max)] [skip-interface interface-name]
— force-switch-path [lsp lsp-name] [path path-name]
— [no] force-switch-path [lsp lsp-name]
— resignal {lsp lsp-name path path-name | delay minutes}
— switch-path [lsp lsp-name] [path path-name]
— trap-suppress number-of-traps time-interval
— update-path {lsp lsp-name path current-path-name new-path new-path-

name}

Clear Commands

clear

— router

—mpls

— interface [ip-int-name]
— lsp lsp-name

—rsvp

— interface [ip-int-name] [statistics]
— statistics

Page 72 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

Debug Commands

debug

— router

MPLS and RSVP

— mpls [lsp lsp-name] [sender source-address] [endpoint endpoint-address] [tunnel-id tunnel-

id] [lsp-id lsp-id]

—no mpls

— [no] event

— all [detail]
—no all
— frr [detail]
—no frr
— iom [detail]
—no iom
— lsp-setup [detail]
—no lsp-setup
— mbb [detail]
—no mbb
— misc [detail]
—no misc
— xc [detail]
—no xc

— rsvp [lsp lsp-name] [sender source-address] [endpoint endpoint-address] [

id] [lsp-id lsp-id] [interface ip-int-name]

—no rsvp

— [no] event

— all [detail]
—no all
— auth
—no auth
— misc [detail]
—no misc
— nbr [detail]
—no nbr
— path [detail]
—no path
— resv [detail]
—no resv
— rr
—no rr

— [no] packet

— all [detail]
—no all
— ack
— bundle [detail]
—no bundle
— hello [detail]
—no hello
— path [detail
—no path
— patherr [detail]
—no patherr
— pathtear [detail]
—no pathtear
— resv [detail]

]

tunnel-id tunnel-

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 73

Command Hierarchies

—no resv
— resverr [detail]
—no resverr
— resvtear [detail]
—no resvtear
— srefresh [detail]
—no srefresh

Page 74 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

MPLS Configuration Commands

Generic Commands

shutdown

Syntax [no] shutdown

Context config>router>mpls

config>router>mpls>interface
config>router>mpls>lsp>primary
config>router>mpls>lsp>secondary

Description This command administratively disables an entity. When disabled, an entity does not change, reset, or

remove any configuration settings or statistics.

MPLS is not enabled by default and must be explicitely enabled (no shutdown).

The operational state of the entity is disabled as well as the operational state of any entities contained
within. Many objects must be shut down before they may be deleted.

The no form of this command places the entity into an administratively enabled state.

Default no shutdown

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 75

MPLS Commands

MPLS Commands

mpls

Syntax [no] mpls

Context config>router

Description This command enables the context to configure MPLS parameters. MPLS is not enabled by default

and must be explicitely enabled (no shutdown). The shutdown command administratively disables
MPLS.

The no form of this command deletes this MPLS protocol instance; this will remove all configuration
parameters for this MPLS instance.

MPLS must be shutdown before the MPLS instance can be deleted. If MPLS is not shutdown, when
the no mpls command is executed, a warning message on the console displays indicating that MPLS
is still administratively up.

dynamic-bypass

Syntax dynamic-bypass [enable | disable]

no dynamic-bypass

Context config>router>mpls

Description This command disables the creation of dynamic bypass LSPs in FRR. One or more manual bypass

LSPs must be configured to protect the primary LSP path at the PLR nodes.

Note :Implict NULL must be enabled for use of Manual Bypass or Dynamic Bypass (FRR facility) if
the 7210 is used as a egress LER and/or is a Merge Point.

Default enable

frr-object

Syntax [no] frr-object

Context config>router>mpls

Description This command specifies whether fast reroute for LSPs using the facility bypass method is signalled

with or without the fast reroute object using the one-to-one keyword. The value is ignored if fast
reroute is disabled for the LSP or if the LSP is using one-to-one Backup.

Default frr-object — The value is by default inherited by all LSPs.

Page 76 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

hold-timer

Syntax hold-timer seconds

no hold-timer

Context config>router>mpls

Description This command specifies the amount of time that the ingress node holds before programming its data

plane and declaring the LSP up to the service module.

The no form of the command disables the hold-timer.

Default 1 second

Parameters seconds — Specifies the time, in seconds, for which the ingress node holds before programming its

data plane and declaring the LSP up to the service module.

Values 0 — 10

resignal-timer

Syntax resignal-timer minutes

no resignal-timer

Context config>router>mpls

Description This command specifies the value for the LSP resignal timer. The resignal timer is the time, in

minutes, the software waits before attempting to resignal the LSPs.

When the resignal timer expires, if the new computed path for an LSP has a better metric than the
current recorded hop list, an attempt is made to resignal that LSP using the make-before-break
mechanism. If the attempt to resignal an LSP fails, the LSP will continue to use the existing path and
a resignal will be attempted the next time the timer expires.

The no form of the command disables timer-based LSP resignalling.

Default no resignal-timer

Parameters minutes — The time the software waits before attempting to resignal the LSPs.

Values 30 — 10080

srlg-frr

Syntax srlg-frr [strict]

no srlg-frr

Context config>router>mpls

Description This command enables the use of the Shared Risk Link Group (SRLG) constraint in the computation

of FRR bypass or detour to be associated with any primary LSP path on this system.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 77

MPLS Commands

When this option is enabled, CSPF includes the SRLG constraint in the computation of a FRR detour
or bypass for protecting the primary LSP path.

CSPF prunes all links with interfaces which belong to the same SRLG as the interface which is being
protected, i.e., the outgoing interface at the PLR the primary path is using. If one or more paths are
found, the MPLS/RSVP task will select one based on best cost and will signal the bypass/detour. If
not and the user included the strict option, the bypass/detour is not setup and the MPLS/RSVP task
will keep retrying the request to CSPF. Otherwise, if a path exists which meets the other TE
constraints, other than the SRLG one, the bypass/detour is setup.

A bypass or a detour LSP path is not guaranteed to be SRLG disjoint from the primary path. This is
because only the SRLG constraint of the outgoing interface at the PLR the primary path is using is
checked.

When the MPLS/RSVP task is searching for a SRLG bypass tunnel to associate with the primary path
of the protected LSP, it will first check if any configured manual bypass LSP with CSPF enabled
satisfies the SLRG constraints. The MPLS/RSVP skips any non-CSPF bypass LSP in the search as
there is no ERO returned to check the SLRG constraint. If no path is found, it will check if an existing
dynamic bypass LSP satisfies the SLRG and other primary path constraints. If not, then it will make
a request to CSPF.

Once the primary path of the LSP is set up and is operationally up, any subsequent changes to the
SRLG group membership of an interface the primary path is using would not be considered by the
MPLS/RSVP task at the PLR for bypass/detour association until the next opportunity the primary
path is re-signaled. The path may be re-signaled due to a failure or to a make-before break operation.
Make-before break occurs as a result of a global revertive operation, a timer based or manual re­optimization of the LSP path, or a user change to any of the path constraints.

Once the bypass or detour path is setup and is operationally UP, any subsequent changes to the SRLG
group membership of an interface the bypass/detour path is using would not be considered by the
MPLS/RSVP task at the PLR until the next opportunity the association with the primary LSP path is
re-checked. The association is re-checked if the bypass path is re-optimized. Detour paths are not re­optimized and are re-signaled if the primary path is down.

Enabling or disabling srlg-frr only takes effect after LSP paths are resignaled. This can be achieved
by shutting down and re-enabling MPLS. Another option is using the tools perform router mpls
resignal command. However, note that while the latter might be less service impacting, only
originating LSPs can be resignaled with the tools command. If also local transit and bypass LSPs are
to be resignaled, the tools command must be executed on all ingress nodes in the network. The same
might be locally achieved by disabling and enabling using the configure router mpls dynamic-
bypass command, but this can trigger the LSP to go down and traffic loss to occur in case detour or
bypass LSP is in use.

An RSVP interface can belong to a maximum of 64 SRLG groups. The user configures the SRLG
groups using the command config>router>mpls>srlg-group. The user configures the SRLG groups
an RSVP interface belongs to using the srlg-group command in the config>router>mpls>interface
context.

The no form of the command reverts to the default value.

Default no srlg-frr

Parameters strict — Specifies the name of the SRLG group within a virtual router instance.

Val ues no slr-frr (default)

srlg-frr (non-strict)
srlg-frr strict (strict)

Page 78 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

user-srlg-db

Syntax user-srlg-db [enable | disable]

Context config>router>mpls

Description This command enables the use of CSPF by the user SRLG database. When the MPLS module makes

a request to CSPF for the computation of an SRLG secondary path, CSPF will query the local SRLG
and compute a path after pruning links that are members of the SRLG IDs of the associated primary
path. When MPLS makes a request to CSPF for an FRR bypass or detour path to associate with the
primary path, CSPF queries the user SRLG database and computes a path after pruning links that are
members of the SRLG IDs of the PLR outgoing interface.

If an interface was not entered into the user SRLG database, it is assumed that it does not have any
SRLG membership. CSPF will not query the TE database for IGP advertised interface SRLG
information.

The disable keyword disables the use of the user SRLG database. CSPF will then resume queries into
the TE database for SRLG membership information. The user SRLG database is maintained.

Default user-srlg-db disable

srlg-database

Syntax [no] srlg-database

Context config>router>mpls

Description This command provides the context for the user to enter manually the link members of SRLG groups

for the entire network at any node that needs to signal LSP paths (for example, a head-end node).

The no form of the command deletes the entire SRLG database. CSPF will assume all interfaces have
no SRLG membership association if the database was not disabled with the command
config>router>mpls>user-srlg-db disable.

router-id

Syntax [no] router-id ip

Context config>router>mpls>srlg-database

Description This command provides the context for the user to manually enter the link members of SRLG groups

for a specific router in the network. The user must also use this command to enter the local interface
SRLG membership into the user SRLG database. Use by CSPF of all interface SRLG membership
information of a specific router ID may be temporarily disabled by shutting down the node. If this
occurs, CSPF will assume these interfaces have no SRLG membership association.

The no form of this command will delete all interface entries under the router ID.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 79

MPLS Commands

Parameters ip-address — Specifies the router ID for this system. This must be the router ID configured under the

base router instance, the base OSPF instance or the base IS-IS instance.

Val ues [a.b.c.d]

interface

Syntax interface ip-address srlg-group group-name [group-name...(up to 5 max)]

no interface ip-address [srlg-group group-name...(up to 5 max)]

Context config>router>mpls>srlg-database>router-id

Description This command allows the operator to manually enter the SRLG membership information for any link

in the network, including links on this node, into the user SRLG database.

An interface can be associated with up to 5 SRLG groups for each execution of this command. The
operator can associate an interface with up to 64 SRLG groups by executing the command multiple
times.

CSPF will not use entered SRLG membership if an interface is not validated as part of a router ID in
the routing table.

The no form of the command deletes a specific interface entry in this user SRLG database. The
group-name must already exist in the config>router>mpls>srlg-group context.

Default none

Parameters ip-int-name — The name of the network IP interface. An interface name cannot be in the form of an

IP address.

srlg-group group-name — Specifies the SRLG group name. Up to 1024 group names can be defined

in the config>router>mpls context. The SRLG group names must be identical across all routers
in a single domain.

label-map

Syntax [no] label-map in-label

Context config>router>mpls>interface

Description This command is used on transit routers when a static LSP is defined. The static LSP on the ingress

router is initiated using the config router mpls static-lsp lsp-name command. An in-label can be
associated with either a pop or a swap action, but not both. If both actions are specified, the last
action specified takes effect.

The no form of this command deletes the static LSP configuration associated with the in-label.

Parameters in-label — Specifies the incoming MPLS label on which to match.

Val ues 32 — 1023

Page 80 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

pop

Syntax [no] pop

Context config>router>mpls>if>label-map

Description This command specifies that the incoming label must be popped (removed). No label stacking is

supported for a static LSP. The service header follows the top label. Once the label is popped, the
packet is forwarded based on the service header.

The no form of this command removes the pop action for the in-label.

Default none

shutdown

Syntax [no] shutdown

Context config>router>mpls>if>label-map

Description This command disables the label map definition. This drops all packets that match the specified in-

label specified in the label-map in-label command.

The no form of this command administratively enables the defined label map action.

Default no shutdown

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 81

MPLS Commands

swap

Syntax swap {out-label | implicit-null-label} nexthop ip-address

no swap {out-label | implicit-null-label}

Context config>router>mpls>interface>label-map

Description This command swaps the incoming label and specifies the outgoing label and next hop IP address on

an LSR for a static LSP.

The no form of this command removes the swap action associated with the in-label.

Default none

Parameters implicit-null-label — Specifies the use of the implicit label value for the outgoing label of the swap

operation.

out-label — Specifies the label value to be swapped with the in-label. Label values 16 through

1,048,575 are defined as follows:
Label values 16 through 31 are reserved.
Label values 32 through 1,023 are available for static assignment.
Label values 1,024 through 2,047 are reserved for future use.
Label values 2,048 through 18,431 are statically assigned for services.
Label values 28,672 through 131,071 are dynamically assigned for both MPLS and services.
Label values 131,072 through 1,048,575 are reserved for future use.

Val ues 16 — 1048575

nexthop ip-address — The IP address to forward to. If an ARP entry for the next hop exists, then the

static LSP will be marked operational. If ARP entry does not exist, software will set the
operational status of the static LSP to down and continue to ARP for the configured nexthop.
Software will continuously try to ARP for the configured nexthop at a fixed interval.

static-lsp

Syntax [no] static-lsp lsp-name

Context config>router>mpls

Description This command is used to configure a static LSP on the ingress router. The static LSP is a manually

setup LSP where the nexthop IP address and the outgoing label (push) must be specified.

The no form of this command deletes this static LSP and associated information.

The LSP must be shutdown first in order to delete it. If the LSP is not shut down, the no static-lsp lsp­name command generates a warning message on the console indicating that the LSP is
administratively up.

Parameters lsp-name — Name that identifies the LSP.

Val ues Up to 32 alphanumeric characters.

Page 82 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

push

Syntax no push label

push label nexthop ip-address

Context config>router>mpls>static-lsp

Description This command specifies the label to be pushed on the label stack and the next hop IP address for the

static LSP.

The no form of this command removes the association of the label to push for the static LSP.

Parameters label — The label to push on the label stack. Label values 16 through 1,048,575 are defined as

follows:

Label values 16 through 31 are 7750 SR reserved.

Label values 32 through 1,023 are available for static assignment.

Label values 1,024 through 2,047 are reserved for future use.

Label values 2,048 through 18,431 are statically assigned for services.

Label values 28,672 through 131,071 are dynamically assigned for both MPLS and services.

Label values 131,072 through 1,048,575 are reserved for future use.

Values 16 — 1048575

nexthop ip-address — This command specifies the IP address of the next hop towards the LSP egress
router. If an ARP entry for the next hop exists, then the static LSP is marked operational.

If ARP entry does not exist, software sets the operational status of the static LSP to down and
continues to ARP for the configured nexthop. Software continuously tries to ARP for the configured
nexthop at a fixed interval.

shutdown

Syntax [no] shutdown

Context config>router>mpls>static-lsp

Description This command is used to administratively disable the static LSP.

The no form of this command administratively enables the staticLSP.

Default shutdown

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 83

MPLS Commands

to

Syntax to ip-address

Context config>router>mpls>static-lsp

Description This command specifies the system IP address of the egress router for the static LSP. This command

is required while creating an LSP. For LSPs that are used as transport tunnels for services, the to IP
address must be the system IP address. If the to address does not match the SDP address, the LSP is
not included in the SDP definition.

Parameters ip-address — The system IP address of the egress router.

Default none

static-lsp-fast-retry

Syntax static-lsp-fast-retry seconds

[no] static-lsp-fast-retry

Context config>router>mpls

Description This command specifies the value used as the fast retry timer for a static LSP.

When a static LSP is trying to come up, the MPLS request for the ARP entry of the LSP next-hop
may fail when it is made while the next-hop is still down or unavailable. In that case, MPLS starts a
retry timer before making the next request. This enhancement allows the user to configure the retry
timer, so that the LSP comes up as soon as the next-hop is up.

The no form of the command reverts to the default.

Default no static-fast-retry-timer

Parameters seconds — Specifies the value, in seconds, used as the fast retry timer for a static LSP.

Val ues 1-30

Page 84 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

MPLS Interface Commands

interface

Syntax [no] interface ip-int-name

Context config>router>mpls

Description This command specifies MPLS protocol support on an IP interface. No MPLS commands are

executed on an IP interface where MPLS is not enabled. An MPLS interface must be explicitly
enabled (no shutdown).

The no form of this command deletes all MPLS commands such as label-map which are defined
under the interface. The MPLS interface must be shutdown first in order to delete the interface
definition. If the interface is not shutdown, the no interface ip-int-name command does nothing
except issue a warning message on the console indicating that the interface is administratively up.

Default shutdown

Parameters ip-int-name — The name of the network IP interface. An interface name cannot be in the form of an

IP address. If the string contains special characters (#, $, spaces, etc.), the entire string must be
enclosed within double quotes.

Values 1 to 32 alphanumeric characters.

admin-group

Syntax [no] admin-group group-name [group-name...(up to 5 max)]

Context config>router>mpls>interface

Description This command configures the admin group membership of an interface. The user can apply admin

groups to an IES, VPRN, network IP, or MPLS interface. Each single operation of the admin-group
command allows a maximum of five (5) groups to be specified at a time. However, a maximum of 32
groups can be added to a given interface through multiple operations. Once an admin group is bound
to one or more interface, its value cannot be changed until all bindings are removed. The configured
admin-group membership will be applied in all levels/areas the interface is participating in. The same
interface cannot have different memberships in different levels/areas. It should be noted that only the
admin groups bound to an MPLS interface are advertised in TE link TLVs and sub-TLVs when the
traffic-engineering option is enabled in IS-IS or OSPF. IES andVPRN interfaces do not have their
attributes advertised in TE TLVs.

The no form of this command deletes one or more of the admin-group memberships of an interface.

The user can also delete all memberships of an interface by not specifying a group name.

Default no admin-group

Parameters group-name — Specifies the name of the group with up to 32 characters. The association of group

name and value should be unique within an IP/MPLS domain.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 85

MPLS Commands

srlg-group

Syntax [no] srlg-group group-name [group-name...(up to 5 max)]

Context config>router>mpls>interface

Description This command defines the association of RSVP interface to an SRLG group. An interface can belong

to up to 64 SRLG groups. However, each single operation of the srlg-group command allows a
maximum of 5 groups to be specified at a time.

The no form of this command deletes the association of the interface to the SRLG group.

Default none

Parameters group-name — Specifies the name of the SRLG group within a virtual router instance up to 32

characters.

te-metric

Syntax te-metric value

no te-metric

Context config>router>mpls>interface

Description This command configures the traffic engineering metric used on the interface. This metric is in

addition to the interface metric used by IGP for the shortest path computation.

This metric is flooded as part of the TE parameters for the interface using an opaque LSA or an LSP.
The IS-IS TE metric is encoded as sub-TLV 18 as part of the extended IS reachability TLV. The
metric value is encoded as a 24-bit unsigned integer. The OSPF TE metric is encoded as a sub-TLV
Type 5 in the Link TLV. The metric value is encoded as a 32-bit unsigned integer.

When the use of the TE metric is enabled for an LSP, CSPF will first prune all links in the network
topology which do not meet the constraints specified for the LSP path. Such constraints include
bandwidth, admin-groups, and hop limit. Then, CSPF will run an SPF on the remaining links. The
shortest path among the all SPF paths will be selected based on the TE metric instead of the IGP
metric which is used by default.

The TE metric in CSPF LSP path computation can be configured by entering the command
config>router>mpls>lsp>cspf>use-te-metric.

Note that the TE metric is only used in CSPF computations for MPLS paths and not in the regular
SPF computation for IP reachability.

The no form of the command reverts to the default value.

Default no te-metric

The value of the IGP metric is advertised in the TE metric sub-TLV by IS-IS and OSPF.

Parameters value — Specifies the metric value.

Val ues 1 — 16777215

Page 86 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

LSP Commands

lsp

Syntax [no] lsp lsp-name [bypass-only]

Context config>router>mpls

Description This command creates an LSP that is signaled dynamically by the .

When the LSP is created, the egress router must be specified using the to command and at least one
primary or secondary path must be specified. All other statements under the LSP hierarchy are

optional. Notre that the maximum number of static configurable LSPs is 4.

LSPs are created in the administratively down (shutdown) state.

The no form of this command deletes the LSP. All configuration information associated with this LSP
is lost. The LSP must be administratively shutdown before it can be deleted.

Default none

Parameters lsp-name — Name that identifies the LSP. The LSP name can be up to 32 characters long and must be

unique.

bypass-only — Defines an LSP as a manual bypass LSP exclusively. When a path message for a new

LSP requests bypass protection, the PLR first checks if a manual bypass tunnel satisfying the
path constraints exists. If one if found, the selects it. If no manual bypass tunnel is found, the
dynamically signals a bypass LSP in the default behavior. The CLI for this feature includes a
knob that provides the user with the option to disable dynamic bypass creation on a per node
basis.

adaptive

Syntax [no] adaptive

Context config>router>mpls>lsp

Description This command enables the make-before-break functionality for an LSP or LSP path. When enabled

for the LSP, make-before-break will be performed for primary path and all the secondary paths of the
LSP.

Default adaptive

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 87

MPLS Commands

adspec

Syntax [no] adspec

Context config>router>mpls>lsp

Description When enabled, the ADSPEC object will be included in RSVP messages for this LSP. The ADSPEC

object is used by the ingress LER to discover the minimum value of the MTU for links in the path of
the LSP. By default, the ingress LER derives the LSP MTU from that of the outgoing interface of the
LSP path.

Note that a bypass LSP always signals the ADSPEC object since it protects both primary paths which
signal the ADSPEC object and primary paths which do not. This means that MTU of LSP at ingress
LER may change to a different value from that derived from the outgoing interface even if the
primary path has ADSPEC disabled.

Default no adspec — No ADSPEC objects are included in RSVP messages.

Parameters

bgp-transport-tunnel

Syntax bgp-transport-tunnel include | exclude

Context config>router>mpls>lsp

Description This command allows or blocks RSVP-TE LSP to be used as a transport LSP for BGP tunnel routes.

Default bgp-transport-tunnel exclude

Parameters include — Allows RSVP-TE LSP to be used as transport LSP from ingress PE to ASBR in the local

AS.

exclude — Blocks RSVP-TE LSP to be used as transport LSP from ingress PE to ASBR in the local
AS.

cspf

Syntax [no] cspf [use-te-metric]

Context config>router>mpls>lsp

Description This command enables Constrained Shortest Path First (CSPF) computation for constrained-path

LSPs. Constrained-path LSPs are the ones that take configuration constraints into account. CSPF is
also used to calculate the detour routes when fast-reroute is enabled.

Explicitly configured LSPs where each hop from ingress to egress is specified do not use CSPF. The
LSP will be set up using RSVP signaling from ingress to egress.

If an LSP is configured with fast-reroute frr-method specified but does not enable CSPF, then
neither global revertive nor local revertive will be available for the LSP to recover.

Page 88 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

Default no cspf

Parameters use-te-metric — Specifies to use the use of the TE metric for the purpose of the LSP path computation

by CSPF.

exclude

Syntax [no] exclude group-name [group-name...(up to 5 max)]

Context config>router>mpls>lsp

Description This command specifies the admin groups to be excluded when an LSP is set up in the primary or

secondary contexts. Each single operation of the exclude command allows a maximum of 5 groups to
be specified at a time. However, a maximum of 32 groups can be specified per LSP through multiple
operations. The admin groups are defined in the config>router>mpls>admin-group context.

Use the no form of the command to remove the exclude command.

Default no exclude

Parameters group-name — Specify the existing group-name to be excluded when an LSP is set up.

fast-reroute

Syntax fast-reroute frr-method

no fast-reroute

Context config>router>mpls>lsp

Description This command creates a pre-computed detour LSP from each node in the path of the LSP. In case of

failure of a link or LSP between two nodes, traffic is immediately rerouted on the pre-computed
detour LSP, thus avoiding packet-loss.

When fast-reroute is enabled, each node along the path of the LSP tries to establish a detour LSP as
follows:

• Each upstream node sets up a detour LSP that avoids only the immediate downstream node, and
merges back on to the actual path of the LSP as soon as possible.

If it is not possible to set up a detour LSP that avoids the immediate downstream node, a detour
can be set up to the downstream node on a different interface.

• The detour LSP may take one or more hops (see hop-limit) before merging back on to the main
LSP path.

• When the upstream node detects a downstream link or node failure, the ingress router switches
traffic to a standby path if one was set up for the LSP.

Fast reroute is available only for the primary path. No configuration is required on the transit hops of
the LSP. The ingress router will signal all intermediate routers using RSVP to set up their detours. TE
must be enabled for fast-reroute to work.

If an LSP is configured with fast-reroute frr-method specified but does not enable CSPF, then neither
global revertive nor local revertive will be available for the LSP to recover.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 89

MPLS Commands

The no form of the fast-reroute command removes the detour LSP from each node on the primary
path. This command will also remove configuration information about the hop-limit and the
bandwidth for the detour routes.

The no form of fast-reroute hop-limit command reverts to the default value.

Default no fast-reroute — When fast-reroute is specified, the default fast-reroute method is one-to-one.

Parameters Values one-to-one — In the one-to-one technique, a label switched path is established

which intersects the original LSP somewhere downstream of the point of link or
node failure. For each LSP which is backed up, a separate backup LSP is
established.

bandwidth

Syntax bandwidth rate-in-mbps

no bandwidth

Context config>router>mpls>lsp>fast-reroute

Description This command is used to request reserved bandwidth on the detour path. When configuring an LSP,

specify the traffic rate associated with the LSP.

When configuring fast reroute, allocate bandwidth for the rerouted path. The bandwidth rate does not
need to be the same as the bandwidth allocated for the LSP.

Default no bandwidth — Bandwidth is not reserved for a rerouted path.

Parameters rate-in-mbps — Specifies the amount of bandwidth in Mbps to be reserved for the LSP path.

hop-limit

Syntax hop-limit limit

no hop-limit

Context config>router>mpls>lsp>fast-reroute

Description For fast reroute, how many more routers a detour is allowed to traverse compared to the LSP itself.

For example, if an LSP traverses four routers, any detour for the LSP can be no more than ten router
hops, including the ingress and egress routers.

Default 16

Parameters limit — Specify the maximum number of hops.

Val ues 0 — 255

Page 90 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

node-protect

Syntax [no] node-protect

Context config>router>mpls>lsp>fast-reroute

Description This command enables or disables node and link protection on the specified LSP. Node protection

ensures that traffic from an LSP traversing a neighboring router will reach its destination even if the
neighboring router fails.

Default node-protect

from

Syntax from ip-address

Context config>router>mpls>lsp

Description This optional command specifies the IP address of the ingress router for the LSP. When this

command is not specified, the system IP address is used. IP addresses that are not defined in the
system are allowed. If an invalid IP address is entered, LSP bring-up fails and an error is logged.

If an interface IP address is specified as the from address, and the egress interface of the nexthop IP
address is a different interface, the LSP is not signaled. As the egress interface changes due to
changes in the routing topology, an LSP recovers if the from IP address is the system IP address and
not a specific interface IP address.

Only one from address can be configured.

Default The system IP address

Parameters ip-address — This is the IP address of the ingress router. This can be either the interface or the system

IP address. If the IP address is local, the LSP must egress through that local interface which
ensures local strictness.

Default System IP address

Values System IP or network interface IP addresses

hop-limit

Syntax hop-limit number

no hop-limit

Context config>router>mpls>lsp

config>router>mpls>lsp>fast-reroute

Description This command specifies the maximum number of hops that an LSP can traverse, including the ingress

and egress routers. An LSP is not set up if the hop limit is exceeded. This value can be changed
dynamically for an LSP that is already set up with the following implications:

If the new value is less than the current number of hops of the established LSP, the LSP is
brought down. Software then tries to re-establish the LSP within the new hop-limit number. If

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 91

MPLS Commands

the new value is equal to or greater than the current number hops of the established LSP, then the
LSP is not affected.

The no form of this command returns the parameter to the default value.

Default 255

Parameters number — The number of hops the LSP can traverse, expressed as an integer.

Val ues 2 — 255

include

Syntax [no] include group-name [group-name...(up to 5max)]

Context config>router>mpls>lsp

config>router>mpls>lsp>primary
config>router>mpls>lsp>secondary

Description This command specifies the admin groups to be included when an LSP is set up. Up to 5 groups per

operation can be specified, up to 32 maximum.

The no form of the command deletes the specified groups in the specified context.

Default no include

Parameters group-name — Specifies admin groups to be included when an LSP is set up.

metric

Syntax metric metric

Context config>router>mpls>lsp

Description This command specifies the metric for this LSP which is used to select an LSP among a set of LSPs

which are destined to the same egress router. The LSP with the lowest metric will be selected.

Default 1

Parameters metric — Specifies the metric for this LSP which is used to select an LSP among a set of LSPs which

are destined to the same egress router.

Val ues 1 — 65535

Page 92 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

to

Syntax to ip-address

Context config>router>mpls>lsp

Description This command specifies the system IP address of the egress router for the LSP. This command is

mandatory to create an LSP.

An IP address for which a route does not exist is allowed in the configuration. If the LSP signaling
fails because the destination is not reachable, an error is logged and the LSP operational status is set
to down.

Default No default

Parameters ip-address — The system IP address of the egress router.

retry-limit

Syntax retry-limit number

no retry-limit

Context config>router>mpls>lsp

Description This optional command specifies the number of attempts software should make to re-establish the

LSP after it has failed LSP. After each successful attempt, the counter is reset to zero.

When the specified number is reached, no more attempts are made and the LSP path is put into the
shutdown state.

Use the config router mpls lsp lsp-name no shutdown command to bring up the path after the retry­limit is exceeded.

The no form of this command revert the parameter to the default value.

Default 0 (no limit, retries forever)

Parameters number — The number of times software will attempt to re-establish the LSP after it has failed.

Allowed values are integers in the range of 0 to 10000 where 0 indicates to retry forever.

Values 0 — 10000

retry-timer

Syntax retry-timer seconds

no retry-timer

Context config>router>mpls>lsp

Description This command configures the time, in seconds, for LSP re-establishment attempts after it has failed.

The no form of this command reverts to the default value.

Default 30

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 93

MPLS Commands

Parameters seconds — The amount of time, in seconds, between attempts to re-establish the LSP after it has

failed. Allowed values are integers in the range of 1 to 600.

Val ues 1 — 600

rsvp-resv-style

Syntax rsvp-resv-style [se | ff]

Context config>router>mpls>lsp

Description This command specifies the RSVP reservation style, shared explicit (se) or fixed filter (ff). A

reservation style is a set of control options that specify a number of supported parameters. The style
information is part of the LSP configuration.

Default se

Parameters ff — Fixed filter is single reservation with an explicit scope. This reservation style specifies an

explicit list of senders and a distinct reservation for each of them. A specific reservation request
is created for data packets from a particular sender. The reservation scope is determined by an
explicit list of senders.

se — Shared explicit is shared reservation with a limited scope. This reservation style specifies a

shared reservation environment with an explicit reservation scope. This reservation style creates
a single reservation over a link that is shared by an explicit list of senders. Because each sender is
explicitly listed in the RESV message, different labels can be assigned to different sender­receiver pairs, thereby creating separate LSPs.

shutdown

Syntax [no] shutdown

Context config>router>mpls>lsp

Description This command disables the existing LSP including the primary and any standby secondary paths.

To shutdown only the primary enter the config router mpls lsp lsp-name primary path-name
shutdown command.

To shutdown a specific standby secondary enter the config router mpls lsp lsp-name secondary
path-name shutdown command. The existing configuration of the LSP is preserved.

Use the no form of this command to restart the LSP. LSPs are created in a shutdown state. Use this
command to administratively bring up the LSP.

Default shutdown

Page 94 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 95

MPLS Commands

Primary and Secondary Path Commands

primary

Syntax primary path-name

no primary

Context config>router>mpls>lsp

Description This command specifies a preferred path for the LSP. This command is optional only if the

secondary path-name is included in the LSP definition. Only one primary path can be defined for an
LSP.

Some of the attributes of the LSP such as the bandwidth, and hop-limit can be optionally specified as
the attributes of the primary path. The attributes specified in the primary path path-name command,
override the LSP attributes.

The no form of this command deletes the association of this path-name from the LSP lsp-name. All
configurations specific to this primary path, such as record, bandwidth, and hop limit, are deleted.
The primary path must be shutdown first in order to delete it. The no primary command will not
result in any action except a warning message on the console indicating that the primary path is
administratively up.

Default none

Parameters path-name — The case-sensitive alphanumeric name label for the LSP path up to 32 characters in

length.

secondary

Syntax [no] secondary path-name

Context config>router>mpls>lsp

Description This command specifies an alternative path that the LSP uses if the primary path is not available.

This command is optional and is not required if the config router mpls lsp lsp-name primary path-
name command is specified. After the switch over from the primary to the secondary, the software

continuously tries to revert to the primary path. The switch back to the primary path is based on the
retry-timer interval.

Up to eight secondary paths can be specified. All the secondary paths are considered equal and the
first available path is used. The software will not switch back among secondary paths.

Software starts the signaling of all non-standby secondary paths at the same time. Retry counters are
maintained for each unsuccessful attempt. Once the retry limit is reached on a path, software will not
attempt to signal the path and administratively shuts down the path. The first successfully established
path is made the active path for the LSP.

The no form of this command removes the association between this path-name and lsp-name. All
specific configurations for this association are deleted. The secondary path must be shutdown first in

Page 96 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

order to delete it. The no secondary path-name command will not result in any action except a
warning message on the console indicating that the secondary path is administratively up.

Default none

Parameters path-name — The case-sensitive alphanumeric name label for the LSP path up to 32 characters in

length.

adaptive

Syntax [no] adaptive

Context config>router>mpls>lsp>primary

config>router>mpls>lsp>secondary

Description This command enables the make-before-break functionality for an LSP or a primary or secondary

LSP path. When enabled for the LSP, make-before-break will be performed for primary path and all
the secondary paths of the LSP.

Default adaptive

bandwidth

Syntax bandwidth rate-in-mbps

no bandwidth

Context config>router>mpls>lsp>primary

config>router>mpls>lsp>secondary

Description This command specifies the amount of bandwidth to be reserved for the LSP path.

The no form of this command resets bandwidth parameters (no bandwidth is reserved).

Default no bandwidth (bandwidth setting in the global LSP configuration)

Parameters rate-in-mbps — The amount of bandwidth reserved for the LSP path in Mbps. Allowed values are

integers in the range of 1 to 100000.

Values 0 — 100000

exclude

Syntax [no] exclude group-name [group-name...(up to 5 max)]

Context config>router>mpls>lsp>primary

config>router>mpls>lsp>secondary

Description This command specifies the admin groups to be excluded when an LSP is set up. . Up to 5 groups per

operation can be specified, up to 32 maximum. The admin groups are defined in the
config>router>mpls>admin-group context.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 97

MPLS Commands

Use the no form of the command to remove the exclude command.

Default no exclude

Parameters group-name — Specifies the existing group-name to be excluded when an LSP is set up.

hop-limit

Syntax hop-limit number

no hop-limit

Context config>router>mpls>lsp>primary

config>router>mpls>lsp>secondary

Description This optional command overrides the config router mpls lsp lsp-name hop-limit command. This

command specifies the total number of hops that an LSP traverses, including the ingress and egress
routers.

This value can be changed dynamically for an LSP that is already set up with the following
implications:

If the new value is less than the current hops of the established LSP, the LSP is brought down. MPLS
then tries to re-establish the LSP within the new hop-limit number. If the new value is equal or more
than the current hops of the established LSP then the LSP will be unaffected.

The no form of this command reverts the values defined under the LSP definition using the config
router mpls lsp lsp-name hop-limit command.

Default no hop-limit

Parameters number — The number of hops the LSP can traverse, expressed as an integer.

Val ues 2 — 255

path-preference

Syntax [no] path-preference value

Context config>router>mpls>lsp>secondary

Description This command enables use of path preference among configured standby secondary paths per LSP. If

all standby secondary paths have a default path-preference value then a non-standby secondary path
remains an active path, while a standby secondary is available. A standby secondary path configured
with highest priority (lowest path-preference value) must be made the active path when the primary is
not in use. Path preference can be configured on standby secondary path.

The no form of this command resets the path-preference to the default value.

Default 255

Parameters value — Specifies an alternate path for the LSP if the primary path is not available.

Val ues 1–255

Page 98 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

record

Syntax [no] record

Context config>router>mpls>lsp>primary

config>router>mpls>lsp>secondary

Description This command enables recording of all the hops that an LSP path traverses. Enabling record

increases the size of the PATH and RESV refresh messages for the LSP since this information is
carried end-to-end along the path of the LSP. The increase in control traffic per LSP may impact
scalability.

The no form of this command disables the recording of all the hops for the given LSP. There are no
restrictions as to when the no command can be used. The no form of this command also disables the
record-label command.

Default record

record-label

Syntax [no] record-label

Context config>router>mpls>lsp>primary

config>router>mpls>lsp>secondary

Description This command enables recording of all the labels at each node that an LSP path traverses. Enabling

the record-label command will also enable the record command if it is not already enabled.

The no form of this command disables the recording of the hops that an LSP path traverses.

Default record-label

srlg

Syntax [no] srlg

Context config>router>mpls>lsp>secondary

Description This command enables the use of the SRLG constraint in the computation of a secondary path for an

LSP at the head-end LER.

When this feature is enabled, CSPF includes the SRLG constraint in the computation of the
secondary LSP path. This requires that the primary LSP already be established and is up since the
head-end LER needs the most current ERO computed by CSPF for the primary path. CSPF would
return the list of SRLG groups along with the ERO during primary path CSPF computation. At a
subsequent establishment of a secondary path with the SRLG constraint, the MPLS/RSVP task will
query again CSPF providing the list of SLRG group numbers to be avoided. CSPF prunes all links
with interfaces which belong to the same SRLGs as the interfaces included in the ERO of the primary
path. If CSPF finds a path, the secondary is setup. If not, MPLS/RSVP will keep retrying the requests
to CSPF.

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 99

MPLS Commands

If CSPF is not enabled on the LSP name, then a secondary path of that LSP which has the SRLG
constraint included will be shut down and a specific failure code will indicate the exact reason for the
failure in show>router>mpls>lsp>path>detail output.

At initial primary LSP path establishment, if primary does not come up or primary is not configured,
SRLG secondary will not be signaled and will put to down state. A specific failure code will indicate
the exact reason for the failure in show>router>mpls>lsp>path>detail output. However, if a non­SRLG secondary path was configured, such as a secondary path with the SRLG option disabled,
MPLS/RSVP task will signal it and the LSP use it.

As soon as the primary path is configured and successfully established, MPLS/RSVP moves the LSP
to the primary and signals all SRLG secondary paths.

Any time the primary path is re-optimized, has undergone MBB, or has come back up after being
down, MPLS/RSVP task checks with CSPF if the SRLG secondary should be re-signaled. If MPLS/
RSVP finds that current secondary path is no longer SRLG disjoint, for example, it became
ineligible, it puts it on a delayed MBB immediately after the expiry of the retry timer. If MBB fails at
the first try, the secondary path is torn down and the path is put on retry.

At the next opportunity the primary goes down, the LSP will use the path of an eligible SRLG
secondary if it is UP. If all secondary eligible SLRG paths are Down, MPLS/RSVP will use a non
SRLG secondary if configured and UP. If while the LSP is using a non SRLG secondary, an eligible
SRLG secondary came back up, MPLS/RSVP will not switch the path of the LSP to it. As soon as
primary is re-signaled and comes up with a new SLRG list, MPLS/RSVP will re-signal the secondary
using the new SRLG list.

A secondary path which becomes ineligible as a result of an update to the SRLG membership list of
the primary path will have the ineligibility status removed on any of the following events:

1. A successful MBB of the standby SRLG path which makes it eligible again.

2. The standby path goes down. MPLS/RSVP puts the standby on retry at the expiry of the retry
timer. If successful, it becomes eligible. If not successful after the retry-timer expired or the
number of retries reached the number configured under the retry-limit parameter, it is left
down.

3. The primary path goes down. In this case, the ineligible secondary path is immediately torn
down and will only be re-signaled when the primary comes back up with a new SRLG list.

Once primary path of the LSP is setup and is operationally up, any subsequent changes to the SRLG
group membership of an interface the primary path is using would not be considered until the next
opportunity the primary path is re-signaled. The primary path may be re-signaled due to a failure or
to a make-before-break operation. Make-before-break occurs as a result of a global revertive
operation, a timer based or manual re-optimization of the LSP path, or an operator change to any of
the path constraints.

One an SRLG secondary path is setup and is operationally UP, any subsequent changes to the SRLG
group membership of an interface the secondary path is using would not be considered until the next
opportunity secondary path is re-signaled. The secondary path is re-signaled due to a failure, to a re­signaling of the primary path, or to a make before break operation. Make-before break occurs as a
result of a timer based or manual re-optimization of the secondary path, or an operator change to any
of the path constraints of the secondary path, including enabling or disabling the SRLG constraint
itself.

Also, the user-configured include/exclude admin group statements for this secondary path are also
checked together with the SRLG constraints by CSPF

The no form of the command reverts to the default value.

Page 100 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide

MPLS and RSVP

Default no srlg

standby

Syntax [no] standby

Context config>router>mpls>lsp>secondary

Description The secondary path LSP is normally signaled once the primary path LSP fails. The standby keyword

ensures that the secondary path LSP is signaled and maintained indefinitely in a hot-standby state.
When the primary path is re-established then the traffic is switched back to the primary path LSP.

The no form of this command specifies that the secondary LSP is signaled when the primary path
LSP fails.

Default none

7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide Page 101

MPLS Commands

Page 102 7210 SAS OS 7210 SAS-K 2F4T6C MPLS Guide