Avaya Interface and Router Redundancy User Manual

Conﬁguring Interface and Router Redundancy

BayRS V ersion 12.00 Site Manager Software Version 6.00

Part No. 117346-A Rev. A September 1997

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117346-A Rev. A

About This Guide

Before You Begin .............................................................................................................xiv

Conventions .....................................................................................................................xiv

Acronyms ......................................................................................................................... xv

Ordering Bay Networks Publications ...............................................................................xvi

Bay Networks Customer Service .....................................................................................xvi

How to Get Help .............................................................................................................xvii

Chapter 1 Interface Redundancy Overview

Active Interface ...............................................................................................................1-1

Redundant Interfaces .....................................................................................................1-1

Interface Roles ...............................................................................................................1-2

Determining the Active Interface ..............................................................................1-2

Reset Active Feature .........................................................................................1-2

Determining Priority .................................................................................................1-2

BofL Parameters and Role Change Speed on Ethernet ....................................1-3

Hot and Warm Standby .....................................................................................1-3

Active Interface MAC Address ........................................................................................1-4

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Chapter 2 Router Redundancy Overview

Primary Router ...............................................................................................................2-1

Dedicated Secondary Router .........................................................................................2-1

Redundancy Protocol .....................................................................................................2-2

Role Change ...................................................................................................................2-6

Router Failure ..........................................................................................................2-6

Interface Failure .......................................................................................................2-6

BofL Parameters and Role Change Speed for Ethernet ....................................2-6

Resource Availability ................................................................................................2-7

Requirements .................................................................................................................2-7

Chapter 3 Implementation Notes

Planning Your Network ....................................................................................................3-1

Protocols Supported .......................................................................................................3-2

LAN Interfaces ................................................................................................................3-2

Router Redundancy Requirements ................................................................................3-3

Using Interface and Router Redundancy in Combination ..............................................3-3

Compatibility ...................................................................................................................3-4

Chapter 4 Conﬁguring Interface Redundancy

Enabling Interface Redundancy ......................................................................................4-1

Adding and Deleting Interfaces within a Group ..............................................................4-6

Removing Interface Redundancy from a Circuit .............................................................4-7

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Chapter 5 Conﬁguring Router Redundancy

Enabling Router Redundancy .........................................................................................5-2

Creating a Group Conﬁguration File ...............................................................................5-2

Router Redundancy Group Parameters .........................................................................5-8

Conﬁguring Resources .................................................................................................5-12

Router Redundancy Resource Parameters ..................................................................5-15

Applying a Group Conﬁguration File .............................................................................5-17

Router Redundancy Member Global Parameters .........................................................5-20

Sending the Conﬁguration Files to the Routers ............................................................5-22

Conﬁguring Router Redundancy on Model 5380 Routers ............................................5-22

Conﬁguring Router Redundancy on One 5380 Router ..........................................5-22

Conﬁguring Router Redundancy on Different 5380 Routers ..................................5-23

Removing Router Redundancy ....................................................................................5-23

Appendix A Site Manager Default Parameter Settings

Appendix B Router Redundancy Examples

Example 1: Two Routers at the Same Site .................................................................... B-1

Router Bootup ......................................................................................................... B-1

Possible Scenarios .................................................................................................. B-2

Secondary Router Degraded ............................................................................ B-2

Secondary Router Becomes Inoperable ........................................................... B-2

Primary Router Degraded ................................................................................. B-2

Primary Router Fails ......................................................................................... B-2

Possible Complications ........................................................................................... B-3

Router Boots and Cannot Detect Another Member .......................................... B-3

Second Router Boots After First Router’s Bidding Timer Expires ..................... B-3

Manual versus Auto Role Switching ................................................................. B-3

Example 2: Three Routers at the Same Site ................................................................. B-4

Example 3: Router Redundancy with Wide Area Networks ........................................... B-5

Example 4: Router Redundancy with Ethernet Switches .............................................. B-7

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vii

Appendix C Worksheets for Conﬁguring Router Redundancy

Appendix D BofL Parameters

Setting BofL Parameters ................................................................................................D-1

Index

viii

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Figures

Figure 4-1. Add Circuit Window ..................................................................................4-2

Figure 4-2. Edit Connector Window ............................................................................4-3

Figure 4-3. Circuit Deﬁnition Window .........................................................................4-4

Figure 4-4. Select Primary Window ............................................................................4-5

Figure 4-5. Circuit Deﬁnition Window with Primary Interface .....................................4-5

Figure 5-1. Main Site Manager Window .....................................................................5-3

Figure 5-2. Add Circuit Window ..................................................................................5-4

Figure 5-3. Select Protocols Window .........................................................................5-5

Figure 5-4. Router Redundancy Circuit Window ........................................................5-6

Figure 5-5. R.R. Group Global Parameters Conﬁguration Window ............................5-7

Figure 5-6. RREDUND Router Redundancy Resource List Window .......................5-13

Figure 5-7. Router Redundancy Resource Window .................................................5-14

Figure 5-8. Conﬁguration Manager Window in Member Mode .................................5-17

Figure 5-9. Conﬁguration Manager Window for Member Conﬁguration ...................5-18

Figure 5-10. R.R. Member Global Parameters Conﬁguration Window .......................5-18

Figure 5-11. Save Conﬁguration File Window ............................................................5-19

Figure B-1. Router Redundancy: Two Routers at the Same Site ............................... B-1

Figure B-2. Router Redundancy: Three Routers at the Same Site ............................ B-4

Figure B-3. Router Redundancy with Wide Area Networks ....................................... B-5

Figure B-4. Router Redundancy with 281xx Fast Ethernet Switches ........................ B-7

Figure D-1. Edit CSMA/CD Parameters Window ....................................................... D-2

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Tables

Table 2-1. Redundancy Protocol PDU Flow Diagram for Role Bidding ....................2-2

Table 2-2. Redundancy Protocol PDU Flow Diagram for SOS PDUs .......................2-5

Table 3-1. Using Interface Redundancy across Slots with Router Redundancy .......3-4

Table A-1. Router Redundancy Group Global Parameters ...................................... A-1

Table A-2. Router Redundancy Member Global Parameters ................................... A-2

Table A-3. Router Redundancy Resource Parameters ............................................ A-2

Table C-1. Group Mode Planning Worksheet ...........................................................C-1

Table C-2. Resource Planning Worksheet ................................................................C-2

Table C-3. Member Mode Planning Worksheet ........................................................ C-2

117346-A Rev. A

About This Guide

Bay Networks® redundancy services enhance router resilience by enabling a router to recover from either interface or router failure with minimal delay.

Interface redundancy protects your network from failures of individual LAN interfaces on a router. Router redundancy protects your network from failures of the entire router. You can use these services separately or in combination to ensure smooth and continuous operation of your network.

If you want to Go to

117346-A Rev. A

Learn about interface redundancy and special aspects of the Bay Networks implementation of interface redundancy

Learn about router redundancy and special aspects of the Bay Networks implementation of router redundancy

Implement interface redundancy and router redundancy Chapter 3 Conﬁgure interface redundancy Chapter 4 Conﬁgure router redundancy Chapter 5 View default parameter values for router redundancy Appendix A Review examples of how you can use router redundancy in your

network Review worksheets that help you conﬁgure router redundancy Appendix C Conﬁgure BofL parameters Appendix B

Chapter

Chapter 2

Appendix B

xiii

Configuring Interface and Router Redundancy

Before You Begin

Before using this guide, you must complete the following procedures:

• Create and save a conﬁguration ﬁle.

• Retrieve the conﬁguration ﬁle in local or remote mode. Refer to Make sure that you are running the latest version of Bay Networks Site Manager

and router software. For instructions, refer to

7–11.xx to Version 12.00

Conventions

angle brackets (< >) Indicate that you choose the text to enter based on the

bold text

Conﬁguring and Managing Routers with Site Manager

Upgrading Routers from Version

description inside the brackets. Do not type the brackets when entering the command. Example: if command syntax is you enter

ping 192.32.10.12

ping

Indicates text that you need to enter, command names, and buttons in menu paths. Example: Enter

Example: Use the Example: ATM DXI > Interfaces >

wfsm &

dinfo

command.

PVCs

PVCs button in the window that appears when you select the Interfaces option from the ATM DXI menu.

for instructions.

<ip_address>

identiﬁes the

xiv

italic text

Indicates variable values in command syntax descriptions, new terms, ﬁle and directory names, and book titles.

quotation marks (“ ”) Indicate the title of a chapter or section within a book.

screen text

Indicates data that appears on the screen. Example:

Set Bay Networks Trap Monitor Filters

117346-A Rev. A

About This Guide

separator ( > ) Separates menu and option names in instructions and

internal pin-to-pin wire connections. Example: Protocols > AppleTalk identiﬁes the AppleTalk option in the Protocols menu.

Example: Pin 7 > 19 > 20

vertical line (|) Indicates that you enter only one of the parts of the

command. The vertical line separates choices. Do not type the vertical line when entering the command. Example: If the command syntax is

Acronyms

show at routes show at routes

BofL Breath of Life FDDI Fiber Distributed Data Interface IP Internet Protocol IPX Internet Packet Exchange LAN local area network MAC media access control MIB management information base OUI organizationally unique identiﬁer PDU protocol data unit VLAN virtual LAN WAN wide area network

nets

, you enter either

show at nets

, but not both.

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Configuring Interface and Router Redundancy

Ordering Bay Networks Publications

To purchase additional copies of this document or other Bay Networks publications, order by part number from Bay Networks Press numbers:

• Phone--U.S./Canada: 888-422-9773

• Phone--International: 510-490-4752

• FAX--U.S./Canada and International: 510-498-2609 The Bay Networks Press catalog is available on the World Wide Web at

support.baynetworks.com/Library/GenMisc

available on the World Wide Web at

support.baynetworks.com/Library/tpubs

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You can purchase a support contract from your Bay Networks distributor or authorized reseller, or directly from Bay Networks Services. For information about, or to purchase a Bay Networks service contract, either call your local Bay Networks ﬁeld sales ofﬁce or one of the following numbers:

™

at the following

. Bay Networks publications are

xvi

Region Telephone number Fax number

United States and Canada

Europe 33-4-92-96-69-66 33-4-92-96-69-96 Asia/Paciﬁc 61-2-9927-8888 61-2-9927-8899 Latin America 561-988-7661 561-988-7550

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508-916-8880 (direct)

508-916-3514

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support.baynetworks.com

117346-A Rev. A

How to Get Help

If you purchased a service contract for your Bay Networks product from a distributor or authorized reseller, contact the technical support staff for that distributor or reseller for assistance.

If you purchased a Bay Networks service program, call one of the following Bay Networks Technical Solutions Centers:

Technical Solutions Center Telephone number Fax number

Billerica, MA 800-2LANWAN 508-916-3514 Santa Clara, CA 800-2LANWAN 408-495-1188 Valbonne, France 33-4-92-96-69-68 33-4-92-96-69-98 Sydney, Australia 61-2-9927-8800 61-2-9927-8811 Tokyo, Japan 81-3-5402-0180 81-3-5402-0173

About This Guide

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xvii

Chapter 1

Interface Redundancy Overview

Interface redundancy provides backup of one interface by another within a single router. It protects your network from partial router or installation failures; it also enables you to maintain data transmission for critical interfaces without the expense of two routers.

You conﬁgure interfaces to be members of an group includes an services, and one or more interface fails.

You can conﬁgure multiple interface redundancy groups on the same router.

Active Interface

The active interface performs normal bridging and routing services. When you conﬁgure interface redundancy, you select one interface on the router

to have the highest priority for being the active interface. That interface is the

designated primary interface

primary interface is the active interface for the redundancy group. If the active interface fails, however, another interface in the group becomes the new active interface.

Redundant Interfaces

All members of an interface redundancy group other than the active interface are redundant interfaces. A redundant interface has no function other than to serve as a backup.

active interface,

redundant interfaces,

. Under normal circumstances, the designated

interface redundancy group

which performs normal routing and bridging

which take over if the active

. The

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1-1

Configuring Interface and Router Redundancy

Interface Roles

Bay Networks interface redundancy software determines which interface in a redundancy group becomes the active interf ace if the current acti v e interface f ails. The software also determines the priority for each of the remaining members of the group to become the active interface.

Determining the Active Interface

When you boot a router conﬁgured with interface redundancy, the designated primary interface has 12 seconds to become active. If it does become active, data transmission begins normally.

If the designated primary interface does not become active within 12 seconds, the redundant interface with the highest priority becomes the active interface, and transmission begins. The 12-second initialization period occurs only once, and applies only to the designated primary interface. After initialization, all redundant interfaces are ready to become active immediately if the active interface fails.

Reset Active Feature

Interface redundancy includes a Reset Active feature that allows you to force the interface you have designated as primary to become the active interface. Using this feature may improve network performance. Refer to Cha information about accessing the Reset Active feature.

Determining Priority

The redundant interface with the highest priority becomes the active interface if the active interface fails.

During startup, if the designated primary interface fails to become active, the following interfaces become active, in this order:

1. Redundant interfaces on the same slot as the designated primary interface

2. Redundant interfaces on other slots

1-2

pter 4 for

117346-A Rev. A

Interface Redundancy Overview

During normal data transfer, if the active interface fails, the following interfaces become active, in this order:

1. Redundant interfaces on the slot that is processing the routing/bridging table for this circuit

2. Redundant interfaces on other slots

BofL Parameters and Role Change Speed on Ethernet

When you enable BofL, the router only sends BofL messages if the interface is idle. If the interface is transmitting regular data trafﬁc, it does not send BofL messages.

Three parameters control BofL. The BofL Retries parameter sets the number of BofL messages the interface transmits before the router declares the circuit down. The number of seconds between BofL messages is the value of the BofL Timeout parameter divided by the BofL Timeout Divisor parameter.

To increase the speed of detecting failed interfaces and changing roles on Ethernet connectors, set the BofL Timeout parameter to a short interval, such as 1 second. If you also set the BofL Retries parameter to 4, and accept the BofL Timeout Divisor parameter default value of 1, a role change occurs in under 5 seconds. If you set the BofL Timeout Divisor parameter to a higher value, the router sends BofL messages so frequently that the cost in LAN bandwidth and CPU overhead is high.

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Refer to Appendix D for parameter descriptions and instructions for using Site Manager to edit these parameters.

Hot and Warm Standby

When a redundant interface takes over for a f ailed interface without interruption in service, it does so under one of two conditions:

hot standby

warm standby.

Hot Standby

When an active interface fails, but the circuit is still up, the new active interface retains access to the routing/bridging tables, and can continue transmission immediately.

1-3

Configuring Interface and Router Redundancy

Only if the routing/bridging tables are on another slot from the new active interface is there any loss in performance. The priority rules for interfaces to become active operate to avoid this situation whenever possible.

Warm Standby

When the active interface fails and the circuit has gone down, the CPU module processing the routing/bridging table is at fault, and the router loses the routing/bridging tables.

Transmission continues, but is slower than hot standby, because the new active interface must relearn the routing/bridging tables.

Active Interface MAC Address

When you conﬁgure interface redundancy, the active interface uses the following MAC address in hexadecimal radix:

0x 2

y yy

xx xxxx

• 0x 2 indicates that the address is locally administered by Bay Networks.

1-4

•

y yy indicates the circuit number.

• A2 identiﬁes the Bay Networks organizationally unique identiﬁer (OUI).

• xx xxxx is the unique router identiﬁcation number.

The active interface in an interface redundancy group uses the MAC address for all trafﬁc, including Breath of Life (BofL). The MAC address switches among interfaces in the interface redundancy group so that it always represents the active interface.

The MAC address affects the setup of network-layer protocol adjacent hosts on adjacent routers. For example, if you have adjacent routers and the IP adjacent host is deﬁned with its next hop being the active interface in an interface redundancy group, the adjacent host MAC address must be the active interface’s MAC address; that is, 0x 2y yy A2xx xxxx

The circuit number maps to a virtual LAN (VLAN) on the router. Multiple VLANs on the same router can be connected to frame switches.

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Interface Redundancy Overview

You ﬁnd the complete MAC address for the active interface in the interface management information base (MIB) -- Ethernet or FDDI -- of the router on which interface redundancy is conﬁgured. For example, if you are conﬁguring Ethernet, you can ﬁnd the active MAC address in the Ethernet MIB by entering the following command from the Technician Interface:

get wfCSMACDEntry.wfCSMACDMadr.*

Among the entries displayed in the MIB is the MAC address 0x 2y yy A2xx xxxx

, which is used for interface redundancy. If you conﬁgure more

than one interface redundancy group on the same router, you will see more than one entry with the same MAC address. This is not a problem because the two redundancy groups are in different subnets.

117346-A Rev. A 1-5

Chapter 2

Router Redundancy Overview

Router redundancy protects a network from the irrecoverable failure of an entire router. You conﬁgure routers to be members of a router redundancy group. The group includes a primary router that performs normal routing and bridging services, and one or more secondary routers that take over if the primary router fails.

Note: You can conﬁgure multiple router redundancy groups on the same

network.

Primary Router

Bay Networks router redundancy software allows you to decide which router has priority to be the primary router. It includes conﬁgurable bidding timers and timeout periods. These values determine how and when a router in a redundancy group changes roles from secondary to primary.

Dedicated Secondary Router

Bay Networks recommends that you conﬁgure router redundancy so that a secondary router has no function other than to serve as a backup. A router so conﬁgured is a dedicated secondary router.

You can conﬁgure a redundant router to carry other trafﬁc, unrelated to that of its redundancy group. Be aware, however, that if a secondary router becomes the primary router in a redundancy group, it stops performing any other data transfer operations; its role in the group takes precedence over any other functions you assign it.

117346-A Rev. A 2-1

Configuring Interface and Router Redundancy

Redundancy Protocol

Routers in a redundancy group all begin in the secondary role. A router assumes the primary role according to the following criteria, which the redundancy protocol considers in the following order:

1. Number of good interfaces

2. Number of reachable resources

3. Priority to become primary, which you conﬁgure

4. Lowest member ID (for further information, see the Member ID parameter in

Chapter 5)

For example, if two routers in a router redundancy group ha ve the same number of good interfaces, the protocol considers the number of reachable resources each router has. But if one router has a larger number of good interfaces, that router becomes primary without consideration of subsequent criteria.

The routers use a bidding process to determine which router becomes the primary router. If the group has more than two members, the bidding process also determines which of the backup routers is the best secondary router. The bidding process consists of an exchange of messages called protocol data units (PDUs).

able 2-1 provides a detailed description of this process.

Table 2-1. Redundancy Protocol PDU Flow Diagram for Role Bidding

Router A PDU Router B

Starts in secondary role. Starts in secondary role. Sends Hello PDUs at periodic intervals.

These PDUs start the bidding for the primary role.

2-2 117346-A Rev. A

Hello PDU Role = Secondary

---------------->

Receives Hello PDU from Router A and stores its contents in the redundancy group database.

Checks to see if Router A is a better primary router; if so, Router B does not plan to change roles.

(continued)

Router Redundancy Overview

Table 2-1. Redundancy Protocol PDU Flow Diagram for Role Bidding

Router A PDU Router B

Receives Hello PDU from Router B and stores its contents in the redundancy group database.

Checks to see if Router B is a better primary router; if so, Router A does not plan to change roles.

After the bidding period times out, the software determines that Router A is the best primary router. Router A sends the SOS New Primary PDU, and then changes role to become the primary router.

Receives the periodic Hello PDU and updates the redundancy group database, including each member’s interf ace status information.

Continues sending periodic Primary Hello PDUs with local interface status information. The Primary Hello PDUs from the primary router have additional meaning to other members of the redundancy group.

Hello PDU Role = Secondary <----------------

SOS New Primary PDU Role = Secondary

---------------->

Hello PDU Role = Secondary <----------------

Hello PDU Role = Primary

---------------->

Time Passes

Starts sending Hello PDUs at periodic intervals; these PDUs are Router B’s bids for the primary role.

After the bidding period times out, the software determines that another member of the router redundancy group is the best primary router. Router B remains in a secondary role and continues to monitor the redundancy group status.

Continues sending periodic Hello PDUs with local interface status information.

Receives the periodic Primary Hello PDUs and updates the redundancy group database, including each member’s interf ace status information. Restarts the Primary OK Timer.

(continued)

Primary router fails. Router A is in an unknown state; ma y not

have received this PDU.

Router A remains in an unknown state; may not have received this PDU.

117346-A Rev. A 2-3

SOS New Primary PDU Role = Secondary <----------------

Hello PDU Role = Primary <----------------

Primary OK Timer expires for Router B determines that the primary router has failed.

Based on information in the redundancy group database, the software determines that Router B is the best secondary router to become the new primary router.

Router B sends an SOS New Primary PDU, which prevents any other secondary router in the group from becoming the primary router.

Router B becomes the new primary router. As the new primary router, Router B

periodically sends Primary Hello PDUs with local interface status information.

times.

+ 61 hidden pages

Avaya Interface and Router Redundancy User Manual

Contents

Figures

Tables

About This Guide

Before You Begin

Conventions

Acronyms

Ordering Bay Networks Publications

Bay Networks Customer Service

How to Get Help

Active Interface

Redundant Interfaces

Interface Roles

Determining the Active Interface

Determining Priority

Active Interface MAC Address

Primary Router

Dedicated Secondary Router

Redundancy Protocol