Cisco Systems Ws-C4507r+e User Manual

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6

Configuring Supervisor Engine Redundancy on the
Catalyst 4507R and 4510R Switches

This chapter describes how to configure supervisor engine redundancy on the Catalyst 4507R and
Catalyst 4510R switches.

This chapter consists of the following major sections:

• Overview of Supervisor Engine Redundancy, page 6-1

• Understanding Supervisor Engine Redundancy, page 6-2

• Supervisor Engine Redundancy Guidelines and Restrictions, page 6-3

• Configuring Supervisor Engine Redundancy, page 6-4

• Synchronizing the Supervisor Engine Configurations, page 6-5

• Performing a Software Upgrade, page 6-6

• Copying Files to the Standby Supervisor Engine, page 6-7

Note For complete syntax and usage information for the switch commands used in this chapter, look at the

Cisco Catalyst 4500 Series Switch Command Reference and related publications at this location:

http://www.cisco.com/en/US/products/hw/switches/ps4324/index.html

If the command is not found in the Catalyst 4500 Command Reference, it is located in the larger Cisco
IOS library. Refer to the Catalyst 4500 Series Switch Cisco IOS Command Reference and related
publications at this location:

http://www.cisco.com/en/US/products/ps6350/index.html

Overview of Supervisor Engine Redundancy

Catalyst 4500 series switches allow a standby supervisor engine to take over if the primary supervisor
engine fails, thereby allowing the switch to resume operation quickly in the event of a supervisor engine
failure. This capability is called supervisor engine redundancy. In software, this capability is enabled by
route processor redundancy (RPR) operating mode.

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Understanding Supervisor Engine Redundancy

The standby supervisor engine runs in RPR mode. When RPR mode is used, the standby supervisor
engine partially boots and keeps synchronized copies of the active configuration, which shortens the time
needed to bring up the standby supervisor engine and have it start handling traffic from 1.5 minutes (for
a cold boot on the standby) to 30 seconds (to finish the boot and reestablish links).

In addition to the reduced switchover time, supervisor engine redundancy supports the following:

• Online insertion and removal (OIR) of the standby supervisor engine.

• Software upgrade. (See the “Performing a Software Upgrade” section on page 6-6.)

• Auto-startup and bootvar synchronization.

• Hardware signals that detect and decide the active or standby status of supervisor engine.

• Automatic switchover to the standby supervisor engine if the active supervisor engine ever fails.

When the switch is powered on, the two supervisor engines determine which will serve as the primary
and which will be the standby. Usually, the supervisor engine that boots first, either in slot 1 or 2,
becomes the active supervisor engine.

A switchover will occur when one or more of the following events take place:

• The active supervisor engine fails or is removed.

• A user forces a switchover.

Chapter 6 Configuring Supervisor Engine Redundancy on the Catalyst 4507R and 4510R Switches

• A user reloads the active supervisor engine.

• A core dump occurs.

Note In a switchover, there is a disruption of traffic because some address states are lost and then restored after

they are dynamically redetermined.

Table 6-1 lists the chassis and supervisor support for redundancy.

Table 6-1 Chassis and Supervisor Support

Chassis
(Product Number) Supported Supervisor Engines

Catalyst 4507R
(WS-C4507R)

Supports redundant Supervisor Engine II-Plus and
(WS-X4013+) and redundant Supervisor Engine V, Supervisor
Engine IV (WS-X4515)

Catalyst 4510R
(WS-C4510R)

Supports redundant Supervisor Engine VSupervisor Engine V,
(WS-X4516)

Understanding Supervisor Engine Redundancy

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These sections describe supervisor engine redundancy:

• Operation, page 6-3

• Supervisor Engine Synchronization, page 6-3

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Chapter 6 Configuring Supervisor Engine Redundancy on the Catalyst 4507R and 4510R Switches

Operation

With supervisor engine redundancy enabled, the standby supervisor engine automatically takes over for
the primary supervisor engine if the active supervisor engine fails or if a manual switchover occurs. The
standby supervisor engine has already been automatically initialized and configured, shortening the
switchover time. Supervisor engine redundancy provides these additional benefits:

• Online insertion and removal (OIR) of the standby supervisor engine

Supervisor engine redundancy allows OIR of the standby supervisor engine for maintenance. When
the standby supervisor engine is inserted, the active supervisor engine detects its presence and
begins to transition the standby supervisor engine to the fully initialized state.

• Software upgrade

To minimize software upgrade and downgrade times, you can preload the standby supervisor engine
with the software version you want to upgrade or downgrade to and then configure the system to
switch over to the standby supervisor engine.

Supervisor engine redundancy also supports manual user-initiated switchover. You can initiate a
switchover with the redundancy force-switchover command.

Supervisor Engine Redundancy Guidelines and Restrictions

Supervisor Engine Synchronization

Because the standby supervisor engine is not fully initialized, it interacts with the active supervisor
engine only to receive configuration changes as they occur, keeping the configuration information on
both supervisor engines identical. This synchronization of the startup configuration file is enabled by
default in RPR mode. You cannot enter CLI commands on the standby supervisor engine.

When a standby supervisor engine is running in RPR mode, the following operations trigger
synchronization of the configuration information:

• When a standby supervisor engine first comes online, the configuration information is synchronized

from the active supervisor engine to the standby supervisor engine. This synchronization overwrites
any existing startup configuration file on the standby supervisor engine.

• If the auto-synch command is enabled, changes to the startup configuration on the active supervisor

engine are automatically synchronized on the standby supervisor.

Supervisor Engine Redundancy Guidelines and Restrictions

The following guidelines and restrictions apply to supervisor engine redundancy:

• Supervisor engine redundancy does not provide supervisor engine load balancing or any other

feature requiring two active supervisor engines. Only one supervisor engine is active. Network
services are disrupted until the standby supervisor engine takes over and the switch recovers.

• When using RPR mode with WS-4513+ and WS-X4515 supervisor engines, only the Gig 1/1 and

Gig 2/1 Gigabit Ethernet interfaces on each supervisor engine are available. The Gig 1/2 and Gig
2/2 interfaces are not available.

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Note This restriction applies only to the WS-4513+ and WS-X4515 supervisor engines. The

WS-X4516 supervisor engines support all four Gigabit Ethernet interfaces in RPR mode.

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