CHA PTER
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
6-2
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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Configuring Supervisor Engine Redundancy
• With supervisor engine redundancy enabled, the supervisor engines may run different releases of
Cisco IOS software if both releases are Cisco IOS Release 12.1(12c)EW or later.
• The Forwarding Information Base (FIB) tables are cleared on a switchover. As a result, routed traffic
is interrupted until route tables reconverge.
• Static IP routes are maintained across a switchover because they are configured from entries in the
configuration file.
• Information about dynamic states maintained on the active supervisor engine is not synchronized to
the standby supervisor engine and is lost on switchover. Dynamic state information (such as border
gateway protocol [BGP] session information) is lost at switchover.
• The Catalyst 4507R switch and the 4510R switches are the only Catalyst 4500 series switch that
support supervisor engine redundancy.
• The Catalyst 4510R switch supports the WS-X4516 supervisor engine only. The Catalyst 4507R
switch supports the other redundant supervisor engines (Supervisor Engine II-Plus and Supervisor
Engine IV and WS-X4516). Do not mix and match different supervisor models in a redundancy
configuration.
• The active and standby supervisor engines must be in slots 1 and 2.
• Both the active and standby supervisor engines must support redundancy (Supervisor Engine
II-Plus, Supervisor Engine IV, and Supervisor Engine V). Earlier versions are not supported.
Chapter 6 Configuring Supervisor Engine Redundancy on the Catalyst 4507R and 4510R Switches
• Each supervisor engine must have the resources to run the switch on its own, which means that each
supervisor engine has its own Flash device and console port connections.
• Make separate console connections to each supervisor engine. Do not connect a Y cable to the
console ports.
• You must set the configuration register in the startup-config to autoboot. (See the “Modifying the
Boot Field” section on page 3-21.)
• With redundancy enabled, the supervisor engines can run different releases of Cisco IOS software
provided both releases are Release 12.1(12c)EW or later.
Note There is no support for booting from the network.
If these requirements are met, the switch functions in RPR mode by default.
Configuring Supervisor Engine Redundancy
Supervisor engine redundancy is configured by default when a second supervisor engine is detected.
This example shows how to display the redundancy state:
Switch#show redundancy states
my state = 13 -ACTIVE
peer state = 4 -STANDBY COLD
Mode = Duplex
Unit = Primary
Unit ID = 1
6-4
Redundancy Mode (Operational) = RPR
Redundancy Mode (Configured) = RPR
Split Mode = Disabled
Manual Swact = Enabled
Communications = Up
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Synchronizing the Supervisor Engine Configurations
client count = 4
client_notification_TMR = 30000 milliseconds
keep_alive TMR = 4000 milliseconds
keep_alive count = 1
keep_alive threshold = 7
RF debug mask = 0x0
Switch#
Synchronizing the Supervisor Engine Configurations
During normal operation, the startup-config, boot variables, config-registers, and VLAN database
configuration are synchronized by default between the two supervisor engines. In a switchover, the new
active supervisor engine uses the current configuration.
To manually synchronize the configurations used by the two supervisor engines, perform this task on the
active supervisor engine:
Command Purpose
Step 1
Step 2
Step 3
Step 4
Step 5
Switch(config)# redundancy
Switch(config-red)# main-cpu
Switch(config-r-mc)# auto-sync {startup-config |
config-register | bootvar | standard}
Switch(config-r-mc)# end
Switch# copy running-config startup-config
Enters redundancy configuration mode.
Enters main-cpu configuration submode.
Synchronizes the configuration elements.
Returns to privileged EXEC mode.
Forces a manual synchronization of the configuration
files in NVRAM.
Note This step is not required to synchronize the
running configuration file in dynamic
random-access memory (DRAM).
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Note The auto-sync command controls the synchronization of the CONFIG-REG, BOOTVAR and
STARTUP/PRIVATE configuration files only. The calendar and vlan database files are always
synchronized when they change.
This example shows how to reenable the default automatic synchronization feature using the auto-sync
standard command to synchronize the startup-config and config-register configuration of the active
supervisor engine with the standby supervisor engine: updates for the boot variables are automatic and
cannot be disabled.
Switch(config)# redundancy
Switch(config-red)# main-cpu
Switch(config-r-mc)# auto-sync standard
Switch(config-r-mc)# end
Switch# copy running-config startup-config
Note To manually synchronize individual elements of the standard auto-sync configuration, disable the default
automatic synchronization feature.
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Chapter 6 Configuring Supervisor Engine Redundancy on the Catalyst 4507R and 4510R Switches
Performing a Software Upgrade
This example shows how to disable default automatic synchronization and allow only automatic
synchronization of the config-registers of the active supervisor engine to the standby supervisor engine,
while disallowing synchronization of the startup configuration:
Switch(config)# redundancy
Switch(config-red)# main-cpu
Switch(config-r-mc)# no auto-sync standard
Switch(config-r-mc)# auto-sync config-register
Switch(config-r-mc)# end
Performing a Software Upgrade
The software upgrade procedure supported by supervisor engine redundancy allows you to upgrade the
Cisco IOS software image on the supervisor engines without reloading the system.
To perform a software upgrade, perform this task:
Command Purpose
Step 1
Switch# copy source_device:source_filename
slot0:target_filename
Copies the new Cisco IOS software image to bootflash on
both supervisor engines.
Step 2
Step 3
Or:
Switch# copy source_device:source_filename
bootflash:target_filename
Or:
Switch# copy source_device:source_filename
slaveslot0:target_filename
Or:
Switch# copy source_device:source_filename
slavebootflash:target_filename
Switch# config terminal
Switch(config)# config-register 0x2
Switch(config)# boot system flash
device:file_name
Switch# copy running-config start-config
Configures the supervisor engines to boot the new image.
Saves the configuration.
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Chapter 6 Configuring Supervisor Engine Redundancy on the Catalyst 4507R and 4510R Switches
Command Purpose
Step 4
Switch# redundancy reload peer
Reloads the standby supervisor engine and bring it back
online (running the new version of the Cisco IOS
software).
Note Before reloading the standby supervisor engine,
Step 5
Switch# redundancy force-switchover
Conducts a manual switchover to the standby supervisor
engine. The standby supervisor engine becomes the new
active supervisor engine running the new Cisco IOS
software image. The modules reload and the module
software downloads from the new active supervisor
engine.
The old active supervisor engine reboots with the new
image and becomes the standby supervisor engine.
Copying Files to the Standby Supervisor Engine
make sure you wait long enough to ensure that all
configuration synchronization changes have
completed.
This example shows how to perform a software upgrade:
Switch# config terminal
Switch(config)# config-register 0x2
Switch(config)# boot system flash slot0: cat4000-is-mz.121-11b.EW
Switch# copy running-config start-config
Switch# redundancy reload peer
Switch# redundancy force-switchover
Switch#
Copying Files to the Standby Supervisor Engine
If you want to manually copy a file from the active supervisor engine to the slot0: device on the standby
supervisor engine, use this command:
Switch# copy source_device:source_filename slaveslot0:target_filename
To copy a file to the bootflash: device on a standby supervisor engine, use this command:
Switch# copy source_device:source_filename slavebootflash:target_filename
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Copying Files to the Standby Supervisor Engine
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