Cisco Systems WSC4500X16SFP Supervisor Engine Redundancy Guidelines and Restrictions

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Software Configuration Guide—Release 12.2(25)SG

OL-7659-03

Chapter6 Configuring Supervisor Engine Red undancy Using RPR and SSO

Supervisor Engine Redundancy Guidelines and Restrictions

When a redundant supervisor engine runs in SSO mode, the following events trigger synchronization of

the configuration information:

•When the active supervisor detects the redundant supervisor engine, sync hronization of the

persistent and running configuration takes place, allowing the redundant supervisor engine to arrive

at a fully-initiated state.

•When real-time changes occur, the active supervisor engine synchronizes the running-config and

(or) the persistent configuration (if necessary) with the redundant supervisor engine.

•When you change the configuration, you must use the write command to allow the active supervisor

engine to save and synchronize the startup configuration of the redundant supervisor engine.

Supervisor Engine Redundancy Guidelines and Restrictions

The following guidelines and restrictions apply to supervisor engine redundancy:

•RPR requires Release 12.1(12c)EW, Release 12.1(19)E or later releases. SSO requires Release

12.2(20)EWA.

•The Catalyst 4507R switch and the 4510R switch are the only Catalyst 4500 series switches that

support supervisor engine redundancy.

•The Catalyst 4510R switch only supports the WS-X4516 and WS-X4516-10GE supervisor engines.

The Catalyst 4507R switch supports supervisor engines WS-X4013+, WS-X4515, and WS-X4516.

•To select the 10-Gigabit Ethernet or Gigabit Ethernet uplinks on the WS-X4516-10GE, use the

hw-module uplink select command.

•Redundancy requires both supervisor engines in the chassis to be of th e same supervisor engine

model and to use the same Cisco IOS software image.

•When you use the WS-X4013+ and WS-X4515 supervisor engines in RPR or SSO mode, only the

Gig1/1 and Gig2/1 Gigabit Ethernet interfaces are available, but the Gig1/2 and Gig2/2 uplink ports

are unavailable.

•When the WS-X4516 active and redundant supervisor engines are installed in the same chassis, the

four uplink ports (Gig1/1, Gig2/1, Gig 1/2, and Gig2/2) are available.

•The active and redundant supervisor engines in the chassis must be in slots 1 and 2.

•Each supervisor engine in the chassis must have its own Flash device and console port connections

to operate the switch on its own.

•Each supervisor engine must have a unique console connection. Do not connect a Y cable to the

console ports.

•Supervisor engine redundancy does not provide supervisor engine load balancing.

•The Cisco Express Forwarding (CEF) table is cleared on a switchover. As a result, routed traffic is

interrupted until route tables reconverge. This reconvergence time is minimal because the SSO

feature reduces the supervisor engine redundancy switchover time from 30+ seconds to subseco nds,

so Layer 3 also has a faster failover time if the switch is configured for SSO.

•Static IP routes are maintained across a switchover because they are configured from entries in the

configuration file.

•Information about Layer 3 dynamic states that is maintained on the active supervisor engine is not

synchronized to the redundant supervisor engine and is lost on sw itchover.