8-7
Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 8 Configuring Supervisor Engine Redundancy Using RPR and SSO Supervisor Engine Redundancy Guidelines and Restrictions
• In Cisco IOS Release 12.2(25)SG and later releases, when using a Supervisor Engine V-10GE
(WS-X4516-10GE) on a Catalyst 4510R series switch, you can select to use both the 10-Gigabit
Ethernet and Gigabit Ethernet uplinks concurrently, but only with a WS-X4302-GB in slot 10. If
either the 10-Gigabit Ethernet or Gigabit Ethernet uplinks are selected, then any line card is allowe
d in slot 10. To select the uplinks, use the hw-module uplink select configuration command. In
Cisco IOS releases earlier than 12.2(25)SG, you cannot use the 10-Gigabit Ethernet and Gigabit
Ethernet uplinks concurrently.
• When you select 10-Gigabit Ethernet uplinks on WS-X4516-10GE and WS-X4013+10GE
Supervisor Engines in RPR or SSO mode, only TenGigabitEthernet 1/1 and 2/1 interfaces are
available. Similarly, when you select Gigabit Ethernet uplinks, only GigabitEthernet 1/3, 1/4, 2/3,
and 2/4 interfaces are available. When you select to use both uplinks concurrently,
TenGigabitEthernet 1/1 and 2/1 interfaces and GigabitEthernet 1/3, 1/4, 2/3, and 2/4 interfaces are
available.
• Redundancy requires both supervisor engines in the chassis to have the same components (model,
memory, NFL daughter card), 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 subsecond,
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 switchover.
• Starting with Cisco IOS Release 12.2, if an unsupported condition is detected (such as when the
active supervisor engine is running Cisco IOS Release 12.2(20)EW and the redundant supervisor
engine is running Cisco IOS Release 12.1(20)EW), the redundant supervisor engine is reset multiple
times and then placed in ROMMON mode. It is important to follow the procedures outlined in the
“Performing a Software Upgrade” section on page 8-13.
• If you are running (or upgrading to) Cisco IOS Release 12.2(20)EWA or
Cisco IOS Release 12.2(25)EW and are using a single supervisor engine in a redundant chassis
(Catalyst 4507R or Catalyst 4510R series switch), and you intend to use routed ports, do one of the
following:
–
Use SVIs instead of routed ports.
–
Change the redundancy mode from SSO to RPR.