Cisco WS-X6066-SLB-APC - Content Switching Module Software Manual page 500

MSFC Redundancy
Failure Case 3: Active Sup #1 Fails
This sequence occurs when the active supervisor engine (Sup #1) fails:
1.
2.
3.
4.
Failure Case 4: Standby Sup #2 Fails
This sequence occurs when the standby supervisor engine (Sup #2) fails:
1.
2.
3.
Failure Case 5: New or Previously Failed Supervisor Comes Back Online
This sequence occurs when the previously failed supervisor engine (Sup #2) comes online:
1.
2.
3.
4.
Configuring Redundancy with HSRP
Although the supervisor engine software high-availability feature maintains the protocol state between
redundant supervisor engines, you need to configure HSRP for failover between redundant MSFCs.
HSRP is used to provide the first-hop, unicast redundancy. You can configure one or more HSRP groups
on MSFC VLAN interfaces to provide automatic routing backup for your network. Each VLAN interface
in an HSRP group shares a virtual IP address and MAC address. You can configure end stations and
other devices to use the HSRP address as the default gateway so that if one router interface fails, service
is not interrupted to those devices.
The interface with the highest HSRP priority is the active interface for that HSRP group.
Note PFC2: The PFC2 supports a maximum of 16 unique HSRP group numbers. You can use the same
HSRP group numbers in different VLANs. If you configure more than 16 HSRP groups, this
restriction prevents use of the VLAN number as the HSRP group number.
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
22-26
Because the Layer 3 state is maintained, MLS entries of MSFC #1 gracefully age out of the
Sup #2 Layer 3 cache while MSFC #2 takes temporary ownership of these MLS entries using its
XTAG value.
The standby supervisor engine maintains the Layer 2 state so that there is no Layer 2 convergence
time.
MSFC #2 removes all dynamic and reflexive ACLs programmed in hardware by MSFC #1.
MSFC #2 reprograms the static ACLs in the Sup #2 ACL ASIC. MSFC #2 is now the designated
MSFC.
MLS entries for MSFC #2 gracefully age out of the Sup #1 Layer 3 cache while MSFC #1 takes
temporary ownership of these MLS entries using its XTAG value.
MLS entries from MSFC #1 are not affected.
MSFC #1 removes all dynamic and reflexive ACLs programmed in hardware by MSFC #2.
MSFC #1 remains the designated MSFC.
Sup #1 continues to be the active supervisor engine.
Sup #2 synchronizes its image and configuration with Sup #1 (unless high-availability versioning is
enabled).
MSFC #2 (on Sup #2) comes up. If the HSRP preempt for VLAN 21 is configured, then MSFC #2
becomes HSRP active. The MLS entries for MSFC #1 are purged and then relearned via MSFC #2.
MSFC #1 remains the designated MSFC for the static ACLs.
Chapter 22 Configuring Redundancy
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