Cisco catalyst 6500 series Configuration Note page 82

Configuring Fault Tolerance
Connection redundancy by configuring a link that has a 1-GB per-second capacity. Enable the
•
calendar in the switch Cisco IOS software so that the CSM state change gets stamped with the
correct time.
The following command enables the calendar:
Cat6k-2# configure terminal
Cat6k-2(config)# clock timezone WORD offset from UTC
Cat6k-2(config)# clock calendar-valid
Because each CSM has a different IP address on the client-side and server-side VLAN, the CSM can
send health monitor probes (see the
the network and receive responses. Both the active and standby CSMs send probes while operational. If
the passive CSM assumes control, it knows the status of the servers because of the probe responses it has
received.
Connection replication supports both non-TCP connections and TCP connections. Enter the replicate
csrp {sticky | connection} command in the virtual server mode to configure replication for the CSMs.
The default setting for the replicate command is disabled.
Note
To use connection replication for connection redundancy, enter these commands:
Cat6k-2# configure terminal
Cat6k-2(config)# no ip igmp snooping
You need to enter the no ip igmp snooping command because the replication frame has a multicast type
destination MAC with a unicast IP address. When the switch listens to the Internet Group Management
Protocol (IGMP) to find the multicast group membership and build its multicast forwarding information
database (FIB), the switch does not find group members and prunes the multicast table. All multicast
frames, from active to standby, are dropped causing erratic results.
If no router is present on the server-side VLAN, then each server's default route points to the aliased IP
address.
Figure 7-1
Catalyst 6500 Series Content Switching Module Configuration Note
7-2
"Configuring Probes for Health Monitoring" section on page
shows how the secure (router) mode fault-tolerant configuration is set up.
Chapter 7 Configuring Redundant Connections
9-1) to
OL-4612-01