23-27
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 23 Configuring Redundancy
MSFC Redundancy
Note While the examples are specific to the PFC, the failover scenarios for the PFC2/MSFC2 would be similar
for handling the ACLs and the CEF table entries. On a Supervisor Engine 2, the designated MSFC2
programs many of the ASICs on the PFC2 including building the CEF table. In a designated MSFC2
HSRP failover to the nondesignated MSFC2, the PFC2 continues to function with the CEF table that is
programmed by the previously designated MSFC2. Similar to the process with the MLS cache in a
Supervisor Engine 1/MSFC configuration, the newly designated MSFC2 reprograms the CEF table with
its own entries and the old entries age out.
Figure 23-4 Single Chassis with Dual Supervisor Engines and Dual MSFCs
Failure Case 1: Designated MSFC #1 Fails
This sequence occurs when the designated MSFC #1 fails:
1. The MLS entries for MSFC #1 gracefully age out of the Sup #1 Layer-3 cache, while MSFC #2
takes temporary ownership of these MLS entries using its XTAG value.
2. The MLS entries for MSFC #2 are not affected.
3. MSFC #2 removes all the dynamic and reflexive ACLs that are programmed in the hardware by
MSFC #1.
4. MSFC #2 reprograms the static ACLs in the Sup #1 ACL ASIC because it is now the designated
MSFC.
Failure Case 2: Nondesignated MSFC #2 Fails
This sequence occurs when the nondesignated MSFC #2 fails:
1. The 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.
2. The MLS entries from MSFC #1 are not affected.
3. MSFC #1 removes all the dynamic and reflexive ACLs that are programmed in the hardware by
MSFC #2.
4. MSFC #1 remains the designated MSFC.
To Next Page
Loading...
Need help?
General