CSCsm30320 Bug Details
REP When Traffic is sent on higher VLAN IDs, conv timings > 225ms
Symptom : In case of failure, sometimes the traffic sent on higher VLAN IDs takes around 225ms to recover.
Conditions : If there are a large number of vlans configured on the Switch having the ALT port,
then in case of failure, traffic on the higher vlan ids takes more time to recover as compared to the traffic on lower vlan ids. The more the number of vlans configured on the switch having ALT port, more is the convergence time for the traffic on highest vlan configured.
Work around: None
Software Versions Effected : 12.2(44)SG onward
Supervisors and Fixed Configuration Switches Effected : All Catalyst 4500 and 4900.
Further Problem Description :
On failure, ALT port has to be unblocked for each VLAN to which it belongs. Catalyst 4500 and 4900 Software unblocks the ALT port for each VLAN starting from VLAN 1 and going one-by-one upto the highest vlan configured. Hence, traffic sent on higher vlan ids has higher convergence timing.
In the current case, the switch having the ALT port has 4K vlans.