06-08-2009 07:20 AM - edited 03-06-2019 06:08 AM
Hi Folks,
Does anyone know what the recovery time would be if the stackmaster fails? In this case, the stack is running some L3 features and routing etc...
The time i am interested in is the time from the failure, to the time that all the L3 next hops become available with the new master back online.
TIA
Alan
06-08-2009 07:49 AM
All stack members share the routing table, and can continue routing traffic.
This is what documentation say, I have not tried yet.
"If a stack master fails, the stack detects that the stack master is down and elects one of the stack members to be the new stack master. During this period, except for a momentary interruption, the hardware continues to forward packets with no active protocols.
However, even though the switch stack maintains the hardware identification after a failure, the routing protocols on the router neighbors might flap during the brief interruption before the stack master restarts."
Guido
06-08-2009 09:03 AM
* Make sure you implement NSO/SSF
* In a routing stack , use the "stack-mac persistent" feature. This way the stacks mac address (default gateway etc) will not change during master failover.
* Also carefully look at your other L3 links, so you don't blackhole any traffic if one switch in a stack fails and the rest stays up.
Then convergence should be fairly quick
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