2 4510's, One with Dual SUP's, One with Single

Unanswered Question
Oct 20th, 2009

Hello Everyone,

Need your input on the following:

I have an existing 4510 with dual sup configuration (active/standby) sso mode. We will be adding another 4510 as a redundant chassis. I am planning on implementing HSRP, and configure it both switches as Active/Standby setup.

My question is regarding the existing switch with the dual SUP's. Should I leave it as such? Make it the active switch. I don't think I need to configure HSRP on the standby SUP, right?

I guess what I am hoping to happen is, if the active SUP fails, the standby SUP takes over on the same switch. If the whole switch fails, the secondary switch takes over.

Is that how it would work? Any other solutions to consider with what I will have in terms of hardware?


I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Jon Marshall Tue, 10/20/2009 - 16:46


Will the redundant chassis have 2 supervisors as well ?

If not there is an argument to just have one supervisor in each switch as failover can be quicker between chassis than it is between supervisors within the same chassis. Really depends on how fast you need failover to work.


isalem Tue, 10/20/2009 - 18:02


No, only the active chassis will have the 2 supervisors. The standby chassis will have just one supervisor. I am not running a routing protocol, just Layer-3 interfaces with static routes. I am assuming if the active supervisor fails in the active chassis, the standby supervisor would take over prior to the standby chassis. Does that make sense?

Reza Sharifi Tue, 10/20/2009 - 16:52

Hi Imad,

Since failover in SSO mode is in sub seconds and HSRP failover takes about 2 seconds the second sup should take over before the standby HSRP does.

But I would still get on outage window and test it.



isalem Tue, 10/20/2009 - 18:05


That is exactly what I am hoping for. Do you think it would be more reliable to just have one supervisor in each chassis?

Reza Sharifi Wed, 10/21/2009 - 06:19


I think with 2 chassis and 1 Sup in each chassis you are good to go. I only use 2 Sups if I do not have chassis redundancy like in the access closets where I have 200 people connected to one chassis.




This Discussion