2504 LAG to Redundant 4500 Switches

[Scott Pickles]

Can I create two separate LAG groups to two different 4500 switches that are etherchanneled together?  The docs on the 2500 indicate that the LAG ports must go to the same switch unless it's a 6000 in VSS mode or Nexus VPC.  However, I'm just looking for essentially a cold stand by failover, not active-active.  Attached are some diagrams.

[Rasika Nayanajith · Accepted solution]

NO, once you enable LAG, all ports of controller belong to same port group. So other end should be VSS/VPC pair if it is two different chassis

HTH

Rasika

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[Scott Pickles]

That's what I figured.  I'll set everything up and then just keep the ports on the backup chassis shut down.  It won't be automatic failover, but then again wireless for us isn't mission critical.

[Scott Fella]

Scott,

Since the 2504 is typically in smaller environments due to the AP limit and client limit, what you can look at is not using LAG, but defining a primary and secondary port.  So if port 1-2 is on switch 1 and port 3-4 is on switch 2, you can setup the 2504 like this:

Management interface:

  port 1 primary

  port 3 backup

Dynamic interfaces for your SSID's:

  port 2 primary

  port 4 backup

You can define some dynamic interfaces using the same as management also, but at least you have redundancy if a chassis fails with no manual intervention.

-Scott 

[Scott Pickles]

Scott - 

Yup.  But it's been a while since I've used dynamic interfaces and was hoping to have 2 GB throughput rather than 1 GB.  I think I'll hook it all up physically the way I want it and keep the ports on the backup switch shut down.  Then I'll just open them in the event of a failure.