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kridsana_52318's avatar
kridsana_52318
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Feb 21, 2014

vPC and LACP: why passive mode?

Question about LACP and vPC.

 

I have a problem with a BIG-IP pair connected to two Cisco N7K switches, with an LACP trunk with vPC. As per this solution article: http://support.f5.com/kb/en-us/solutions/public/13000/100/sol13142.html LACP is active on the switches and passive on the BIG-IPs.

 

During switch failover, the trunk member interfaces go down for a period of time. I want to change LACP to active-active mode (which is what Cisco recommends), but I want to understand why F5 suggests passive mode, in case I'm just creating a new problem trying to solve this one.

 

Does anyone know what the impact of running LACP in active-active mode with vPC on N7Ks is?

 

Thanks,

 

cr Adam

 

application delivery
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BIG-IP Access Policy Manager (APM)
deployment
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1 Reply

  • Night_67217's avatar
    Night_67217
    Historic F5 Account
    Feb 21, 2014

    Hi Adam,

     

    I'm not an expert in this area, however, if I do remember correctly, I have encountered this issue once in the past, when the config wasn't according to that SOL article. What happened was that on the BigIP, the interfaces would keep going in and out of LACP (link x removed from aggregation, link x added to aggregation, link y removed from aggregation, link y added to aggregation) and so on and so forth. As you can see in that SOL article, it's not linked to a BugID for F5, so I don't think it's something that can be fixed at OS level, but rather *in order for this to work, the settings need to be like this". Also, the SOL points out Cisco Nexus switches as well, so this SOL is targeted to a specific configuration.

     

    Hope this helps!