LACP or not in vPC?

[tiwang]

hi out there

I have defined a vPC between 2 sets of nexus boxes:

nx51 ----vpc11--><--------vpc21--------nx53

II II

vpc10 peerlink vpc20 peerlink

II II

nx52-----vpc11--><---------vpc21------nx54

vpc10 & vpc20 is running lacp but vpc11 & 21 are not - I just defined the portchannels - but not as active

Do I get any benefits of running LACP on these ports when I am running this on multi-chassis vpc?

Or should I run lacp - define the portchannel as "active" ?

best regards /ti

[usujlana]

Hi,

You do not have to absolutely use mode ON. but the LACP presents better troubleshooting methodology. there are a host of commands in LACP that we can use to narrow down on miss-wiring etc. I know from experiance that connections between N5K and N7K work much better with LACP.

Thanks,

~Upinder Sujlana

[vdsudame]

also if there is any loss of signal wrt end device ports and before the physical interface goes down, lacp will kick in and make sure the switch stops sending traffic to the port vs the switch keep sending traffic until the physical port goes down. so lacp is advantageous in some ways.

[Chad Peterson]

As Upinder said LACP can help out by eliminating problems with miss-wiring.  This is the #1 reason I suggest LACP.

You won't see a performance difference as far as throughput with or w/o LACP...but it does buy you some assurance that negotiation will happen before we assume these two links should be treated as 1.  In my opinion the small time it takes for LACP to go through its handshake is will worth mitigating the risks of configuring static port-channels.

Chad