To Aggregate or not (Teaming)

[raulgomez101]

Hello,

First time posting here so be gentle :)

I am a network guy and now I am helping the Server guys. They said they always create the network Teaming on the Server side and never bother to change any config on the catalyst switch.

Now that we are creating a new server, I wonder if I should create a port channel (or aggregation) for this new Hyper-V host.  The server is Windows and has 4 NICs and uses a Broadcomm controller.

My question is: Should I create a port channel for the server ?  What do you normally do in your company?  I am looking for best practices. My humble opinion is that I should Team on the Windows Server side (they call it teaming) and I should create a port channel to aggregate all 4 ports.

As a side note, my server guy tells me they always create 2 teamings, so if one breaks, the other takes control. So basically 2 NICs in one teaming, and 2 in the other. And I can see that there is NO port-channel configuration on the Catalyst switch side. So the switch is unaware of the teaming.

Your opinion is appreciated. Thank you.

[Reza Sharifi · Accepted solution]

Hi and welcome to the forum.

So, you could put all 4 links in a Portchannel and configure it as LACP or mode on. Usually, the server side supports both if not they definitely support mode on.

You can also leave the port simply as trunk ports with no Portchannel at all.  In this scenario, the server NICs are configured as HA, so when one link goes down the next one will take over.  If this is a new deployment, I recommend you test both scenarios and pick what is best for your environment. It is critical to test and deploy it correctly, if not when you want to upgrade your switches, your VM/storage will have downtime and that is usually not a good thing.

HTH

[raulgomez101]

Thank you Reza,

So, if I don't enable the port-channel on the Catalyst side, the links as you mentioned will not be aggregating but only HA ?  That is what I thought, but I wanted confirmation.

I think if I enable link aggregation on the Cisco side, I will aggregate the bandwidth AND I will have HA in case something happens.

So, in your experience, is it more common to enable the port-channel ?  I would assume so. I'm still puzzled that the server guys do teaming on the Server side only.

Thanks,

[Joseph W. Doherty]

"So, if I don't enable the port-channel on the Catalyst side, the links as you mentioned will not be aggregating but only HA ?"

I recall (?) some servers supported a teaming configuration that provided extra link capacity in just one direction without requiring any special configuration on the switch.

[Reza Sharifi]

So, if I don't enable the port-channel on the Catalyst side, the links as you mentioned will not be aggregating but only HA ?  That is what I thought, but I wanted confirmation.

Not 100% sure but I think so.  I think HA means you are using one link at a time. 

So, in your experience, is it more common to enable the port-channel ?  I would assume so. I'm still puzzled that the server guys do teaming on the Server side only.

It depends, some servers guys don't like Portchannel at all and they just want to use the uplink as trunk ports and let the server take care of link failover and redundancy. I have actually tested this with Nexus FEXs with VM and dell chassis and the link failover works just fine without any port-channel.

Either scenario should work fine but to eliminate the chance of any STP issues, I would try and use Portchannel.

HTH