Nexus 1000V, Cisco 3750 Uplink Switches (port-channel or not??)

[Duane Haas]

Have two stacked cisco 3750 switchs that I plan to connect two nics from each vsphere host to.  My questions is, do the ports need to be configured in a port channel on the 3750 side, or if i plan on using vPC host mode, do i just configured the ports as standard trunk ports and let nexus 1000v handle lacp?  been trying to find a decent configuration guide for a NON-HA setup and have not found anything, whatever help you can give would be great.

[Robert Burns · Accepted solution]

You have two options which are documented in the Nexus 1000v Interface Configuration Guide.

1. Use vPC-HM (MAC Pinning) which requires no upstream switch port channeling (channel-group mode on mac-pinning)

or

2. Since your 3750's are stacked, you could create a single port channel on the 3750 side using active or on.  This would contain all four interfaces going to the same host. On the N1K side your port profile would have "channel-group mode active" in the uplink port profile.

Regards,

Robert

[Duane Haas]

Thanks for the great response Robert, any preference with why I would chose one over the other?  If i chose the vPC-HM, do i just configure the ports as trunks ports then?

[Robert Burns]

There's two ways to look at it.

With MAC Pinning configurate is simple and there's no upstream switch changes required to implement.  For simplicity sake I love it.  This utilizes the uplinks as inidivudal links though, and each VM's virtual interface is "pinned" to one uplink - unless there's a failure in which it re-pinns to another link.   In this setup, there's no balancing of traffic, so one uplink could get saturated with a heavy I/O VM. 

This is where the pure Port Channel (LACP or Static) has the advantage of aggregating all the links into one.  This lets the traffic be hashed accordingly and better spreads the load across the links.  LACP is the preferred against static as the health of the channel is monitored as well.  There's still redundancy in the event any single link fails, the only drawback is that there is a little upstream switch configuraiton to complement the N1K channel config.

Regards,

Robert

[Duane Haas]

Great feedback and thanks again Robert.  Appreciate you taking the time to answer my questions