Nexus 1000v and Nexus 2248 FEX

[stephen.ehlas]

Hi

I have two Nexus 2248 FEX TOR design, and I need to connect my four ESX 5.1 servers. My initial design used the Nexus 1000v, 2 etherchannels upto the nexus 2248's and a vpc link for redundency

   N2k          N2k

     |               |

     |    vPC     |        

     |               |

------------------------

          N1K

------------------------

I'm not sure if this is possible due to the BPDU's received on the 2248 stop me attaching another switch (nexus 1000v) underneath it. Is this correct?

Also, if I can not use vPC to uplink to the N2K doe sthis mean I need 2 etherchannels, with STP to block one link?

How have other people over come this issue? I'm sure I'm not the only one

Regards

Steve

[mwronkow · Accepted solution]

Hello Steve,

This is the recommended topology for N1k hosts.  N1k drops all BPDUs on ingress interface and do not transmit any - we don't run STP.  Use LACP for PCs.

Matthew

[stephen.ehlas]

Hi Matthew

Thanks for the quick reply. Am I right in assuming that this means I will have to implement MAC pinning on the etherchannels?

Steve

[mwronkow]

Hello Steve,

No. I would run VPC across the N2ks with LACP port-channels.

Follow page 2 "N1k on UCS-C or Rack Mount servers connected to Nexus 5k/7k switches with vPC" in this doc:

https://supportforums.cisco.com/docs/DOC-18222

Matthew