Nexus 1000v - Port Channels to a pair of 3550's

[xiaolonguk]

Guys

Wondering if you can help me.  Im trying to setup the 1KV with a pair of 3550s, in what might be a odd configuration and not possible.

basically I want to connect all the odd ESX hosts to the odd number 3550 and the even  ESX hosts to the even 3350.  I then want to create a port-channel using either PaGP or LACP. The two switches are ether-channelled together using LACP forwarding all the necessary vLANS

I can get this to work fine using MAC pinning, but if I configure a port-channel on the physical switch and on the VSM.  I loose connectivity to all the ESX hosts.

If I log into an ESX host, and look at the VEM.  All the interfaces are in forwarding, and the control/packet vLANs are being passed on the uplinks.  The physical switch says its aggregating the port-channel with two NICs.  If I connect to VI on the ESX host and run up the console to the VSM, its says its also aggregating.

I thought that the loss of connectivity might be down to spanning tree, but since the VSM/VEMs dont support it I ruled it out.

Is this configuration possible?  Like I say, I can get MAC pinning working and vPC-HM.

The 1000v guide doesnt say you cant do this?  but it does say you should only create tradtional port channels to stacked switches.  But if spanning tree isnt an issue.  Why should this be?

Thanks

[Robert Burns]

Jon,

This is certainly possible, but with a few considerations and config requirements.

1. 1000v supports static or negociated (LACP) port channels only.  No PAgP.

2. If you want to setup LACP between your VEM hosts & 3550's you need to ensure you configure it on both side.

1000v Side

port-profile type ethernet system-uplink

  vmware port-group

  switchport trunk allowed vlan x-y

  switchport mode trunk

  channel-group auto mode active

  no shutdown

  system vlan x,y,z

  state enabled

3550 Side

interface gi0/3, gi0/4

switchport

switchport mode trunk

spanning-tree portfast edge trunk

spanning-tree bpdufilter enable

channel-group 2 mode active

interface Port-channel2

switchport

switchport trunk encapsulation dot1q

switchport trunk allowed vlan x-y

switchport mode trunk

spanning-tree portfast edge trunk

spanning-tree bpduguard enable

Note: This might give you an aggregated link (one advantage over mac pinning), but you lose the redundancy if your switch fails (unless this is a stack).  If you only had 2 switches upstream (non stacking) than mac pinning would allow you to connect one link to each of your two upstream switches.  This would protect you against a link or switch failure. 

Make sure the config on both sides is correct to support your LACP configuration and you should find it works fine.

Regards,

Robert