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Nexus 1000v VSM to VEM communication via vSwitch or pNIC on VEM?


We just did a configuration for a Nexus 1000v 4.0(4)SV1(3a) and ESX4.1. We have physical  uplinks for the host on both DVS and VSwitch. VSM is attached to vSwitch.

When we added the ESX host into the DVS, we were then left with a situation where we had a uplink on the vSwitch and another uplink on the DVS.

The immediate status after that move was that the ethernet link on VSM didn't come up, no matter what, but the ESX host was effectively joined to DVS.

After a VSM reboot, the pNIC on the DVS came up and traffic started flowing (mgmt, control and packet vlans are marked as system vlans, even though VSM is not behind VEM).

My question then is related to VSM to VEM communication. If we still have a pNIC on the vswitch, can the VEM use that for VSM registration? Can we have a conflict when there's the possibility of VSM to VEM communication over vSwitch AND DVS? Would that justify the link not coming up on the N1K?

The symptoms are that when doing a sh interface status, or trying to shut/no shut the down interface, the command CLI takes a big moment to provide any output, and usually it fails...



Everyone's tags (5)

Re: Nexus 1000v VSM to VEM communication via vSwitch or pNIC on

Hi Gustavo,

like I see in my LAB, the VEM VSM communication on the same EXSI Server go through the pNIC.

One pNic is attached to the vSwitch, here my VSM is connected.

The second NIC was used for the VEM (DVS).

I disconnected the pNIC cable of the VEM (DVS) and my VEM was gone.. in "show module"

Like I understand the NX Design the control, packet, MGM traffic will always use the pNIC's and there are now "inter host" connections between vSwitch and DVS.

Hope that helps.



New Member

Re: Nexus 1000v VSM to VEM communication via vSwitch or pNIC on

In this case the environment is ESX, not ESXi. Given that there is a Service Console, where mgmt, control & packet are also allowed, I'm wondering if that could justify the fact that the pnic on the DVS had not come up, but the module got registered on to the VSM. Unfortunately on the LAB I also only have ESXi, so I cannot really replicate the issue...

Thanks for your reply.

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