syslog Alert msg - %VEM_MGR-SLOT3-2-VEM_SYSLOG_CRIT: VLAN_MISCONFIG -

[robwu2006]

Hi All,

We are currently getting this error message after I attach a vmnic to the cisco 1kv :

%VEM_MGR-SLOT3-2-VEM_SYSLOG_CRIT: VLAN_MISCONFIG : Multiple uplinks/port-channels with common VLANs detected.

This can cause packet loops.

Ensure that channel is configured on profile having multiple ports on VEM and no more than one channel on VEM is carrying a particular VLAN.

I've tried to look up this command, but cannot find references to this, or what this message is actually saying/how to fix etc.

[Robert Burns]

This means one of two things.

Either

a) You have multiple uplinks in your Ethernet Port Profile, without a Channel-group command

or

b) You have more than one Ethernet Uplink Port Profile allowing the same VLAN.  << Likely your issue.

**Each VLAN can only be allowed on one Ethernet Uplink Port Profile.

Ex. - BAD

Uplink Profile 1

switchport trunk allowed vlan 1,2,3

Uplink Profile 2

switchport trunk allowed vlan 3,4,5

**VLAN 3 violates the exclusivity rule

Ex - GOOD

Uplink Profile 1

switchport trunk allowed vlan 1,2,3

Uplink Profile 2

switchport trunk allowed vlan 4,5,6

Regards,

Robert

[robwu2006]

Thanks Robert, thats really ususal to know!

We had symptom 'a' actually.

I'm just wondering which channel-group command(s) I should use on the uplink profiles?

bascially our setup is NOT vPC capable for now at the physical switch end, but it is a cisco box so we can do cdp.

Cheers,

Rob

[Robert Burns]

In terms of "which uplink method to use" - I'd recommend MAC-Pinning.  This is still referred to as VPC-HM (Virtual Port Channel  Host Mode).  This is a form of VPC, but only from the 1000v's perspective.  It does not require anything to be channeled upstream and is compatibile with Cisco & non-Cisco switches.  This method is tried & tested, doesn't rely on timers (as CDP mode does) and is the simplest to troubleshoot.  All you need to configure on the upstream ports is ensure they're a Trunk, allow the necessary VLANs, and enable Port Fast & BPDU Filtering.

On the 1000v side, all you need is a one line added to your uplink port profile:

channel-group auto mode on mac-pinning

And you're all set to add 1 to 32 phsycial NICs to this port profile!

Regards,

Robert

[robwu2006]

Great Robert, thanks for that tip!

Also did you happen to do this video on this topic, I found this one very useful!

http://www.youtube.com/watch?v=4aHJtX3ZUZg

Cheers,

Rob

[Robert Burns]

Glad it helped - and yes I did do that video a couple years ago

I'll have to update it as there have been some slight changes since version 1.2

Regards,

Robert