CDP not working in vCenter with hardware VN-Link

[peter.robertson]

I have configured hardware VN-Link and created a vDistributed Switch through UCSM.  I created a network control policy enabling CDP and applied it to the static vNICs in my ESXi service profiles.  The static vNICs were used as the uplinks when I added the ESXi hosts to the vDS.  But when I try and access the CDP information associated with the adapters in the uplink port group I continue to get the "Cisco Discovery Protocol is not available on this physical adapter."   I did not apply the CDP network control policy to the dynamic vNICs.  We are running ESXi 4.1 U1 on B200 M2 blades, 1.4(3l)

Any suggestions greatly appreciated!

[Robert Burns]

Peter can you confirm whether or not CDP functions when the vmnic is connected to a vSS? (Standard vSwitch). 

Thanks,

Robert

[peter.robertson]

Hi Robert! 

Yes, CDP works fine with a regular vSwitch.   

Thanks,

Pete

[Robert Burns]

I've recreated a similar issue.  Of my two uplinks connected to the PTS, I can currently only get CDP action on one of them (never both).  But if either NIC is moved to the vSS, CDP works on both. 

Let me dig further on this and get back to you.  If I find it's a bug, I'll bring you back a bug ID.

Regards,

Robert

[peter.robertson]

I wish I could say that I am able to get as far as you have... even with one uplink in the vSS and CDP working for that uplink, the other uplink in the vDS is still not working. 

Thanks for taking a look!  It was great to meet you at CL11.

[Robert Burns]

Peter,

Thanks for your patience.  After a lengthy discussion with our Dev team I've learned that with the PTS - we do not expect CDP to function. 

Since this is a "pass through switch", we don't utilize the two vmnic uplinks interfaces of the DVS.  They are only created & displayed to satisfy the VMware API.  These vmnics are not used, so CDP information is never passed from UCS, through them to the ESX host.  The PTS uplinks are dummy vEth interfaces which pretend to act as phsyical interfaces.

Now, each dynamic vNIC can have CDP passed through to the Guest VM OS (assuming the network control policy is set on the dynamic vNIC).  If the guest OS can interpret CDP, it will have access to this information.

In my testing I was being hasty.  The times I "did" see CDP was in the 30sec window before the CDP info aged out.  After 30sec I also do not show any CDP info on PTS uplinks. 

Hope this helps!

Robert

P.S. Great catching up and talking with you also at Cisco Live.  See you next year!