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UCS VNIC doubt

                   While creating UCS VNIC, we define list of vlans and along with native vlan.

Doubt:-

The list of vlans which are selected while creating vnic has nothing to do with the vnic seen by the OS loaded on to the blade.

The OS when it boots will see a number of NIC connected to it. It is unaware of any vlan being associated and in fact by default this wont do any trunking.

All of the vlan selected while creating the vnic has got significance only on the veth logical interface.

Doubt 2:

The VNIC, has it got anything to do with VNTAG ? it is not aware of any vntag and vntag is inserted by IOM or by the Adapter ? or will there be any double tagging of vntag ?

Please help me to understand

regards

Prasad

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Cisco Employee

UCS VNIC doubt

Hello Prasad,

From OS perspective, each NIC maps to single VLAN / subnet unless if OS & drivers are capable of logical interfaces and VLAN tagging.

Regarding VNTAG, as vNIC interface receives frames from OS, it inserts VNTAG and sends towards FI. For server traffic towards host, FI adds VNTAG and sends to it to vNIC. The adapter removes the tag before delivering the frame to OS.

In some scenarios ( based on adapter type ) , IOM will add / remove VNTAG.

Frames are switched using VNTAG within UCS.

HTH

Padma

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