tagged and untagged vlan on vNIC

[Sotu0001]

I have a q. concerning use of VLANs on vSphere (6.5).

I have a VM carrying application expecting 2 tagged and 1 untagged VLANs on the same vNIC.

I understand there is an option of specifying a list of vlans in the port group in which case these are all tagged ones. The problem comes with the one untagged expected on the same vNIC.

From what I see the only option seems to be specifying vid=4095 in vDS which result in Virtual Guest Tagging (VGT). In this case I can tell the switch to make the particular port being part of vlan vidA (untagged) as well as vidB and vidC (tagged vlans).

My questions are as follows.:

1. will it i.e. use of 0-4095 on vDS do what I expect it to do?
2. are there any limitations or things that I have to do? Specifically I wonder about use of vSS or vDS. As it seems (kb1004252) the advised method is to use vSS with 4095 or alternatively vDS with a list. The article does not say exactly whether this means untagged vlan is also allowed.
3. is this the only option or are there any other options.

The vSphere I have to help configure is on customer site which means I cannot really try beforehand hence this question.

Thanx in advance.

[daphnissov]

Just out of curiosity (and also because there may be another way), what is the use case where one VM can only have one vNIC and is expected to receive traffic from two tagged VLANs and one native VLAN?

[Sotu0001]

I did not say one vNIC but I have a problem with one.

How VM is structured I have no control of so I have to do what its description says is required and this is one vNIC facing a cluster of VMs with

- untagged vlan for bootstrapping

- tagged vlan configuration of machines after bootstrap

Bootstrap is not going to work on a tagged vlan.

The design of this machine is tightly coupled with the cluster it starts and controls. The tagged VLANs are used to allow it to be part of control networks.

As I have no control of the way this is done inside the application. I can either provide required services to the vNIC or I guess I could also try to use 2 vNICs and bridge them in the VM. Not sure if that is a good option I try to do if all other fails. I am just a bit surprised. I had no trouble doing it on VBox and other hypervisors. I am sure it works here too, need just to find out how.

Regards