Port on the same VLAN untagged and tagged at the same time

RouterOS General
1

Hi all,
I have a CRS328-24P-4S+ and, even if I know that it’s not an optimal solution but I cannot fix it on the other end, I need to have a VLAN (let’s say ID 15) both untagged and tagged at the same time.
Is it possible to achieve this?

Looks like that when I assign a PVID to a port and the add it also under tagged, it’s not working..


Thanks,
Gabriele

2

How would you send out packets on this VLAN? Either you tag them, or you don’t, it’s mutually exclusive.

3

Mmhh yes you are right. I have to create another VLAN untagged and then route through CRS.
Stupid vmware and Intel AMT..

4

It is possible! On vlan bridge filtering one can make a hybrid port. This may be necessary when connecting to a VOIP device which needs the tagged vlan but can send onward the untagged vlan to the PC or something like that, cannot remember the exact order. In this case one leave the bridge port as though it was a trunk port (without any special rules - basically admit all) and on the bridge vlan rule one tags the bridge and VOIP vlan and untags the vlan for the pc. Not sure on the switch version of the setup.

5

A hybrid port means that it acts as an access one (tagless frames on the wire) for a single VLAN, and as a trunk one for other VLANs, but each particular VLAN must be handled either one way or the other, not both simultaneously. You would have to duplicate each frame and send it once tagged and once tagless to achieve this, which no switch I’ve ever met does.

6

Please see diagram #4.
https://wiki.mikrotik.com/wiki/Manual:Bridge_VLAN_Table

7

That’s not what the original poster was asking about. That diagram shows a use case where two PVIDs are carried on one cable if I was looking at the right one. The original question was about a single PVID being both tagged and untagged on a single cable, which is not possible by definition.

8

Yes you are both right, not possible for the SAME vlan, I obviously missed that small point LOL.