Passing 802.1Q frames between two non-trunk ports?

  • 22 November 2017
  • 1 reply

HI there,

Suppose I have a linux machine, with two ethernet ports, both of which are acting as switchports (We're using Cumulus Linux on Quanta switches, so this is the case).

I have ethernet frames that I want to pass between these two ports. Some of these frames may contain 802.1q vlan tags, but I won't know in advance which VLAN ids, so I can't easily pre-define them on the switch ports.

I want the tagged frames to pass, un-modified, between the two ports, as if they were simply physically wired together, such that the vlan tags are not stripped as they usually would be if they hit a bridge or a non-trunk port.

Does anyone know of a way to do this?

I didn't find the right solution from the internet.

whiteboard animation

1 reply

make a vlan aware 802.1ad bridge, then put two ports in same bridge-access vlan.

I never tried, but I think it might work for you.