Question about guest network 1 and VLAN 501

[purpleman]

Hi everyone.

When I enable guest network 1 on my AC68U (on the 2.4 band only) with access intranet disabled it creates a new virtual interface called wl0.1 and it appears to set up a 501 vlan and a new bridge (br1) that includes wl0.1 (guest network) , eth0.501 (wan), eth1.501 (2.4ghz interface), and eth2.501 (5ghz interface).

Based on this and what I read, I'm assuming that the isolation mechanism (for guest network slot 1 specifically) is based on all the guest traffic contained in vlan 501. Therefore, I expected client traffic coming in from wl0.1 to be tagged for vlan 501. However, when running tcpdump for wl0.1 and generating client traffic I can see that all the frames coming in it are untagged.

Trying to understand the mechanism here. Why aren't the frames tagged? If they're not part of vlan 501, what creates the separation?

Thanks for anyone who can help explain!

 

[purpleman]

Adding - I thought my mistake was looking at the traffic of wl0.1 instead of looking at br1.
But even if I look at the tcpdump of br1, the ethertype shows regular IPv4 and I see no 501-tagged frames at all.

Very confused here. The router went through all the trouble of defining a vlan for the guest network and it's not even tagging anything? I must be missing something.

Any help will be appreciated!

 

[rung]

I think vlan is used for the AiMesh backhaul traffic so the packets get properly routed to the main lan bridge br0 or guest virtual bridges br1 or br2.