how a router handles untagged traffic
Posted on 2014-07-27
let's say I have a router on a stick topology with 2 sub-interfaces, representing 2 vlans. let's say one of these is untagged. When my router receives traffic from the untagged vlan it's going to be expecting a vlan tag per the command encapsulation dot1q. I know i can use the command encapsulation dot1q vlan 10 native or whatever. My question is that if i didn't tell my router to specifically accept un-tagged traffic would routing work between the 2 vlans? If i just set up my sub interfaces to include the subnet of the un-tagged traffic?
One a similar note, at my current job i've been configuring all of our waps as flex-connect where I trunk the ports between the wap and the switch but tell the switch to untag the traffic on the wap subnet (native vlan 200). On my router i have a sub-interface that corrensponds to the subnet of my wap (with the command encapsulation dot1q 200). Routing works fine. i can ping the waps etc. . I guess my question is why. The traffic coming from my wap isn't tagged with the vlan id 200 and my router is expecting that vlan tag. I think i'm confusing myself here. :) a little enlightenment would be appreciated.