[j-nsp] RE - 6. vlan-id 0 (Bit Gossip)

sthaug at nethelp.no sthaug at nethelp.no
Fri Jul 10 13:22:46 EDT 2009

> Actually, there is this rare breed of Ethernet frames that have a tag, 
> but specify VLAN ID 0.  These are sometimes called 802.1p tagged 
> frames, since the other part of the 802.1Q frame that everyone forgets 
> about is the 802.1p [1] bits for link-layer QOS.  You can't set the 
> p-bits without using an 802.1Q tagged frame, so if you actually want 
> to treat the traffic as belonging to the default port VLAN as assigned 
> to the port on the router or switch rather than a specific VLAN 
> number, you use VLAN 0 in the frame.

However, I've never seen such an Ethernet frame in real life.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no

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