Ethernet LAN VLAN operation in Transparent bridging

Hi
If a bridge is configured in "Transparent Bridging" mode then the bride
protocol entities Viz. STP, GVRP, GMRP are disabled and the bridge
forwards frames based on learned MAC information. Is the behaviour same
for both untagged and tagged (VLAN) frames ? Or does it drops VLAN
tagged frame ?

Thanks in advance
Pritam

pritamganguly@gmail.com wrote:


If by "Transparent Bridging", you mean 802.1D operation (as opposed
to 802.1Q), then the bridge becomes agnostic to VLAN tags.  However,
such bridges are still expected to run STP and, optionally, GMRP.

Anoop

Hi
By transparent bridging I meant only "bridge forwarding" behaviour
without any bridge to bridge protocol executing.
 http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/transbdg.htm

In this case the bridge should forward all frames received according to
the learned MAC addresses. My question was will this bridge forward
VLAN tagged frames too or drop them?

Another question will a VLAN unaware bridge forward VLAN tagged frames?

Regards
Pritam

pritamganguly@gmail.com writes:


And the answer was "it will forward them". VLAN tagged frames look
to non-VLAN-aware bridges like any other frame. VLAN tagging is
done by using a special ethertype encoding. Ethertypes are NOT
looked at by normal (non-VLAN-aware) bridges.


This is not another question. Yes, it will.

You seem to think that running "bridge protocols" like STP, somehow
influences VLAN function. It doesn't. Those concept are independant,
to the best of my knowledge.

best regards
  Patrick

Except that a maximum length ethernet frame with a tag added is effectively
oversize by 4 bytes.

So a VLAN unaware bridge may well drop the frame size oversize is an error.

--
Regards

Stephen Hope - return address needs fewer xxs