Hi
few Questions about draft-martini-l2circuit-encap-mpls-03.txt:
1. In section 4.3 it is stated (about the VLAN tag) “…and MAY be overwritten by the egress router.”
What are the cases in which this might happen?
>> So the SP doesn't need to have same vlan id at both ends. But this will prevent STP working
correctly unless the PE can modify the STP message accordingly.
[Anoop Ghanwani] STP doesn't use the VLAN ID. In 802.1Q, all VLANs use the same spanning
tree. Besides I don't think the draft is trying to support bridging. It just provides point-to-point Ethernet link.
In this case, does the VLAN tag lose its original meaning and functions only as a VC ID (more like a DLCI in F/R)?
2. Is the reason for carrying the ethernet VLAN L2 encapsulation (section 4.3 "For an Ethernet 802.1q VLAN the entire Ethernet frame without the
preamble or FCS is transported as a single packet") is only to preserve the original SA & DA ?
>> 802.1p will be preserved as well.
Michael
Thanks
Amir.