Subject: Encap BPDUs has some problem in "draft-ietf-l2vpn-vpls-ldp-05.txt"

From: "Jong-Hwan.Hyon\(Jerry\)" <[email-masked]>
Date: Mon, 31 Jan 2005 15:29:41 +0900

Hi folks,
I've got a question about the use of "Encapsulation of BPDU" in VPLS
Section 5.2 in page 11 of draft-ietf-l2vpn-vpls-ldp-05.txt  states:
 
" For STP to work in qualified mode, a VPLS PE must be able to forward STP
BPDUs over the proper VPLS instance. In a hierarchical VPLS case (see
details in Section 10), service delimiting tags (Q-in-Q or Martini) can be
added by MTU-s nodes such that PEs can unambiguously identify all customer
traffic, including STP/MSTP BPDUs. In a basic VPLS case, upstream switches
must insert such service delimiting tags. When an access port is shared
among multiple customers, a reserved VLAN per customer domain must be used
to carry STP/MSTP traffic. The STP/MSTP frames are encapsulated with a
unique provider tag per customer (as the regular customer traffic), and a
PEs looks up the provider tag to send such frames across the proper VPLS
instance. ."
 
If I have 1 sites, and this site has three location(branch), A, B, C. 
And loc.A uses a QinQ or Martini, and other locations, B and C use basic
vpls mode(access mode), then the BPDUs port type is not match among each
others.
Location A's BPDUs look as Trunk,  B and C switch discard these BPDUs
because of port type mismatch.
 
In this case, the STP don't work properly. Isn't it?
 
Can someone explain to me please?
 
Thanks,
Jerry.
 
***Pls, excuese my poor engilsh!!! **