Subject: Resend: Comments on the L2 VPN framework and solutions documents

From: Joris wils <[email-masked]>
Date: Mon, 21 Apr 2003 12:00:36 -0400

At the system manager's request because the note might have gotten stuck in
the mail server.

-----Original Message-----
From: Joris wils 
Sent: Monday, April 21, 2003 10:17 AM
To: 'Muneyoshi Suzuki'; [email-masked]
Cc: [email-masked]
Subject: RE: Comments on the L2 VPN framework and solutions documents

Muneyoshi,

>I think there is a much simple and robust solution. Connect Provider
Bridges
>with point-to-point LSPs and use STP/RSTP in the network, and don't use 
>split-horizon scheme. Needless to say LSPs must be raw mode; tagged mode
>violates the standard. 

>In this case, if PEs are connected with full mesh LSPs, reliability of a 
>single PE is:

>1- {(1- R^2) ^ (N -1)}.

>Obviously, this is a robust solution because it use LSPs as parallel
system.
>Furthermore, this does not need to revise the existing standards, it only
>needs Q-in-Q or MAC-in-MAC specification in 802.1ad.

Please verify my understanding: are you proposing that vendors add Bridging
to their MPLS devices; Bridging over MPLS as it were, MPLS is the Transport.
correct?  If so, I have noticed, that vendors are quietly adding Bridging to
their ATM, Frame and TDM devices as well.  802.1ad could interconnect all
these devices, regardless of which media they use as the Transport.  

My question is: how do you deal with (portions of) the network, for which a
spanning tree would be a very inefficient forwarding means, because the
physical topology does not approximate a tree?

Thank you,
Joris Wils 
Consulting SW Engineer
Coriolis Networks
[email-masked]/978-264-1904x667