Subject: [PWE3] Some doubts in RFC 4447

From: Sriram K <[email-masked]>
Date: Wed, 30 Sep 2009 11:27:57 +0530

Hi All,

I have some doubts on PWE3 using LDP. It would be helpful if someone could
clarify them. I might clearly miss few things, please bear with me.

1. Will there be a scenario to use the same PWid at both the end points? Or
is it up to the administrator to decide what to use (assign same PWid at
both the ends or assign different end point identifiers using the
Generalized PWid FEC element)?

2. Is the AGI field in the Generalized PWid FEC element used to identify the
PW. In that case, can we assume it is similar to the PWid field of the PWid
FEC element.

3. Is the Group ID field of the PWid FEC element and the value in the
Grouping ID TLV of the Generalized PWid FEC element similar? If not how
different are they?

4. RFC 4447 Section 3, Page 6, Para 4

"It is REQUIRED that the same PW ID and PW type be assigned for a given
circuit in both directions. The group ID MUST NOT be required to match in
both directions."

Could some one explain the above statement? It seems to contradict the use
of Generalized PWid FEC element. And how will the PW be mapped to a VPLS
instance if the group ID doesn't match in both the directions?

Thanks in advance.

Regards,
Sriram