Subject: RE: [PWE3] [Fwd: I-D ACTION:draft-muley-pwe3-redundancy-00.txt]

From: "Praveen Muley" <[email-masked]>
Date: Sun, 1 Oct 2006 23:13:44 -0700

Lucy :
      Most of the scenarios are about failure on of the dual homed PE and
hence protection to any pseudo-wire service offered. Even though the
protection is done at CE level, in order not to have any asymmetrical
forwarding of traffic and ability to have status which helps in
idenifying/selection of the preferred pseudowire apart from being
operationally UP. The first scenario is applicable where it is only possible
to provide AC redundancy to one CE.
           The second scenario is  helpful in avoiding propogation of
failure on one side of network to otherside of the customer network. This is
useful where it is only possible or desireable to run a local redundancy
scheme on the ACs. The competition issue mentioned in second scenario can be
solved by Tie-breaking rules and exact failure conditions. We will enhancing
Tie-breaking rule part anyways for the fourth scenario. Please let us know
if you have any specific competition issues in mind.
              Regarding fourth scenario, we are working on it and hoepfully
will be covering it up in next version of draft.

Thanks,
Praveen

Hello Muley,

The draft proposes some redundancy configurations for PW. Here are some
questions about applications for these configurations.
1) The first scenario in figure 1 shows an asymmetrical protection. The
protection is done at CE on one side and at PE at another side.  The
redundancy is achieved at duel PEs on one side. What application needs this
kind of asymmetrical protection?
In most of cases, PW protection can be configured from either CE or PE
symmetrically. Dual homing can be achieved by 1+1 or 1:1 protection at CE
directly.
2) The second scenario in figure 2 shows double protection at both CE and
PE. This is more expensive configuration and PW availability is close to
dual homing protection from CE directly. In addition, double protection
could raise the competition situation.
Again, what application requires this configuration?
3) The third scenario in figure 3 has the same issue as the first. 
4) The fourth scenario is valuable. PW protection needs to consider how to
do in multi-segment environment.

Best Regards,
Lucy Yong

-----Original Message-----
From: Stewart Bryant [mailto:[email-masked]]
Sent: Wednesday, September 27, 2006 8:58 AM
To: pwe3
Subject: [PWE3] [Fwd: I-D ACTION:draft-muley-pwe3-redundancy-00.txt]

-------- Original Message --------
Subject:                 I-D ACTION:draft-muley-pwe3-redundancy-00.txt
Date:            Tue, 26 Sep 2006 10:50:01 -0400
From:            [email-masked]
Reply-To:                [email-masked]
To:              [email-masked]

A New Internet-Draft is available from the on-line Internet-Drafts 
directories.

                 Title                           : Pseudowire (PW) 
Redundancy 
                 Author(s)               : P. Muley, et al.
                 Filename                : 
draft-muley-pwe3-redundancy-00.txt
                 Pages                           : 11
                 Date                            : 2006-9-26
 
This document describes a few scenarios where PW redundancy is 
needed. A set of redundant PWs is configured between PE nodes in SS- 
PW applications, or between T-PE nodes in MS-PW applications. In 
order for the PE/T-PE nodes to indicate the preferred PW path to 
forward to one another, a new status bit is needed to indicate the 
preferential forwarding status of active or standby for each PW in 
the redundancy set. This draft specifies a new PW status bit for this 
purpose.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-muley-pwe3-redundancy-00.txt

To remove yourself from the I-D Announcement list, send a message to 
[email-masked] with the word unsubscribe in the body of 
the message. 
You can also visit https://www1.ietf.org/mailman/listinfo/I-D-announce 
to change your subscription settings.

Internet-Drafts are also available by anonymous FTP. Login with the 
username "anonymous" and a password of your e-mail address. After 
logging in, type "cd internet-drafts" and then 
"get draft-muley-pwe3-redundancy-00.txt".

A list of Internet-Drafts directories can be found in
http://www.ietf.org/shadow.html 
or ftp://ftp.ietf.org/ietf/1shadow-sites.txt

Internet-Drafts can also be obtained by e-mail.

Send a message to:
                 [email-masked].
In the body type:
                 "FILE 
/internet-drafts/draft-muley-pwe3-redundancy-00.txt".
 
NOTE:            The mail server at ietf.org can return the document in
                 MIME-encoded form by using the "mpack" utility.  To use 
this
                 feature, insert the command "ENCODING mime" before the 
"FILE"
                 command.  To decode the response(s), you will need 
"munpack" or
                 a MIME-compliant mail reader.  Different MIME-compliant 
mail readers
                 exhibit different behavior, especially when dealing with
                 "multipart" MIME messages (i.e. documents which have been 
split
                 up into multiple messages), so check your local 
documentation on
                 how to manipulate these messages.

Below is the data which will enable a MIME compliant mail reader
implementation to automatically retrieve the ASCII version of the
Internet-Draft.

_______________________________________________
pwe3 mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/pwe3

_______________________________________________
pwe3 mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/pwe3