Subject: RE: [PWE3] Generic PW - Is there a need?

From: Sasha Vainshtein <[email-masked]>
Date: Fri, 17 Feb 2006 09:54:40 +0200

Luca, Florin and all,
Sorry for a possibly naive question, but did anybody consider
carrying IS-IS along an IP PW using the Associated Channel mechanism
defined in draft-ietf-pwe3-cw-06.txt and allocating a dedicated Channel
Type in the appropriate IANA registry?

In this way:
- fate-sharing of IP and IS-IS packets along the PW would be guaranteed
- potential MS-PW issues could be handled in a generic manner
- performance would not be an issue (presumably IS-IS traffic is
  negligible when compared with the IP traffic)
- It would be possible (and easy) for a pair of PEs to negotiate
  specific Associated Channel Type(s) they support during the setup
  by adding an appropriate Interface Parameter sub-TLV thus making it
  a scalable approach (at least,as long as we are talking about some
  control protocols accompanying data and not about true "data"
  multi-protocol.

It would be interesting to see which use case for the generic packet PW
would remain unresolved.

My 2 c.

Regards,
                 Sasha

-----Original Message-----
From: Luca Martini
To: Florin Balus
Cc: pwe3 pwe3; Danny McPherson
Sent: 2/16/2006 8:53 PM
Subject: Re: [PWE3] Generic PW - Is there a need?

Florin Balus wrote:
>
> I believe there is a need for a multiprotocol PW as we want some flows
> to share really the same path: i.e. I want the IP data packets to
follow
> the same path as the IS-IS protocol that provides the routing
exchanges.
> There could be also simplifications related to the fact that an
> enterprise customer will not need to buy different PWs for each
> encapsulation if the resulted connections go between the same 2 sites:
> IPv4, IPv6, IS-IS etc... Think also about PWs as uplinks for Managed
CE
> <Virtual> Routing not only just for ACs...
>
>   

Are you talking about having some kind of layer3 PW ?
what next ? a TCP PW , an UDP PW , and a Rip PW ?

The IS-IS case is a black sheep indeed , as we are using an non IP 
protocol to route IP.
As I explained before the answer for that is to use the true layer2 
protocol, not an IP PW.

Luca

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From: Luca Martini <[email-masked]>
Date: Fri, 17 Feb 2006 10:01:37 -0700

Yes that is what florin proposed at some point.
However that changes the architecture, and does not really share the 
same path. The associated channel might not be HW switched. ( and it is 
not meant to transport user routing information )
However , I have not seen much market demand for this or IP PWs I doubt 
it worth the effort. Just use a normal L2 PW if ISIS is needed.

Luca