Subject: RE: draft-raggarwa-rsvpte-pw-01.txt

From: "Nurit Sprecher" <[email-masked]>
Date: Thu, 24 Mar 2005 14:53:55 +0200

Hi Eric, 
The requirement draft has been just accepted as a WG document. It
indicates that there some consensus on the requirements for the traffic
engineering of multi-segment pseudowires. I did not hear or see any
reference to these requirements (except of mine). 
The requirement draft brings us new requirements for TE MS PWs. The
existing two protocols are not aligned with the requirements and
currently have no means to signal TE information. They should be
significantly extended to support the new requirements. Currently they
can not signal explicit route information, not QoS parameters, not
Diffserv/Diffserv-TE information, not traffic priorities, not
requirements for resiliency, not resource classes, no crouchback
information, etc. The TE information must be signaled to allow the S-PEs
to select the appropriate Tunnel for the PWs. Otherwise; a lot of
configuration should be configured at the S-PEs. In addition, the error
messages that they support do not contain enough information, etc. 
However, there is a natural protocol which is already defined and
deployed for TE Tunnels and have the capability to signal the TE
information. This protocol should be minimally extended to include the
PW identifier and the control word. 
In addition, when only TE is deployed, why should we maintain and manage
two different protocols, one for the tunnels setup and one for the PW,
instead of using the same protocol, which is appropriate for both?
Nurit.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Eric Rosen
Sent: Wednesday, March 23, 2005 6:34 PM
To: Stewart Bryant
Cc: pwe3
Subject: Re: [PWE3] draft-raggarwa-rsvpte-pw-01.txt 

I oppose accepting this draft as a WG draft. 

We already have  two PW setup protocols, and there  has been no
demonstrated
need for a third. 

Anyone who  thinks that  this draft is  even worth considering  should
first
attempt to attain consensus on  the requirements for the traffic
engineering
of multi-segment  pseudowires.  Then they should be  prepared to
demonstrate
that the requirements cannot be met with the existing model.

Neither one of these efforts has taken place. 

To take  this a  bit further, I  would say  that with the  existing
protocol
model, traffic engineering of PWs  reduces to the traffic engineering of
the
PSN  tunnels through which  the PWs  travel.  The  tunnel setup
protocol is
independent of  the PW setup protocol, and  RSVP-TE could be used  to
set up
the tunnels.  I don't see what's  lacking in this model, but perhaps
someone
can provide a detailed example  in which some putative requirement
cannot be
met with this  model.  That would help us to  understand whether the
claimed
need  for a new  protocol is  based on  facts, or  is just  another
tiresome
"let's have another protocol war" effort.

If it  turns out that  the only shortfall  with existing procedures  is
that
existing PW setup protocols need to  carry some opaque parameters to
pass to
the tunnel setup  parameters, I would not  say that that is a  defect in
the
existing model.

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