Subject: Re: RSVP-TE and PW

From: Eric Rosen <[email-masked]>
Date: Wed, 29 Sep 2004 09:27:03 -0400

> given that RSVP-TE has some advantage w.r.t LDP (e.g. QoS)

The "some advantage" is not relevant in this context.  

The network  layer tunnels  through which  the PWs flow  may have  QoS.  The
attachment circuits which are connected to each other via a PW may have QoS.
But I  don't think there is  any notion of QoS  which is specific  to the PW
itself, rather than to the network layer or the attachment circuits.

Therefore, any QoS  parameter carried in the PW  setup protocol would really
be just an opaque object to that protocol.  A PW endpoint might want to pass
this object  to the network layer, saying  in effect "put this  PW through a
tunnel that has this QoS".  A PW  endpoint might want to pass this object to
the NSP layer, saying in effect  "set up the attachment circuit according to
these  QoS parameters".   But  the  PW setup  protocol  doesn't actually  do
anything itself  with the QoS parameter,  other than to carry  it around and
pass it off. The only QoS  requirement for the PW signaling protocol is that
it  be able to  carry an  opaque QoS  object from  one endpoint  to another.
RSVP-TE has  no advantage over LDP  with respect to the  carrying of objects
from one endpoint to another.

---

From: Stewart Bryant <[email-masked]>
Date: Wed, 29 Sep 2004 14:56:59 +0100

>[dc] IMHO given that RSVP-TE has some advantage w.r.t LDP (e.g. QoS) why
>don't use RSVP-TE for both signalling PW and MPLS LSP?
>  
>
As Peter says there is a proposal before the WG, but I don't see what 
advantage
this would add over using the LDP mechanism that we have already defined in
conjunction with RSVP-TE in the datapath.

- Stewart