Subject: RE: [NSIS] Some charter scoping / restrictions

From: [email-masked]
Date: Tue, 21 May 2002 08:43:14 +0300

Hi Kamel,

> Does this mean that NSIS is moving toward a direction similar 
> to what SIP is doing?

SIP messages don't follow the routing (or media) path, is working
at a different layer.  

Beside those comments, I'm not exactly sure what you mean.  Could
you be more specific?

John

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

---

From: Mauricio Arango <[email-masked]>
Date: Wed, 22 May 2002 17:05:00 -0400

John,

I think Kamel's message raises a valid point by asking about NSIS's
relationship with SIP. Assuming NSIS is about next steps in 
signaling, general purpose and not just QoS, the effort should 
address its relationship with key existing signaling protocols,
SIP being one of them.

Regarding the NSIS requirement of following paths determined 
by L3 routing, it is something that SIP messages do when
traveling between a SIP user agent (NSIS end-system) and a SIP proxy,
or between SIP proxys. With SIP, if an end system chooses the
next hop as the other end system (no intermediate 
proxys), messages between them will follow a L3-routed path.

However, a combination of L3 routing and higher-level routing
could be convenient for NSIS. For example one may want to 
have L3 routing from an end system up to a certain edge router,
and then to follow higher level routing between proxys.
I believe this has been also addressed for RSVP in:
draft-ietf-rsvp-proxy-03.txt

Additional reasons for considering SIP include its use
of SDP to describe what is being negotiated as well as 
all the other mechanisms for setting up, modifying and
terminating general purpose sessions.

SIP is one possibility, there are others, in general these 
are general-purpose protocols for transporting control
information over overlay networks on top of IP transport.
These overlay networks assume the use of relays (proxys) 
that provide higher level routing. Other examples to think
about are BEEP/APEX and JXTA.
Regards,

Mauricio Arango

--------------------