Subject: TSVDIR review for draft-ietf-cuss-sip-uui-reqs

From: Joe Touch <[email-masked]>
Date: Fri, 04 Nov 2011 13:42:19 -0700

Hi, all,

I've reviewed this document as part of the transport area directorate's 
ongoing effort to review key IETF documents. These comments were written 
primarily for the transport area directors, but are copied to the 
document's authors for their information and to allow them to address 
any issues raised. The authors should consider this review together with 
any other last-call comments they receive. Please always CC 
[email-masked] if you reply to or forward this review.

We appreciate that this doc went through last call Oct 13; this request 
was received after that event.

This document describes the issues in exchanging user-to-user call 
control information in SIP.

There are no transport protocol issues in this document.

The document does use the term "transport" frequently, most often as a 
verb meaning "exchange". I would encourage the authors to consider 
changing those uses to avoid confusion with "transport" as related to 
Layer 4 protocols.

The one exception is the Overview (Sec 1) sentence, where the term 
"transport" is used. Here I would encourage the authors to use the term 
"session":

   ..."Providing informatoin and
   understanding of the UUI to the transport layer (SIP in this case)
   ...

There are two additional issues:

- the term "screen pop" in Sec 2.1 is unclear (do you mean "popup"?)

- Sec 2.2 (Proxy Retargeting) talks about URI changes
	it's not clear whether the addresses referred to here
	are Transport Layer (e.g., IP addresses), or other
	addresses
If these are transport layer addresses, there may be interactions with 
NATs and/or transport protocols that should be addressed. This section 
would benefit from a specific example as well.

I would be glad to discuss these issues further if useful.

Joe