Subject: [SIP] Thread summary: 11/19-11/25

From: Brian Bascom <[email-masked]>
Date: Tue, 12 Dec 2000 02:19:54 -0500

SIP list thread starting from 11/19 through 11/25.

11/19/2000 Record-Route consensus - Robert Fairlie-Cuninghame restarted old
discussion about proposed Record-Route changes, including handling non-SIP
URIs, the "stack-popping" behavior preventing proxies from seeing earlier
headers and losing state info, and detecting new parameters in Record-Route.
Strong discussion of not allowing non-SIP URIs in the Record-Route. Only
apparent consensus: UAS should not "mangle" the reverse Record Route. Very
lively discussion, still ongoing (although thread changed a couple of times,
including "New Section 6.34").

11/19/2000 New I-D on multiparty conferencing models - Jonathan Rosenberg
submitted draft on six ways to do multiparty conferencing with "vanilla"
SIP. Brought under serious fire as regards assumptions about SIP UA behavior
not specified in the rfc.

11/20/2000 Spaces in SIP URL - Sreenivasa Reddy D. asked if spaces (and by
extension, line breaks) are allowed in SIP URLs. rfc 2396 prohibits in URLs,
although escaped spaces allowed.

11/20/2000 URL Comparison - Stuart Wray pointed out inconsistencies in
2543bis draft concerning matching of URL parameters, and use of A records
with default SIP port 5060. Authors admitted some textual errors, but issue
of omitting ports discussed.

11/20/2000 VIA Response - Uri Baniel wondered how a response to a multicast
request should be returned

11/21/2000 SIP Extensions for Presence - Hisham Khartabil asked a number of
questions about transferring subscriptions without waiting for timeouts and
responding to Contact-less SUBSCRIBES with 4XX messages rather than simply
failing to act on the SUBSCRIBE

11/21/2000 Registration Question - Bill Moloney asked if a redirect such as
301 Moved Permanently occurs, what is the scope of that action? Only MUST
impact the current transaction, but MAY impact future similar transactions
(depending on implementation).

11/21/2000 More Torture Test Messages Available - Neil Deason added more
Bakeoff stumpers to the list

11/21/2000 Deprecate Early Media - Billy Biggs described problems with media
arriving before the 200 OK, raising the question again for attention.
General agreement.

11/21/2000 Changing CODEC - Mo Zonoun asked how to change codecs without
disrupting the established call. For sending codec, any listed in SDP can be
used; for codec to receive from, need to re-INVITE and include different
codec choices. Disagreement on whether to end call if re-INVITED party can't
support new codec, or use existing codec and reject re-INVITE.

11/21/2000 I-Ds - Gerhard Gross announced two QoS I-Ds: QoS and AAA Usage
with SIP based IP Communications, and COPS Usage for SIP.

11/21/2000 New I-D: draft-hamer-sip-session-auth-00.txt - Louis-Nicolas
Hamer requested comments on his I-D dealing with session setup with media
authorization.

11/22/2000 Multi-proxy authentication deadlock - Alexandre Charest requested
an example of the deadlock situation arising from an expired challenge after
a successful response.

11/22/2000 Via procession rules - Hisham Khartabil asked about what a UAC is
expected to do when processing a response with more than its own VIA
headers. Answer: it shouldn't be receiving more than its own (UA was acting
as UAS, not UAC, or was broken).

11/22/2000 I-D ACTION:draft-rosenberg-sip-entfw-00.txt - Internet-Drafts
announced availability of SIP Traversal through Residential and Enterprise
NATs and Firewalls. Some comments on divergence from "typical" web traffic
patterns causing problems.

11/22/2000 INVITE/200 OK/BYE or INVITE/200 OK/ACK/BYE? - Vijay Gurbani posed
the question as to the proper response to contemporaneous 200 OKs received
by a forking proxy. Latter is correct; ambiguity in bis draft acknowledged.

11/22/2000 Multiple location - Sanjiv Deshpande asked whether a UAS
receiving a forked INVITE can, after responding to the forked INVITE but
before receiving an ACK, make another call. Received brusque response from
Jonathan Rosenberg concerning protocol versus implementation; moderate
third-party flame ensued.

11/22/2000 draft-rosenberg-sip-app-components-00.txt - Gonzalo Camarillo
raised the point that TSS services work similarly to MCU services (which
require one INVITE per party), so the correct way to invite for TSS is with
two INVITES instead of one INVITE containing two media descriptions.

11/22/2000 Preview of draft-calhoun-sip-aaa-reqs-00.txt - Tony Johansson
announced updated version of AAA Requirements for IP Telephony/Multimedia.

11/22/2000 New ISUP mapping draft - Adam Roach announced new ISUP to SIP
mapping draft.

11/22/2000 New SUBSCRIBE/NOTIFY draft available - Adam Roach announced new
draft incorporating changes to the -01 draft.

11/22/2000 The parser - Robert Kajun asked how the SIP parser should
operate, and whether the @ character could be escaped.

11/22/2000 Help with sip - Arun Kumar Chippada asked if it is possible to
run SIP Proxy Server and SIP UA on same machine. Yes, it is.

11/23/2000 Inviting users to join a centralized conference - Ya-Ching Tan
asked whether using REFER method to inviting users to a conference was
intentionally omitted. No, it was omitted unintentionally and will be
included in next draft.

11/23/2000 Multiple headers of a given type - M. Ranganathan asked for a
list of SIP headers that can appear multiple times in a message. Any header
whose BNF begins with # can appear multiple times.

11/24/2000 NEW I-D: fid SDP attribute - Gonzalo Camarillo announced a new
version of the SDP media alignment draft.

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