[Serusers] Instant Messaging User Agent Interoperabilityproblem

Victor Huertas Garcia vhuertas at hotmail.com
Fri Jul 1 16:30:10 CEST 2005


Thank you very much!

A very good explanation.

Victor

>From: "Samuel Osorio Calvo" <samuel.osorio at nl.thalesgroup.com>
>To: <vhuertas at hotmail.com>, <jan at iptel.org>, <klaus.mailinglists at pernau.at>
>CC: <serusers at lists.iptel.org>
>Subject: Re: [Serusers] Instant Messaging User Agent 
>Interoperabilityproblem
>Date: Fri, 01 Jul 2005 13:27:53 +0200
>
>Hi!
>
>Regarding IM within SIP, there are two modes: paging and session.
>The first is a kind of sms service, where users sends *few* messages(if you 
>are not a teenager... ;) ) . This is provided by the standard SIP request 
>MESSAGE.
>The session mode provides the typical chat scenario, where users are typing 
>*constantly* message and they are exchanged in (soft) real time. This is 
>provided by the MSRP protocol defined by the IETF's group SIMPLE. In that 
>case, the MSRP session parameters are carried in the SDP body of the 
>INVITE. Once the Offer/Answer is completed, both end points can send 
>messages via the MSRP session.
>
>For both modes, SIP proxies (SER) do not require extended capabilities 
>because in both cases SIP requests (MESSAGE for paging and INVITE for 
>session) are proxied normally and finally arrive to the end points. The 
>main difference lies in the UA: the paging mode is widely supported because 
>almost all UA supports MESSAGE request, while the session mode is not yet 
>so extended because MSRP is quite new.
>
>Although Messenger started (>4.6 I think) with plain SIP supporting only 
>MESSAGE requests, it needed a chat session mode to be implemented and since 
>MSRP was not still finished, microsoft decided to develop its own protocol 
>(strange, isn't it?). That is why new versions of microsoft messenger are 
>not compatible with standard SIP UA.
>
>Once MSRP is extended (there's an open source implementation in 
>www.sipfoundry.org), standard SIP UA (excluding microsfot thing) will be 
>fully interoperable both in paging mode (MESSAGE) and session mode (MSRP).
>
>My 0.02,
>
>Samuel.
>
>
>Unclassified.
> >>> "Victor Huertas Garcia" <vhuertas at hotmail.com> 07/01/05 12:40PM >>>
>
>
>Hi all,
>
>I am testing the Instant Message Service with the SER v0.8.14 and I see 
>that
>it routes them correctly towards the destination user agent. However, what 
>I
>have seen is a tremendous imcompatibility between user agents of different
>vendors.
>
>Here just a bit of this:
>
>IM between two Windows Messenger 4.7.
>
>What I see it that the very first MESSAGE in the conversation is sent
>towards the SER and it routes it perfectly but the subsequent MESSAGES are
>exchange between both Messengers directly!!! It is weird... but this is how
>it is working.
>
>IM between Window Messenger 4.7 and EyeBeam v1.1
>
>The EyeBeam always send the MESSAGES towards the SIP proxy and messenger
>receive them with no problem. However, when the messenger tries to send a
>MESSAGE in the conversation it even doesn't send the packet (I tried to
>capture it with Ethereal and no packet was sent at all) and subsequently
>tell you that the text message could not be delivered to the destination.
>
>IM between EyeBeam v1.1
>
>No problem at all.
>
>IM involving Windows Messenger 5.1
>
>This version of messenger sends an INVITE to the destination before issuing
>the MESSAGE. With EyeBeam is a total disaster and the comunication is not
>possible.
>
>
>My conclusion is that the SER has not implication in such incompatibility 
>at
>all and that is a matter of interoperability among vendors and different
>implementations of SIMPLE. Do you agree?
>
>Thanks in advance
>
>Victor
>
>
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