Subject: RE: [Simple] Content indirection - Uploading large messages

From: [email-masked]
Date: Tue, 21 Jan 2003 11:58:49 +0200

Please take a look at

http://www.ietf.org/internet-drafts/draft-khartabil-sip-congestionsafe-ci-01.txt

I'm planning to update this to include a UA posting (eg: contents for PUBLISH or MESSAGE).

Regards,

Hisham

-----Original Message-----
From: ext Cnaan Oded [mailto:[email-masked]]
Sent: Tuesday, January 21, 2003 11:51 AM
To: [email-masked]
Cc: Rapaport Orly
Subject: RE: [Simple] Content indirection - Uploading large messages

Sean, 

Thanks for the prompt reply. 

You may be right that the details of how large payloads are sent from the UA to the server (in case these are not the same entities and that there is a network based server) are outside SIMPLE scope but it seems to me that the first hurdle SIMPLE will face would be -interoperability. If you leave this question open for proprietary solutions, applications from different vendors will not be able to co-exist on the same network. If you look at the WG charter, you will find that "The IETF has committed to producing an interoperable standard for these services ". 

The charter also refers to RFC 2778 and CPIM which require defining how messages are sent from UAs to servers, regardless of their size.

Moreover, if you look at 3GPP requirements from SIMPLE (e.g., draft-niemi-simple-im-wireless-reqs-00)  they require that "The content size MUST NOT be limited by the Instant Messaging, or message session protocols" - SIMPLE must be able to specify how this is done.

I believe SIMPLE WG should define at least a 'default' behavior for these cases, or refer to an external standard, such as MM1.

Oded Cnaan 

-----Original Message----- 
From: Sean Olson [ mailto:[email-masked]] 
Sent: Tuesday, January 21, 2003 9:46 AM 
To: 'Cnaan Oded'; [email-masked] 
Subject: RE: [Simple] Content indirection - Uploading large messages 

The draft intentionally does not address the how the content is placed 
on the content server to begin with. 
That is a separate problem that has many disparate solutions and does 
not necessarily need to be standardized. 
The interesting thing about standardizing the content-indirection 
mechanism is that it involves two SIP entities 
and directly impacts the SIP signaling. The transfer of content, either 
from the UA to the server, or between UAs 
is best handled outside of SIP ... the very point of the draft. 

Some important things to note: 

1) The "server" does not have to be distinct from the UA. They can be 
one in the same. 
2) The URL does not have to be an HTTP URL, though this will be probably 
be one of the more common schemes used. 
   For example, an LDAP URL might very be appropriate for certain types 
of content 
3) HTTP is ideal for conveying meta-data about the content it carries, 
but that argument is best handled outside of SIMPLE 
4) It was never envisoned that MESSAGE would be used to send these large 
payloads -- the entire point of content 
   indirection is to offload this to a non-SIP carrier. 
5) There is nothing mutually exclusive of content-indirection and MMS. 
Nor is there anything that compels one to use 
   MMS for this task in the draft. It's simply outside the scope of this 
draft. 
6) Is there something particularly non-concrete about the draft? ;-) 
7) This mechanism is not tied to any particular architecture, though 
some architectures may have more pressing need for 
   it than others. 

cheers, 
sean 

-----Original Message----- 
From: [email-masked] [ mailto:[email-masked]] On Behalf Of 
Cnaan Oded 
Sent: Monday, January 20, 2003 11:05 PM 
To: [email-masked]' 
Subject: [Simple] Content indirection - Uploading large messages 

The content-indirection draft (the latest I could find was 
draft-ietf-sipping-content-indirect-02.txt) describes how messages or 
notifications carry a URL in order to allow the UA to retrieve the 
(usually large) content over other transports (e.g., HTTP). The draft 
however does not specify how large content is uploaded from the UA to 
the server. 

Using HTTP per se is not sufficient for uploading messages over HTTP as 
there is some meta-data that needs to be attached to the document such 
as sender, recipient(s), message type etc. The MMS standard have already 
solved these details in their MM1 protocol (over HTTP as well). 

Note also that using the MESSAGE method is not a good practice as well 
as it would generate huge load on the CSCFs (in mobile networks that 
deploy IMS/MMD infrastructure), denying them from performing call 
control tasks. 

1. How should large messages be sent from the UA to the server? any 
specific draft? 
2. Does the SIMPLE WG intend to reuse the MM1 specifications or invent a 
new one? 
3. What's the status of this work within the SIMPLE WG? Are there any 
concrete contributions? 

Thanks, 
Oded Cnaan 
Comverse