SIP in higher education

[(Dennis Baron)]

From the SIP.edu Conference Call January 06, 2005 minutes:
>                                                  Harvard, unlike MIT,
> has lists of numbers associated with some email addresses, and options
> for return results for these cases are being discussed. Possibilities
> include returning no values,  or multiple values either in a list or
> prioritized in some format. No participants in this call know offhand
> what the RFC specifies for multiple results.

I think I said that I'd check to see if I recalled correctly about
this being in the RFC... sure enough:

RFC 3261            SIP: Session Initiation Protocol           June 2002
21.3.1 300 Multiple Choices

   The address in the request resolved to several choices, each with its
   own specific location, and the user (or UA) can select a preferred
   communication end point and redirect its request to that location.

   The response MAY include a message body containing a list of resource
   characteristics and location(s) from which the user or UA can choose
   the one most appropriate, if allowed by the Accept request header
   field.  However, no MIME types have been defined for this message
   body.

   The choices SHOULD also be listed as Contact fields (Section 20.10).
   Unlike HTTP, the SIP response MAY contain several Contact fields or a
   list of addresses in a Contact field.  UAs MAY use the Contact header
   field value for automatic redirection or MAY ask the user to confirm
   a choice.  However, this specification does not define any standard
   for such automatic selection.

      This status response is appropriate if the callee can be reached
      at several different locations and the server cannot or prefers
      not to proxy the request.

Seems like you could do some interesting things with this but I've
never seen an implementation of this on the client or server side.
Has anybody come across a SIP UA that does something with a
300 Multiple Choices response?

                        Dennis

=========================================================================

Dennis Baron; Information Services & Technology     
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Senior Strategist for Integrated Communications        
sip:
Massachusetts Institute of Technology; Room E19-738   tel:+1-617-252-1232
77 Massachusetts Avenue;  Cambridge, MA  02139-4307   fax:+1-617-253-8000

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