No Subject

re-INVITE. 

2. call-leg ID lookups in gateways are much faster now, since the tags and 
call-ids are just strings. Matching is now case-sensitive string compares. 
Much easier than URL comparison. 

3. Overlap dialing is easier. The reason we've had to send each digit as a 
new call leg, is that we needed to change the To field and the request URI. 
By definition, this meant a new call leg. Now, we can send all of that 
within a single call leg. Much cleaner. 

4. The Replaces draft benefits. We've already identified a need for the 
Replaces header to identify the entire call leg thats being replaced. This 
gets big when it carries two URLs, two tags, and a call-id. Now, we can 
throw away the URLs. This shortens the header and makes matching of the 
call-leg IDs easier. 

5. It works with existing proxies. 

THe main drawback, of course, is that this won't interoperate with rfc2543 
UAs. Thats fixable with Supported; the UAC indicates Supported: 
new-call-leg-id in the INVITE if it understands this. In that case, any 
responses or re-invites that change the URLs include a Require: 
new-call-leg-id. 

I fully admit that this may not be worth the pain. However, I'd welcome 
comments from others on whether its useful to consider further. 

-Jonathan R. 

--- 
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave. 
Chief Scientist                             First Floor 
dynamicsoft                                 East Hanover, NJ 07936 
jdrosen@dynamicsoft.com                     FAX:   (973) 952-5050 
http://www.jdrosen.net <http://www.jdrosen.net>                       PHONE:
(973) 952-5000 
http://www.dynamicsoft.com <http://www.dynamicsoft.com>  
  

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-------------
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Jay Batson
CEO
Pingtel Corp.
mailto:jbatson@pingtel.com <mailto:jbatson@pingtel.com> 
781-938-5306 (office)




_______________________________________________
Sip mailing list  http://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sipping@ietf.org for new developments on the application of sip