Subject: [Sipping] new I-D: Redirection Service capability in SIP

From: "Sanjoy Sen" <[email-masked]>
Date: Mon, 26 Nov 2001 17:25:01 -0600

All,
 
    We've submitted a new ID draft-bharatia-sipping-redirect-00.txt which
analyzes the requirements for SIP to carry redirection-related information
to support various redirection-based services such as Voice-mail, ACD etc.
Although current SIP does support redirection capabilities, it needs to
carry certain additional pieces of information to enable interworking with
such legacy services as a SIP call to a PSTN voicemail and vice-versa. These
addititonal pieces of information are listed, along with the reason why
they're needed, and which SIP headers might carry some of these information.
We also analyze some of the existing solutions (such as Diversion header,
RFC 3087), and finally discuss using three proposed headers to carry these
information - 1) State, 2) Cookie and 3) Remote-Party-Id. Our solution bias
towards the RPI header are due to - a) it is used for privacy (which is an
important requirement) and the redirection information really characterizes
a remote party endpoint, and b) its a current WG draft. For more details,
please refer to:
 
http://search.ietf.org/internet-drafts/draft-bharatia-sipping-redirect-00.tx
t
<http://search.ietf.org/internet-drafts/draft-bharatia-sipping-redirect-00.t
xt> 
 
Any comments/feedback will be very much appreciated.
 
Regards,
 
Sanjoy Sen
Nortel Networks

========== 
Abstract: SIP is selected as a session control protocol for many VOIP 
   applications. Hence it should provide capabilities for supporting 
   such redirection-based services as automatic call distribution for 
   call centers, third-party voicemail, follow-me service etc. The 
   concept of Call Redirection is implicit in the capabilities already 
   defined for SIP Proxies and Clients. However, in order to allow 
   redirection to be used as a component of other services (in 
   particular voicemail), and in order to facilitate inter-working with 
   existing services, these capabilities needs to operate in a 
   consistent and well-defined way, and also need to support transfer 
   of certain additional pieces of information, such as redirecting and 
   redirected-to addresses, redirecting reason, redirection counter 
   etc. This draft discusses this required set of information, 
   evaluates existing work and proposes solution to this effect.