1. 1 © 1999, Cisco Systems, Inc. Course Number Presentation_ID Peer-to-Peer 3rd party call control Rohan Mahy—Cisco Systems rohan@cisco.com

2. 2 Presentation_ID © 1999, Cisco Systems, Inc. Peer to peer 3pcc — Problem Set Current 3pcc reproduces centralized control model of xGCP or PSTN (but needed for SIP interworking with H.323, RTSP, HTTP, etc.) Make 3pcc distributed Softphone directs my phone to dial, etc. Use request vs. control model Get status via notifications

3. 3 Presentation_ID © 1999, Cisco Systems, Inc. Peer-to-peer 3pcc — Proposal If you can parse SIP URIs with method parameters and headers (needed for VoiceXML, etc.) and... If you support REFER, turns out you have everything you need for “control” Use Refer-To URLs with method parameter SUBSCRIBE/NOTIFY is a reasonable way to get status

4. 4 Presentation_ID © 1999, Cisco Systems, Inc. Next steps Come up with SIP-Status event Choose REFER, PHONECTL, or some new method Choose authentication model Does this fit in call control framework?