1 / 22

Interworking Between SIP/SDP and H.323

Agenda Compare SIP/H.323 Problems in interworking Possible solutions Conclusion Q/A. Interworking Between SIP/SDP and H.323. Kundan N. Singh, Dept. of Computer Science, Columbia University kns10@cs.columbia.edu. What is H.323 ?. Multimedia Communication Protocol. Terminal/ User Agent.

hanlon
Download Presentation

Interworking Between SIP/SDP and H.323

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Agenda Compare SIP/H.323 Problems in interworking Possible solutions Conclusion Q/A Interworking Between SIP/SDP and H.323 Kundan N. Singh, Dept. of Computer Science, Columbia University kns10@cs.columbia.edu Kundan Singh/SIP-H.323

  2. What is H.323 ? Multimedia Communication Protocol Terminal/ User Agent Terminal/ User Agent Gatekeeper Q931 H245 RTP RAS H450 MCU (Conferencing) Gateway (Bridge to another network) H323 Box H323 Network Kundan Singh/SIP-H.323

  3. What is SIP ? Session Initiation Protocol for Internet Registrar Redirect Proxy Servers UserAgent UAS/UAC Kundan Singh/SIP-H.323

  4. H.323 vs SIP Typical UserAgent Protocol stack for Internet Terminal Control/Devices Terminal Control/Devices H.245 RTCP Q.931 RAS RTCP SIP SDP Codecs Codecs RTP RTP TPKT TCP UDP Transport Layer IP and lower layers Kundan Singh/SIP-H.323

  5. SIP vs H.323 • Binary ASN.1 PER encoding • Sub-protocols: H.245, H.225 (Q.931, RAS, RTP/RTCP), H.450.x... • H.323 Gatekeeper • Text based request response • SDP (media types and media transport address) • Server roles: registrar, proxy, redirect Both use RTP/RTCP over UDP/IP Kundan Singh/SIP-H.323

  6. Interworking ProblemsCall setup translation H.323 SIP Q.931 SETUP INVITE Destination address (Bob@office.com) Q.931 CONNECT 200 OK Terminal Capabilities Media capabilities (audio/video) Terminal Capabilities ACK Open Logical Channel Media transport address (RTP/RTCP receive) Open Logical Channel • Multi-stage dialing • H.323v2 Fast-start is optional Kundan Singh/SIP-H.323

  7. H.323 Gatekeeper SIP registrar H.323terminal SIP user agent Interworking ProblemsUser Registration ? H.323 SIP Alias: Henry E164: 7040 sip:sam@home.com sip:7063@gateway.com • Location independent user identifier ? • Use information from both networks Kundan Singh/SIP-H.323

  8. Interworking ProblemsMedia Description SIP/SDP (dynamically choose from listed modes) List of alternative set of algorithms. audio G.711 Mu law, G.723.1, G.728 video H.261 H.323/H.245 (declare your exact modes) Supports inter-media constraints { [G.711 Mu law, G.711 A law][H.261 video]} { [G.723.1] [no video] } • Translation in both directions • Algorithm selection by end-systems Kundan Singh/SIP-H.323

  9. Interworking ProblemsCall Services • H.323 Conferencing: centralized signaling control, MC (Multi-point Controller) • Supplementary services, like call transfer: H.450.x • SIP Conferencing: centralized bridged + decentralized distributed • REFER, 3pcc Kundan Singh/SIP-H.323

  10. Interworking ProblemsSecurity and QoS • H.323 uses H.235, whereas SIP uses Basic, Digest, PGP • Media Traffic end-to-end; QoS ? Kundan Singh/SIP-H.323

  11. What we want ? • Transparent translation • Minimum modification in SIP or H.323 • Use features from both SIP and H.323 • Direct RTP/RTCP traffic; end-to-end Kundan Singh/SIP-H.323

  12. H.323 Gatekeeper + SGW pc1.office.com SIP registrar server H.323 terminal 128.59.19.200 SIP user agent User registrationRegistration info to foreign network REGISTER henry@office.com Contact:pc1 home.com INVITE henry@office.com 3xx Moved Contact:pc1 RRQ henry@office.com Contact:128.59.19.200 sam@home.com use SIP REGISTER and/or H.323 RRQ/RCF Kundan Singh/SIP-H.323

  13. SIP registrar server + SGW H.323 Gatekeeper pc1.office.com H.323 terminal 128.59.19.200 SIP user agent User registrationRegistration info from foreign network LRQ/LCF home.com INVITE henry@office.com 200 OK RRQ henry@office.com Contact:128.59.19.200 sam@home.com use SIP OPTIONS and/or H.323 LRQ/LCF Kundan Singh/SIP-H.323

  14. User registrationDifferent Architectures • SGW co-located with H.323 gatekeeper • SGW co-located with SIP registrar/proxy server • Independent SGW Kundan Singh/SIP-H.323

  15. 200 OK. ACK RTP/RTCP Call Setupwith H.323v2 Fast Start (Almost) One-to-one mapping between SIP and H.323 messages. H323 SIP Setup/FastStart INVITE Connect/FastStart Reverse direction is similar Kundan Singh/SIP-H.323

  16. Call Setupwithout Fast Start H.323 SIP Q.931 SETUP INVITE Destination address (Bob@office.com) Q.931 CONNECT 200 OK Terminal Capabilities Media capabilities (audio/video) Terminal Capabilities ACK Open Logical Channel Media transport address (RTP/RTCP receive) Open Logical Channel Accept the call from H.323, forward to SIP after OLC ? Not desirable. Kundan Singh/SIP-H.323

  17. Acknowledgement Acknowledgement RTP/RTCP Call Setupwithout Fast Start, SIP to H.323 H323 SIP Setup/Q931 INVITE Signaling Gateway Connect/Q931 Capabilities/H245 Capabilities/H245. Media Transport Address 200 OK. Open Logical Channel/ H245 ACK Open Logical Channel / H245 Kundan Singh/SIP-H.323

  18. Acknowledgement Acknowledgement Open Logical Channel RTP/RTCP Call Setupwithout Fast Start, H.323 to SIP H323 SIP Setup/Q931 INVITE Signaling Gateway Connect/Q931 200 OK ACK Capability Exchange Media Transport Address Open Logical Channel Re-INVITE/SIP+SDP Kundan Singh/SIP-H.323

  19. Media Capability • Modify SIP/SDP : multiple capability sets, or... • Let the SGW choose a sub-set of capabilities for SIP side • Re-INVITE or change in H.323 mode or logical channels, whenever it changes Kundan Singh/SIP-H.323

  20. ConclusionWhat can be done ? What can’t ? • Basic audio/video call • Transparency of User registration • Advanced calls with complex sessions • Conferencing • SIP centered, H.323 centered • Other supplementary services • . . . Kundan Singh/SIP-H.323

  21. ConclusionStatus • IETF mailing list “sip-h323@egroups.com”. Finalizing requirements document • IMTC and ETSI TIPHON • Convergence between SIP and H.323 in newer versions Kundan Singh/SIP-H.323

  22. ConclusionImplementation - sip323 • Prototype (free download) system at http://www.cs.columbia.edu/~kns10/software/sip323 • Other information at http://www.cs.columbia.edu/~kns10/research/gw • My contact info: kns10@cs.columbia.edu Kundan Singh/SIP-H.323

More Related