A Conference Gateway Supporting Interoperability Between SIP and H.323 Jiann-Min Ho (Presenter) Jia-Cheng Hu Information Networking Institute Peter Steenkiste School of Computer Science Dept. of Electrical and Computer Engineering Carnegie Mellon University
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A Conference Gateway Supporting Interoperability Between SIP and H.323 Jiann-Min Ho (Presenter) Jia-Cheng Hu Information Networking Institute Peter Steenkiste.
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A Conference Gateway Supporting Interoperability Between SIP and H.323
Jiann-Min Ho (Presenter) Jia-Cheng Hu
Information Networking Institute
Peter Steenkiste
School of Computer Science
Dept. of Electrical and Computer Engineering
Carnegie Mellon University
Agenda
Overview
Target network and goal
Signaling protocols and comparison
Design
Implementation
Performance evaluation
Discussion
Related work
Conclusion
Overview -Multi-party Media Conference
Media conference application drivers Network bandwidth and endpoint capability
Signaling and media streaming protocols Signaling protocols:
H.323 clients are lack of conference information, LDAP is not supported.
Media streams (RTP) are forwarded via GCCG; no support from media mixing/transcoding components/gateways.
Performance Evaluation
Correctness of conferencing signaling flow via GCCG
Testbed configuration One GCCG Server (Linux PC) and Five PC Clients (NT) Video Conferencing Software
MS NetMeeting version 3.01 and the MBone tools SDR v2.9 and VIC v2.8.
Common communication mode - H.261 Network Configuration
10 Mbs shared Ethernet
Performance Evaluation (cont.)
GCCGServer
H.323client
H.323client
H.323client
H.323client
H.323client
RTTMeasurement
Media StreamsRTP(H.261)
GCCGServer
SIPclient
H.323client
SIPclient
SIPclient
SIPclient
RTTMeasurement
Media StreamsRTP(H.261)
multicast
Performance Evaluation (cont.)
6
8
10
12
14
16
18
1 2 3 4 5Number of Participants
Ave
rage
RTT
(ms)
Scenario 1(H.323 clients)
Scenario 2(SIP clients)
Comparison of Average RTT
Discussion
Negotiation of Media Capabilities
Common conference media type (no transcoding GW) H.323 – determined by MC via H.245 procedures SIP – use a proxy server to query media capability information.
OPTION message can be applied. Standard? Draft?
Translation of message syntax between H.245 and SDP
Change of media stream codec gracefully?
Discussion (cont.)
Session Advertising Conference information advertisement
SIP – operate with SAP (push) H.323 – LDAP can be used (pull) if clients require this feature
Conference information mapping
Adaptation of Call Signaling Semantics Reduce signaling overhead via H.323 FastConnect
Conference Control H.323 – ITU-T T series, e.g. T.124, GCCP… SIP – drafting, standards?
Discussion (cont.)
IP Multicast Characteristic of the architecture – open conference
Authorization, authentication, encryption Application level support – conference server (GCCG) and
clients (H.323/SIP) IP multicast support – match application needs
Access media streaming multicast address H.323 – determined by MC SIP – from SAP messages malloc
Related Work
Several active groups, e.g. aHIT! from IMTC, ITU-T SG 16 and TIPHON, and …
H.323/SIP signaling gateway - Columbia University
Our prototype implementation focus Multi-party media conferencing signaling support IP multicast efficiency
Conclusion
Completion of interoperability for H323 and SIP in multiparty media conferencing sessions
Recommendation for raised interoperability issues.