v SIP message example (the below message is from RFC2543) INVITE sip: watson @boston. bell-telephone com SIP/2.0 Via:S|P20UDP169130125 From: <sip: a.g. bell@bell-telephone com> To: T A Watson <sip: watson@bell-telephone com> Call-ID: 187602141351@worcester. bell-telephone com Content-Length: 885 Encryption: PGP version2 6.2, encoding=ascii NOTE: MIME security with pretty good privacy(PGP), RFC 2015, October 1996 sIP has only a limited number of methods 1)Invite, 2) ACK, 3)Options, 4 )Bye, 5 Cancel, 6)Register Cancel: unusually cancel a connection which is going on 202l/1/27 Dr. Zhangi xU, National Key Lab on isN, Xidian University
2021/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University 16 ✓ SIP message example (the below message is from RFC2543) INVITE sip:watson@boston.bell-telephone.com SIP/2.0 Via: SIP/2.0/UDP 169.130.12.5 From: <sip:a.g.bell@bell-telephone.com> To: T. A. Watson <sip:watson@bell-telephone.com> Call-ID: 187602141351@worcester.bell-telephone.com Content-Length: 885 Encryption: PGP version=2.6.2, encoding=ascii NOTE: "MIME security with pretty good privacy (PGP)", RFC 2015, October 1996. SIP has only a limited number of methods: 1) Invite, 2) ACK, 3)Options, 4) Bye, 5)Cancel, 6)Register Cancel: unusually cancel a connection which is going on
√H323ⅴs.SIP Items 9.323 SIP M essages Binary-based Text-based Develop UpdateComplicated Easy Elements Hundreds 37 headers Interactions Complicated Simple Setup of a task V1(call, ctrl, media 3 round-trip, V2 faststarf/ Single round-trip Extensibility ITU developed only Any registered Codecs Scalability(large State State or stateless number of call processing Mobility supportLimited Easier Market Becoming less Growing extensively 202l/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University 17
2021/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University 17 ✓ H.323 vs. SIP Messages Develop & Update Complicated Elements & Interactions Hundreds, Complicated Setup of a task V.1(call,ctrl,media) 3 round-trip, V.2 faststart Extensibility ( Codecs) ITU developed only Market Becoming less Mobility support Limited Scalability (large number of call processing) State Binary-based Easy 37 headers, Simple Single round-trip Any registered Growing extensively Easier State or stateless Text-based Items H.323 SIP
☆ IP Telephone ☆ General Definition In contrast to traditional telephone in CS network, it means real-time services. such as vojce. video, etc transferred in best-effort Ps network Brief history ime Events Players First commercial IP March 1995 Vocaltec phone for PCs 1996 PC-to-phone, Phone-to-phone Free world Dialup, MIT, 1997-1998 Part commercial application Vocaltec, Net2 phone 1999~ High density (4-8 T1/E1), Audiocodes, analogic, large capacity(100T1)(NMS. 202l/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University
2021/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University 18 ❖ IP Telephone ❖General – Definition In contrast to traditional telephone in CS network, it means real-time services, such as voice, video, etc, transferred in best-effort PS network. – Brief history Time Events March,1995 First commercial IP phone for PC’s 1999~ High density (4~8 T1/E1), large capacity (>100T1) 1997~1998 Part commercial application 1996 PC-to-phone,Phone-to-phone Players Vocaltec Audiocodes, analogic, NMS,… Vocaltec, Net2phone,… Free world Dialup,MIT,…
☆ IP Phone network away IP backbone Gatekeeper network PSTN PSTN FAX Telephone 是 Fax Telephone Gateke Hong Kong New York Fax PSTN Shangh Telephone 202l/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University
2021/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University 19 ❖ IP Phone Network IP backbone network New York Fax Telephone Gatekeeper PSTN Gateway Telephone Fax Gatekeeper PSTN Gateway Shanghai FAX Telephone Gatekeeper PSTN Gateway Hong Kong
Call Procedure Pick the hook up(Off-hooks), dial special service number ex 17900 for China telecom Voice response: Please input account password When it is OK, voice response: input the called number, ex 86-21-5678# for Shanghai Voice response: the time allowed XXX, please wait Local Gateway performs PSTN-IP translation, send necessary info to remote gateway by using H 323 or SIP Remote gateway is ringing to the called user, performs the negotiation of parameters, such as coding, RTP/RtCP sessions, etc If user answered, the info is sent to original gateway Voice transmission begins 202l/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University
2021/1/27 Dr. Zhanqi XU, National Key Lab on ISN, Xidian University 20 – Call Procedure • Pick the hook up (Off-hooks), dial special service number, ex 17900 for China Telecom • Voice response: Please input account & password • When it is OK, voice response: input the called number,ex 86-21-56781234# for Shanghai • Voice response: the time allowed XXX, please wait • Local Gateway performs PSTN-IP translation , send necessary info. to remote gateway by using H.323 or SIP • Remote gateway is ringing to the called user, performs the negotiation of parameters, such as coding, RTP/RTCP sessions,etc. • If user answered, the info. is sent to original gateway • Voice transmission begins