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Agenda • Crash course on H323 • How is SIP different ? • Problems in Interworking • Possible Solutions • Current Implementation/Status • Q/A • Demo 25-May-17 © 1999, Columbia University Multimedia Communication Protocol Terminal/ User Agent Q931 H245 RTP RAS H450 Gatekeeper (Guardian) MCU (Meeting Hall) H323 Box Gateway (Bridge to another network) H323 Network 25-May-17 © 1999, Columbia University Terminal/ User Agent Terminal Control/Devices Codecs Q931 H245 RAS RTCP RTP TPKT TCP UDP IP and lower layers H323 Stack 25-May-17 © 1999, Columbia University A IP Router User Agent IP Router Guardian Meeting Hall User Agent B C H323 On Internet, Physical Configuration 25-May-17 User Agent © 1999, Columbia University A Guardian User Agent User Agent Meeting Hall User Agent C B Logical Configuration 25-May-17 © 1999, Columbia University •Take permission from your guardian •Find the address of the person to call •Dial the number/Pick up the phone •Tell the other party what all languages you can speak/understand •Wait for him to tell you his capabilities •Tell him what language you are going to speak during the conversation •Start talking (and listening) •When you are done say Bye to other party •Hang up •Inform your guardian that you are done. 25-May-17 © 1999, Columbia University •Take permission from your guardian ( RAS Admission Control) •Find the address of the person to call ( RAS Address resolution) •Dial the number (Q931 call setup) •Tell the other party what all languages you can speak/understand (H245 capability negotiation) •Wait for him to tell you his capabilities (H245 Capability negotiation) •Tell him what language you are going to speak during the conversation (H245 Logical channel signaling; languages=codecs) •Start talking (and listening) (Data transfer using RTP/RTCP) •When you are done say Bye to other party (H245 end session) •Hang up (Q931 call termination) •Inform your guardian that you are done. (RAS Admission Control) 25-May-17 © 1999, Columbia University Some additional things are also required. •Search for your guardian (RAS Gatekeeper discovery) •You can operate without a guardian •You can use multiple languages to communication •You can switch language during your talk as long as you talk what the other guy understands, however you have to explicitly tell him that you are switching. •Saying Bye before hanging up is optional And many more . . . 25-May-17 © 1999, Columbia University + It works + There are many existing implementation ... Some are free. + Supports lots of languages (codecs). + Interoperable with other other protocols H320 (ISDN), H324 (POTS). - Too complicated (a) ASN (b) Huge - Lots of protocols are combined together under the heading H323 ... Redundancy. - Guardian is overloaded and Meeting hall is full !! - Firewalls ? ...Difficult to develop. 25-May-17 © 1999, Columbia University Text based ... No legacy from ISDN/POTS Mr. B, you are invited to talk to me. I can understand English and German. OK, But I can understand English and French only. Let’s talk Mr. A Words... Mots... Words ... Words ... Words... Words ... Wörter ... Words 25-May-17 © 1999, Columbia University Mr. B SIP/IP H323/IP Cellular PSTN ISDN 25-May-17 © 1999, Columbia University SIP/IP Gateway H323/IP Cellular Gateway Gateway ISDN PSTN 25-May-17 © 1999, Columbia University • User Registration • H245 <=> SDP • Direct Data Traffic between SIP and H323 • Transparent Support for Codecs • Call sequence mapping (next slide) 25-May-17 © 1999, Columbia University H323 Network SIP Network Dial Mr X Mr. B, you are invited to talk to me. I can understand English and German. Pickup...Connected I speak/understand English andFrench. Mr. A Mr. X OK, But I can understand English and French only. I’ll speak English Let’s talk I’ll speak French Words... Words... Words... 25-May-17 Words... © 1999, Columbia University Mr. B H323 Network SIP Network Dial Mr A Mr. X Pickup...Connected Mr. A, you are invited to talk to me. I can understand English and German. I speak/understand English andFrench. Mr. A I understand English andGerman. I’ll speak English OK, But I can understand English only. I’ll speak English Let’s talk Words... Words... Words... 25-May-17 Words... © 1999, Columbia University Mr. B H323 Network SIP Network Dial Mr B Pickup...Connected Mr. B, you are invited to talk to Mr A. He can understand English only. I speak/understand English (default). Mr. A Mr. B Mr. X I’ll speak English OK, But I can understand English and French only. I’ll speak English Let’s talk Words... Words... Words... 25-May-17 Words... © 1999, Columbia University H323 Network SIP Network Dial Mr B Mr. B, you are invited to...English OK, ... English and French only. Pickup...Connected I understand En and Fr. Mr. A Mr. B Mr. X I’ll speak English I’ll speak English Let’s talk Words... Words... Words... 25-May-17 Words... © 1999, Columbia University All these solutions have one or the other problem. We Need Smart H323 Phone ... Dial Mr B, Also I can speak English and can Understand English and German Pickup..Connected, OK...I understand English and I’ll speak German. H323 V2.0 Fast Connect 25-May-17 © 1999, Columbia University H323 Network SIP Network Mr. B, you are invited to talk to Mr A. He speaks English and understands English and French Dial Mr B. Speak En Understand En and Fr Pickup...Connected Speak English and understand English. OK, ... I understand English and German. Let’s talk. But Mr A understands only English. Mr. A Mr. X Words... Words... Words... 25-May-17 Words... © 1999, Columbia University Mr. B • Two way call. Either side can initiate the call • Fast Connect as well as non-Fast connect • RTP packets directly between the endpoints • Codecs supported ? • Multiple calls simultaneously - ? • User Registration - NO • Call transfer and Multiparty conference - NO 25-May-17 © 1999, Columbia University Signaling GatewayApplication API API H323 Library SIP Library H323 Cloud 25-May-17 SIP Cloud © 1999, Columbia University H323 SIP Signaling Gateway PC PC E-Phone (Embedded SIP user agent) ® Windows Netmeeting® V3.0.1 LAN Signaling Connection (Q931,H245,SIP,etc) Data Connection (RTP/RTCP) 25-May-17 © 1999, Columbia University