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454-319/1: Vo ice over IP. Lecture No. 8 SIP/SDP protocols – UA, Registrar, Redirect and Proxy Servers. Miroslav Voz ňák VŠB - Technical University of Ostrava Department of Telecommunications Faculty of Electrical Engineering and Computer Science 17. listopadu 15, 708 33 Ostrava – Poruba
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454-319/1: Voice over IP Lecture No.8 SIP/SDP protocols – UA, Registrar, Redirect and Proxy Servers Miroslav Vozňák VŠB - Technical University of Ostrava Department of Telecommunications Faculty of Electrical Engineering and Computer Science 17. listopadu 15, 708 33 Ostrava – Poruba mailto:miroslav.voznak@vsb.cz http://homel.vsb.cz/~voz29 Miroslav Voznak, lecture on SIP
Session Initiation Protocol a kernel of this protocol is specified in RFC 2543 , 99 MMUSIC WGMultiparty Multimedia Session Control RFC 3261 , 2002 SIP WG many extensions, contributors WG’sas SIPPING, SIMPLE (presence), IPTEL (cpl and trip), SPIRITS, PINT nowadays more than 70 RFC’s are regarding to SIP the features: text-oriented similar to HTTP end-to-end Miroslav Voznak, lecture on SIP
Session Initiation Protocol signaling protocol enabling a creation, modification and termination of a general session SDP is used for resolving the media description voice and video stream through RTP voice, video, text (instant messaging, presence, games ...) are the target applications on the transport layer using TCP, UDP or TLS Miroslav Voznak, lecture on SIP
Addressing Miroslav Voznak, lecture on SIP
Addressing SIP URI (Uniform Resource Identifier) sip:user@host:port;uri-parameters Miroslav Voznak, lecture on SIP
SIP elements User Agent – UA Client, UA Server UAC is a part sending the Requests and receiving the Responses UAS is a part receiving the Requests and sending the Responses SIP server – Proxy, Registrar, Redirect, Location SIP Proxy – header analyzing and handling, call routing (Requests and Responses) Miroslav Voznak, lecture on SIP
SIP elements Redirect Server – returns a new location for requests (a list of URI’s) Registrar Server – a receiving Registration Requests, an actualization of Location database (LS), maintains mapping from names to addresses Location Server – a storing location information of UA’s and other SIP Proxies Miroslav Voznak, lecture on SIP
types of SIP Proxy a classification of SIP Proxy: stateful (keeping the requests and responses, recognizing a repeating message, is able to detect a message loop, supports a forking) stateless (only forwarding) Stateful SIP Proxy can be: transaction stateful (only status a request – response) dialog stateful (all messages regarding a paticular call) Miroslav Voznak, lecture on SIP
Architecture Public Switched Telephone Network PSTN Gateway UA SIP softphone SIP Proxy, Registrar Server UA SIP Phone H.323 Endpoint H.323 Gatekeeper SIP/H.323 Gateway Miroslav Voznak, lecture on SIP
Thank you for your attentionmiroslav.voznak@vsb.cz Miroslav Voznak, lecture on SIP