Transcript Lecture 1
RTMM, VoIP, VVoIP, NGN, Convergence? Alfredo Terzoli / Mosioua Tsietsi PLAN • • • • • • • Admin Real time communication today: your experience A bit of terminology The Internet for transport of real-time data An initial smattering of protocols Convergence What do you expect from this module? Admin • Length of each lecture: 1 to 1.5 hours • Expected study time, for each lecture: at least 3 hours (this excludes practicals) • Schedule: most days of the week, starting at 8:30 or 9:00 • Main practical will be the creation of service, which will be presented to the class Real time communication today • • • • • • • • Skype (desktop / cell) Gtalk (desktop / cell) MSN Fring (mobile) Yeigo (mobile) … PC to telephone / cellphone Telephone/cellphone to telephone/cellphone RTMM • RealTime MultiMedia: – all media, obviously (smell anybody? The power of digitization!) – in particular, naturally, voice and video – the way we are proceeding we should call it RTMMoIP. (or RTMMoATM?) – BTW, how do you conceptualize the Internet? VoIP/VVoIP • Voice/video over the Internet Protocol – two classic ways of deploying VoIP, for the enterprise or for the long haul (they can be combined) – we will use this term as equivalent to RTMM – are we going to talk just about real-time multimedi? Actually not. An important part of the course is to talk about service provision in a converged telecommunication environment IP to transport voice • Can the Internet transport voice? (This is a major change! Up to recently only Telco's have been doing it.) • Let’s be more precise: can the INTERNET PROTOCOL be used to transport voice? Realtime communication • Two problems: – (easy!) how can a telephone conversation become DATA? – does this type of DATA have special requirements? A conversation becomes DATA And it is transported… Another view! Digitized voice: demanding DATA! So, is VoIP possible or not? • Yes, it is possible, but things do need some work here and there, depending on the setting. Once the stuff is done, though, we will get Video transport almost for free too! Different settings… Internet LAN RTP, RVSP, DiffServ, IPv6 • RTP: Realtime Transport Protocol (has a companion, RTCP) • RSVP: Resource Reservation Protocol • DiffServ: Differentiated Services • IPv6: IP version 6, the next version of the Internet (Video) Telephony vs Streaming • Real-time communication is the next frontier of the Internet • Telephony, Video telephony, Audio and Videoconferencing are more demanding than STREAMING, which has ‘softer’ real-time constraints. Why VoIP/Convergence? • Packet based networks are in general more bandwidth-efficient than legacy voice networks Why VoIP/Convergence? • Much easier to create ‘services’ • Services need DATA, and data is much easier to access and distribute if your network is already a data network. Example: create a a service to read end-of-the-year marks to students phoning in (put in at Rhodes in 2002-3 by Jason Penton) Why VoIP/Convergence? • Much easier to extend later to other media • Because of digitization, other media can be treated very much in the same way: once digitized, they are just data Example: extend the system to support video. (And let’s not forget smells! ;-) Typical deployment Local VoIP Endpoints SIP IAX H.323 MGCP Internet SER GnuGK Asterisk iLanga proxy Legacy PBX BRI PRI iLanga Core PSTN BRI PRI Legacy service provider use TDM network 1 SER GnuG K Asteris k iLanga proxy iLanga Core TDM network 2 SER IP Network (Typically not the Internet) GnuG K Asteris k iLanga proxy iLanga Core NGN • Next Generation Network (replaces and extends IN, the Intelligent Network) – telecommunication network, such a Telco network, where service creation is easy and can be done by third parties (that is, not directly by the Telco owning the network) – the ‘opening’ of the network is done introducing elements such OSA/Parlay gateways – loved by telecommunication engineers! NGN and Internet • The Internet is a good candidate to be the ‘de facto’ realization of a NGN – big statement, of course – and maybe the Internet is going to change name… – to say the least, it won’t be the ‘legacy network’ that NGN will have to carry into the future Questions? URLs to follow • http://en.wikipedia.org/wiki/Telecommunication_convergence (an overview on convergence in telecommunication and a springboard for many other related topics; in particular, follow up the link http://en.wikipedia.org/wiki/Telecommunication_convergence ) • http://www.cs.virginia.edu/~cs757/slidespdf/757-09-overlay.pdf (clear explanation of what an overlay network is) • http://www.kcnap.com/whatisanap.html (an idea of interconnection on the Internet: and how the Internet is actually formed, but helps with the idea of an overlay too)