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Introduction to SIP. Larry Amiot Northwestern University Internet2 Commons Site Coordinator Training September 27, 2004 Austin, Texas. How Do We Communicate?. Telephone (home, work, & cell phone) Email Text messaging - PowerPoint PPT Presentation


  • Larry AmiotNorthwestern

    Internet2 Commons Site Coordinator TrainingSeptember 27, 2004Austin, TexasIntroduction to SIP

  • How Do We Communicate?Telephone (home, work, & cell phone)EmailText messagingData sharing (PowerPoint, applications, white board, desktop, etc.)Audio/videoFile transferInk- tablet PC

  • Questions?but how do we know where to find the person we want to communicate with...and given the availability of my resources, which of the persons devices do I want to communicate with..and what is the address of that device..and how does the person control his active/inactive devices..and how do we authenticate people..and how do we bridge this between organizations

  • Enter the Session Initiation Protocol (SIP)An emerging signaling protocol for: Initiating,Managing, and Terminating messaging, voice, and video sessions Internet Engineering Task Force (IETF)Developed by the SIP Working GroupPublished as IETF RFC 3261Connectivity using IPMay be extended for services such as:call control services, mobility,interoperability with telephony systems, and more

  • SIP and its Extensions

    PresenceThe willingness and ability of a user and their devices to communicate with other users on the networkSIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE)AuthenticationOffice integration

  • SIP EntitiesUser AgentUser Agent Client (UAC)User Agent Server (UAS)Redirect ServerProxy Server Registrar

  • SIP Session Establishment and Call TerminationFigure courtesy of Radvision Ltd

  • Session Description Protocol (SDP)SDP is the protocol used to describe multimedia session announcement, multimedia session invitation and other forms of multimedia session initiation.A multimedia session is defined, for these purposes, as a set of media streams that exist for a duration of time.RFP 2327

  • Figure courtesy of Radvision LtdCall Redirection Using a Redirect Server

  • Figure courtesy of Radvision LtdCall Proxy Scenario

  • Authentication- RFC 3261Any time that a proxy server or UA receives a request, it MAY challenge the initiator of the request to provide assurance of its identity. No authorization systems are recommended or discussed in this document. The "Digest" authentication mechanism described in this section provides message authentication and replay protection only, without message integrity or confidentiality. Basic should not be usedMicrosoft LCS supports Kerberos and NTLM

  • A Few Multipoint SIP Implementation ExamplesThere is considerable point-to-point SIP-based videoconferencing going onThe following examples concentrate on multipoint videoconferencingMicrosoft Live Communications ServerWave3 SessionsRadvision ViaIP

  • Windows Messenger- The Microsoft Approach

  • Windows Messenger

    SIP-based Runs on Windows XP systems (sorry no Macs)Core Features:Presence and contact list managementInstant MessagingVoice and VideoData collaboration and File transferPC to PhoneAdministrative Policies to enable/disable featuresAcoustic Echo Cancellation in software

  • Windows Messenger

    Microsoft .Net SIP server or enterprise SIP serverCan not go point-to-point using IP addressing- needs proxy serverMicrosoft Live Communications Server (LCS) is their proxy server

  • InternetWindows Messenger ClientsMicrosoft Live Communication ServerSIP Point-to-Point Interoperability Using the Microsoft LCSMicrosoft Active Directory

  • Radvision MCUSIPH.323InternetH.323 ClientsWindows Messenger ClientsMicrosoft Live Communication ServerSIP/H.323 Interoperability Using the Radvision MCUMicrosoft Active Directory

  • Radvision MCUSIPH.323InternetH.323 ClientsWindows Messenger ClientsMicrosoft Live Communication ServerSIP/H.323 Interoperability Using the Radvision MCUIMfirstMicrosoft Active Directory

  • Wave3s Sessions SIP Client

  • SessionsSip-basedWorks on/between PCs and MACsIM, Audio/video, & data sharingPoint-to-point using IP addressing, or work with a SIP serverWave3 has a server for multipoint videoWAVELETS codec Not compatible with Windows Messenger data sharingNo echo cancellationSession 3.0 betah.261 cif/qcifh.263 cif/qcifadditional audio codecsPresenceIMDTMFSymmetric signaling and symmetric RTP to support NAT traversal solutions.

  • Radvision MCUSIPH.323InternetH.323 ClientsSession ClientsYour Favorite SIP ServerSIP/H.323 Interoperability Using the Radvision MCU

  • Radvision MCUSIPH.323InternetH.323 ClientsWave3 Session ClientsIPtel SIP ServerSIP Evaluation at Northwestern UniversityH.350 LDAP ServerAuthenticationNot yet working

  • A Few SIP ClientsMicrosoft Windows MessengereCONF (Radvision resale)Wave3 Sessions ( Convergence Laboratory at Claremont Graduate University (

  • A Few SIP Proxy ServersMicrosoft Live Communications ServerHCL Technologies (

  • SummarySIP is an emerging TechnologyStaying with single a vender solution is currently workableInteroperability between vender products is still in early stagesMultipoint conferencing is possibleData Sharing is still an interoperability problemSelection of a SIP Proxy Server is critical as is its method of authentication


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