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Larry Amiot Northwestern University amiot@northwestern

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

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Larry Amiot Northwestern University amiot@northwestern

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  1. Introduction to SIP Larry Amiot Northwestern University amiot@northwestern.edu Internet2 Commons Site Coordinator Training September 27, 2004 Austin, Texas

  2. How Do We Communicate? • Telephone (home, work, & cell phone) • Email • Text messaging • Data sharing (PowerPoint, applications, white board, desktop, etc.) • Audio/video • File transfer • Ink- tablet PC

  3. 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

  4. 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 Group • Published as IETF RFC 3261 • Connectivity using IP • May be extended for services such as: • call control services, • mobility, • interoperability with telephony systems, and more

  5. SIP and its Extensions • Presence • The willingness and ability of a user and their devices to communicate with other users on the network • SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) • Authentication • Office integration

  6. SIP Entities • User Agent • User Agent Client (UAC) • User Agent Server (UAS) • Redirect Server • Proxy Server • Registrar

  7. Application SIP Session Establishment and Call Termination Figure courtesy of Radvision Ltd

  8. 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

  9. Call Redirection Using a Redirect Server Figure courtesy of Radvision Ltd

  10. Call Proxy Scenario Figure courtesy of Radvision Ltd

  11. Authentication- RFC 3261 • Any 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 used • Microsoft LCS supports Kerberos and NTLM

  12. A Few Multipoint SIP Implementation Examples • There is considerable point-to-point SIP-based videoconferencing going on • The following examples concentrate on multipoint videoconferencing • Microsoft Live Communications Server • Wave3 Sessions • Radvision ViaIP

  13. Windows Messenger- The Microsoft Approach

  14. Windows Messenger • SIP-based • Runs on Windows XP systems (sorry no Macs) • Core Features: • Presence and contact list management • Instant Messaging • Voice and Video • Data collaboration and File transfer • PC to Phone • Administrative Policies to enable/disable features • Acoustic Echo Cancellation in software

  15. Windows Messenger • Microsoft .Net SIP server or enterprise SIP server • Can not go point-to-point using IP addressing- needs proxy server • Microsoft Live Communications Server (LCS) is their proxy server

  16. SIP Point-to-Point Interoperability Using the Microsoft LCS Microsoft Live Communication Server Microsoft Active Directory Internet Windows Messenger Clients

  17. SIP/H.323 Interoperability Using the Radvision MCU Microsoft Live Communication Server Radvision MCU SIP H.323 Microsoft Active Directory Internet Windows Messenger Clients H.323 Clients

  18. SIP/H.323 Interoperability Using the Radvision MCU Microsoft Live Communication Server Radvision MCU SIP IMfirst H.323 Microsoft Active Directory Internet Windows Messenger Clients H.323 Clients

  19. Wave3’s Sessions SIP Client

  20. Sip-based Works on/between PCs and MACs IM, Audio/video, & data sharing Point-to-point using IP addressing, or work with a SIP server Wave3 has a server for multipoint video WAVELETS codec Not compatible with Windows Messenger data sharing No echo cancellation Session 3.0 beta h.261 cif/qcif h.263 cif/qcif additional audio codecs Presence IM DTMF Symmetric signaling and symmetric RTP to support NAT traversal solutions. Sessions

  21. SIP/H.323 Interoperability Using the Radvision MCU Your Favorite SIP Server Radvision MCU SIP H.323 Internet Session Clients H.323 Clients

  22. SIP Evaluation at Northwestern University IPtel SIP Server Radvision MCU SIP Authentication H.323 H.350 LDAP Server Internet Wave3 Session Clients H.323 Clients Not yet working

  23. A Few SIP Clients • Microsoft Windows Messenger • eCONF (Radvision resale) • Wave3 Sessions (www.wave3software.com) • Network Convergence Laboratory at Claremont Graduate University (ncl.cug.edu)

  24. A Few SIP Proxy Servers • Microsoft Live Communications Server • HCL Technologies (www.hcltech.com) • Indigo • Ubiquity • SNOM • VOCAL • Iptel • DynamicSoft • Siemens • Nortel • eCONF

  25. Summary • SIP is an emerging Technology • Staying with single a vender solution is currently workable • Interoperability between vender products is still in early stages • Multipoint conferencing is possible • Data Sharing is still an interoperability problem • Selection of a SIP Proxy Server is critical as is its method of authentication

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