Introduction to SIP Larry Amiot Northwestern University Internet2 Commons Site Coordinator Training March 22, 2004 Indianapolis, Indiana

2 How Do We Communicate?  Telephone (home, work, & cell phone)   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 SIP Session Establishment and Call Termination Figure courtesy of Radvision Ltd Application

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 Figure courtesy of Radvision Ltd Call Redirection Using a Redirect Server

10 Figure courtesy of Radvision Ltd Call Proxy Scenario

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 SIP Implementation Examples  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

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

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

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

Radvision MCU SIPSIP H.323 Internet H.323 Clients SIP/H.323 Interoperability Using the Radvision MCU eCONF SIP Clients UAC UAS

21 Wave3’s Session SIP Client

22 Session  Sip-based  Works on/between PCs and Macs  IM, Audio/video, & data sharing  Can go point-to-point using IP addressing  Can work with a SIP server  Wave3 has a server for multipoint video  Released version (WAVELETS codec) not compatible with H.323 Windows Messenger Working on new H.261/H.263 video encoder for compatibility  Not compatible with Windows Messenger data sharing  No echo cancellation  No presence yet

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

24 A Few SIP Clients  Microsoft Windows Messenger  eCONF (Radvision resale?)  Wave3 Session (  Network Convergence Laboratory at Claremont Graduate University (ncl.cgu.edu)

25 A Few SIP Proxy Servers  Microsoft Live Communications Server  HCL Technologies (  Indigo  Ubiquity  SNOM  VOCAL  Iptel  DynamicSoft  Siemens  Nortel  eCONF

26 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