Transcript SIP
Introduction to SIP
Larry Amiot
Northwestern University
[email protected]
Internet2 Commons Site Coordinator Training
March 22, 2004
Indianapolis, Indiana
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
2
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
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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
4
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
5
SIP Entities
User Agent
• User Agent Client (UAC)
• User Agent Server (UAS)
Redirect Server
Proxy Server
Registrar
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Application
SIP Session Establishment and Call Termination
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Figure 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
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Call Redirection Using a Redirect Server
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Figure courtesy of Radvision Ltd
Call Proxy Scenario
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Figure courtesy of Radvision Ltd
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
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A Few SIP Implementation
Examples
Microsoft Live Communications Server
Wave3 Sessions
Radvision ViaIP
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Windows Messenger- The Microsoft
Approach
13
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
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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
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SIP Point-to-Point Interoperability Using the Microsoft LCS
Microsoft Live
Communication
Server
Microsoft
Active
Directory
Internet
Windows Messenger
Clients
SIP/H.323 Interoperability Using the Radvision MCU
Radvision
MCU
H.323
Microsoft Live
Communication
Server
S
I
P
Internet
H.323 Clients
Microsoft
Active
Directory
Windows Messenger
Clients
SIP/H.323 Interoperability Using the Radvision MCU
Radvision
MCU
H.323
S
I IMfirst
P
Internet
H.323 Clients
Microsoft Live
Communication
Server
Microsoft
Active
Directory
Windows Messenger
Clients
SIP/H.323 Interoperability Using the Radvision MCU
UAS
Radvision
MCU
H.323
S
I
P
eCONF SIP
Clients
Internet
H.323 Clients
UAC
Wave3’s Session SIP Client
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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
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SIP/H.323 Interoperability Using the Radvision MCU
Radvision
MCU
H.323
Your Favorite
SIP Server
S
I
P
Internet
H.323 Clients
Session Clients
A Few SIP Clients
Microsoft Windows Messenger
eCONF (Radvision resale?)
Wave3 Session
(www.wave3software.com)
Network Convergence Laboratory at
Claremont Graduate University
(ncl.cgu.edu)
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A Few SIP Proxy Servers
Microsoft Live Communications Server
HCL Technologies (www.hcltech.com)
Indigo
Ubiquity
SNOM
VOCAL
Iptel
DynamicSoft
Siemens
Nortel
eCONF
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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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