Internet Telecom Expo 2000 - September 20, 2000 SIP vs. H.323 SIP vs. H.323 Will the Real IP...

www.dynamicsoft.comInternet Telecom Expo 2000 - September 20, 2000SIP vs. H.323

SIP vs. H.323Will the Real IP Telephony Please Stand Up?

Jonathan Rosenberg

Chief Scientist


Session Initiation Protocol (SIP) Developed in mmusic Group in IETF

Proposed standard RFC2543, February 1999 Work began 1995 Part of Internet Multimedia Conferencing Suite

Main Functions Invite users to sessions

Find the user’s current location, match with their capabilities and preferencesin order to deliver invitation

Carry opaque session descriptions

Modification of sessions Termination of sessions


Session Initiation Protocol (SIP) cont.

Main Features Personal mobility services Wide area operation Session flexibility

Voice; video; games; chat; virtual reality; etc.

Leverages other Internet protocols


Protocol Components User Agent Client (UAC)

End systems Send SIP requests

User Agent Server (UAS) Listens for call requests Prompts user or executes program to determine response

User Agent UAC plus UAS


Protocol Components cont.

Redirect Server Network server - redirects users to try other server

Proxy Server Network server - a proxy request to another server can “fork” request to

multiple servers, creating a search tree

Registrar Receives registrations regarding current user locations


SIP Architecture

Request

Response

Media

1

2

3

45

67

8

9

1011

12

SIP Client

SIP Redirect Server

SIP ProxySIP Proxy

SIP Client(User Agent Server)

Location Service

13

14


Primary Advantages

Extensibility

Flexibility

Scalability

New Services


Extensibility Primary Goal: Ensure Baseline Operation Always Works

Maintain “backward compatibility”

Numerous Ways to Extend New Optional Headers New Mandatory Headers

Negotiation to common set New Methods New Body Types Extensions are Named

Registered with IANA com.example.feature naming convention


Flexibility SIP is a Protocol Component, not a Complete Solution

Does not Specify Codecs Media Transport Routing Exchanges Database Billing Records

Does not specify architectures

Does not specify services

Result: Service Providers can Build the Network They Want, not the one the

Standard Body Wants


Scalability Internet Model for Scalability

Fast and simple in the core Smarter towards the periphery Example: RSVP vs. Diffserv

SIP Uses Internet Model Stateless fast proxies in the core Stateful proxies at the periphery Call-stateful proxies at the edge

CSFProxy

CSFProxy

CSFProxy

CSFProxy

CSFProxy

CSFProxy

CSFProxy

CSFProxy

Edge

Periphery

Core SF

Proxy

SF Proxy

SF Proxy

SF Proxy

SL Proxy

CSF

SF

SL

Call Stateful

Stateful

Stateless


How SIP Enables New Services Fundamental Strengths

SIP leverages the power of web and email URLs for Addresses MIME bodies Email routing

It therefore, works well with these applications

Technical Proof Points Caller ID with vCards Caller ID with JPEG Transfer to Web Web IVR


Information Resource Jonathan Rosenberg

[email protected] +1 732.741.7244

Internet Telecom Expo 2000 - September 20, 2000 SIP vs. H.323 SIP vs. H.323 Will the Real IP...

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