SIP vs H323 Over Wireless networks

Presented by Srikar Reddy Yeruva

InstructorChin Chin Chang

Voice Over Internet Protocol

VOIP protocols: H.323

SIP (session initiation protocol) MEGACO (circuit switched to packet switched)

MGCP (media gateway control protocol)

TWO Famous Protocols: SIP

H.323

H 323

Defined by ITU-T (international telecommunication union)

H323 uses:

Terminal gateway

Gate keeper

H 323 basic architecture

There are different features:

Local features: II type features: III type features

Repeat a call with gate keeper Signaling Call list call admission call transfer local address book Authorization call completion Speed dialing call detail recording call forwardingMute …..etc number suppression call hold

H323 VS SIP

H.323 is the more mature of the two, but problems may arise due to lack of flexibility. 

SIP is currently being defined in a

robust way and has greater scalability which could ease internet application integration.

H-323 The type III functionality is split by h323 by

many protocols This makes it more complex while taking

over from one protocol to another. Every function has its own protocol. But has many functions than SIP like: Message waiting indication Name identification Call offer Call intrution

Definition of SIP SIP was defined in 1999 by IETF’s MMUSIC

to provide a mechanism to allow voice data and video integration

SIP provides the foundation for building converged networks that support seamless integration with traditional voice networks, email, the World Wide Web, and next-generation technologies such as instant messaging and 3rd Generation Partnership Project (3GPP) mobile networks.

SIP- Components

SIP user agent

SIP proxy server

SIP redirect Server

SIP registrar server

An Integrated Communications Scenario

                                                                                           

SIP (session initiation protocol)

Build a network

Sip global distance call includes many technologies

includes H.323, sip,ss7 etc….

Ip phone

Sip service delivery architecture

Security H323:Defines security mechanisms and

negotiation facilities via H.235, can also use SSL for transport-layer security.

SIP: Http like encryption Cryptographically secure authentication

and encryption is supported hop-by-hop via SSL/TSL, but SIP could use any transport-layer or HTTP-like security mechanism, such as SSH or S-HTTP.

Billing

H323: Direct call model, endpoint reports to the gatekeeper

SIP: Proxy gets the billing information the proxy has to stay in the calling

signal path to detect when the call ends

call signaling could be delayed

ADDRESSING

H323: Flexible addressing mechanisms,

including URLs and E.164 numbers.

SIP: SIP only understands URL-style

addresses

multimedia H.323 fully supports video and data

conferencing. Procedures are in place to provide control for the conference as well as lip synchronization of audio and video streams

SIP: SIP has limited support for video and no

support for data conferencing protocols like T.120. SIP has no protocol to control the conference and there is no mechanism within SIP for lip synchronization

References Microtronix systems ltd http://microtronix.ca/sip_vs_h323.htm Tmcnet http://www.tmcnet.com/it/0801/0801radv.htm iptel.org http://www.iptel.org/info/trends/sip.html Cisco corporations www.cisco.com

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