Real Time Messaging Server Using Web Services*

AgendaIntroduction and Motivation

SIP standard and advantages

H.32x standard

Basic Real Time Transport Protocol

Formulation Plan and Methodology

Implementation

Future Work*

IntroductionConferencing has been on the research agenda for many years and is rapidly gaining interest in the field of communication.

It is advantageous to people who dont want to spend their time and money flying all over the world for face-to-face meetings.

International standardization bodies have defined protocols for multimedia conferencing. The International Telecommunication Union (ITU) has made H.32x standard.*

Motivation*

Session Initiation Protocol (SIP)SIP: A proposed solution by Internet Engineering Task Force (IETF)

SIP is an application-layer signaling protocol for creating, modifying and terminating sessions with one or more participants.

Can be used for voice, video, instant messaging, gaming, etc.

Lightweight, flexible and extensible and moreover scalable.*

SIP AdvantagesLoop detection: When trying to locate a user, loops can occur. Loops are easily detected using SIP headers, as they specify all proxies that have handled the SIP packet.

Distributed control: In H.32x, there is a need for a central point when performing multiuser calls, which means that this central point must be dimensioned for the size of the call. On the other hand, SIP sessions are distributed.

Small connection overhead: Establishing a connection using H.32x takes about three times the data and turnarounds compared to when using SIP.*

H.32x StandardHandling conferencing data packets

Different platform desktops

ITU developed H.32x series, to facilitate the compatibility:

H.322 (guaranteed bandwidth)

H.323 (non-guaranteed bandwidth)

H.324 (Applications over PSTN and mobile phones)*

H.32x vs. SIPOn comparing H.32x and SIP protocols, it is found that H.32x is widely deployed and more mature only because of its early adoption by the market

But H.32x has several problems, including scalability issues.

On the contrary, SIP is more lightweight, flexible and extensible. It is a text-based protocol which can easily interact with other internet protocols.*

Real Time Transport Protocol RTP is a transport protocol for real-time applications. It is used for the transport of real-time data, including audio and video.

RTP provides support for applications with real-time properties such as continuous media (e.g., audio and video), including loss detection, security and content identification.

RTP does not guarantee quality-of-service for real time services.*

Architecture*

Formulation PlanPackage multimedia data into RTP packets.

Focus: It is a SIP user agent responsible for the management of the conference using SIP signaling protocol.

The focus can also act as a notifier, accepting subscriptions to the conference, and notifying subscribers about changes to the conference state.

A mixer is responsible for handling the multimedia streams, and generating output streams which can be distributed to participants.*

ProcedureAfter capturing the packets at the server, the same will be sent to the client site.

As soon as streams arrive at client site, a player will be created so as to play the RTP streams for video data.

A transmitting module will be developed at the server site to transmit the data. A receiving module will be developed at the client site which will receive the data streams.

Finally, the modules will be tested and integrated to implement conferencing.*

Tasks to be performedAn interface would be developed for capturing the video packets from a webcam and displaying the same on the terminal for a single user.

The above implementation would be modified to capture video packets and transfer the same across multiple users thus developing a conferencing system.

After the core implementation of conferencing system is complete, an attempt would be made to add mining structures that will give detailed information about the user, what kind of conferencing he/she does and with which user he/she interacts most of the time.*

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