“ACT”Audio Conference over ATM

Network with TRM

Technion - Israel Institute of TechnologyElectrical Engineering Faculty

Computer Networks Laboratory

Under the supervision:Youval NahumRemus Koos

Michael MoreinisMichael Maziar

Project Goals

• Building the Audio Conference Manager

• Implementation of Server-Client Messages

• Communication Channels

• Client-Server Relationship Structure

Description

• There is a significant need in fast & reliable communication over computer networks

• One of the communication implementations is AUDIO CONFERENCING

• In order to run the AUDIO CONFERENCE convenient, the manager should be implemented

• The ATM Network doesn’t support reliable connection - there is a need for IP control connections.

Competitive Analysis

• Others Audio Conferencing tools – Slow communication– No manager implemented

• Audio conference with TRM – Audio Transfer over ATM - fast communication– TRM - fair management

• Weaknesses of ACT– No user interface (at this point)– No additional tools (whiteboard, video etc.)

Technology• ATM Networks

– fast communication– large data (audio) - low latency

• TRM - time resource manager– fairness in time allocation – no interference to speaker

• IP control connections– reliable connection (necessary for control)– standard communication protocol

Hardware/Software Resources

• Sun Workstations • ATM Network cards FORE/ATM• Native ATM API

• SUN Audio tools

- AudioRecord

- AudioPlay

- AudioTool - set the audio devices

Communication Channels

ATM

EthernetE thernetE thernet

W orkstation W orkstation W orkstation

Host

AudioEquipm ent

AudioEquipm ent

AudioEquipm ent

Another channel is MULTICAST ATM connection from server to each client

Request Queue

Client 1Request

C lient NRequest

C lient 4Request

C lient 3Request

C lient 2Request

The FIFO QUEUE - "First In - First Out"

Each one of therequests m ay bewithdrown at any

stage of execution

• Each client may have one request only

• Time allocation is equal to all clients

Link List of Conference Participants

Pointer onnext

Com puteraddress

ATM ThreadID

IP Tread ID

IP sockeddescriptor

Pointer onnext

Com puteraddress

ATM ThreadID

IP Tread ID

IP sockeddescriptor

Pointer onnext

Com puteraddress

ATM ThreadID

IP Tread ID

IP sockeddescriptor

Pointer onnext

Com puteraddress

ATM ThreadID

IP Tread ID

IP sockeddescriptor

• New participant - new member of LL is created

• Participant is down - member of LL is deleted, Request Queue is updated

Client Software

Client Softw areEthernetcontrol

outgoingconnection

Ethernetcontrol

incom ingconnection

ATMoutgoingsim plex

connection

ATMincom ingm ulticast

connection

• Each Client runs number of threads

• The treads cannot be switched by user

• Need for data locks

Server Software

Server Softw are

CLIENT1 CLIENT2 CLIENT N

ATM IP1 IP2 ATM IP1 IP2 ATM IP1 IP2

M ulticast

ATM

Algorithmroutine

• Audio Buffer

• Global Data Locks

Server-Client Messaging

• Client Requests– demand

– remove

– exit

• Client Messages– start

– stop

– exit

– conference state messages

Server-Client Messaging

• Server Statistics– Clients connected

– Request queue

• Server Timing– Set-up the conference

– Conference timing

– Conference state messages

Conclusions• Audio Devices

– Easy to implement– Low quality – High Latency

• ATM Networks– Fast – Unreliable connection– Convenient for large data transfer

• TRM – Improves the performance – Fairness & Convenience – Order in Conference