Network Research Group Universiti Sains Malaysia

Table of Contents zBNT zATM zATM Building Blocks yPhysical Layer yATM Layer zTransmission Delay zSystem Works

OBJECTIVE zThis simulator will be developed to provide the user to analyze the factors that should be considered when a packet is sent from one node (source) to another node (destination)in broadband network.

Broadband Network Technology IS BASICALLY A DIGITAL VIRTUAL CIRCUIT FOR MOVING FIXED SIZED PACKETS (CELLS) FROM SOURCE TO DESTINATION AT VARIOUS SPEEDS. BASED ON ATM TECHNOLOGY

Fast Packet Switching Technology Information Transmission Technology Supports Variable Bit Rate (VBR) & Constant Bit Rate (CBR) information Connection-Oriented -> Uses pre-established virtual channels which are like telephone calls Requires all end stations to convert information into small, fixed- sized cells Cells are placed on appropriate virtual channel Asynchronous Transfer Mode

Control User ATM Adaptation Layer ATM Layer Physical Layer Plane Management Layer Management Control/User Plane

Physical Layer zIs concerned with transmitting raw bits over a communication channel. zThe physical transmission medium Copper Fiber

ATM Layer Has the same function as the Network layer in OSI model Deals with moving cells from source to destination It has the characteristic of a network layer protocol:- End to end virtual circuit Switching Routing It is connection oriented Four main area will be covered in this layer : Cell format Header Connection Setup Routing and Switching

Cell Format Cells are 53bytes (5bytes header and 48bytes payload) 2 interfaces I) UNI II) NNI User Network Interface is between a host and an ATM Network Network Network Interface is between two ATM switches

AAL ATM PHYSICAL HEADER PAYLOAD 5 BYTES48 BYTES ATM Cell Format

Connection Setup A connection must be established before a packets is sent (connection-oriented) A setup message is sent to setup a connection and a release message is to release the connection

Routing To determine the path taken by a message (virtual path and virtual circuit) Takes place in ATM Layer There are many routing techniques :- Fixed Flooding Adaptive Isolated Distributed Centralized

Transmission Delay When packets are sent from source to destination, a transmission time is taken which is the transmission delay. Transmission delay, T is the time period between the time that the first bit of the message enters to the fiber and the time the last bit of message exits from the other end. Transmission delay is given by the formula below:- T = L/C + 8N/B + X

L/C - Propagation delay (time taken to send packets from source to destination) 8N/B - Time period the first bit of message exits from the other end and the time that the last bit of message exits there X - Delay in ATM switch ( in most cases the delay is estimated to be less than 10 milisec) Since it is based on TCP/IP protocols, the propagation delay will be 2 x L/C. This is the time taken to send packets and receive acknowledgement (ACK) from the receiver.

System Works zThe user will be allowed to create nodes (transmitter and ATM switch) throughout Malaysia zUser are allowed to send packets through any path based on the bandwidth provided

Preliminary Studies : Research Studies & Information Gathering Phase I : Physical Layer Transmission Of Data Over Communication Channels Phase II : ATM Layer ATM Simulation based on the layer 2 Final Phase : TCP/IP Implementation & Simulation In Putra Jaya