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Network Research Group
Universiti Sains Malaysia
Table of Contents
BNT
ATM
ATM Building Blocks
Physical Layer
ATM Layer
Transmission Delay
System Works
OBJECTIVE
This 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
Asynchronous Transfer Mode
•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
Plane Management
Layer Management
Control/User Plane
Control
User
ATM Adaptation Layer
ATM Layer
Physical Layer
Physical Layer
Is concerned with transmitting raw bits
over a communication channel.
The 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
5 BYTES
48 BYTES
HEADER
PAYLOAD
ATM Cell Format
PHYSICAL
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
 The user will be allowed
to create nodes
(transmitter and ATM
switch) throughout
Malaysia
 User are allowed to send
packets through any path
based on the bandwidth
provided
Apr - Jun 1997
Jul - Sept 1997
Oct - Dec 1997
Jan - Oct 1998
Preliminary Studies
RM100 000
Phase I
RM125 000
Phase II
RM 15 000
RM100 000
Preliminary
Studies :
Research
Studies &
Information
Gathering
RM 225 000
Phase I :
Physical Layer
Transmission Of
Data Over
Communication
Channels
RM 240 000
Phase II :
ATM Layer
ATM
Simulation
based on the
layer 2
Final Phase
RM80 000
Final Phase :
TCP/IP
Implementation &
Simulation In
Putra Jaya