International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 4 – Feb 2015
Analysis of VBR Traffic on ATM Network using
Simulation Method
Rohini Sharma
Deepak Aggarwal
Department of Computer Science
Baba Banda Singh Bahadur College
of Engg. & Tech., Fatehgarh Sahib
Assistant Professor
Department of Computer Science
Baba Banda Singh Bahadur College of
Engg. & Tech., Fatehgarh Sahib
Abstract—ATM or Asynchronous Transfer Mode is a ATM connection. Each cell consists of 5 byte cell-header and
network transfer technique that supports a large variety of
applications having diverse performance requirements and
service. Traffic bandwidths and traffic types are supported
by it from constant, fixed rate traffic to the traffic that is
highly bursty. The delay bandwidth and loss requirements of
the present day real time multimedia traffics greatly differ
from that of the traditional non - real time traffic. Non-real
time traffic needs reliable service, but it can tolerate delay.
Contrary to this, the real - time traffics are stream –
oriented, in a way that they can bear some loss, but they
must be delivered within a bounded delay for obtaining the
desired QoS. The ATM network is applicable of the B-ISDN
which can be used for satisfying this ambition to its
simplicity and efficiency. The ATM traffic is managed and
routed differently in CBR and VBR categories in the
network. This paper analyzes the performance of the VBR
traffic on ATM network by employing simulation
methodology. For the given traffic characteristics, many
parameters such as mean delay, throughput, distance, buffer
size, are examined. Also, the paper proposes the importance
and role of priority mechanisms to control cell losses in
ATM networks.
48 byte payload (user data) making it 53 byte long. Simulation
technique is employed for modelling and designing
communication networks. System simulation is the only
technique for calculating performance. Different problems,
like setting up different network topologies and evaluating
their performance parameters are presented during the
simulation of large, complicated high-speed networks.
Therefore, simulation plays an increasingly pivotal role in the
designing and modelling of communication networks.
A. ATM ARCHITECTURE
ATM combines both hardware and software which can either
form a high-speed backbone or offer an end-to-end network.
ATM architecture consists of ATM structure as well as its
software components, as shown by Fig.1. The most important
layers of ATM are the physical layer, the ATM Adaptation
layer and the ATM layer.
Keywords— ATM, Quality of Service, CBR, VBR
I. INTRODUCTION
Asynchronous Transfer Mode (ATM) is a network
architecture that is connection oriented as well as high
performance. It has been designed for carrying traffic for (BISDNs) Broadband Integrated Services Digital Networks
(ITU, 1995 and Prycker, 1995). There are a number of digital
communications like voice and video telephony, data file
transfers, broadcast video and World Wide Web (WWW)
applications, etc. supported by ATM. These services have
traditionally been provided by logically and physically
separate networks named as the telephony networks, the
Internet and the cable-TV networks. All these networks have
been tailored for supporting the Quality of Service (QOS)
required by its applications. But, in an integrated service
network we must accommodate applications with highly
different Quality of Service requirements li available
bandwidth, minimum end-to-end delay, and minimum cell
loss probability. ATM is connection oriented. Also, once a
connection has been set up, resources are reserved from
source to destination along a path. A stream of fixed-size
packets known as cells are transmitted (ITU, 1991a) at every
ISSN: 2231-5381
Fig.1. ATM Architecture
B. ATM TRAFFIC MANAGEMENT
Several services and connections are shared by ATM network
each with a different characterization. The needed bit rate can
range from a few kbps to several Mbps range (Berger et al.,
1998). Some services can bear a few cell losses whereas
others cannot; some services have stronger real-time
constraints than others. All connections can have an effect on
each other within such a network. Binding these effects is the
duty of traffic control along with achieving the following two
main goals:


Providing specified and guaranteed Quality of
Service level.
Employing available network resources efficiently.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 4 – Feb 2015
C. TRAFFIC CHARACTERISTICS
The following transmission characteristics differentiate video,
voice and data:
Video—the transmission characteristics of real-time video
traffic are similar to that of voice traffic, but it also needs high
bandwidth. Video traffic becomes more vulnerable to error
than uncompressed video while compression techniques are in
use.
Voice— there a flow of traffic with a pattern that is regular at
a fixed rate which is sensitive to delay variation and delay.
Voice traffic becomes more vulnerable to error than
uncompressed voice when compression techniques are in use.
Data—the flow of traffic is in an irregular pattern often
known asbursty owing to its amount of traffic and variability
in rate.
For the overall health and performance of the ATM network,
traffic management is important. Through multiple service
categories and Quality of Service implementation, the
different transmission requirements of mixed traffic on a
common network are satisfied by ATM.
D. ATM SERVICE CATEGORIES
There are four major types of traffic, each of which could be
managed and routed differently in the network. These are:




Constant Bit Rate (CBR)
Variable Bit Rate (VBR)
Unspecified Bit Rate (UBR)
Available Bit Rate (ABR)
E. ATM TRAFFIC PARAMETERS
The traffic parameters explained below are employed for
qualifying the different ATM service categories:
Minimum Cell Rate (MCR): it can be defined as the cell rate
at which the edge device is always allowed to transmit.
Peak Cell Rate (PCR): it is the cell rate which the edge
device cannot exceed. There are some service categories that
have a limit on the number of cells which can be sent at the
PCR without there being a penalty traffic contract violation.
Cell Delay Variation Tolerance (CDVT): it is the allowable
deviation in cell times for PVC which is transmitting above
the PCR. It also allows a specific number of cells to arrive
quicker than the expected cell interarrival time without there
being a penalty for traffic contract violation.
Maximum Burst Size (MBS): it is the number of cells
transmitted by the edge device up to the PCR for a fixed time
period without there being a penalty for traffic contract
violation.
F. ATM QOS PARAMETERS:
Constant Bit Rate (CBR): CBR is employed for any data type
for which the end-systems need predictable response time and
a static bandwidth amount constantly available throughout the
life-time of the connection and predictable response time. The
bandwidth amount is characterized by a PCR (Peak Cell
Rate). Such applications include services like telephony
(voice services), video conferencing or any type of on-demand
service, like interactive audio and voice.
Variable Bit Rate (VBR): This service category is employed
for connections transporting traffic at variable rates — traffic
which counts on correct timing between the traffic source and
destination. Compressed video stream is an example of traffic
requiring this type of service category.
Available Bit Rate (ABR): ABR employs Resource
Management (RM) cells for providing feedback which
controls the traffic source in response to variations in
available resources within the interior ATM network. The
ABR flow control specification employs these RM cells for
controlling the cell traffic flow on ABR connections. The endsystem is expected to adapt its traffic rate as per the feedback
enabling it to obtain its right share of available network
resources. Providing fast access to available network
resources up to the specified Peak Cell Rate is the goal of
ABR.
ISSN: 2231-5381
Unspecified Bit Rate (UBR): This service category is
employed for connections transporting variable bit rate traffic
for which there is no reliance on time synchronization
between the traffic source and destination. But, unlike ABR, it
does not have flow-control mechanisms for dynamically
adjusting the bandwidth amount available to the user. UBR in
general is employed for applications which are very tolerant to
cell loss and delay.
The QoS parameters used for managing cell loss and cell
delay over the ATM network for every ATM service category
is defined by the ATM Forum specifications. Some of these
QoS parameters are negotiable and some are not.
Negotiable QoS Parameters: The following are the cell delay
and cell loss parameters that fall under the category of
negotiable QoS parameters.
Cell Delay Parameters
Two negotiable parameters for cell delay are supported by the
ATM Forum specifications:
Maximum cell transfer delay (maxCTD):it is the maximum
length of time allowable for the network for transmitting a cell
from the source UNI device to the destination UNI device.
Peak-to-peak cell delay variation (peak-to-peak CDV): it is
the maximum variation allowable from the fixed CTD for
every cell that is transmitted from the sender UNI device to
the reciever UNI device. It represents the allowed distortion or
jitter between cell inter-arrival times over the network.
Non-Negotiable QoS Parameters
During the connection setup on the ATM network, the
following parameters are not exchanged:
Cell error ratio (CER): it is the allowable percentage of cells
which can be in error.
Severely errored cell block ratio (SECBR): it is the maximum
allowable cell blocks percentage which can be very likely in
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 4 – Feb 2015
error. A cell block is defined as the number of transmitted
cells that are transmitted consecutively on a particular
connection. It is considered highly errored when more than a
maximum number of lost cells, errored cells or misinserted
cells are occurring within that cell block.
Cell misinsertion rate (CMR): it is the maximum allowable
rate of misinserted cells.
II. LITERATURE REVIEW
There has been a lot of research on the performance of an
ATM network and simulation of various parameters related to
it. Tran Cong Hung et al [1] described six QoS parameters
used for measuring the network performance for a given
connection in ATM network and simulating the delay
parameter measurement of the ATM networks to solve Cell
Transfer Delay by employing simulation method.
Fig.2. The Main Screen
Hassan Naser et al [2] calculated ATM layer performance of
a fixed bit rate MPEG2 connection. It also describes the effect
of various network/source parameters on the CDV and end-toend delay of variance connection. Finally it shows that the
correlation is decreasing function by examining variation in
the cell delay correlation of reference connection.
George Benke et al [4], describes a method for generating
self-similar traffic that can be used for driving network
simulation models. Finally, it shows a magnitude order
improvement in queue length for traffic loading which is selfsimilar.
B. CREATE SCENARIO
In this screen, adding CPE (Customer Premises Equipment)
and Switch with eight ports are created by default on the
environment builder establishing connections between CPE
and Switch. The connections between two CPEs cannot be
made in the network. A switch can have more than one CPE
attached to it. Click on the two devices and connect any two
devices. The connection possibilities are CPE to switch and
Switch to Switch.
III. METHODOLOGY
In this paper first of all, the innovations in the field of design
and development of ATM networks and traffic management
in ATM networks have been dealt with. After this, the
network resource management techniques have been
elaborated to control traffic effectively. Also, the importance
and role of priority mechanisms to control cell losses in ATM
networks have been studied and finally the modelling of VBR
traffic is presented. The performance of the VBR traffic on
ATM network using simulation methodology has been
analysed. Netsim simulator has been used for the given traffic
characteristics. Many parameters such as mean delay,
throughput, distance, buffer size, are examined.
A. MAIN SCREEN
Fig.3. Create Scenario
The main screen of the simulator displays different icon like
ATM CPE (Customer Premises Equipment), Switch, Trace,
Properties, Simulate. Click on the icon, drag and drop them C. GENERATE TRAFFIC
To generate traffic get the option window and select
for each having performing different function.
properties of CPEs, Switches and link properties shown in
below tables.
Switch Properties
Switch 1
Switch 2
Port
Buffer Size (KB)
Switching Techniques
8
8
Priority
8
8
Priority
Table 1: Switch Properties
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 4 – Feb 2015
CPE Properties
CPE
Application
1
Destination
CPE2
Transmission Type
Point to Point
Data Size(Bytes)
1024
Data Generated Rate(Kbps)
512
Duration
1 to 10
Data Type
Data
Peak Cell Rate per sec
1000
Cell Delay Variation Time( in 1000
Micro sec)
Scheduling Technique
Priority
Payload(%)
100
Table.2. CPE Properties
Link Properties
Distance (km)
Table.3. Link Properties
Link 1
Link2
1000
1000
Link3
Fig.5. Between normalized throughput and distance
1000
The distance along x-axis and normalized throughput along yaxis shows in the above graph. The values between these two
Data Rate
0.064
0.064
0.064
parameters are shown in the table below. As the distance
D. SIMULATION
increases the normalized throughput decreases because
distance between source and destination effects the packets
After create scenario and generate traffic, simulate an
numbers on the receiving side.
environment using LAN/WAN components like CPE’s
Switches, Hubs and Routers. At the end of simulation, Netsim
Table.4. Normalized throughput and distance
generates a report of the network’, performance.
Error Rate
No Error
No Error
No Error
Normalised throughput
Distance
71.9422
100
71.9416
200
71.9409
300
71.9403
400
71.939
500
71.939
600
71.936
700
71.936
800
71.935
900
71.934
1000
71.933
1500
71.932
2000
71.931
2500
Fig.4. Network Performance Report
IV. RESULTS
On increasing the distance between the two ATM switches,
different parameters have been measured again and compared
the results as per the changing environment.
Comparisons between distance with Time: Time or mean
Comparisons between distance and normalized Throughput: delay taken for successful packets transfer from source to
Normalized throughput means successful packets transfer destination increases while increasing distance between them.
from source to destination Distance between the two switches
increases normalized throughput decreases.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 4 – Feb 2015
traffic effectively. The importance and role of priority
mechanisms to control cell losses in ATM networks have also
been studied. The performance of the VBR traffic on ATM
network using simulation has been analysed. After simulation,
it has been found that as the distance increases the normalized
throughput decreases because distance between source and
destination effects the packets numbers on the receiving side.
Hence, the importance and role of priority mechanisms to
control cell losses in ATM networks has been proposed. As a
future scope, the comparative analysis can be done for the
usage of different parameters like cell loss ratio and cell
errored ratio.
REFERENCES
Fig.5. Between distance and Time
The distance along x-axis and time along y-axis shows in the
above graph. The values between these two parameters are
shown in the table 5 below. As the distance increases the time
taken by packets from source to destination also increase
because distance between source and destination effects the
packets numbers on the receiving side.
Table.5. between distance and time
Distance
100
200
300
400
500
600
700
800
900
1000
1500
2000
2500
Time
42744.24
45743.8
48743.4
51743
54742.6
57742.2
60740.6
63740.1
66673.7
69739.2
84740.2
99739.6
114732.3
V. CONCLUSION
In this paper, many parameters such as mean delay,
throughput, distance, buffer size, are examined. The distance
between the two ATM switches, different parameters have
been measured again and the results have been compared as
per the changing environment. Also, the network resource
management techniques have been elaborated to control
ISSN: 2231-5381
[1] Dr. Rajesh Goel, Sagar, ―Wireless ATM Based Network for Multimedia
Personal Communication Service‖ International Journal of Advanced
Research in Computer Science and Software Engineering, Volume 4, Issue 3,
March 2014.
[2]HasanHarasis, ―Rerouting Schemes for Wireless ATM Networks‖
Scientific Research, August, 2014.
[3]R. Manivasikaran, U.B.Desai, AbhayKarandikar ― End to End Simulation
of VBR traffic over ATM network using CIPP Network traffic model‖.
[4]Hassan Harasis, ―Losses in wireless ATM networks‖, Scientific Research,
Vol.5 No.3, August 2013.
[5] Tran Cong Hung, Pham Minh Ha, Sang Sig Nam, Bui XuanLoc ―
Performance parameters for cell transfer variations and cell transfer timing in
ATM network‖, Asian Info-communications council, 28th Conference,
November, 2002.
[6] Tran Cong Hung, Pham Minh Ha, Sang Sig Nam ―Illustration of the
traffic conformance in ATM network‖, ETRI , 2001.
[7] Amy R. Reibman and Arthur W. Berger , ―Traffic Descriptors for VBR
Video Teleconferencing Over ATM Networks‖, IEEE/ACM Transactions on
Networking, VOL. 3, NO. 3, JUNE 2005.
[8] ] A. Hameed and Ali Oudah, ―Routing Schemes for Wireless ATM
Networks‖ International Journal of Energy, Information and
Communications, Vol.5, Issue 3 (2014).
[9] Chia Shen, ―On ATM Support for Distributed Real-Time Applications‖,
Mitsubushi Electric Research Laboratories, April 1996.
[10] NikolaosAnerousis, Aurel A. Lazar, ―Virtual Path Control for ATM
Networks with Call Level Quality of Service Guarantees‖,
[11]KimmoAhonen,―QoSandATM‖https://www.netlab.tkk.fi/opetus/s38130/k
99/presentations/6.pdf.
[12] NirajNake, ―An Overview of Network Architecture and security
framework of Asynchronous Transfer Mode‖ International Journal of
Scientific and Research Publications, Volume 3, Issue 4, April 2013.
[13] Hoon Lee, ―Charging the real-time VBR traffic in ATMnetworks‖ IEEE,
pages 419 – 424, 2000.
[14] Parag Jain, Sandip Vijay, S. C. Gupta, ―Performance Analysis &QoS
Guarantee in ATM Networks‖ Global Journal of Computer Science and
Technology, 2009.
[15]Tran Cong Hung, Pham Minh Ha, Sang Sig Nam, Bui XuanLoc ―ATM
Network’s delay parameter measurement using simulation method‖.
[16] Hassan Naser, Alberto Leon Garcia ―A Simulation study of Delay and
Delay Variation in ATM networks: CBR traffic‖.
[17] Nikos Passas and LazarosMerakos, ―Wireless ATM‖ The Wiley
Encyclopaedia of Telecommunications.
[18] George Benke, Jim Brandt, Helen Chen, SiamekDastangoot, Gregory J.
Miller ― Performance Analysis of ATM ABR service under self-similar traffic
in the presence background VBR traffic‖, SAND--96-8558C; CONF961069—1ON: DE96009086; TRN: AHC29619%%122, 5th January, 2006.
[19]John Cleary, Murray Pearson, Ian Graham, Brian Unger, ―High
Performance Simulation for ATM Network Development‖, Final Study
Report
for
New
Zealand
TeleCom,
June,
2006.
http://www.ijettjournal.org
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