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International Journal of Emerging
Technology & Research
Volume 1, Issue 3, Mar-Apr, 2014 (www.ijetr.org) ISSN (E): 2347-5900 ISSN (P): 2347-6079
© Copyright reserved by IJETR 130
Comparative Performance Evaluation Of Multimedia
Traffic Over Multi-Protocol Label Switching using Virtual
Private Network (VPN) Internet Cloud And Traditional
Internet Protocol Networks
Ezeh G.N, Onyeakusi C.E, Adimonyemma T.M, Diala U.H.
Dept. of Electrical/Electronic Engineering, Federal University of Technology Owerri,
P.M.B 1526, Owerri, Imo State, Nigeria.
ABSTRACT
This work investigated and discussed the performance of Multimedia traffic (Voice, Video and data)
over Multiprotocol Label Switching (MPLS) on Internet Virtual Private Network (VPN) cloud. The
motivation for this work is founded on the fact that the traditional IP network has various limitations
viz-High delays, low latency, jittering, etc, hence very unsuitable for Multimedia traffic propagation
over the internet backbone. For effective throughput, and good utilization of resources for Multimedia
traffic, this work investigated a Multiprotocol Label Switching (MPLS) testbed (Multiconsole MPLS
VPN Model) which ensures the reliable delivery of the real time services with high transmission
speed and lower delays. This work considers Traffic Engineering (TE) as the major feature of MPLS
as TE temporarily reduces the packet drops and latency by over 60%. Various testbeds were studied
for performance analysis in this work. The adopted metrics in context includes Packet End-to-End
delay (Pv), Point-to-Point utilization (Pu), and throughput (Pt). From the research results, the MPLS
VPN scenario gave Point-to-point throughput = 2.44% (1Kbps), Point-to-Point Utilization Pu =
34.09% (0.06), and Packet delay variation Pv = 37.5% (0.15Secs) while that of frame relay IP
backbone scenario gave Point-to-point throughput (bytes/secs) = 97.56% (40Kbps), Point-to-Point
Utilization = 65.91% (0.116), and Packet delay variation = 62.5% (0.250Secs). Consequently, the
results show that for multimedia traffic propagation, using the above QoS metrics, MPLS VPN
network offers better performance when compared with the traditional IP network model based on
frame relay circuit thereby nullifying a stipulated null hypothesis stated in this work.
Keywords:- MPLS, TE, IP, VPN, LSP, RSVP
I. INTRODUCTION
Contemporarily, with the advent of
Internet cloud computing, there is now a
shift on how applications and services are
used on the internet. With a wide variety
of applications and services provided on
Internet, there is an increase in the number
of internet users particularly realtime
application users on internet [1].Since the
conventional IP networkis highly insecure,
and uses best-effort services which
doesnot provide guarantee-of-services and
Traffic Engineering (TE), leveraging
multi-Protocol Label Switching (MPLS)
which is an emerging technology is shown
to play an important role in the next

International Journal of Emerging Technology & Research
131
© Copyright reserved by IJETR
generation networks. MPLS is considered
ideal for Multimedia applications.
Developing a network model that will
scale gracefully to support large
multimedia traffic in a secure manner
without compromise to guarantee-of-
service, with predictable minimum delays
and zero packet loss will be widely
accepted. A candidate testbed called
MulticonsoleMPLS VPN model is
proposed and modeled while presenting it
in this work. It is based on MPLS
undelaying architecture to handle
multimedia traffic in both small scale and
complex environments. In the model,
Label Switched Paths (LSP) is set based
on constraints (considering bandwidth
availability, administration policies, etc)
which the packets are routed. The LSPs
are virtual connections which are used to
transmit the packets reliably (which is
required for the multimedia traffic) in
network cloud. Before the packet ingress
into the label edge routers and label switch
routers, an access list policy is blinded on
traffic tunneled securely into the MPLS
VPN. This forms a secured security
framework in this work before the label
switched packet switched security in the
Multiconsole MPLS VPN domain.
Besides, this work defines Multiconsole
MPLS as a layer 2/3 enhancement over the
existing MPLS networks. It utilizes
Resource Reservation Protocol (RRP), and
Path selection based on Available
Bandwidth Estimation (ABE) to securely
manage traffic from the sources to the
Multiconsole MPLS VPN cloud.
II. COMPARATIVE ANALYSIS OF
IP AND MPLS NETWORK
A. INTERNET PROTOCOL
Internet Protocol (IP) allows a global
network among an endless mixture of
systems and transmission media [4]. The
main function of IP is to send the data
from the source to destination. Data is sent
in the form of packets and this is routed
through a chain of routers and multiple
networks to reach the destination. In the
Internet each router takes independent
decision on each incoming packet. When a
packet reaches a router, depending on the
destination address in the packet header
the router forwards the packet to the next
hop by consulting itsforwarding table. The
process of forwarding the packets by the
routers is done until the packet reaches the
destination.
In conventional IP routing, to build routing
tables, each router runs IP routing
protocols like Border Gateway Protocol
(BGP), Open Shortest Path First (OSPF)
or Intermediate System-to-Intermediate
System (IS-IS)[1].These protocols enable
the routers to build the forwarding table.
For forwarding the packet and controlling
the routing tables, data plane and control
plane are the main components. The data
plane is a forwarding component which is
responsible for forwarding packets from
input interface to output interface on
router. In the data plane forwarding,
decisions are made by consulting the
routing table. The control plane is the
controlling component which is
responsible for construction and
maintenance of routing table. The control
plan uses the information from the routing
protocols such as open shortest path first
(OSPF), Intermediate system to
Intermediate system (IS-IS) and Border
Gateway Protocols (BGP) in building and
updating the routing table. These two
planes are integrated in the traditional
routers.

132
LIMITATIONS OF IMPLEMENTING
MULTIMEDIA APPLICATION IN IP
NETWORKS
It is very challenging to implement the
real-time application like VoIP in the
conventional IP network. IP mostly work
on the best-effort service which does not
guarantee the delivery of the services. The
following factors describe the limitations
of IP networks to implement
Multimedia/VoIP applications viz:
- Routing in IP is designed to calculate
the shortest path towards the
destination but not the best path.
- In IP networks routing is done in the
Network layer which is slower than
the switching.
- Most of the links in IP networks are
either under-utilized or over-utilized
caused by its routing process, which
results in congestion for over-utilized
links.
- IP networks are not scalable and TE
is difficult to implement.
Multimedia/VoIP application require
guarantee of services with predictable
minimum delay and low packet loss. This
can be achieved by implementing the
MPLS networks. In MPLS network, Label
Switched Path (LSPs) are set based on
constraints (considering the bandwidth
availability, administration policies etc) on
which the packets are routed. The LSPs
are the Virtual connections which are used
to transmit the packets reliably, which is
desirable for transmitting the VoIP traffic.
B. MPLS NETWORK
Multiprotocol Label Switching (MPLS) is
an evolving technology for high
performance packet control and
forwarding mechanism for routing the
packets in the data networks [5]. MPLS is
a switching mechanism that assigns labels
(numbers) to packets, and then forward
packets based on labels. The labels are
assigned at the edge of the MPLS network,
and forwarding inside the MPLS network
is done solely based on labels. Labels
usually correspond to a path to Layer 3
destination addresses; similar to IP
destination- based routing. Labels can also
correspond to Layer 3 VPN destinations
(MPLS VPN) or non-IP parameters, such
as a Layer 2 circuit or outgoing interface
on the egress router. That means it acts
like glue between layer 3 and 2 to make
forwarding decision based on who is
available, such as Any Transport over
MPLS (AToM), quality of service (QoS),
or source address [2,3].
Multiprotocol Label Switching (MPLS) is
a tunnelling technology used in many
service provider networks [4], MPLS
domain has two main types of switches:
MPLS core switch which consists of Label
Switch Routers (LSRs) and the other is
MPLS edge which consists of Label Edge
Routers (LERs).
Also, MPLS has evolved into an important
technology for efficiently operating and
managing IP networks because of its
superior capabilities in providing traffic
engineering (TE) and virtual private
network (VPN) services [5]. MPLS is not
a replacement for the IP but it is an
extension for IP architecture by including
new functionalities and applications. The
main functionality of the MPLS is to
attach a short fixed-label to the packets
that enter into MPLS domain. A label is a
short fixed entity with no internal
structure. Label is placed between Layer2
(Data Link Layer) and Layer3 (Network

133
Layer) of the packet to form Layer 2.5
label switched network on layer 2
switching functionality without layer 3 IP
routing [5,6,7] . Therefore Packets in the
MPLS network are forwarded based on the
Labels.
1. MPLS ARCHITECTURE
The MPLS domain is described as a
contiguous set of nodes which operate
MPLS routing and forwarding [1]. MPLS
domain is divided into MPLS core which
consists of Label Switch Routers (LSRs)
and MPLS edge which consists of Label
Edge Routers (LERs). The main
terminologies of MPLS technology are
explained as follows [1, 8]:
i. Label Switch Router (LSR) - Any
router which is located in the MPLS
domain and forwards the packets based on
label switching is called LSR. When an
LSR receives a packet it checks the look-
up table and determines the next hop,
before forwarding the packet to next hop,
it removes the old label from the header
and attaches new label.
Figure 1: Label Switched routers [14]
Figure 2: Label Edge routers [14]
An LSR has the capability to understand
MPLS labels andresponsible for receiving
and transmitting a labelled packet on a
data link in MPLS network. Three
operations are associated with LSRs viz:
pop, push and swap. InMPLS network,
there are three types of LSRs [9, 10, 11,
12]:
• Ingress LSRs: receive an unlabelled
packet, add a label to that packet andsend
it via data link.
• Egress LSRs: receive labelled packets,
remove the label or set of labels andsend
them via data link.
• Intermediate LSRs: perform an operation
on incoming labelled packet and switch
the packet on the correct data link [11].
ii. Label Edge Router (LER) – A packet
enters into MPLS domain through LER
which is called Ingress router. Packet
leaves the MPLS domain through LER
which is called Egress router. LER has an
ability to handle L3 lookups and is
responsible for adding or removing the
labels from the packets as they enter or
leave the MPLS domain. The LERs work
as QoS decision points in MPLS network.
By using port numbersin layer-4 of the
packets, QoS policies can be established
and managed [13]. The LERsare

134
responsible for adding or removing labels
from the packets [12, 13].
iii. Label Distribution Protocol (LDP) -
It is a protocol in which the label mapping
information is exchanged between LSRs.
It is responsible for establishing and
maintaining labels.
iv. Forward Equivalence Class (FEC) –
It is considered as the set of packets which
have related characteristics and are
forwarded with the same priority in the
same path. This set of packets is bounded
to the same MPLS label. Each packet in
MPLS network is assigned with FEC only
once at the Ingress router.
v. Label Switched path (LSP) – LSP is
the path set by the signalling protocols in
MPLS domain. In MPLS domain there
exists number of LSPs that originate at
Ingress router and traverses one or more
core LSRs and terminates at Egress router.
A LSP consists of a sequence of LSRs that
switch a labelled packet through an MPLS
network. In MPLS network, the first LSR
of an LSP is the ingress LSR for thatLSP,
and the last LSR of the LSP is the egress
LSR. The intermediate LSRs areworking
in between the ingress and egress LSRs
[15, 16].
Figure 3:Label Switched Paths (LSPs) [14]
In MPLS routers, control plane and data
plane are separated entities. This
separation allows the deployment of a
single algorithm that is used for multiple
services and traffic types [17].
The label-swapping forwarding algorithm
explains how the packets are routed in the
MPLS domain which is described in the
following steps, viz:
i. When a packet enters the MPLS domain,
a label of short fixed-length is inserted in
the packet header by the Ingress router.
FEC is identified from the label.
ii. The packets belonging to one particular
FEC are forwarded through the same path
through the MPLS network even though
all the packets do not have the same
destination address.
iii. The path on which the packets are
forwarded to the next hop in the network is
LSP.
iv. Every hop in MPLS network forwards
the packets based on the label but not on
IP address. This is done until the packets
reach the final hop in MPLS network and
then the label is removed by Egress router
and normal IP forwarding resumes.
v. The Ingress and Egress routers are the
LER’s and the hops within the MPLS
domain are LSR’s.
C. TRAFFIC ENGINEERING
The term Traffic Engineering (TE) refers
to optimization of network configuration
under given network and traffic
constraints. This includes transport control
to maximizethroughput under fairness
constraints between users or routing to
achieveresilience to router or link failure.
However, in the literature, traffic
engineeringis mostly associated with

135
adapting the routing function to the traffic
situation tomake better use of available
network resources [18].
Again, TE is a mechanism that controls the
traffic flows in the networks and provides
the performance optimization by optimally
utilizing the network resources [18].
Figure 4: Traffic Engineering Process
diagram.[19]
In order to find a suitable routing setting, a
number of steps need to be executed.These
steps are illustrated in Figure 4 above. The
first step is to collect the
necessaryinformation about network
topology and the current traffic situation.
Most traffic engineering methods need as
input a traffic matrix describing the
demandbetween each pair of nodes in the
network. Obtaining the traffic matrix in a
largeIP backbone can be a challenging task
and the traffic matrix must be estimated
from other available data. The traffic
matrix together with network constraints
such as network topology and link
capacities is used as input to the
optimizationof the routing. The outputfrom
the optimizations need to be translated
intoparameter values of the routing
protocol in use and distributed to the
routers.
Omitted in the figure 4 is a feed-back loop
from the output to the input of the traffic
engineering process. A change in the
routing will affect the traffic saturating the
network because packets will be routed on
different paths due to interactions between
inter and intradomain routing. One
approach to handle the feedback loop is to
use control theoretic methods to design a
routing function that converges to an
optimal solution and is stable. This is
referred to as reactive traffic engineering.
Proactive traffic engineeringis another
approach used to find a routing setting that
isable to perform well under wide variety
of traffic situations [7]. A third alternative
is to omit the feedback loop and regard the
traffic situation as independent of the
routing; a fair assumption from the
perspective of the communication end
points. Some of the key features of TE are
resource reservation, fault-tolerance and
optimum Resource utilization [8]
III. MPLS TE IMPLEMENTATION
REQUIREMENTS
The main objective of considering TE is to
efficiently use the available network
resources and increase service quality of
applications on the Internet. The
motivation behind MPLS TE is Constraint
Based Routing (CBR) which takes
bandwidth, policies and network topology
(IP routing uses OSPF that calculates
shortest path between the nodes and does
not concernif that path has enough
resources). Factors put into consideration
for establishing a path(path refers to LSPs)
in MPLS domain to forward the packets
includes viz:
• Every LSR should consider complete
topology of the network (only OSPF and
IS-IS hold the entire topology).
• Every LER should be able to make an
LSP tunnel on demand.

136
IV. VIRTUAL PRIVATE
NETWORKS (VPN)
The VPN is defined in this work as a
network in which connectivity among
multiple private Wide AreaNetworks
(WANs) is deployed using shared MPLS
IP infrastructure with the same policies as
a private network [14].
It is an extension of a private intranet
through a publicnetwork infrastructure to
provide a secure, cost effective and
reliable communicationchannel between
two ends as depicted in figure 5.
Figure 5: VPN consist of private networks
connected through a public network [14]
VPN Advantages
The advantages and disadvantages of VPN
have been outlined below [5, 6, 7]:
VPN offers number of following
advantages
• Lower cost of implementation
• Reduced support cost
• Better connectivity
• Better Security
• Better bandwidth utilization
• Scalability
VPN Disadvantages
There are following disadvantages
associated with VPNs
• Internet dependent
• Lack of legacy protocols support
A. MPLS VIRTUAL PRIVATE
NETWORK (VPN) INTERNET
Beside the use of MPLS in TE, it can also
be used in implementing provider
provisioned VPNs. Using MPLS for
implementing VPNs is a viable alternative
to using a pure layer-2 solution, a pure
layer-3 solution, or any of the tunnelling
methods commonly used for implementing
VPNs. When deciding on implementing an
IP/MPLS-based VPN, the service provider
has two choices:
A layer-3 approachcommonly referred
to as MPLS Layer-3 VPNs.
A layer-2 approach commonly
referred to as MPLS Layer-2 VPNs.
Evaluating the merits of a given approach
should be based on – but not necessarily
restricted to – the following aspects of the
approach [9]:
Type of traffic supported.
Scalability.
Deployment complexity.
VPN connectivity scenarios that could
be offered to the customer using this
approach.
Service provisioning complexity.
Complexity of management and
troubleshooting.
Deployment cost.
Management and maintenance costs.
V. SURVEY METHODOLOGY
This involves the study of physical
network testbeds with the view to finding
out the type of network architecture,
topology, traffic/services propagated on
the network, as well as the QoS metrics
used to access such networks, etc.
The advantage is that it gives an idea on
how to formulate or develop a proposed

137
network model for the purposes of
validating the intended hypothesis. The
methodology leveraged in this research is
the simulation approach. Empirical
Research is based on experimentation or
direct observation, i.e. evidence. This kind
of research is often conducted to answer
specific questions or to test hypothesis
[20]. This work will present the simulation
design and the results of empirical
research while at the same time carry out
confidence analysis to resolve the stated
hypothesis.
A. SIMULATION TOOL
OPNET Modeller: This accelerates the
research and development (R&D)process
for designing and analysing the behaviour
of devices, protocolsapplications, and
communication networks. OPNET
Modeller includes adevelopment
environment for modelling of all network
types and technologies including VoIP,
TCP, OSPFv3, MPLS, IPv6, and Others
[20]. The easy-to-use GUI structure of
thismodeller enables users to design,
simulate and view the results without
having good programming knowledge or
skills.
B. SIMULATION
FRAMEWORK
Figure 6: Simulation framework
A= System of Interest(SOI),
B= Specification model,
C= DEVS scenarios (MPLS & IP),
D= Test case Scenarios,
E= Model Checking,
F= DEVS Simulation,
G= Result.
C. CAPACITY MODELLING IN
PROPOSED MPLS VPN
ARCHITECTURE
Figure 7:Proposed MPLS VPN analytical
model
The approach for capacity estimation is
based on the use of Equations 1, 2 and 3.
The MPLS VPN Network Operating
Centres can enquire each router in the
domain to supply the ingress Ip or egress
Op and obtain the information about the
available bandwidth on each of its
interfaces. The most accurate approach
will be to collect information from all
possible sources at the highest possible
frequency allowed by the LSP update
interval constraints. This approach can be
very efficient in terms of signalling and
data storage. Furthermore, it can minimize
traffic redundancies; memory requirements
for data storage and the signalling effort
for data retrieval.We define for a link
between two nodes Xkand Yk
C
F
E
B
G
D
A

138
Let the input gateway capacity be given by
Ip=൫∑ ܺ௞ + ∑ ‫ݓܤ‬௡
௝
௡
௝ୀଵ ൯…………….. (1)
Let the output gateway capacity be given
by
OP=൫∑ ‫ݕ‬௞ + ∑ ‫ݓܤ‬௡
௝
௡
௝ୀଵ ൯ ………….…(2)
Where j,n are integer values, Bw is the
available bandwidth, Xkis the input vector
(Ingress) while ykis the output vector
(Egress)
Hence, the MPLS VPN Cloud Capacity is
given by
Cp=Ip+OP……………………………(3)
In this work, since the model seeks to
achieve path information of already
established LSP, the re-optimization is
done primarily at the MPLS VPN cloud
that is, the Network Operating centre
(NOC) rather than in the edge routers. The
algorithm below satisfies the optimization
problem. In this case, it explains how to
re-route an LSP that is already established
to carry multimedia traffic on the network.
Algorithm:
Start ( )
1. Define nodes X1……..Xn
2. Filter incoming traffic & LSP (based
on priority i.e video-voice-data).
3. Re-route LSP in the cloud
4. Receive LSP by nodes Y1…Yn
End;
Form (1), the filtering reduces the number
of unwanted or unauthorized LSP. This
improves bottleneck on the network link
using dijkstra shortest path with the weight
function defined by:
W(e)=1,
݂݅ ݁݀݃݁ ݁ ݀‫ ݐ݋݊ ݏ݁݋‬ℎܽ‫ݐ݅ݓܾ݀݊ܽ ݈ܾ݈݁ܽ݅ܽݒܽ ݁ݒ‬ℎ ݂‫ݓ݁݊ ݎ݋‬
0 ,if otherwise…………. 4
The dijkstra shortest path aims to avoid
bottlenecks or minimize it for multimedia
traffic propagation. Let Nmin denote Min
Value, Nmaxdenote Max value.
The object function ݂(‫)ݔ‬Min
∑ ‫ܥ‬ଵ௘∈ாభ
(e)ܺଵ+∑ ‫ܥ‬ଶ௘∈ாమ
(e)ܺଶ+
∑ ‫ܥ‬ଵ௘∈ாభ
(e)ܺଵ+
∑ ‫ܥ‬ଷ௘∈ாయ
(e)ܺଷ+………………∑ ‫ܥ‬௡௘∈ா೙
(e)
ܺ௡…………………………………. …5
Subject to traffic behaviour ∑ ‫ݒ‬௢
௝
௜ + ∑ ‫ݒ‬ௗ௢
௝
௜
+ ∑ ‫ݒ‬௢ௗ
௝
௜ >0……………………………6
Where c1,c2,c3,….cn denotes traffic cost
functions , E R+ denotes the edge
routers, X1, X2, X3………Xn toY1, Y2, Y3,
………Yndenotes the input and output
vectors respectively.
VI. SIMULATION AND RESULTS
ANALYSIS
Task: Hypothesis Formulation
Null Hypothesis H0: There is no
statistical variation between the QoS
responses of traditional IP backbone for
multimedia propagation and MPLS VPN
backbone for multimedia propagation.
Alternate Hypothesis Ha:There is
statistical variation between the QoS
responses of traditional IP backbone for
multimedia propagation and MPLS VPN
backbone for multimedia propagation.
A. ASSUMPTIONS
It is very hard to predict the behaviour of
MPLS VPN backbone becausedifferent
design and implementation factors are

139
involved in the network such as in
modelling the VoIP traffic, voice codec,
calls per hour, type of service (ToS), etc.
This work will simulate the different
MPLS VPN models by considering the
QoS, RIPv2 or OSPF as IGP, and BGP as
EGP. Also, 75% of link capacity is
allowed for VoIP traffic to protect it from
bursts.
B. SIMULATION PARAMETERS
Table 1 shows our simulation parameters
in this research. In this work, to validate
the system performance of the MPLS VPN
model, OPNET Modeller was used to
achieve the objective as discussed earlier.
After setting up the model, a simulation
run was carried out to generate our
graphical plots shown in this work. Also, a
consistency test was carried out which
shows that the design model is stable and
consistent before the simulation execution.
Tables were configured and adapted in the
MPLS VPN setup.
Table 1: Evaluation Table for MPLS
VPN and Frame Relay-IP Backbone
Parameters MPLS-VPN Frame
Relay IP
No of Local
Clients
8 8
No of remote
terminals
5 5
No of
Gateway
Servers
7 7
No of Local
Servers
7 7
Multimedia
Traffic State
profile
Enabled
(Voice,
Video&Data)
Enabled
Application Enabled Enabled
Profile (Voice,
Video&Data)
Internet
Type
MPLS VPN Frame
Relay IP
RSVP Enabled Enabled
Table 2: Profile Attribute
SN
1 LDP
ConfigurationsStatus
Enabled
2 Discovery Config. Enabled
3 Session Config. Enabled
4 Recovery Config. Enabled
5 Label Config. Enabled
6 Advertisement Policy No Delay
7 Signalling DSCP CS6/NC1
8 Re-optimization
Timer(sec)
3600
9 Delay (sec) 20
10 Retry Timer (sec) 120
11 Propagation TTL Enabled
12 Traffic Engineering BGP
13 Fast Reroute Status LSP Config
14 Revert Timer (Sec) LSP Config
15 Label Space
Allocation
Global GLA
16 CSPF Optimization
Metric
TE Link
Cost
17 Number of Shortest
path
5
C. PERFORMANCE EVALUATIONS
For analysis of results, the following
discrete event simulation (DEVS) statistics
are chosen for MPLS VPN, viz: MPLS
VPN Utilization (tasks/sec), MPLS VPN
Throughput (pkts/sec) and Point-to-Point
Queuing Delay (sec). A discussion on the
obtained results is carried out below.

140
1. MPLS VPN THROUGHPUT
(BITS/SECS)
Throughput is a measurement of the
average rate that data (in bits) can be sent
between one user and another and is
typically reported in kilobits per second or
megabits per second. Throughput is, thus,
computed using the amount of data in the
payload area of the highest protocol layer
(e.g., the UDP payload size) of the
transmitted packets. As shown in figure 8,
the throughput response is peak at 1kbps
and remained stable throughout the
lifecycle of the network. In this research, it
was observed that the throughput response
of figure 1 for IP frame relay maintained
several oscillations and was unstable
throughout the lifecycle of the traffic,
though with a higher peak value of
30kps.This work then opines that optimal
throughput behaviour is significant with
MPLS VPN even at 1kpbs while at 30kbps
its behaviour is unacceptable owing to the
oscillatory trade-off. Hence, from the
graphs, it is observed that there is an
increase in the performance when the
multimedia traffic is transmitted using
MPLS technology than from frame relay
IP backbone.
Figure 8: MPLS VPN throughput
Response (Bits/Secs)
2. MPLS VPN TUNNEL DELAY
(SECS)
This is quite different from latency which
generally does not vary for different
protocols or traffic types. Figure 3 shows
the MPLS VPN Tunnel Delay (Secs) or
the packet end-to-end delay of MPLS and
IP network model. There are many
factorsthat determinethe quality of voice
traffic as well as other traffic, which
include the choice of codec, packet loss,
delay, jitter as well as the medium of
propagation. As shown in figure 3, the
end-to-end delay in a network is about
0.15secs which is greater than 80ms. As
such for MPLS VPN to establish
acceptable VoIP calls, it will take a lesser
time compared with the end-to-end delay
in the plot of figure 7, which is 0.250secs.
This work then argues that for all
multimedia traffic, MPLS VPN network
reaches the end-to-end delay threshold at
lesser time compared with the traditional
IP based network owing to its efficient and
superior capabilities in providing traffic
engineering (TE) over virtual private
network (VPN) interfaces.
Figure 9: MPLS VPN Tunnel Delay (Secs)

141
3. AVERAGE UTILIZATION
Traffic Engineering (TE) is a mechanism
that controls the traffic flows in the MPLS
VPN networks and provides the
performance optimization by optimally
utilizing the network resources. Some of
the key features of TE are resource
reservation, fault-tolerance and optimum
Resource utilization. As shown in
figure10, the MPLS VPN model reached a
peak of about 0.06 (tasks/sec) and quickly
dropped to about 0.01(tasks/sec) optimally
while for figure 13, its utilization peak
dropped from 0.116(tasks/sec) to
0.01(tasks/sec) showing that
comparatively, MPLS have better resource
utilization.
Figure 10: Average Utilization for MPLS
Figure 11: Frame Relay IP throughput
(Bits/Secs)
Figure 12: Frame Relay IP End to End
Delay
Figure 13: Frame Relay Utilization Plots

142
D. HYPOTHESIS VALIDATION
ANALYSIS
The simulation statistics were generated
from figures 8 to figure 13 and the
summarized statistics table is shown in
table 3. From the table 3, the parametric
variables (PV) viz: Throughput
(Pt),Utilization (Pu), and delay (Pv), were
computed after the simulation runs.
Considering the algorithm and equation
models developed, the introduction of
these QoSparameters in the simulation
testbed reveals that MPLS VPN model is
more efficient as the QoSvariables Pt, Pu,
and Pv for the various resources, as
depicted in table 3. The overallresults
highlight the effectiveness of MPLS VPN
model for production deployment. From
table 3, there is statistical variation
between the QoS responses of traditional
IP backbone for multimedia propagation
and MPLS VPN backbone for multimedia
propagation; hence the null hypothesis is
rejected while we accept the alternate
hypothesis.
Table 3:Summary of evaluation
Analysis
s/n QoS
parametric
variables
(PV)
IP
Backbone
MPLS
Backbone
1. Point to
point
Throughput
Pt
97.56%
(40kbps)
2.44%
(1kbps)
2. Point to
point
Utilization
Pu
65.91%
(0.116)
34.09%
(0.06)
3. Packet
delay
Variation Pv
62.5%
(0.25secs)
37.5%
(0.15secs)
VII. SUMMARY
Multi-Protocol Label Switching, is quickly
replacing frame relay and ATM as the
technology of choice for carrying high-
speed data and digital voice on a single
connection. MPLS not only provides
betterreliability and increased
performance, but can often decrease
overall costs through increased network
efficiency. Its ability to assign priority to
packets carrying voice traffic makes it the
perfect solution for carrying VoIP calls.
MPLS as an emerging technology ensures
the reliable delivery of the internet
services with high transmission speed and
lower delays. The key feature of MPLS is
its Traffic Engineering (TE) which is used
for effectively managing the networks for
efficient utilization of network resources.
Due to lower network delay, efficient
forwarding mechanism, scalability and
predictable performance of the services
provided by MPLS technology, this makes
it more suitable for implementing real-time
applications such as Voice and video.
VIII. CONCLUSION
In this work, the performance of
multimedia traffic over MPLS VPN
Internet was carried out while making
comparison with the conventional Internet
Protocol (IP) network. Analytical models
for capacity management and on-demand
optimization was developed. Various
system models with a LSP flow algorithm
were derived. OPNET IT guru was used to
simulate both networks and the
comparison is made based on the metrics
such as Point to point Throughput
(bits/secs), end-to-end delay (secs) and

143
utilization (tasks/secs). The simulation
results are analysed and it shows that
MPLS based solution provides better
performance in implementing the VoIP
application. In this work by using the
selected QoS metrics, an estimate
justification on the use of MPLS VPN on
today’s bandwidth constrained networks
will be widely accepted. This research can
help the network operators or designers to
determine the best type of network
backbone to use in propagating multimedia
traffics in real networks.
IX. REFERENCES
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[3]. Nader F.Mir., Albert Chien,
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ICSS‟02, conference.
[4]. James Reagan, ''CCIP MPLS
Study Guide 2ndEdition''.
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International Conference on
Availability, Reliability and
Security, IEEE.
[6]. Anders Gunnar, “Towards Robust
Traffic Engineering in IP
Networks, M.Sc thesis, 2007.
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144
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