my project publication

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

Volume 1, Issue 3, Mar-Apr, 2014 (www.ijetr.org) ISSN (E): 2347-5900 ISSN (P): 2347-6079

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.



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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



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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.



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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=�∑ �� + ∑ ��

�� …………….. (1)

Let the output gateway capacity be given

by

OP=�∑ �� + ∑ ��

�� ………….…(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,

��ℎ��ℎ��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 �(�)Min

∑ !�"∈$% (e)��+∑ !&"∈$' (e)�&+

∑ !�"∈$% (e)��+

∑ !("∈$) (e)�(+………………∑ !"∈$* (e)

�…………………………………. …5

Subject to traffic behaviour ∑ �+, + ∑ �-+

,

+ ∑ �+-, >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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