PERFORMANCE ANALYSIS OF MULTI-PROTOCOL LABEL SWITCHING NETWORKjoics.org/gallery/ics-1207.pdf · New...

PERFORMANCE ANALYSIS OF

MULTI-PROTOCOL LABEL SWITCHING NETWORK

1Kiran and 2Sanjay Kumar Mathur

1Stuent, Shekhawati Institute of Engineering & Technology,Sikar, Rajasthan Technical

University

2Assistant Professor, Shekhawati Institute of Engineering & Technology,Sikar, Rajasthan

Technical University

[email protected]

ABSTRACT

New model in routing architectures, a multi-protocol label switching (MPLS), is changing the

way packets in the Internet Protocol (IP) is transmitted into the network. MPLS is also able to

offer Traffic engineering (TE) as a key element in reducing congestion through efficient network

resource balance and management. MPLS is also able to offer Traffic engineering (TE) as a key

element in reducing congestion through managing effective network resources and

load balancing.The assessment of performance is made based on jitter, latency,

packet delay variations and end to end delay and in network parameters. QoS integration with

the MPLS-TE can improve the network performance. For implementing a QoS on a network that

can affect the network performance, assorted scheduling algorithms can be used. This paper

presents a study of service quality technology per application in the IP/MPLS networks. This

research shows the pertinence of an architectural design in which DiffServ, MPLS and Traffic

Engineering will work together to overcome QoS-capable IP networks challenges.

Keywords: Performance Analysis, Protocol, Network, Multi-protocol label switch

1. Introduction

Day after day technologies develops. Companies are adopting new technologies for upgrading

their services and networks. However, companies need a single network infrastructure that can

provide a broad array of services and help in reducing their network costs. The various types of

network applications are data, voice and video. When a regular data is transmitted over a

network, no service guarantees are required. Instead of three different networks, companies

would like to use a single network to transmit data, voice and video to drive down costs and

service attempts. These requirements are met by new network infrastructures. With the switched-

circuit networks being supplanted by packet-switched networks, a great deal of service providers

Journal of Information and Computational Science

Volume 9 Issue 8 - 2019

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use existing and next-generation services with the technology of IP / MPLS and their future

flexibility, network scalability and reduced cost of new services.

Figure 1: MPLS Network Architecture

Different simulations and tests for MPLS performance on IP networks have been carried out.

Bandwidth, latency, throughput, jitter and error rate are the performance measurements for the

network. Network simulators like ns-2, ns-3, OMNEST, Riverbed Modeler, MatLab and

OMNEt+ are used for simulations. These generally are used in analyzing network performances.

D. Adami et al., [1] talked about designing and developing control and data planes needed in a

MPLS node to sustain the Label Switching Path (LSP). Simulator and new software modules

have been developed and implemented to calculate Peer-to-Peer (P2P) communication, the

transmission mechanism, the RSVP-TE signaling protocol and LSP paths.

The new ns-2 module was proposed by D. Adami et al., [1] to speed up DiffServ-aware MPLS

design, development and deployment. MPLS DiffServ conscious module allows network

operators to provide services requiring strict QoS guaranteeing quality performances. Using the

Ns-2 simulator, the new software module simulates the RSVP-TE protocol as well. D. Wright,

[2] compared performance of MPLS networks and IP networks for voice data. A network

topology is designed and a NS2 based simulation tool is used to send bulk data within a network.

Network performance is measured with MPLS enabled or disabled. The author illustrates that

MPLS network may perform better than the traditional IP networks. Rahman et al. 2008, [3]

presented an overview of MPLS networks and compared performance of IP routing and the

MPLS forwarding mechanism.

It has been observed that Researchers have not discussed TE, even though TE is very

important part of MPLS. It has also been observed that in none of the cases MPLS-TE has been

implemented and the evaluations have been made without considering traffic of real

time.However, it is widely accepted that during deployment of new network service as for

example VoIP in an enterprise infrastructure, it is essential to consider network traffic. Thus,

failing to consider the existing network traffic and measuring network performance in a

simulated environment may not give the same performance result compared to deployed network

service.

Our study mainly aims at evaluating the efficiency of the MPLS-TE voice traffic network

implemented by QoS [4]. Choosing the scheduling algorithms involved in implementing QoS

may change the parameters of QoS performance. Another objective is to make a comparison of



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the proposed network scenarios using various scheduling algorithms. The comparison takes into

account performance parameters, end-to-end delay, jitter and variations in packet delay.

The designing of different scenario network models for MPLS.

Analyze the performance parameters of jitter, changes in packet delays and end-to-end

delays.

Analysis of these performance constraints in MPLS-TE network implemented in QoS

architecture

A configuration of the studied techniques is applied to a testbed where voice traffic is

injected into the network in addition to best effort traffic.

The focus of the scheduling algorithms used in the implementation of QoS process so

as to decide which has better performance.

1. Methodology

We have chosen simulation as alternative because of the unavailability of a real MPLS

network for our research. Additionally, it is conceptually and computationally easy and takes less

time to understand various modifications through simulations. Without literature review and

selection of papers, research cannot achieve its goal. For our work, we chose Saunders et. al's

deductive approach [5].

• A study of the understanding documents and a determination of the limitations and

parameters to be considered for analytical purposes.

• Determination of a simulation model using the network simulater tool for simulation.

• Adequate model to support the application in real time.

• Becoming a measure of analysis justifies research using simulated data.

2. NS2 Network Simulator Setup and Implementation

Figure.3 shows simplified flowchart of the ns-2 simulator, with implementation of different

protocols at different stages.



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Figure 2: NS2 simulator schematic flow chart

3. Simulation Topology / Simulation Scenario

In this model, we had established the traffic path in the network with multiple sources. First,

external traffic has been established between the client and server nodes. Further internal traffic

has been created among various sites to have multiple cumbersome traffic paths which are

normal in a real time backbone network. Initially simulation was done without RSVP-TE

implementation i.e., with MPLS LDP, and then the same model has been simulated after RSVP-

TE deployment [3], Figure 3. We have taken the metrics of bandwidth utilization, end-to end

delay and packet loss ratio for evaluation. Average data consumption is the bandwidth utilization

during the simulation time which has been calculated by calculating the number of packets

received at both the sinks multiplied by the packet size. End to end delay has been calculated by

obtaining the average time taken by the data packets to reach the destination sinks.



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Figure 3: Simulation model topology with RSVP-TE

Figure 4: Experiment of MPLS networking in nam window using NS2

For the simulation, a network topology of six MPLS capable routers were connected (Figure

3, node 5 to node 11). The no. of “VoIP application generated can be of increasing in nature, and

accordingly the link should be optimized. The network consisted of workstations on which both

the client and server application are running for FTP application, Video application and VoIP

applications. Out of the six MPLS routers at one end was an egress router (Node 7), at the other

end was ingress router (Node 5) which are collectively known as LER. The other four routers are

LSR routers”.

In NS2 simulation there were 10 MPLS capable routers inter-connected to one and other. “To

cope with the dynamic nature of VoIP call occurrence, ppp_adv link was used which has a

provision of providing variable data rate. Also, ppp_ds3 link was used for interconnection

between edge and core routers. In order to visualize the impact of congestion in presence of

different traffic variants, ppp_ds3 link that can support data rate of 44.7 mbps is optimally

enough. MPLS Attribute Definition block is responsible for configuring the Traffic Trunks and

Forward Equivalence Class (FEC)” [7]. The simulation model in ns2 running in nam window,

see Figure 4. “Out of the eleven MPLS routers at one end was an ingress router (Node 1), at the

other end was ingress router (Node 6) which are collectively known as LER. The other four

routers are LSR routers. The LSPs were set for the defining the path for traffic. The profile



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configuration was set up for creating user profiles referring to the Application Configuration.

The QoS block is used for defining the protocols that are supported at the IP layer”.

4. Integration of MNS with QOSPF Routing Module

“Integration means that if programmer while writing simulation script for MNS enables

QOSPF (while making MPLS nodes). Then, whenever a route computation is required, MNS

will compute routes by OSPF algorithm with QoS extensions. So, if QOSPF is enabled then

QOSPF agent also is attached to the node along with MPLS Classifier and CR-LDP agent.

Briefly, following are the places where both the modules will need to communicate.

• Initialization- Both modules will send their packets for getting information about links,

bandwidths, topology map and will build their databases. QOSPF module should always take

bandwidth information from MNS Resource Manager.

• Route Selection- Whenever MNS module gets a request for a path having some minimum

bandwidth then instead of using its own ways of route computation, the parameters should be

passed to QOSPF routing module, which should then compute the route and pass the route as a

string of node ID to MNS and then reservation should be made along that route by MNS.

• Route Formation- Whenever MNS node receives Label Request message and its Admission

Control update the resource table, then QOSPF routing module should also update itself from

there.

• Route Failure- When the reservation of bandwidth for a route is in progress and if in between

some node is found deficient of required bandwidth then notification messages for failure are

send to previous nodes which then update their bandwidth databases accordingly. QOSPF

module should update itself for each node here also.

• Route Preemption- Sometime according to set/hold priority some CR-LSPs are preempted, at

that time also bandwidth changes should be communicated”.



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5. Network Traffic Generation

Figure 5: Occurrence of firstfault in MPLS model

In Figure 5 there is a link failure between LSR-3 and LSR-2, LSR-2 is directly connected to

backup path, so FIS will reach to LSR-4 immediately. On receiving the FIS, LSR-4 will send the

mapping message to its respective neighbors and packets will switch over from working path to

recovery path. So the new path will be 1-2-4-5-6-10.

Figure 6: Occurrence of secondfault in MPLS model

In Figure 6 there are two link failure between a) LSR4 and LSR2 and b) LSR-8 and LSR-7,

while LSR-2 is directly connected to backup path, so FIS will reach to LSR-3 immediately. On

receiving the FIS, LSR-3 will send the mapping message to its respective neighbors and packets

will switch over from working path to recovery path. So the new path will be 1-2-3-4-5-6-10.



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Figure 7: Occurrence of 3rd fault (Multiplefault tolerance) in MPLS model

6. Results and Analysis

For analysing the performance of MPLS network regarding voice, jitter, Packet Delay

Variation and End-to-End delay were considered as our means for assessment. Executing

simulation for multiple times with various seed values also helped us to observe the effects that

random values have on the simulation outcome (Figure 5-7). The simulation was made to run for

an hour for every scenario to let it achieve its steady state. It was noted that in the simulation, the

traffic for the VoIP starts at 50th second and terminates after 3600 seconds. In every scenario, at

each 2 seconds the VoIP calls are added, from the beginning of the simulation to its end. The

simulation output data was saved in a spreadsheet.

Then, the mean value along with the deviation from the mean value was graphically

represented by moving the data collected to Microsoft Excel program. For the QoS implemented

MPLS-TE networks and regular MPLS-TE network, the average jitter and End-to-End delay are

depicted in Figure 8 and Figure 9, respectively. Additionally, Figure 8 and Figure 9 also depicts

the standard deviation present in the simulation output due to variation in seed values.

This graph for the deviation in addition to the average graph is plotted to inquire if our

simulation data were prone to the random values produced. The assessment was performed by

determining the average value and then finding the upper and lower deviation with respect to the

average value.



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Figure 8: Avg. Jitter in QoS implemented MPLS-TE network

Description of the Graphs

In Figure 8,Jitter_avg_MPLS-TE represents the average jitter present in MPLS-TE network in

presence and absence of QoS.jitter_avg_WFQ, jitter_avg_PQ and jitter_avg_FIFO are MPLS-TE

networks with the implementation of QoS with WFQ, PQ and FIFO used as scheduling

algorithms, respectively.The upper and lower dotted lines stand for the Standard deviation from

the average.

Jitter is the unwanted variation in the delay of packets [8], therefore it’s always preferable to

have less jitter as it can result the abandoned of the packets at the receiving terminal. Figure 4.10

depicts the graph for End to End delay. We can see from both the Figure 4.9 and Figure 4.10 that

WFQ has not given good performance even on comparing with FIFO with respect to jitter and

end-to-end delay. This is due to the reason that WFQ is compromising end-to-end delay and jitter

process in the network since it is more directed towards with the maintaining the fairness and

congestion avoidance.



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Figure 9: Avg. End to End Delay (ETED) in QoS implemented MPLS-TE networks

In Figure 9, Avg_ETED_MPLS-TE represents the end to end delay generated in without QoS

implemented MPLS-TE network.Avg_ETED_PQ, Avg_ETED_FIFO and Avg_ETED_WFQ are

end to end delay in QoS implemented MPLS-TE network with PQ, FIFO and WFQ algorithm

used for scheduling respectively.The upper and lower dotted lines stand for the Standard

deviation from the average.

In Figure 9, a little existence of deviation at the beginning of simulation with MPLS-TE

network is observed but deviation is minimal as the time progresses. Though little presence of

deviation was observed at the beginning of simulation, we also saw that, the deviation observed

was negligible.

The graphical analysis points that in few cases there was a little deviation present but they

were essentially negligible. Although in few cases, the little deviation was seen in the starting of

the simulation, we also observed that it sparsely coincided with the average as the time

progressed.

Figure 10: Packet Delay Variation (PDV) in QoS implemented MPLS-TE networks and

MPLS-TE network

In Figure 10,Avg-MPLS-TE stands for Packet Delay Variation seen on average in MPLS-TE

network without the implementation of QoS.Avg-FIFO, Avg-WFQ and Avg-PQ are end to end



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delay in QoS implemented MPLS-TE network with FIFO, WGQ and PQ used as scheduling

algorithm, respectively.

Figure 10 demonstrates the corresponding Packet Delay Variation (PDV) graph. As defined

by the IETFT, the variation in one-way delay of partcular packets is called as PDV. Similar to

the case of both the End-to-End Delay and Jitter when compared on the grounds of PDV, the

QoS enabled MPLS network performs better [6]. The graph also demonstrates that Priority

queuing, when utilised as the scheduling criteria for DiffServ architecture, performance better for

our network model.

7. CONCLUSION AND FUTURE WORK

The performance variation occurring in the network before and after the MPLS-TE network

implementation with QoS was analyzed in this study. Variety of scheduling algorithms were

utilised in the procedure of implementing QoS to see whether they had any role in the output

from the network, particularly for voice application. After the examination of the literature

review and outcome from the simulation, we came to the conclusion that the implementation of

QoS in MPLS-TE network gave better results than regular MPLS-TE network for the application

voice packet transfer as it generated lower jitter and lower delay. The performance of the

network for video traffic handling can also be compared with similar experiment analogous to

this study. This is another possible extension to this study. There are still many works remaining

in the progress of end-to-end QoS management for multi-service in IP networks. Those

configurations can in fact be extended and refined to carry out all kinds of traffic, add more

restrictions on QoS parameters and extend the configurations to a large network, composed of

several and heterogeneous domains.

REFRENCES

[1] D. Adami, C. Callegari, S. Giordano, F. Mustacchio, M. Pagano and F. Vitucci,

“Overview of the RSVP-TE Network Simulator: Design and Implementation”, Proceedings of

Internet Performance, Simulation, Monitoring and Measurements (IPS-MOME), 276-281, 2005.

[2] D. Wright, “Voice over MPLS compared to voice over other packet transport

technologies,” Communications Magazine, IEEE, vol. 40, no. 11, pp. 124-132, 2002.

[3] M. A. Rahman, A. H. Kabir, K. A. M. Lutfullah, M. Z. Hassan, and M. R. Amin,

“Performance analysis and the study of the behavior of MPLS protocols,” in Computer and

Communication Engineering, 2008. ICCCE 2008. International Conference on, 2008, pp. 226-

229.

[4] B.Enders, "Quality of Service for Voice over IP ", Chesapeake NetCraftsmen, 2003.

[5] M. Saunders, P. Lewis, and A. Thornhill, Research Methods for Business Students.

Pearson Education, 2009.



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[6] O. Gure, B. K. Boyaci, and N. O. Unverdi, “Analysis of the service quality on MPLS

networks,” in Circuits and Systems for Communications (ECCSC), 2010 5th European

Conference on, 2010, pp. 43-46

[7] L. Balliache, “Forwarding Equivalence Class (FEC).” Cited from

http://www.opalsoft.net/qos/MPLS-13.htm.

[8] “MPLS Protocol Family - MPLS | LDP | CR-LDP | RSVP-TE.” Cited from

http://www.protocols.com/pbook/MPLS.htm#LDP.

[9] S. Blake, D. Black, M. Carlson, E. Davies, Z. Wang, and W. Weiss, “An Architecture for

Differentiated Services”, RFC 2475, [December 1998].



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