Simulation of OSPF Routing Protocol Using OPNET Module

(A Routing Protocol Based on the Link-State Algorithm)

Mehboob Nazim Shehzad (01085), Najam-Ul-Sahar (1253)

mehboobfraz85@gmail.com), shinysehar@gmail.com

Dept. of Computer science and Technology Supervised by: Dr. Jamil Ahmad and Abdul Hannan

jamil@iqraisb.edu.pk, hannan@iqraisb.edu.pk

Iqra University Islamabad

Abstract:

The Open Shortest Path First (OSPF) protocol, defined in RFC 2328, is an Interior Gateway Protocol Used to distribute routing information within a single Autonomous System [1]. This report examines how OSPF works and how it can be used to design and build large and complicated networks. OSPF is well known routing Protocol in internet field. It is link state routing algorithm protocol, which base on cost. This paper presents a detailed simulation approach for deploying OSPF routing protocol successfully. The simulation uses the OPNET network simulator. In simulator make two (2) scenarios like, (i) No Area, (ii) Area. The paper describes modeling and representation of background and OSPF traffic, as well as various simulation configurations.

Keywords: OPNET, OSPF, Simulation, Network Design, Network Management, Performance Evaluation

I. Introduction:

A routing protocol is work base on algorithm. Routing algorithm also based on metrics to find the path to transmit data across two networks. Metrics also include (i) Cost (ii) Bandwidth (iii) Maximum Transmit Unit (MTU) (iv) Delay (v) Number of hop count these metrics also save or store in routing table. Routing protocol has two types. First one is interior gate way protocol and other one is Exterior gateway protocol. OSPF is also interior gate way protocol, other interior gate way Protocol are RIP, IS-IS. BGP and BGP4 is Exterior gate way protocol[1…4].

In fact the idea of the OSPF routing protocol is based on link state algorithm. The discussion of the creation of a common interoperable IGP for the Internet started in 1988 and did not get formalized until 1991.At that time the OSPF Working Group requested that OSPF be considered for advancement to Draft Internet Standard [3].So that according to Cisco routing protocol has two schemes of algorithms. The idea of the Link state is also based on link, and Distance vector idea based on the Distance. Distance vector based on the numbers of hops and Links state on base of cast of the link.

The main objective of this work is to develop an OPNET Modeler based simulation based performance of two different routing strategies: First one is No_Area and second one is Area. We implemented an OSPF routing protocol under a simulation platform for evaluating network performance and comparing the mentioned routing strategies.

This paper is organized as follows. Firstly we present an overview of Literature view. Secondly we designed simulation platform. Then, we describe the OSPF routing protocol with considerable details and given the cast of links. Three following subsections respectively present the scenarios used for the routing modeling. Then one section is dedicated for the presentation of simulation results. Some conclusions and comments are found in the last section.

2. Literature Survey

In [1] the author proposes OSPF routing protocol apply on the adaptive dynamic routing strategy in OPNET Modeler. In which author make the adaptive router network and link these router based on cast. Because in that network OSPF work on routers so that OSPF work based on cast. Link cast also change according to the effective bandwidth. Then the processor module also implemented at the routers of effective bandwidths and then traffic select the lowest cast to reach the destination path.

In [2] the author proposes OSPF protocol under different scenarios and under states. In fact the main idea of the researcher is that to test the OSPF routing protocol in different scenarios. Firstly make the network and deploy the OSPF TE (Traffic Engineering) for check the traffic on the network. Then second one is to know router how much take the time for updates. Third one is to check the HELLO packet times. In which we get main idea is that in OSPF routing protocol how much take the time to update the router in case of any router connection fail. In 30 second router update to other then router take

other way chose for send the packet. That network based on 292 nodes and 765 links.

In [3] author proposes protect the network routing protocol and management protocols. Because insider attacks are probably one of the most challenging research problem in network management. In OSPF, a group of router make the network, these routers in that network exchange information and forward packet to each other. In this paper the researcher analyzes the OSPF and identifying the problems that create in that network during forwarding packets. Because if one router have a problem then whole network disturbed due to this one. So that researcher applies one attack to this OSPF network to analyze the performance of the OSPF routing protocol. That attack very powerful and block the router to update in 60 minutes by simple inter one wrong OSPF data unit. This work fully based on simulation and practice.

In [4] author proposes OSPF routing protocol simulation in different categories. First one is Designated Router (DR) elect for constant time. In this case 50 routers can also accept the convergence time, and if any problem create then retransmission possible. Second one is if router has limited input buffers, then the compare the results between election and flooding protocols increase the election time. In that effect create oscillatory behavior. In fact that 20-50 router network has very low impact of buffer size. Third one is that in which DR and BDR are both fails in same time, then convergence time increase. If convergence time increase then the router cannot updated and data dropped in any condition. So that if interval increases then the convergence time decrease.

In [5] author proposes the traffic engineering for adapting the routing of traffic to check the performance and be able to use of network recourses. In this article, researcher describes the intra domain traffic engineering that works base on the interior gateway protocol. Such as most useful interior gateway protocol is OSPF routing protocol. In this report researcher describe the

OSPF configuration of links, based on a wide network view of traffic and topology with in a domain. The researcher also compares different optimization results and collects the data. Main idea of this research paper is also analyze the short path routing protocol are able to flow of traffic in large IP network.

In [6] author describes the internet growth with the passage of time. Internet service Provider (ISPs) increase the traffic demand with new technology and also recourses that utilization. In a network packet also sent from source to destination with following protocol. The most commonly use Intra domain routing protocol is OSPF. In OSPF routing protocol every link have itself cast, but that cast set by a specific formula. The OSPF weight setting is also directly impact on network performance. So that main problem is that which algorithm is more suitable for this purpose. For this purpose researcher collect the results from different optimization scenarios for comparisons. Researcher also applies the linear programming for this purpose, but most commonly algorithm is used for this OSPF is Link State Algorithm.

2.1 OPNET Modeler:

OPNET stood for Optimized Network Engineering Tools [2]. The company's first product was OPNET Modeler, a software tool for network modeling network performance. In OPNET many projects are also simulate in many features [1]. OPNET gave the advantage to simulate any network with different configuration. In OPNET module no need to learn any Language like C++,Java,etc.OPNET Module is very easy to use instead of any else. In that tool control different configurations, traffic, check the interval, sent and receive packets.

3. Simulation Overview:

A simulation for OSPF routing strategy evaluation should consist of the following basic elements: slip8_gtwy routers, PPP_DS3 links and network traffic information. A simulation scenario is built for a Campus through the

specification of the interested network topology and involved network traffic. The network topology is specified through the arrangement of router and links that interconnect these routers. The network has two scenarios. First one is NO Area and other one is Area. The network traffic is specified in the source router by setting the cost of every link that connects each others. Then seating the following information: the start time, the stop time, the statistical distribution for packet interarival times, the statistical distribution for packet sizes and the destination router. Network use the OSPF routing protocol so that all parameters set to be according to OSPF. After having specified the network topology and traffic, a user specifies performance parameters for network condition evaluation and runs simulation under different routing strategies in the platform. Among many parameters for the network performance evaluation we focus on network throughput. Then same process can do for other scenario Area. The comparison between the Scenario No Area and the Scenarios Area can be done through the execution of a simulation sequence. Two scenarios can be specified in the Configure Simulation Advanced, differing only by the option for an adaptive routing or a conventional routing and by the output vector file attributes (where statistics are stored). The execution of the simulation sequence reveals the parameters selected for the network condition evaluation and the comparison of the two scenarios can be done using the View Results Advanced.

3.1 Implementation and Bandwidth:

In fact the network topology make for the decisions to transfer data from one point (Source) to other Point (Destination). Then link these routers with specific link that also describe previous section. The main point of this implementation is that run OSPF on these routers so that firstly select the locations .In other words, OSPF is Interior gate way protocol

so that select the routers sachem in one antonymous system.

Fig a. Network of Routers

According to this network topology routers links A, B and C has a same cast. Then that Routers D and E links has same cast. Also remaining routers F, G and H have same cast. According to Cisco the formula for the cast also predefined. So implements that formula on these routers and gets the cast of different link according to above conditions.

So that OPNET router models also support the formula of Cisco. The default value of the Reference bandwidth is 1,000,000 kbps. (Kilo bits per second)

Cost = (Reference bandwidth) / (Link bandwidth)

Fig b. Network show the cast

According to that Network topology, in first scenario (No Area) source destination is router A and destination router C. In this scenario no area defined so data chose any way to reach destination point. In fact when source point select A and Destination point C there is no area defined. Because set the parameters in OPNET module auto assign IP. Run simulation of this one scenario and save the result of graphs.

Then create another duplicate scenario name Area. Select the path B to H. Also use manually IP (Internet Protocol) to source and destination points. All there routing table also make and auto save in background of OPNET module. Configure the OSPF routing protocol on router. Then collect these two scenarios and run simulation.

Fig c. Colors lines show the Cost (Blue, red, green)

3.2 Routing Tables:

I found that address 192.0.1.1 belongs to router A and address 192.0.1.2 belongs to router B. This means that the link between Router A and Router B carries a common network address and that they are directly linked. I also found that addresses 192.0.2.1 and 192.0.3.1 belong to Router A which are directed to Router C and Router D respectively. I also found that IP address.

192.0.12.1 Belongs to Router A which is nothing but its loop back interface. Similarly, IP addresses belonging to other routers were also determined. Router B�192.0.1.2 (Interface 0), 192.0.8.1(Interface 1), 192.0.13.1(loop back Interface). Router C�192.0.2.2 (Interface 0), 192.0.7.1(Interface 1), 192.0.8.2(Interface 2), 192.0.14.1(loop back Interface). Router D�192.0.3.2 (Interface 0), 192.0.4.1(Interface 1), 192.0.9.2(Interface 2), 192.0.16.1(loop back Interface).

Router E�192.0.5.1 (Interface 0), 192.0.7.2(Interface 1), 192.0.9.1(Interface 2), 192.0.15.1(loop back Interface). Router F�192.0.4.2 (Interface 0), 192.0.10.2(Interface 1), 192.0.11.2(Interface 2), 192.0.19.1(loop back Interface). Router G�192.0.5.2 (Interface 0), 192.0.6.1(Interface 1), 192.0.10.1(Interface 2), 192.0.17.1(loop back Interface). Router H�192.0.6.2 (Interface 0), 192.0.11.1(Interface 1), 192.0.18.1(loop back Interface).

4. Results:

4.1 In No _ Areas Scenario:

(i)Source A to Destination C: In this case when no area defined then any one router selects the any path to reach their destination point. Because according to set the area id then the Router A, B and C have same cost. So that in this case router A is source and router C is destination.

Fig d. Blue line show Source .A to Destination C.

(ii)Source B to Destination H: In this case router selects that path for follow the data.

Fig e. Blue line show Source B to Destination H

4.2 The Areas Scenario:

(i)Source A to Destination C: In this case Area Id to Router A, B and C is 0.0.0.1.For Router D and H is 0.0.0.0, and for the Router F, G and H is 0.0.0.2. So now every router is force that follows the given Id path to reach the destination. When the so the result of A to C is.

Fig f. Blue line show Source .A to Destination C

(ii ) Source B to destination H: In this situation area specify so that router follow the path.

Fig g. Blue line show Source .B to Destination H

5. Conclusion:

This work presents an OPNET Modeler based simulation platform useful for evaluating the influence of an OSPF routing protocol strategy on the network performance. The designed platform permits us to understand the impact caused by the routing decisions taken and help us to evaluate the advantages (or disadvantages) of the strategy in terms of particular network topology and traffic range

6. Futures Work:

OSPF Multiple path implementation in Graphics Network SimulatorNS-2.Cisco also defined the multiple path OSPF routing protocol.

References:

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