53LAB OBJECTIVES The objective of this lab is to confi gure and analyze the performance of the Routing Information Protocol (RIP) model. OVERVIEW A router in the network needs to be able to look at the destination address in the packet and then determine which one of the output ports is the best choice to get the packet to that address. The router makes this decision by consulting a forwarding table. The fundamental problem of routing is: How do routers acquire the information in their forwarding tables? Routing algorithms are required to build the routing tables and, hence, forwarding tables. The basic problem of routing is to fi nd the lowest-cost path between any two nodes, where the cost of a path equals the sum of the costs of all the edges that make up the path. Routing is achieved in most practical networks by running routing protocols among the nodes. The protocols provide a distributed, dynamic way to solve the problem of fi nding the lowest-cost path in the presence of link and node failures and changing edge costs. One of the main classes of routing algorithms is the distance-vector algorithm. Each node constructs a vector containing the distances (costs) to all other nodes and distributes that vector to its immediate neighbors. RIP is the canonical example of a routing protocol built on the distance-vector algorithm. Routers running RIP send their advertisements regularly (e.g., every 30 s). A router also sends an update message whenever a triggered update from another router causes it to change its routing table. The Internet Control Message Protocol (ICMP) can be utilized to analyze the performance of the created routes. It can be used to model traffi c between routers without the need for running applications in an end node. In this lab, you will set up a network that utilizes RIP as its routing protocol. You will analyze the routing tables generated in the routers, and you will observe how RIP is affected by link failures. You will also utilize the ICMP to create echo reply messages (i.e., ping) to analyze the created routes. RIP: Routing Information Protocol A Routing Protocol Based on the Distance-Vector Algorithm 654 Network Simulation Experiments Manual PRE-LAB ACTIVITIES & Read Section 3.3.2 from Computer Networks: A Systems Approach , 5th Edition. : Go to www.net-seal.net and play the following animations: ❍ The Address Resolution Protocol (ARP) ❍ ARP with Multiple Networks ❍ Dynamic Host Confi guration Protocol (DHCP) ❍ Routing PROCEDURE Create a New Project 1. Start OPNET IT Guru Academic Edition · Choose New from the File menu. 2. Select Project and click OK · Name the project <your initials>_RIP , and the scenario No_Failure · Click OK . 3. In the Startup Wizard: Initial Topology dialog box, make sure that Create Empty Scenario is selected · Click Next · Select Campus from the Network Scale list · Click Next three times · Click OK . Create and Confi gure the Network Initialize the network: 1. The Object Palette dialog box should now be on top of your project workspace. If it is not there, open it by clicking . Make sure that the internet_toolbox is selected from the pull-down menu on the object palette. 2. Add to the project workspace the following objects from the palette: one ethernet4_slip8_gtwy router and two 100BaseT_LAN objects. a. To add an object from a palette, click its icon in the object palette · Move your mouse to the workspace · Click to place the object · Right-click to stop creating objects of that type. 3. Use bidirectional 100BaseT links to connect the objects you just added as in the following fi gure. Also, rename the objects as shown (right-click on the node · Set Name ). 4. Close the Object Palette dialog box, and Save your project. Confi gure the Router 1. Right-click on router_1 · Edit Attributes · Expand the IP Routing Parameters hierarchy and set the following: a. Routing Table Export = Once at End of Simulation . This asks the router to export its routing table at the end of the simulation to the OPNET simulation log. 2. Click OK , and then Save your project. The ethernet4_slip8_gtwy node model represents an IP-based gateway supporting four Ethernet hub interfaces and eight serial line interfaces. IP packets arriving on any interface are routed to the appropriate output interface based on their destination IP address. The RIP or the OSPF protocols may be used to dynamically create the gateway's routing tables.55 Choose the Statistics To test the performance of the RIP, we will collect the following statistics: 1. Right-click anywhere in the project workspace and select Choose Individual Statistics from the pop-up menu. 2. In the Choose Results dialog box, check the following statistics: a. Global Statistics · RIP · Traffi c Sent (bits/sec). Add the Remaining LANs 1. Highlight or select simultaneously (using Ctrl + A ) all fi ve objects that you currently have in the project workspace (one router, two LANs, and two links). 2. Press Ctrl + C to copy the selected objects, and then press Ctrl + V three times to paste them to generate three new copies of the objects. 3. Arrange the objects in a way similar to the following fi gure and rename them as shown. 4. Connect routers as shown using PPP_DS3 links. The PPP_DS3 link has a data rate of 44.736 Mbps. RIP traffi c is the total amount of RIP update traffi c (in bits) sent/received per second by all the nodes using RIP as the routing protocol in the IP interfaces in the node. LAB 6 RIP: Routing Information Protocol56 Network Simulation Experiments Manual b. Global Statistics · RIP · Traffi c Received (bits/sec). c. Nodes Statistics · Route Table · Total Number of Updates. 3. Click OK, and then Save your project. Confi gure the Simulation Here we need to confi gure some of the simulation parameters: 1. Click on and the Confi gure Simulation window should appear. 2. Set the duration to be 10.0 minutes . 3. Click on the Global Attributes tab and change the following attributes: a. IP Dynamic Routing Protocol = RIP . This sets the RIP protocol to the routing