DMN2 : ROUTING AND LAN EXPERIMENT. Faculty of Engineering Multimedia University

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1 DMN2 : ROUTING AND LAN EXPERIMENT Faculty of Engineering Multimedia University DMN2 Marking Scheme No Component Criteria Not answered 0 marks Poor 2 marks Acceptable 4 (max) marks 1 Viva Students able to understand some questions related to the experiments 2 Report Report follow scientific format 3 Report The experiment is conducted thoroughly and result is well analyzed 4 Report The report provide good reasons and justifications to support the conclusion Total marks = 16 Lab 1 contributes 5% to the course work mark. 1.0 OBJECTIVES To understand and simulate unicast and multicast protocol. To investigate and observe unicast and multicast protocols implemented in the network layer. To study and analyse the different between IEEE802.3 and CSMA/CD. 2.0 LIST OF EQUIPMENT AND SOFTWARE Computer running ns-allinone (latest release is 2.31) is a package which contains required components and some optional components used in running NS-2. The package contains an "install" script to automatically configure, compile and install these components. Currently the package contains: Tcl release (Main component) Tk release ( Main component) Otcl release 1.13 ( Main component) TclCL release 1.19 ( Main component) Ns release 2.31 (Main component) Nam (Animation purpose) Gnuplot (Plotting purpose) External storage to save the simulation output. 3.0 LAB EXPECTATIONS Review the lecture notes on routing and MAC protocols. Work on the lab experiments. Record results and make analysis from the results experiment. Send lab report two weeks after date of experiment.

2 4.0 INTRODUCTION 4.1 Unicast and Multicast Routing The transport and network layer protocols we have studied so far provide for the delivery of packets from a single source to a single destination. Protocols involving just one sender and one receiver are often referred to as unicast protocols. A number of emerging network applications require the delivery of packets from one or more senders to a group of receivers. These applications include bulk data transfer (e.g., the transfer of a software upgrade from the software developer to users needing the upgrade), streaming continuous media (e.g., the transfer of the audio, video and text of a live lecture to a set of distributed lecture participants), shared data applications (e.g., a whiteboard or teleconferencing application that is shared among many distributed participants), data feeds (e.g., stock quotes), and interactive gaming (e.g., distributed interactive virtual environments or multiplayer games such as Quake). For each of these applications, an extremely useful abstraction is the notion of a multicast: the sending of a packet from one sender to multiple receivers with a single "transmit" operation. In this section we consider the network layer aspects of multicast. We will see that as in the unicast case, routing algorithms play a central role in the network layer. We will also see, however, that unlike the unicast case, Internet multicast is not a connectionless service --state information for a multicast connection must be established and maintained in routers that handle multicast packets sent among hosts in a so-called multicast group. This, in turn, will require a combination of signaling and routing protocols in order to set up, maintain, and tear down connection state in the routers. A node is a compound object composed of a node entry object and classifiers as shown in Figure 1. There are two types of nodes in NS2. A unicast node has an address classifier that does unicast routing and a port classifier. A multicast node, in addition, has a classifier that classify multicast packets from unicast packets and a multicast classifier that performs multicast routing. Figure 1. Node (Unicast and Multicast) In NS, Unicast nodes are the default nodes. To create Multicast nodes the user must explicitly notify in the input OTcl script, right after creating a scheduler object, that all the nodes that will be created are multicast nodes. After specifying the node type, the user can also select a specific routing protocol other than using a default one. Unicast - $ns rtproto type - type: Static, Session, DV, cost, multi-path

3 Multicast - $ns multicast (right after set $ns [new Scheduler]) - $ns mrtproto type - type: CtrMcast, DM, ST, BST For more information about routing, refer to the NS Manual located at The documentation has chapters talk about unicast and multicast routing. 4.2 Local Area Network The Local Area Network (LAN) is by far the most common type of data network. As the name suggests, a LAN serves a local area (typically the area of a floor of a building, but in some cases spanning a distance of several kilometers). Typical installations are in industrial plants, office buildings, college or university campuses, or similar locations. In these locations, it is feasible for the owning organisation to install high quality, high-speed communication links interconnecting nodes. Typical data transmission speeds are one to 100 megabits per second. A wide variety of LANs have been built and installed, but a few types have more recently become dominant. The most widely used LAN system is the Ethernet system developed by the Xerox Corporation. Intermediate nodes (i.e. repeaters, bridges and switches) allow LANs to be connected together to form larger LANs. A LAN may also be connected to another LAN or to WANs and MANs using a "router". IEEE802.3 This type of network was developed by Xerox. It was eventually standardized as the IEEE802.3 based on the Ethernet DIX standard (DIX= Digital, Intel, Xerox). The IEEE802.3 describes all Ethernet based networks; both 10, 100 and 1000 Mbps networks. This means they have a lot in common and are easily connectable to each other. Between two different 10 Mbps standards a repeater with two different interfaces is enough and the same goes for two different 100 Mbps standards. However to connect a 100 Mbps network to a 10 Mbps you need a bridge. This discribes the difference. The difference between the different 10 Mbps standards is situated on Layer 1 of the OSI reference model, where the difference between 10 and 100 Mbps is situated on the MAC-layer which is part of Layer 2 of the OSI reference model. Detailed description According to the OSI layers an Ethernet network looks like this: LLC or LLC + SNAP 2 Data Link MAC 1 Physical Interface + PHY

4 MAC: IEEE802.3 CSMA/CD The complete ethernet networking family is based on the CSMA/CD protocol. CSMA/CD stands for Carrier Sense Multiple Access with Collision Detetection, which means that a station that has something to send listens for a carrier (if someone is already sending something) if not it sends its data. At the moment multiple stations can decide to send their data, since they all heard no carrier, this is the multiple access. After sending the station keeps on listening to the carrier and when they detect that another station started sending too, collision detection, it backs off, waits a random time and starts the whole procedure from scratch. The timing involved for sending and receiving is different for 10 and 100 Mbps ethernet: 10 Mbps 100 Mbps 1000 Mbps Bit Time 100 ns 10 ns 1 ns Interpacket gap 96 bit times or 9.6 µs 96 bit times or 0.96µs 96 bit times or 0.096µs 5.0 EXPERIMENTS START RUNNING KNOPPIX For these experiments, we will be using Knoppix with embedded NS-2. Knoppix is complete Linux distribution that can run for a single CD. Usually this kind of distribution is called a live CD where it can load Linux system without installing it on a hard drive. The distribution used for this experiment come with NS-2 embedded in it. Hence, student can run the NS-2 without having to install it on the hard drive. Please get a Knoppix CD from the lab technician. Note: please insert your thumb drive onto the USB slots before running the Knoppix. Start using Knoppix After Knoppix uploaded, type the command below to run the KDE environment: startx Bring up the Console (Terminal), and setup path for nam and xgraph line by line (press Enter after each line): sh-3.00# PATH= $PATH:/usr/local/ns-allinone-2.29/nam-1.11 sh-3.00# export PATH sh-3.00# PATH= $PATH:/usr/local/ns-allinone-2.29/xgraph-12.1 sh-3.00# export PATH To check either the paths are already set, type the commands below one by one. It should return the path to the required applications: sh-3.00# which ns sh-3.00# which nam sh-3.00# which xgraph

5 To set your working path, type sh-3.00# cd Desktop From now on, save all the documents and files on your desktop. Eject and shutdown Knoppix At the end of session, after logout from the KDE environment, press the below keys simultaneously to eject the CD: Ctrl+Alt+Del 5.1 EXPERIMENT Experiment1: Unicast Routing Run the file name dmn1.tcl ns dmn1.tcl Change the code in line 26 from using DV to LS $ns rtproto DV Change to $ns rtproto LS Make comparison between the two experiments. Now comment out line 26. What can you observed? Discussion: What is the purpose having rtproto in the experiment? Discussion: Discuss what does line 67 and 68 represent? Experiment2: Muticast Routing Run the file name dmn2-1.tcl, dmn2-2.tcl, dmn2-3.tcl, and dmn2-4.tcl. Note: Whenever a clearer animation needed, use the button EDIT on the left hand side of nam window to re-arrange the nodes. Make your observation and record your results. For dmn2-1.tcl, CTR (Centralized Multicast) was performed. Discussion: Why node 4 sending packets from itself? Discussion: Why packet drops in node 0 and node 1? For dmn2-2.tcl, DVMRP (Distance Vector Multicast Routing Protocol) was performed. Discussion: Explain what are represented by purple and green colours, repectively. For dmn2-3.tcl, PIMDM (Protocol Independent Muticast Dense Mode) was performed. Discussion: What difference(s) can you see between dmn2-2.tcl and dmn2-3.tcl? Discussion: What differ dense mode compare to sparse mode. For dmn2-4.tcl, Bi-directional shared tree (Core-Based Trees) was performed. Discussion: What are the red and blue circles outside the nodes represented?

6 5.1.3 Experiment2: Local Area Networks Run the file name dmn3-1.tcl (using IEEE802.3) and dmn3-2.tcl (using CSMA/CD). Discussion: What does the horizontal line represent? Discuss what actually happen at the horizontal line? Discussion: Why are the packets being drop at the end nodes? Discussion: Is there any difference between experiment dmn3-1 and dmn3-2? 6.0 POST-EXPERIMENTAL ANALYSIS AND DISCUSSIONS Explain how CSMA/CD executed. With the help of suitable diagrams, discuss the working of CTR, DVMRP, PIMDM and Core-based tree, respectively. Other than unicast and multicast, two name other distribution manner in a computer network. With the help of suitable diagrams, discuss their operations. Explain how multicast is better than broadcast in a shared medium. 7.0 REFERENCES [1] The Network Simulator - NS-2 (no date). Home page. [Online]. University of Michigan. [2007, June 11]. [2] NS Manual (no date). Home page. [Online]. University of Michigan. [2007, June 11]. [3] NS by Example (no date). Home page. [Online]. University of Michigan. [2007, June 11]. [4] Fred Halsall, Computer Networking and the Internet, 5th Edition, Addison Wesley; 2005