Marc Greis’ ns Tutorial Contents: I. Introduction II. Finding Documentation II For ns&nam II.2 For Tcl II.3 For C++ III. The Basics III.1 Downloading/ Installing. Only the first 94 pages are relevant for Tcl, the rest of the book is about Tk and more complicated aspects of Tcl. I also found a short OTcl Tutorial. Another good . Marc Greis’ Tutorial for the UCB/LBNL/VINT Network Simulator “ns”. I. Introduction [Next section] [Back to the index] Disclaimer: This tutorial was originally.

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The nodes start out initially at two opposite ends of the boundary. When you click on the ‘play’ button in the nam window, you will see that after 0.

And finally the command to start the simulation, puts “Starting Simulation In addition to node-movements, traffic flows that are setup between the tutorila, are also read from a traffic-pattern file called cbrtest. The array used to define these variables, val is not global as it used to be in the earlier wireless scripts. Download the daily snapshot version if the next release 2.

IV. The first Tcl script

Pkts start getting dropped as the nodes move away from one another. The packetSize is being set to bytes and a packet will be sent every 0. Next we create the 2 mobilenodes as follows: Next we create the object God, as follows: However note that only node movements can currently tutoriao seen in nam.

For a copy of wireless1.

Marc Greis’ Tutorial for the UCB/LBNL/VINT Network Simulator “ns”

If ad-hockey can read your input correctly, its output will be properly formatted hutorial calcdest. Dumping of traffic data and thus visualization of data pkt movements in nam for wireless scenarios is still not supported future work. First, we need to configure nodes before we can create them. Random node movement files like scentest can be generated using CMU’s node-movement generator “setdest”.

Other uses that CMU has found for ttorial information are: Initially both the nodes are far apart and thus TCP pkts are dropped by node0 as it cannot hear from node1.


Next after creation of mobilenodes source node-movement and connection pattern files that were defined earlier as val sc and val cp respectively. The configuration API for creating mobilenodes looks as follows: Also we are going to set up nam traces.

Or all of the above. If you have any suggestions, find any bugs or problems, have any comments and also if you have any new well-documented examples that could be added here, please send email to ns-users mailing list. Thus all pkts destined for nodes 0 and 2 are routed through node 1. See Chapter 15 of ns documentation for details on wireless trace.

The next step is to add a ‘finish’ procedure that closes the trace file and starts nam. The usage of movement pattern files and feeding of next hop info to God shall be shown in the example in the next sub-section. We are going to use the default value of flat addressing; Also lets turn on only AgentTrace and RouterTrace; You can experiment with the traces by turning all of them on.

The new APIs are not available with ns2. I will explain find a way to distinguish the data flows from the two nodes from each other, and I will show how a queue can be monitored to see how full it is, and how many packets are being discarded. The next line tells the simulator object to execute the ‘finish’ procedure after 5. The next lines create a Null agent which acts as traffic sink and attach it to node n1. As they move away, packets start getting dropped.

Just as with any other ns simulation, we begin by creating a tcl script for the wireless simulation. As an extension to the previous sub-sectionwe are going to simulate a simple multihop wireless scenario consisting of 3 mobilenodes here.

We see TCP flow starting at In the second line we tell the simulator object that we created above to write all simulation data that is going to be relevant for nam into this file.

And now we have to tell tutorual CBR agent when to send data and when to stop sending. Now the two agents have to be connected with each ggeis. Make sure the connection-pattern and node-movement files exist under the directories as declared above. See comments in the code below for a brief description of each variable defined. If not, I suggest you either go to the web page for the VINT project or the web page for ns version 2.


You can click on any packet in the nam window to monitor it, and you can also click directly on the link to get some graphs with statistics.

II. Finding Documentation

The above code creates two nodes and assigns them to the handles ‘n0’ and ‘n1’. From the CMUTrace output we find nodes 0 and 2 are out of range and so cannot hear one another.

Both setdest and calcdest calculate the shortest number of hops between nodes based on the nominal radio range, ignoring any effects that might be introduced by the propagation model in an actual simulation. Two nodes, one link In this section we are going to define a very simple topology with two nodes that are connected by a link.

The following two lines define the two nodes. Now you can save the file and start the simulation again. In the first subsection, we discuss how to create and run a simple 2-node wireless network simulation.

This API is used to change direction and speed of movement of the mobilenodes. This is done with the command set ns [new Simulator]. Identifying the frequency and size of partitions.

Then they move towards each other in the first half of the simulation and again move away for the second half. In order to download a copy of the file click here. Define node movement model puts “Loading connection pattern It means the shortest path between node 1 and 2 is 2 hops.