Wireless Networking and Systems CSE 590 ns2 tutorial ns2 Network Simulator One of the most popular simulator among networking researchers Discrete event Packet level simulator Events packet like received an ack packet enqueued a data Network protocol stack written in C Tcl Tool Command Language used for specifying scenarios and events Unix Based Runs also in windows using cygwin Simulates both wired and wireless networks Goal of this tutorial Understand how to write Tcl scripts to simulate simple network topologies and traffic patterns Analyze the trace files and understand the performance of the protocols Overview Wired Creating a simple two node network topology Adding traffic to the link UDP traffic TCP traffic Fault injection Wireless TCP performance on a linear chain of n nodes Simple two node wired network n0 Step 1 Step 2 n1 Create a simulator object set ns new Simulator Open trace files set f open out tr w ns trace all f Simple two node wired network n0 Step 3 Step 4 n1 Create two nodes set n0 ns node set n1 ns node Create a duplex link between the nodes ns duplex link n0 n1 1Mb 10ms DropTail Simple two node wired network Create a simulator object set ns new Simulator Open trace files set f open out tr w ns trace all f Define a finish procedure proc finish global ns ns flush trace exit 0 Create two nodes set n0 ns node set n1 ns node Create a duplex link between the nodes ns duplex link n0 n1 1Mb 10ms DropTail Call the finish procedure after 5 seconds of simulation time ns at 5 0 finish Run the simulation ns run Adding traffic to the link n0 n1 udp udp Create a UDP agent and attach it to node n0 set udp0 new Agent UDP ns attach agent n0 udp0 Adding traffic to the link n0 n1 udp udp cbr cbr Create a CBR traffic source and attach it to udp0 set cbr0 new Application Traffic CBR cbr0 set packetSize 500 cbr0 set interval 0 005 cbr0 attach agent udp0 Adding traffic to the link n0 udp udp n1 null null cbr cbr Create a Null agent a traffic sink and attach it to node n1 set null0 new Agent Null ns attach agent n1 null0 Adding traffic to the link n0 udp udp n1 null null cbr cbr Connect the traffic source with the traffic sink ns connect udp0 null0 Schedule events for the CBR agent ns at 0 5 cbr0 start ns at 4 5 cbr0 stop Simulate a simple topology UDP Traffic Create a simulator object sender n0 n1 sender n2 n3 router receiver set ns new Simulator Open trace files set f open out tr w ns trace all f Define a finish procedure proc finish global ns ns flush trace exit 0 Create four nodes set n0 ns node set n1 ns node set n2 ns node set n3 ns node Simulate a simple topology UDP Traffic sender n0 n2 router n3 receiver n1 sender Create links between the nodes ns duplex link n0 n2 1Mb 10ms DropTail ns duplex link n1 n2 1Mb 10ms DropTail ns duplex link n3 n2 1Mb 10ms SFQ Simulate a simple topology UDP Traffic sender n0 n2 router n3 receiver n1 sender Create a UDP agent and attach it to node n0 set udp0 new Agent UDP udp0 set class 1 ns attach agent n0 udp0 Simulate a simple topology UDP Traffic sender n0 n2 router n3 receiver n1 sender Create a CBR traffic source and attach it to udp0 set cbr0 new Application Traffic CBR cbr0 set packetSize 500 cbr0 set interval 0 005 cbr0 attach agent udp0 Simulate a simple topology UDP Traffic sender n0 n2 router n3 receiver n1 sender Create a UDP agent and attach it to node n1 set udp1 new Agent UDP udp1 set class 2 ns attach agent n1 udp1 Simulate a simple topology UDP Traffic sender n0 n2 router n3 receiver n1 sender Create a CBR traffic source and attach it to udp1 set cbr1 new Application Traffic CBR cbr1 set packetSize 500 cbr1 set interval 0 005 cbr1 attach agent udp1 Simulate a simple topology UDP Traffic sender n0 n2 router n3 receiver n1 sender Create a Null agent a traffic sink and attach it to node n3 set null0 new Agent Null ns attach agent n3 null0 Simulate a simple topology UDP Traffic sender n0 n2 router n3 receiver n1 sender Connect the traffic sources with the traffic sink ns connect udp0 null0 ns connect udp1 null0 Simulate a simple topology UDP Traffic Schedule events for the CBR agents ns at 0 5 cbr0 start ns at 1 0 cbr1 start ns at 4 0 cbr1 stop ns at 4 5 cbr0 stop Call the finish procedure after 5 seconds of simulation time ns at 5 0 finish Run the simulation ns run Trace Analysis http nsnam isi edu nsnam index php NS 2 Trace Formats TCP Traffic sender s1 s2 sender s3 sender 0 1 2 are senders 3 is a Gateway 4 receiver G gateway r receiver TCP Traffic Create a TCP agent and attach it to node s1 set tcp1 new Agent TCP Reno ns attach agent s1 tcp1 tcp1 set window 8 tcp1 set fid 1 TCP Traffic Create a TCP agent and attach it to node s2 set tcp2 new Agent TCP Reno ns attach agent s2 tcp2 tcp2 set window 8 tcp2 set fid 2 Create a TCP agent and attach it to node s3 set tcp3 new Agent TCP Reno ns attach agent s3 tcp3 tcp3 set window 4 tcp3 set fid 3 TCP Traffic Create TCP sink agents and attach them to node r set sink1 new Agent TCPSink set sink2 new Agent TCPSink set sink3 new Agent TCPSink ns attach agent r sink1 ns attach agent r sink2 ns attach agent r sink3 TCP Traffic Connect the traffic sources with the traffic sinks ns connect tcp1 sink1 ns connect tcp2 sink2 ns connect tcp3 sink3 TCP Traffic Create FTP applications and attach them to agents set ftp1 new Application FTP ftp1 attach agent tcp1 set ftp2 new Application FTP ftp2 attach agent tcp2 set ftp3 new Application FTP ftp3 attach agent tcp3 TCP Traffic Define a finish procedure proc finish global ns ns flush trace exit 0 ns at 0 1 ftp1 start ns at 0 1 ftp2 start ns at 0 1 ftp3 start ns at 5 0 ftp1 stop ns at 5 0 ftp2 stop ns at 5 0 ftp3 stop ns at 5 25 finish ns run Complex topology and link failure sender 0 6 1 5 2 4 3 receiver Complex topology and link failure Create a simulator object set ns new Simulator Tell the simulator to use dynamic routing ns rtproto DV Define a finish procedure proc finish global ns ns flush trace exit 0 Complex topology and link failure Create seven nodes for set i 0 i 7 incr i set n i ns node Create links between the nodes for set i 0 i 7 incr i ns duplex link n i n expr i 1 …