computer networks
Post on 31-Dec-2015
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Computer Networks
NS
Features
Event driven simulator– developed at UC Berkeley
Network Topologies– nodes (connectivity), links (bandwidth, delay)
Transport Protocols– UDP, TCP (flavors)
Applications– Web, FTP, CBR ...
Router Queue Management– Drop-Tail, RED, CBQ ...
Overview
Write TCL scripts Run, get NS tracefile and NAM tracefile Visualize NAM tracefile Analyze NS tracefile
Running
On shiraz.wpi.edu (Linux box)– need passwords
In: /usr/local/ns-allinone-2.1b5/bin– add to path
Running:– ns dooda.tcl
Output:– dooda.nam and dooda.tr
Visualization
nam dooda.nam Right-click to get
loss and utilization
Analysis
Scripts/Programs in Perl, C, Shell– see stats.pl
Experiments
Fairness and congestion TCP vs. TCP Robust TCP vs. Fragile
TCP TCP vs. UDP Drop-Tail vs. RED (FRED vs. RED)
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