Changes between Version 8 and Version 9 of GENIEducation/SampleAssignments/TcpAssignment/onepage
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- 08/09/13 14:05:26 (11 years ago)
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GENIEducation/SampleAssignments/TcpAssignment/onepage
v8 v9 166 166 }}} 167 167 Run an Iperf client on the Right node with 10 parallel TCP connections (use the -P option), connecting to an Iperf server on the Left node for 60 seconds. Simultaneously, run a 20 Mbps UDP Iperf client on the Top node connecting to an UDP Iperf server session running on the Left node for 60 seconds. 168 '''1.Question:''' What are the throughput shown by the UDP and TCP Iperf server sessions? Why are they what they are?169 '''2.Question:''' Provide the necessary steps and commands to enable queueing disciplines that enforce fairness among all the 11 flows in the network, and demonstrate that your solution is effective.168 1. '''Question:''' What are the throughput shown by the UDP and TCP Iperf server sessions? Why are they what they are? 169 2. '''Question:''' Provide the necessary steps and commands to enable queueing disciplines that enforce fairness among all the 11 flows in the network, and demonstrate that your solution is effective. 170 170 171 171 '''3.3 Reordering [[BR]]''' … … 176 176 }}} 177 177 As before, run a TCP Iperf client on the Right node connecting an Iperf server on the Left for 60 seconds. 178 - 1. Question:What is the TCP goodput?179 - 2. Question:Introduce packet reordering, adding a 75 ms delay variance to the interface L with the following command:178 1. '''Question:''' What is the TCP goodput? 179 2. '''Question:''' Introduce packet reordering, adding a 75 ms delay variance to the interface L with the following command: 180 180 {{{ 181 sudo /sbin/tc qdisc change dev L root handle 1:0 netem delay 100ms 75ms181 sudo /sbin/tc qdisc change dev L root handle 1:0 netem delay 100ms 75ms 182 182 }}} 183 What is the TCP goodput now?184 - 3. Question:By tweaking the parameters in the file ''/proc/sys/net/ipv4/tcp_reordering'', how much can the TCP goodput be improved? What is the best goodput you can show? Why is too high or two low value bad for TCP?183 What is the TCP goodput now? 184 3. '''Question:''' By tweaking the parameters in the file ''/proc/sys/net/ipv4/tcp_reordering'', how much can the TCP goodput be improved? What is the best goodput you can show? Why is too high or two low value bad for TCP? 185 185 186 186 '''3.4 Performance of SACK under Lossy Conditions''' … … 190 190 sudo /sbin/tc qdisc add dev L root handle 1:0 netem loss 10% 191 191 }}} 192 - 1. Question:What kind of goodput do you get using CUBIC with SACK (the default configuration)? Why do you see this performance?193 - 2. Question:Disable SACK at the sender using this command:194 {{{ 195 echo 0 | sudo tee /proc/sys/net/ipv4/tcp sack196 }}} 197 What is the goodput without SACK? In what circumstances is SACK most beneficial? Remember that, due to the random nature of loss events, these experiments must be repeated at least five times to draw any conclusions.192 1. '''Question:''' What kind of goodput do you get using CUBIC with SACK (the default configuration)? Why do you see this performance? 193 2. '''Question:''' Disable SACK at the sender using this command: 194 {{{ 195 echo 0 | sudo tee /proc/sys/net/ipv4/tcp sack 196 }}} 197 What is the goodput without SACK? In what circumstances is SACK most beneficial? Remember that, due to the random nature of loss events, these experiments must be repeated at least five times to draw any conclusions. 198 198 199 199 '''3.5 An Experimental Congestion Avoidance module for Linux'''[[BR]]