Changes between Version 4 and Version 5 of GENIEducation/SampleAssignments/TcpAssignment/onepage


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Timestamp:
08/09/13 13:03:46 (6 years ago)
Author:
epittore@bbn.com
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  • GENIEducation/SampleAssignments/TcpAssignment/onepage

    v4 v5  
    123123}}}
    124124 Specific network setup commands will be provided as needed. [[BR]]
    125  Run an Iperf server on the Left node.
     125 Run an Iperf server on the Left node. On InstaGENI this will be
    126126{{{
    127127/usr/local/etc/emulab/emulab-iperf -s
    128128}}}
    129  The Iperf client will be run on the Right node.
     129 On ExoGENI the command is
     130{{{
     131 iperf -s
     132}}}
     133 The Iperf client will be run on the Right node. On InstaGENI:
    130134{{{
    131135/usr/local/etc/emulab/emulab-iperf -c 10.10.1.1 -t 60
    132136}}}
    133 
    134  Note that the IP address should be the IP of the left node and may be different from this example. The duration for an Iperf session (''-t'' option) is 60 seconds unless otherwise mentioned. Note carefully that some exercises require a much longer duration. Ensure that your sliver lifetimes are long enough to capture the duration of your experiment. All of the experiments should be repeated at least a 5 times (especially when the interfaces include random delays or losses) to ensure confidence in the results, as transient conditions can cause significant variations in any individual run.
     137or ExoGENI:
     138{{{
     139iperf -c 10.10.1.1 -t 60
     140}}}
     141
     142 Note that the IP address specified in the command on the Right node should be the IP of the Left node and may be different from this example. The duration for an Iperf session (''-t'' option) is 60 seconds unless otherwise mentioned. Note carefully that some exercises require a much longer duration. Ensure that your sliver lifetimes are long enough to capture the duration of your experiment. All of the experiments should be repeated at least a 5 times (especially when the interfaces include random delays or losses) to ensure confidence in the results, as transient conditions can cause significant variations in any individual run.
    135143 
    136   1. Question: What are the throughputs as seen in iperf when the Reno and CUBIC algorithms are used on the network with no emulated delay or loss? Which is better?
     144  1. Question: What are the goodputs (throughputs as seen in iperf) when the Reno and CUBIC algorithms are used on the network with no emulated delay or loss? Which is better?
    137145  2. Question: Qualitatively, under what conditions does BIC/CUBIC perform better than Reno’s AIMD?
    138146  3. Question: Change the delay to of interface L to 300 ms using the following command, and run an Iperf session for 1800 seconds.
     
    140148   sudo /sbin/tc qdisc add dev L root handle 1:0 netem limit 1000000000 delay 300ms
    141149   }}}
     150    where the interface L is the interface on the traffic controller connected to the Left node.
    142151    What are the goodputs of Reno and CUBIC? Which performed better? What do you conclude?
    143   4. Question: Repeat the above experiment with 30 parallel connections and 1800 seconds for each algorithm by using the ''-P 30'' option on Iperf. How do CUBIC and Reno differ? What do you conclude?
     152  4. Question: Repeat the above experiment with 30 parallel connections and 1800 seconds for each algorithm by using the ''-P 30'' option on iperf. How do CUBIC and Reno differ? What do you conclude?
    144153  5. Question: Remove the netem queueing discipline which causes delay and add a loss of 5% by using the following commands on the center node. Replace L with the appropriate physical interface. Alternatively, one can change a queueing discipline instead of deleting and adding a new one.
    145154   {{{
     
    148157   }}}
    149158   How do the goodputs of Reno and CUBIC differ under loss for 60 s Iperf sessions? [[BR]][[BR]]
    150  - '''Some Hint/Guidance on how to run the experiments: '''
    151  [[BR]]Use default TCP congestion control (cubic) on left and right, run iperf between them (TCP flow comes from right to left): [[BR]]
    152  On left, run:
    153 {{{
    154 /usr/local/etc/emulab/emulab-iperf -s
    155 }}}
    156  On right, run (10.10.1.1 is the ip address for left in our case, you need to find the actual IP address that is used by left in your own experiment):
    157 {{{
    158 /usr/local/etc/emulab/emulab-iperf -c 10.10.1.1 -t 60
    159 }}}
    160  Let both left and right use reno as the TCP congestion control mechanism, repeat the experiments:
    161 {{{
    162 echo reno | sudo tee /proc/sys/net/ipv4/tcp_congestion_control
    163 }}}
    164159
    165160'''3.2 Ensuring Fairness Among Flows [[BR]]'''