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i am sharing my wireless router with my roommates. through the router statistic view, i see a guy, whose UDP packages send in 5 sec. is only half as much as i did, but the total bytes he send in 5 sec. is twice as much as i did. the TCP package statistic value is almost the same. i think, his network speed is twice as faster as my network speed.

how he did this? i guess he changed his MTU value, is it correct?

i am using win7, i guess so he does.

i am not using any special network driver.

i am not network expert, so no special settings. i guess all protocols are active.

i do not have antivirus, i am using win7 default firewall. not sure about him.

also, i noticed a very interesting pattern. his UDP packages will boost for a while, and then drop to about 10, but the bytes he send/receive keeps a very high value. may be he is using some tool to hide his UDP packages?

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up vote 2 down vote accepted

There are many more variables than just the MTU. You should gather following information on both sides to compare:

  • Which OS is used (protocol stack performance)
  • Which Network card + driver version used (lower ISO OSI layers performance)
  • Which settings were made for networking (which protocols are active and with which settings)
  • Is there an Antivirus/Firewall/other Network analysis tool active?
  • Depending on what is done by the test software: check the if the Hard Disk throughput is a bottleneck, CPU might also be an issue if you have a very slow one.

Generally speaking sending bigger packets - if you can - is always more efficient (less protocol overhead). If for exactly the same task you get only half of the throughput there must be a botlleneck somewhere. The MTU will not change too much to the situation (A x2 factor seems much to me). But it is easy to check if that matters, tweak it to other values to see the impact. Here is a nice explanation on how to find the optimal MTU.

There is no way to hide network packets to the router. The router will see them all, he must be able to redirect them to the right network adapter! Otherwise the packets will end into nirvana. You are doing it right by monitoring the traffic on the central place, the router. The figures you see there can be trusted.

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i guess limiting the number of packets send per sec. is not a good way to limit the bandwidth usage of each host. i have noticed that there are time my machine send only a little packet, but use a lot of bandwidth :) – davidshen84 Jul 11 '10 at 4:09

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