TCP bug?

Wolters, Oliver (
Fri, 5 Jun 1998 12:55:31 +0200

hello all,

I'm new to this list so please don't flame me, if I'm asking an old
question (yes, I searched the archiv but didn't found the answer).

When using TCP sockets on Linux, the following problem occurs:
If I try to send a packet of Data that's a little bit larger than the
MTU of the ethernet-card, the connection slows down rapidly. This
problem does not occur, if I try to send more than 2xMTU Bytes of Data.

For example: The MTU is 1500 Byte => 1460 Byte user-data can be carried.
If I try to send in a loop 100x1461 Byte it needs up to 100 seconds!
If I try to send 100x2921 Bytes (2x1460 + 1) it needs 1 second!
This numbers are related to the MTU.

tcpdump showed, that the ack packets in the first case need 0.5 seconds!

I tried this with kernel 2.0.30 and 2.0.32.

Please could you tell me, if it's a known bug and if a patch is

thanks in advance

Oliver Wolters

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