Re: Anomalous TCP behaviour?

From: Chris Knipe (
Date: Tue Jan 25 2000 - 02:41:10 EST

On Mon, 24 Jan 2000, Anupama Sundaresan wrote:

> Is it normal for TCP to skip a ceratin number of bytes and send
>them later when it receives dup acks?
>The following tcpdump o/p illustrates that TCP sends packets in sequence
>upto a certain point but suddenly skips a certain number of bytes and
>after receiving 5 duplicate acks transmits not 'retransmits' the missing

I Would belive so yes. The IP protocol (I belive), sends all the segments
off to the cable in sequence, but does not gaurantee the correctiveness, or
delivery of the data (thats why we have TCP). I think what wa happening in
your scenario, is that all the packets got sent successfully, but some
segments failed to arrive correct at the remote end, which then
re-requested the data, causing them to look as if it was sent out of
seguence ??

Chris Knipe
Cel: (083) 430 8151
Freelance Internet Developer, Consultant, Administrator & Speaker

To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to

This archive was generated by hypermail 2b29 : Mon Jan 31 2000 - 21:00:32 EST