Hi, first time on the list and not exactly a network
specialist, so bear with me!
I’ve been struggling with a performance problem
where Internet downloads from one machine tend to be about 20% slower than
those from other machines on the network (all Win XP Pro). All settings I can
think of are identical, and the “slow” machine is about the fastest
on the network in all other respects. Ethereal captures do show up some
interesting differences. Traffic from a “slow” machine looks like
this (hope it formats OK):
15818 23.220614
144.135.23.54
192.168.0.5
TCP 4000 > 3091 [ACK] Seq=11378574 Ack=0
Win=7086 Len=1446
15819 23.220806
192.168.0.5
144.135.23.54
TCP 3091 > 4000 [ACK] Seq=0 Ack=11380020
Win=64000 Len=0
15820 23.229900
144.135.23.54
192.168.0.5
TCP 4000 > 3091 [ACK] Seq=11380020 Ack=0
Win=7086 Len=1446
15821 23.230082
192.168.0.5
144.135.23.54
TCP 3091 > 4000 [ACK] Seq=0 Ack=11381466
Win=64000 Len=0
Each ACK acknowledges the segment before it, and has a time to ACK the segment
of around .00018 seconds.
Traffic from a "fast" machine looks like this:
4095 5.885410
144.135.23.54
192.168.0.4
TCP 4000 > 1101 [ACK] Seq=3865158 Ack=0
Win=6810 Len=1446
4096 5.886590
144.135.23.54 192.168.0.4
TCP 4000 > 1101 [ACK] Seq=3866604 Ack=0
Win=6810 Len=1446
4097 5.886617
192.168.0.4
144.135.23.54
TCP 1101 > 4000 [ACK] Seq=0 Ack=3868050
Win=64000 Len=0
4098 5.887665
144.135.23.54 192.168.0.4
TCP
4000 > 1101 [ACK] Seq=3868050 Ack=0 Win=6810 Len=1446
4099 5.889292
144.135.23.54
192.168.0.4
TCP 4000 > 1101 [ACK] Seq=3869496 Ack=0
Win=6810 Len=1446
4100 5.889346
192.168.0.4
144.135.23.54 TCP
1101 > 4000 [ACK] Seq=0 Ack=3870942 Win=64000 Len=0
Each ACK again acknowledges the segment before it, but only every second segment
gets ACK'd. Also the time to send the ACK is now .00003 (much
quicker). I also don't know why the sender's Win size is different in the 2 cases.
Can anyone point me in the right direction here?
Thanks.
Steve