Lousy Network Performance

[Vu Pham]

> -----Original Message-----
> From: linux-users-bounces at linux-sxs.org 
> [mailto:linux-users-bounces at linux-sxs.org] On Behalf Of Kurt Wall
> Sent: Monday, June 27, 2005 9:57 PM
> To: linux-users at linux-sxs.org
> Subject: Lousy Network Performance
> 
> Hi, list,
> 
> How do I go about solving a significant latency problem on my 
> internal network. I have two computers connected via a 
> crossover cable, eth1 on the "server" (luther) to eth0 on the 
> "desktop"
> (easter). Both cards are 10/100. Ping time is atrocious:
> 
> >From luther to easter:
> $ ping -c 10 easter
> 64 bytes from easter (192.168.0.2): icmp_seq=1 ttl=64 time=893 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=2 ttl=64 time=53.6 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=3 ttl=64 time=910 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=4 ttl=64 time=72.6 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=5 ttl=64 time=930 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=6 ttl=64 time=0.699 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=7 ttl=64 time=960 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=8 ttl=64 time=3.69 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=9 ttl=64 time=979 ms
> 64 bytes from easter (192.168.0.2): icmp_seq=10 ttl=64 time=0.694 ms
> 
> --- easter ping statistics ---
> 10 packets transmitted, 10 received, 0% packet loss, time 
> 9071ms rtt min/avg/max/mdev = 0.694/480.691/979.699/455.463 ms
> 
> >From easter to luther:
> $ ping -c 10 luther
> PING luther (192.168.0.1) 56(84) bytes of data.
> 64 bytes from luther (192.168.0.1): icmp_seq=0 ttl=64 time=0.418 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=1 ttl=64 time=1038 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=2 ttl=64 time=38.9 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=3 ttl=64 time=1077 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=4 ttl=64 time=77.2 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=5 ttl=64 time=1116 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=6 ttl=64 time=116 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=7 ttl=64 time=1155 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=8 ttl=64 time=155 ms
> 64 bytes from luther (192.168.0.1): icmp_seq=9 ttl=64 time=1194 ms
> 
> --- luther ping statistics ---
> 10 packets transmitted, 10 received, 0% packet loss, time 
> 9002ms rtt min/avg/max/mdev = 0.418/597.109/1194.010/522.194 
> ms, pipe 3
> 
> I can't see any reason why the latency should be so extreme.
> 

The first thing I would try is to replace  the cross-over cable. One time I
made a cross-over cable by myself and missed one inside string and got
similar problem.

I also would think of having a third box that you can connect each PC to to
check if the problem on which one. 

Vu