How to DIAGNOSE slow network speed.

[Ian Boyd]

i'm getting about 6Mbps on a 100Mbps LAN. Windows XP Professional talking to
Windows 2000 Server, through a 10/100 switching hub. Both machines have
100Mb cards.

i've used performance monitor, and see no abnormal errors in IP, TCP, NBT,
or Network Interface.

i sit in CommView (packet sniffer) and i see my data moving. It's just
moving slow.

Why is it so slow? How can it be slow? The network card accesses the
ethernet wire, it dumps some data on the wire.
Electricity doesn't take time to get from here to there, electrical signals
move essentially at the speed of light.

What is so hard about it not running full speed? Why would it not be
working? What can i see to see that it isn't working? Are there errors when
the network card tried to access the wire? Can i see that anywhere? Are
there collissions? No, it's a switching hub, but can i can see them
anywhere? Are the packets fragmenting on the way to the server? i doubt it,
but can i see that anywhere? Are my responses not coming fast enough? Can i
see the time it takes?


Why is my network slow? And if you say change my cables, NICs, or NIC
drivers, i will choke your tongue out.

 

[David Robbins]

i'm getting about 6Mbps on a 100Mbps LAN. Windows XP Professional talking to
Windows 2000 Server, through a 10/100 switching hub. Both machines have
100Mb cards.

they may have 100mb cards, but are they really running at 100mb? 'switching
hub' doesn't make much sense. hubs are usually dumb, they can only run one
speed, can't do any buffering or speed conversion. a switch is smart, it
can buffer data and may be able to run different speeds on different ports.
so which is it a 'switch' or a 'hub' or could it be a 'router'?

i've used performance monitor, and see no abnormal errors in IP, TCP, NBT,
or Network Interface.

i sit in CommView (packet sniffer) and i see my data moving. It's just
moving slow.

Why is it so slow? How can it be slow? The network card accesses the
ethernet wire, it dumps some data on the wire.
Electricity doesn't take time to get from here to there, electrical signals
move essentially at the speed of light.

What is so hard about it not running full speed? Why would it not be
working? What can i see to see that it isn't working? Are there errors when
the network card tried to access the wire? Can i see that anywhere? Are
there collissions? No, it's a switching hub, but can i can see them
anywhere? Are the packets fragmenting on the way to the server? i doubt it,
but can i see that anywhere? Are my responses not coming fast enough? Can i
see the time it takes?

you will never get 'full speed'. forget about sending 100mb/sec to the
server, there will always be some overhead in the transmission,
acknowledgement, file access, etc that keeps it well below that max speed.
and then if you add in sharing the network with other computers, printers,
routers, etc it will be even slower.

the easiest way to see this is to have a separate piece of hardware
analyzing the stream. unfortunately most of them are expensive and take som
e operator skill to know what you are seeing. some of the network analyzers
you run on your pc are decent, but they are of course limited in that they
are monitoring through the same interface that you are trying to
send/receive data over.

 

[Ian Boyd]

Is it a 'switch' or a 'hub'?

It's a switch.

 

[Mark Mancini]

first verify dns!!! read my dns primer in the new download section of
mcse2000.com

 

[Ian Boyd]

My dns is verified.

first verify dns!!! read my dns primer in the new download section of
mcse2000.com

--
Sincerely,
Mark Mancini, CCA, CCNA, Master CIW&CI, CNE 4&5, MCSE+I 4&2000
www.MCSE2000.com
www.AppLauncher.com



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