how to tell where a network problem is?

  • Thread starter Thread starter djc
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djc

Lets say things are just running real slow between you and a particular
remote site. What is a good way to find out where the problem link is?
tracert? I work really only with LANs and what I do know about WANs does not
get used much so I don't remember a lot of it.

Somewhere in my memory is saying that tracert does not provide accurate
numbers but is only good to see where the packets actually drop out. So it
could detect where a outage is but not necessarily where a big slow down
is.. or where a high level of errors are occuring... please correct me if
I'm wrong.

I'm hoping for a quick example using tools already available via Windows
2000 to get info on where a performance issue may be occuring... anyone?

any info is greatly appreciated, Thanks.
 
My 2 cents.

It's a big question because it really depends on your network.

You can start by looking at logs in routers, w/s, servers.

Duplex mismatches are a common area for slow downs.

You can try a network monitoring program like Solarwinds to check certain
throughputs.

In a Windows domain environment check the DCs logs.

Performance monitor can be used to set up benchmarks.

Even simple ping commands will give evidence of speed from A to B.

There are many file copy tools that measure speed from A to B. (xxcopy
comes to mind)

When users complain about a slow network, you have to look at the big
picture and test things for yourself.

If you're on a budget, try MRTG to monitor your switch ports - we used it
for a long time with good results.

There really are a lot of things that can slow down a network - viruses -
bad NICs - broadcast storms - too many

unnecessary protocols running.

If you're having problems with a WAN - can you call your WAN provider to
check for WAN issues?

It's a good idea to set up performance measures so you have something
concrete to compare with when troubles

start. (Instead of just saying 'it's slow')

Good Luck

Graham
 
its a big question indeed. Thank you for your reply. To be more specific I
will use an example. I think that will help because the situation for which
I'm looking for a way to get info reaches beyond my network. In other words,
I don't have access to install any utility on all the hops for monitoring
etc...

for example:

Lets say I replicate SQL Server data between 2 sql servers, one on my
network and the other on the other side of the country. This is done over
the internet. So there are several hops between my server and the remote
server (through my router, then to my ISP, the out to my ISP's provider
etc.. then through some backbone routers, then to the remote server's ISP,
then to the remote server etc..). Now lets say that replication is failing
due to timeouts and/or general network errors. No configuration changes have
been made on either servers and all works fine normally. Now, I know I have
connectivity to the remote server still. No doubt. But it is sluggish which
does correlate to the sql server errors I recieve.

So what I want to do is find out if this is just a congested internet,
nothing I can fix. Or is there a problem occuring somewhere between my
server and the remote server? I am looking for the type of thing that
tracert gives back but maybe a little more.

So bottom line for me is 1) problem or not? and 2) where?

If there is a problem, the where will let me know if I need to fix
something, OR who to contact to fix it. So if I could get output of
communication from my server to the remote server, showing things like: time
through each hop, number of errors at each hop, which may result in
re-transmissions etc.. Then I could for example, call the remote server's
hosting provider to report the problem... or at least let my superiors know
its NOT our problem. So in response to try to make this a smaller question,
I don't need the detail to solve the problem, but just to be able to say if
there is a problem and where it is occuring in order to let the appropriate
people know to take it further.

not sure if I got all that out right. :(

thanks for the reply agian though.
 
hmm.. that may do it. I will check it out asap.. unfortunately, that may be
tomorrow.

thanks for the reply!
 
djc said:
Lets say things are just running real slow between you and a particular
remote site. What is a good way to find out where the problem link is?
tracert? I work really only with LANs and what I do know about WANs does not
get used much so I don't remember a lot of it.
Somewhere in my memory is saying that tracert does not provide accurate
numbers but is only good to see where the packets actually drop out. So it
could detect where a outage is but not necessarily where a big slow down
is.. or where a high level of errors are occuring... please correct me if
I'm wrong.
I'm hoping for a quick example using tools already available via Windows
2000 to get info on where a performance issue may be occuring... anyone?
Click to expand...
Try to use some network monitoring tool, especially with some
reporting and analyse capabilities. As I know there is a free full
30-days version of netcrunch, and it has such a fetures.

Dave
 
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