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Network Monitoring (please HELP)

By levik7 ·
I am experiencing some issues where I work. I am the Network Administrator and we are runnng a 10/100 network with an external T1 connection. We constantly experience latency in our Internet connection and reduced performance on our own network. OurISP claims all is well on their side, they have run tests on our circuit and have determined that we only peak at 30% utilization on our T1 line. Can someone offer a suggestion as to how this can happen and perhaps a good network monitoring tool to detect the problem.

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Network Monitoring suggestion

by mkern In reply to Network Monitoring (pleas ...

You didn't specify what type of network you are running. Do you have switches or hubs?

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by levik7 In reply to Network Monitoring sugges ...

We are running mostly on switches.
Most of the network of about 70 users are on their own 'segments'. Every 7 or 8 users are connected to a switch and all the switches come in through the patch panel to the main switch.

Hope this is enough info.

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Personal views.

by wpteh In reply to Network Monitoring (pleas ...

30% of utilization is pathetic. Imagine paying $100 for $30 usage. (^o^)

It doesn't matters whether you are using 10BT or 100BT connection, both are more than sufficient to handle your T1 line. Don't look down on 10BT, the transfer rate is at 10 Megabits per second. (180 times of a normal 56kbps modem connection) So with that kind of speed, we can load any web pages without significant latency. Not to mention 100BT connection for some users on your side.

Here are some checks which you cando to narrow down the source of your problem :
1) Protocol set on each PC. Remove all uneccessary ones.
2) Visually check on your switches and hubs...see if there is a high rate of collision and which PCs is transfering most intensively. *You can see from the blinking lights*
3) Network settings on each PCs.

If you are also facing reduced performance on your network, it might be the cause of some faulty network cards out there too.

Good luck.


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Network cards

by levik7 In reply to Personal views.

Thanks for the reply.

What would be the best way to go about checking for faulty network cards?

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by DukeBytes In reply to Network cards

Actually a sniffer software package is the "best" way to find out who is talking and why. You can also figure out if a NIC is bad with this too. SnifferPro is good stuff.

Start logging when it slows down most and find out if anyone is doing something out of the norm, that might help sort out problems too.

5mm is BIG time right about the protocols. Get rid of everything but TCP/IP unless you really really have to keep them. And make plans for getting rid of anything else if you do haveto keep them.

Forcing Full Duplex and 100MB connections at the switch and setting each card to full/100 might help a good bit also. If you have everyone connected to a switch - you should use the bandwidth. Telnet into the switches and look at the stats for the ports - you might find a bad NIC there also if it is generating a lot of errors.

Also - how do you get out to your ISP? - are you using a firewall or a proxy server or just a connection to the router. This could be a problem foryou too - if your using a software Proxy/Firewall (like checkpoint) on a SLOW server (which most people set them up this way???) instead of a Pix or other hardware proxy/firewall - that could just crush your outbound.... It could even be the OS on the proxy/FW server that is doing it to you. A Unix server is good for this - because most people know nothing about Unix and just leave the server alone, and granted most of the time that is all that you have to do to a Unix box - but if the logs are getting full or something like that - it would slow it down or even crash it and no one knows why.

But it still sounds like internal traffic is your problem - find out who is broadcasting all the time and disconnect them

Good luck,

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