Part of network going down

By glong ·
I just found and joined this site today and I must say that I really like all the activity and help going on.

Now to the problem I'm searching for an answer to:

I've recently been hired by the local school district to take over as the network administrator/pc tech.

The high school here is far behind the times. Thankfully, it is not large... only about 500 faculty/students. The network is built with hubs upon hubs upon hubs with old outdated wiring.

Most of the network (the server is novell netware 5.0) works, but they have a big problem with one particular portion of the building going down. 7 rooms in the main building are connected to one switch and the ag building about 40 yard away is connected to this same switch. Those 7 rooms and the ag building will lose connectivity once or twice a day at random times. They have an indoor cat5 wire strung out in the open air with the cable tv and guidewire from one building to the next. Anyway, when I reset that particular switch, the network comes back up.

First thought was a bad switch. So I replaced it with a new one. This had absolutely no effect.

Next, I checked the wire strung from building to building and it has obviously been there for years and it had exposed wires. I figured that was the problem, so I swapped it out with new wire (the only solution I was allowed to pursue since the school may be updated and going wireless this summer.)

This seemed to help the problem a little, but I was resetting the switch once every day or two still.

I then swapped out the old hub sitting in the ag building (where the wire from outside was coming into the ag building from the switch in the main building) and put in a switch. Again, this seemed to help the problem, but didn't solve it. I'm still resetting at random times. Sometimes once every couple days, sometimes once every week or so.

It's always the same portion of the network that goes down. Does anyone know of anything that I may be overlooking?

Just to clarify...

The server hooks to a switch in the server room. That switch is wired to a second switch in the study hall. The study hall switch has connections from 7 classrooms and the connection coming in from a 3rd switch in the ag building.

The ag building and 7 classrooms are the only rooms affected.

I was toying with the idea of rerunning the cable from the server room switch to the study hall switch, but that may not be simple... I would just hook a new wire to the old one and pull it through the ceiling... that would be great, but there may be wires connected together and connected down to things during the run through the ceiling. There are also hundreds of wires going everywhere with very few of them labelled.

Anyway, is there something I may be not realizing that could be making that portion of the network to go down?

I have also tried using different port to connect the study hall LAN wire in the server room with no effect.

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All Answers

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Too much traffic?

by jdmercha In reply to Part of network going dow ...

Have you monitored the traffic going through this switch? Perhaps there is too much of it and the switch can't keep up. Rebooting the switch would then clear out he buffers and allow the switch to continue.

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not sure

by glong In reply to Too much traffic?

I don't think it could be too much traffic... I've changed many of the hubs to switches. The switches I have put in are 24 port rack mount switches. Like I've mentioned before, they won't allow me to spend much money and we have some switches (new) sitting around in storage that have never been used. I started putting those in place of some crowded hubs.

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Several reasons

by w2ktechman In reply to Part of network going dow ...

as you have mentioned has helped, but not solved the problem.
A simple yet often overlooked one, which could cause this problem is brownouts, or spikes in power.

Is a UPS hooked up to the switches? if resetting the switch fixes the issue, it may be due to power issues to it.
I had a similar problem on my home connection, had to reset the router about 1x a week. I threw a UPS on it and havent had any issues in a few months.

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I never even thought of that

by glong In reply to Several reasons

what a good suggestion. I will give that a try as soon as I can locate a UPS. So, yes, all the switches not located in the server room are hooked straight to wall outlets.

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Good start..

by -Q-240248 In reply to Part of network going dow ...

You said hubs upon hubs, then mentioned switches. Are these hubs or switches? It does make a big difference. Cat5 networks allows for no more than 3 hubs in-line to a destination, so if you have more than 3, it's time to make a move to switches or better wiring methods (you mentioned wireless). I think you're going the right route in checking the cabling, good call. There could also be a problem with the outlets, where the workstations plug into the network. I've had outlets go bad where wires start touching and that can also bring down a segment. You can try those as well. Bad cabling on the workstations and even bad nics can cause problems.

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hubs and switches

by glong In reply to Good start..

Yes, they had almost everything hubbed, but started changing it because they had problems. Whenever I make any changes I exchange the hubs with switches.

It's about 90% sure that we will revamp the building and put cisco wireless in place, but I'm looking for any kind of improvement I can get until that happens... but they aren't willing to spend much on stop-gap measures.

I'm sure there are connections going bad, it's all old stuff.

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by Ben "Iron" Damper In reply to Part of network going dow ...

I would replace the power strip and or battery backup unit in the affected area.
At several of our branches we have UPC battery backups and when the battery's go bad in them this very same scenrio occurs.

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