Need Help Troubleshooting a network

[statik213]

I started working parttime at a new place and the guy who used to do their networking/admin got laid off a while go. Anyway they have very old hardware but the network shouldn't be this slow. I know the basics about the networking but don't have a lot of experience with it because it's not exactly my area.

I basically want some pointers to help isolate the problem. I know everyone is going to scream Upgrade but they are financially unstable and don't really want to throw a lot of money in to this sort of a thing. I've got very little to play with.

Transfering a 13mb file from the file server takes about 5~7 minutes (I tried transfering the same size data within the server room via a 'local' hub at it took much less time - so it's not a server problem).

The setup (to my best knowledge):

They have 2 18port 10Base-T hubs (don't know model/make ~ no documentation to be found and didn't want to take it down and shut the network down) that were probably installed about 8 years ago that act and about 30 wired ports of which only about 15 are actually used.

The server room is in a different location and has only one wall port. So everything from the server feeds into one of these 10 mbps hubs thru the wired port. They also have a D-Link 614 router (wireless/100-baset 4-port switch) that acts as DHCP server and gateway for their cable internet connection. The server plugs directly into one port on the router and the another port is used to connect to the rest of the network (to the hubs) wia wall outlet. Another (old) 8 port 10-BaseT hub plugs into the same router/switch with one or two computers connected to it (these computers aren't important).

The setup is moreorless straightforward and had been working fine until about two months ago. Now everything is painfuly slow. Copying files/accessing from the server etc.

How should I go about finding what's wrong? Could it that the wiring has gone bad? Could that degrade performance? Could a bad hub degrade performance?

Any help would be great. Just so you know, I'm not a newbie and can understand advanced stuff so I don't need 'baby' talk - thanks in advance!

 

[JeffMD]

how much traffic is allready going accross the network while you are doing this? with 10mbit you dont have much speed. With 18 people on a hub, everyone is splitting the 10mbits (Hubs broadcast data to all ports, so when one person talks, it hits all the ports, so if someone is taking 2mbits of data,.. and another person is taking 2 mbits of data, you only have 6 mbits to play with, less with overhead), you REALLY don't have much speed. And if one person has a bad card or there is a bad port causing collisions (when one computer trys to talk at the same time another computer does), the hubs speed drops even more.

I won't suggest you upgrade untill I know what exactly is EXPECTED of this network. But this thing is anchient and wasn't expected to cope with the file sizes and A/V duties expected of todays networks.

 

[statik213]

Originally posted by: JeffMD
how much traffic is allready going accross the network while you are doing this? with 10mbit you dont have much speed. With 18 people on a hub, everyone is splitting the 10mbits (Hubs broadcast data to all ports, so when one person talks, it hits all the ports, so if someone is taking 2mbits of data,.. and another person is taking 2 mbits of data, you only have 6 mbits to play with, less with overhead), you REALLY don't have much speed. And if one person has a bad card or there is a bad port causing collisions (when one computer trys to talk at the same time another computer does), the hubs speed drops even more.

I won't suggest you upgrade untill I know what exactly is EXPECTED of this network. But this thing is anchient and wasn't expected to cope with the file sizes and A/V duties expected of todays networks.

Yeah sorry, I should have included that info in my orignal post, thanks for replying.

Well everything there is anceint, most of the machines are p200 mhz or so, they just got 5 new Celeron 2.4 GHzs - the file server runs winnt backoffice server . I doubt if there is much acivity on the network.

It's used for email, web stuff - they have a 500kbps coming in. So even if one person is using all of it shouldn't degrade network performance.

There are 3 or 4 access databases (around 20~40 mb each) hosted on the server that people use at various times. There are one or two more databases but nothing that demanding. Access is smart enough not to lug the whole database over the network and get just waht it needs right? Besides I'm sure that the Database has never been 'repaired/fixed' so it's probably bloated well beyond the actual data size.

Everyone keeps their office (word/excel) on the file server as well - I'm not sure exactly how they do that - they may be directly working off of the server instead of copying finished work their. That may be a reason for the slowdown (didn't think of that)

Overall I'd say that their is hardly any activity their.

I was in the hub room once and I saw the red light on one hub light up a lot - and some other times didn't see it. Could this be caused by one bad NIC? If so is their some (easy) way I can isolate the problem and find which port is bad?

I might be able to talk them into getting 2 24-port 100mbps switches (should be under $200 right?), but I'd like to be certain that it's the hubs that are causing the bottleneck.

 

[TechnoPro]

Can you go in after hours and shut down all client machines except for one and then run a performance test? This way you can test the throughput speeds without all the broadcast traffic from the other nodes.

I've seen NICs that have gone bad that do nothing but generate bogus traffic. And on an already slow, non-switched network, this can really slow things down.

 

[statik213]

Originally posted by: TechnoPro
Can you go in after hours and shut down all client machines except for one and then run a performance test? This way you can test the throughput speeds without all the broadcast traffic from the other nodes.

I've seen NICs that have gone bad that do nothing but generate bogus traffic. And on an already slow, non-switched network, this can really slow things down.

Not that easy to work around my schedule.... yeah but i could try and do that.... i'm going in early on monday and if people aren't in, I'll shut the machines down.....

 

[howdyduty]

Recommend you replace the hubs with switches. Could go with low cost unmanaged switches. Also, Dell has some low cost 24 port switches. Could replace at least one switch. Make sure the servers are on the replaced switch. Hubs are not as efficient as a Switch. Just unplug one Hub and plug in a new Switch. Should be that simple.

 

[statik213]

Originally posted by: howdyduty
Recommend you replace the hubs with switches. Could go with low cost unmanaged switches. Also, Dell has some low cost 24 port switches. Could replace at least one switch. Make sure the servers are on the replaced switch. Hubs are not as efficient as a Switch. Just unplug one Hub and plug in a new Switch. Should be that simple.

Well, I'd like to be certain that the slowdown is caused by the hubs and that the switches WILL fix the problem. I was told that the network became painfully slow about two months ago - and before that it was fine. And like I said, there isn't much activity so 10mbps should be sufficient. An upgrade would be nice, but I would hate for the network to be slow after that......

 

[spidey07]

check overall utilization on the hubs.

also you could have a worm spewing out tons of traffic slowing everything down.

 

[statik213]

Originally posted by: spidey07
check overall utilization on the hubs.

also you could have a worm spewing out tons of traffic slowing everything down.

Hmm... AV is uptodate on all the machines on the network, how would i check this? the hub seems pretty basic and i wouldn't know how to check utilization on the hubs...

 

[spidey07]

Originally posted by: statik213

Originally posted by: spidey07
check overall utilization on the hubs.

also you could have a worm spewing out tons of traffic slowing everything down.

Hmm... AV is uptodate on all the machines on the network, how would i check this? the hub seems pretty basic and i wouldn't know how to check utilization on the hubs...

blinky lights - if they blinky contstantly you have a lot of traffic. also ethereal is a free sniffer that could tell you what is going on/how much traffic.

 

[statik213]

Will look into ethereal... there are a quite a few blinky lights... how good is ethereal

 

[Oakenfold]

I would recommend getting a switch regardless, on that setup all you need is one machine running BT and your entire network is going to crawl. Spidey's suggestion sounds like a great idea, if you want to troubleshoot start with that.

 

[statik213]

I've got ethereal installed on my home network (two pcs / one router) and it's sniffing out network traffic.


How do I interpret all the collected info? How do I use that to tell if there is an excessive amount of network traffic? Never used ethereal before

 

[statik213]

I'm running ethereal on a machine there and I set it to collect packet info. maybe that will be able to throw some light on what's going on.


One thing I noticed was that downloading to a client from the internet was faster than downloading from the internet. That's just wrong....