Slow network connection in office

[jesperloh]

I am puzzled about some problems that occured at my work place. Unmanaged switch like D-link & Linksys was used and it worked pretty fine only for certain areas of the factory. Then office with more workers will be using managed switch to ensure the workers have decent connection to the local server.

Question is, why are some small offices' connection so ridiculously slow?

*Info*

The switches manage 4PCs

Tested - The main connection cable cannot go through the switch to distribute the connection. Even if there is only 1 PC linked to the switch, it will still be slow. It will be at it's max if it didnt go through the switch, but directly to the PC instead.

True enough that unmanaged switch aren't smart enough to allocate the speed, but why is it possible for some other part of the small office to have fast connection even by using the normal unmanaged switch?

Enlighten me, anyone?

 

[Hawkeye22]

It depends on how your network is arranged. Daisy chaining a bunch of switches together decreses throughput on certain segments.

For example, it's better to have 3 switches all connected to one switch than it is to have one switch plugged into the next, which is plugged into the next one, and so on. They can both handle the same number of computers, but the second arrangement will have bandwidth issues

Also, once you daisy chain past 3 switches you may have problems. Ethernet cables should also be kept to under 100 meters.

 

[totalknowledge]

It sounds like you have too much equipment for 4 pc's. You should be able to use just 1 router, and then the modem or whatever connects your router to the outside world.

Perhaps if you list exactly the network equipment you are working with.

 

[Hawkeye22]

Another thing that can slow down traffic is cables that are wired (ended) incorrectly. Running cat5 too close to other electrical wiring can sometimes also lead to problems.

If you have 10/100 nics or 10/100/1000 nics that you have to force to a lower speed or half duplex in order for them to work, it's usually a sign of improperly wired cables.

 

[jesperloh]

Okay, so the thing is like this. The switches are running through optic fiber, which is the main. So lets say that the company have a lot of optic fiber points set up for the switches.

What we do is the optic fiber actually connects to the managed switch, then we splits it out to the office. For certain places, we uses a patch panel just for our convenience to know the allocation of the individual distributed access point.

Well, that aside, everything is fine, until some guys actually requested to have their PCs shifted to a location. Therefore, one ethernet cable was plugged on to the managed switch, and linked it to the router, and distribute to the rest of the 4 PCs. The length of the wire is <10m.

However the case is, for certain locations, they worked fine but not for some. The current office I work in is operating the same way but connection speed wasn't compromise. Weird...........

For the wiring part, I thought so too in the first place. I deduced that it has either got to do with the wiring, or the router. I had also tried to change the port which the cable is being slotted. I tried clamping a new wire to make sure the contact points and the colour orders. The same thing happens (slow).

I've tried changing the speed to all 4 kinds, from 10 full, 10 half, 100 full and 100 half but to no avail. In the end, I changed it back to auto negotiate.

 

[Hawkeye22]

I'm still not sure of your setup. If I understand correctly, your switches are connected to your router via fiber and you use ethernet cabling from the switches to the PC's. I do not see a problem with this setup. if you check the managed switch, are you seeing excessive collisions on any of the ports? If so, check the configuration of the computer attached to that port.

 

[totalknowledge]

Unless I am missing some key point, it all still sounds way over engineered to me. Your distances are less than 10m, you only have 4 pc's, why are you using switches at all and not just a patch panel and the router?

Perhaps a diagram and/or the exact equipment being used would help.

Have you looked at the line noise? Perhaps there is some inadvertent loop in the system that is feeding back on itself.

 

[Hawkeye22]

Unless I am missing some key point, it all still sounds way over engineered to me. Your distances are less than 10m, you only have 4 pc's, why are you using switches at all and not just a patch panel and the router?

Perhaps a diagram and/or the exact equipment being used would help.

Have you looked at the line noise? Perhaps there is some inadvertent loop in the system that is feeding back on itself.

The whole network isn't just 4 pc's. There just happens to be 4 pc's in this one area of the office. Also, the OP hasn't stated his hardware specs. When we were using cisco enterprise routers ($60,000+) lan ports cost about $300/each. This was in the late 90's early 2000's, but I can't imagine enterprise routers coming down in cost much. The default coniguration only came with one lan port. So, perhaps he can't run a line from each computer to the router because there is only one lan port - yes, kind of useless in this configuration, but I'm just stating that we won't know more unless the OP gives out more information.

@OP: As i stated before, a managed switch should show errors per port and other useful information. That is where I'd start looking.

 

[jesperloh]

So the whole thing goes like this. The optic fiber is actually link to a server room, and then further splitted to different parts of the company through optic fiber as well. The unfortunate small offices have managed switch, and they have the optic fiber connected to it, then it will go out to different parts of the building.

One of the cable will be linked to the switch which is 10m away only. and then distribute to the 4PCs.

Ops, forgot to include that I've checked that there are no collision on the ports. The managed switch is Cisco 2960 Cat. Everything is well, until I link it through a small unmanaged switch.

Well, there are more ports that are empty and I've tried a few of them, still showing the same old slow results.

 

[Hawkeye22]

Everything is well, until I link it through a small unmanaged switch.

What is the small unmanaged switch? Even if the ports are rated 10/100/1000, the backplane throughput of this switch may not be fast enough or it may not have enough memory to store-forward packets quickly enough. It will be hard to diagnose this as it's an unmanaged switch. Have you tried taking this switch out of the loop to see if speeds improve?

 

[jesperloh]

The unmanaged switch is distributes the network relentlessly. E.g, D-link. Those kind that you plug the main cable from the managed switch into one of the port, and distributes them to the remaining 4PCs.

I've tested the main directly to one of the PC, and it works fine and thats the reason im puzzled from the start. Why does this happen, and only to few parts of the company. I was suspecting that the switch may not be something i need, but a router. Still, gotta ask around for your opinions to decide if the switch im using is the culprit.

 

[Hawkeye22]

Can't you run a line from the managed switch to the PC's, eliminating the small unmanaged switch... or try replacing the dlink switch with a different switch and see if speed improves. Those small 5 - 8 port switches are primarily made for home networks with just a few computers.

 

[jesperloh]

One small little secret to share with tomshardware family. The company's very calculative and budget =x Well, yea i thought of it. Because there isnt enough ports for 4 PCs, because there're only 2 ports left. Haha! Tried using a different switch, and it's the same.

I understand that these normal switches isnt capable of doing much, but now i know that it's not capable to this extent. I told the person in charge in the offices, and told them to raise their opinions to their superiors to see if they are willing to use their department funds to purpose one to ease their work. =x No other choice, did and checked everything and it's fine until it reaches the normal switch.

So, the switch is the main culprit. Just thought I could have another way around this issue =(