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I live in a large two storey building that used to be a school and we have an internet connection with BT (British Telecoms provider), the connection speed is 12Mb. Basically our connection is slow and very intermittent and I was wondering if anybody here could provide some help or ideas.

There are about 11 people in the building who could be online at any time. We have a router on the ground floor which is bog standard supplied by BT. To provide broadband access to the first and second floors, we used an old switch that the school left, we have a cable running from the router on the first floor to the switch which connects to a wireless router which is configured as a bridge on the second floor supplying broadband access to the first and second floors.

Additionally we have three computers that are connected via the switch through the ethernet sockets left by the school on the ground floor.

The router we use on the second floor came in a pack of two and cost about £15 (bought by another person). Sometimes the connection is perfectly fine, i.e. early hours of the morning or when everybody is out. We contacted BT who say that the connection cannot cope with the numbers of people online, plus I'm not sure whether each person is streaming etc.

Can anybody offer any advice?

Edit

We have 2 routers: main router from isp > switch > cheap brand wireless router >>> 7/8 PCs. Sadly I won't be able to use the Linux PC or do any real level of testing as I'm to blame for this problem and the building manager won't let me do anything more.

I've suggested a new router but that's been dismissed too. The switch was good enough before so they cant see what is wrong with it now.

Somebody suggested a ping flood and I got no packet loss, went through all the QoS options and no change.

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migrated from serverfault.com Feb 26 '11 at 16:31

This question came from our site for professional system and network administrators.

    
At the risk of sounding brusque; your ISP already answered the question -- you have too many people on your grade of connection. –  Scott Pack Feb 26 '11 at 14:54
    
Yep. Get a LES from BT. Between 11 people, you could get the cost down to 60-80 quid a month each, and have 1/11th of 100Mbit, synchronous connection. –  Tom O'Connor Feb 26 '11 at 15:09
    
That argument bothers me when it comes to routers and I hear it from dozens of people daily at my work - "It worked before, it should be fine now" - well, then your cracked radiator block must be fine now as it worked yesterday. Everything breaks, so do routers, do not discount it just because it worked fine yesterday. –  MaQleod Feb 26 '11 at 19:22
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2 Answers

Because there is pretty many people using same connection (and as you said, you have no idea who is using network and for what), best first step may be trying to figure that out.

  1. By asking
  2. With technology.

As 1. is obvious, I'll focus on 2.

It's possible your router include some kind of management interface. Try opening your router address in browser (command route print in Windows and route in Mac OS X/Linux will show it). If not, you are almost out of luck, unless you want to build something.

You can put transparent bridge built with Linux, and then log amount of bandwidth used per computer. Instructions for example in here. You'll need Linux installation CD and computer with (at least) two network interfaces.

You said you have quite cheap router. That might be problem with heavy load, even if network connection is working fine. For example, if there is too many connections open, it might start freaking out by randomly dropping connections or by rebooting (which causes short break). Best way to test: loan better one from friend/workplace/somewhere else and try with it for day or so.

After having some idea about network usage, you can decide what to do next: buy faster internet connection, agree on some usage policies or something else. As already recommended in comments, when there is so many people sharing connection, it might be good idea to change to faster one.

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Here is how you troubleshoot slow connection issues:

Bypass the LAN, directly connect with a single computer to your ISPs device (router, modem, whatever your ISP provided you). Ping your primary DNS for an hour and look for latency, jitter or packet loss and then run a speed test. If everything looks normal here, your problem is only on your network, and I'm betting this is the case.

If your problem is your network, then you probably need a router with better CPU clock cycles or the ability to handle a larger number of clients. Most likely you are using a home grade router and trying to run a business off of it, this does not work. There is no cheap in networking unless you want problems. Buy a business grade router.

Other issues that you can look into are the cabling running between routers and between computers and they can cause a lot of problems when they go bad. Also test all the computers for malware and viruses as a single infected computers can wreak havoc on a network. If you are using wireless, you may not have the signal strength to manage that many clients over the distances you are trying, you may need more access points or to just cable the computers instead. You might also have a utilization issue. Believe it or not, but it doesn't take much to saturate a 12 mbps line. If your upstream is even lower, then saturating that will still kill your downstream, so keep that in mind as well.

Now if you experienced issues while directly connected, then the steps are quite different. First you will need to find where the connection comes in from the street and plug in the ISP device there with a computer, then retest the same way - this bypasses your building wiring and will prove whether or not it is your ISP. If you still experience problems, its time to call your ISP, otherwise you need to repair your building wiring.

When calling your ISP it is important to note that you directly connected to the NID and still had issues, they will likely ask you to do that at some point anyway. You will need to ask them to look for any imbalance, shorts or grounds on the line, any problems with the DSLAM or CMTS port, card, shelf or overall system, any possible trunk issues or problems with their ATM network. Of course there are many other things that will cause what you describe, but you really need to start off with the basics and move on from there.

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