Loops: what they are, and how to prevent them

Granted, many good things come in loops: wedding rings, race tracks, Hula Hoops. But when it comes to ethernet networks, loops are not a good thing.

With the power to turn a ‘network’ into a ‘notwork’ in just a few seconds, loops are easy to cause and troublesome to solve, especially if no steps have been taken to prevent them. It usually goes a bit like this: someone plugs something into a non-corresponding switch, and within a few minutes all your data is stuck looping around that cable.

So, if you think you have a loop, this quick guide will help detect and solve your frustrating problem... 

How to tell if you have a Loop

Before you can start to try and fix the problem, it’s always best to make sure you know what the problem is. For loops, there are a few giveaways:

• Do you have problems accessing local resources - like files on a local network storage or printing on a network printer?
• Do some services, like the Internet, still work, whilst others - such as VoIP phone calls - have stopped working altogether?
• If you conduct a ping test on your gateway (usually your internet router) is there no response, or is it sometimes not responding?

If the answers to the questions above are yes, then congratulations! You might have the dubious pleasure of a loop.

How to fix the Loop

The process of fixing a loop can vary from quick and easy to long and painful. Firstly you need to think to yourself - as well as ask around the office - and see if you or anyone else has recently plugged a cable into the network.

If so, this is most likely the problem, and all it takes is unplugging that cable.

If nothing springs to mind, then sadly the only way to fix it is trial and error: one by one, unplug cables and wait a few moments to see if the network starts to speed up again. Once this happens, you’ve solved the problem, and can replace the other cables.

Without taking precautionary measures beforehand, there is no quick way to fix a loop. Luckily devices like smart switches with loop detection and Spanning Tree Protocol will allow for quick indication of where a loop is coming from and how to disable it.

A forward thinking provider, like Vostron (*wink), ensure that all the necessary precautions are taken to stop loops before they occur, making use of various Spanning Tree Protocols and smart or managed switches.

It’s just another little thing we do to make your life easier.

We hope the info above was useful and helped you solve your loop. If you are still having issues, then it is best to contact your provider. If you do not have a provider, then we can still offer as much help as possible, simply drop us and email or give us a call.