What’s going on?
We’ve recently been having some pretty severe performance problems on ResNet.
What you might notice
If you are sending email, viewing websites, or accessing internal university resources such as Blackboard these will still work – you won’t notice much difference if any.
You could have problems with things that work in real time:
- MSN Messenger or other instant messaging programs keeping disconnecting and reconnecting
- If you try to use Skype you can’t hear the other person
- For gamers, you get very high ping times and packet loss
Performance is worst at peak times of day (generally evenings) when more people are using ResNet.
Why is this happening?
Network traffic (bandwidth) on ResNet goes up every year. This year however it has shot up far more than ever before, probably due to the growing popularity of online video such as YouTube and other sites.
We have taken steps to cope with the increased traffic. The University recently moved to a higher capacity Internet connection (SuperJanet 5) and so we’ve been able to increase the total bandwidth available for ResNet. This is a good thing, and will provide better performance for everyone on ResNet.
In addition for many years we have had a traffic management system on the link between ResNet and the Internet. This works to divide up the amount of capacity fairly between all ResNet subscribers. If we don’t have any traffic management then just a few of the 4500 people on ResNet can fill our entire pipe.
We’ve bought a new higher capacity traffic management system to cope with the new higher traffic levels. However it hasn’t worked as well as we’d hoped and we’ve had problems getting it up and running. At the same time our old traffic management system is creaking badly – it’s pretty old and not working as well as it should.
Because of this for some periods, especially on Thursday 22nd Feb, we’ve been running without any traffic management at all. This means that just a few people on ResNet can generate massive amounts of traffic, and the performance for everyone else really suffers.
What we are doing
We’d like to get much better and more consistent network performance. This is our top priority at the moment.
We are aiming to provide:
- up to 8 Mbit download speed
- latency of 20-60ms to UK sites
- 0-2% packet loss
- consistency at all times of day
These are all trade offs – eg we can increase the download speed (good for people downloading large files) but this would probably increase the latency (not good for gamers or Skype users). We are trying to get the right balance. Sometimes we’ll tweak the settings, get it a bit wrong, and this will temporarily make things worse for some or all people. We’re very sorry about this, but please bear with us while we try to improve matters.
What you can do to help
You can help by
- giving us some feedback on how well ResNet is performing for you,
- keeping your usage low where you can
If you would like to let us know how well ResNet is working for you, please email firstname.lastname@example.org . Please include details of what you were doing and when you tried it.
To reduce your bandwidth usage if you have any form of peer to peer filesharing program (eg Bittorrent, eMule or similar) then shut them down as soon as you finish using them. Don’t leave them running in the taskbar all the time, as they generate huge amounts of traffic even when you personally aren’t downloading a file.
You can see your own usage by looking at Manage My ResNet. Remember we have a fair usage policy on ResNet where you can use transfer 10GB of data per week, and if you go over that you will be warned and then your usage will be restricted.
If we don’t have the traffic management in place it is much easier to go over the 10GB limit, so make sure you keep it under control.