Bandwidth Use

When you use the internet or any other network facility, such as email, what you send and receive is converted to signals travelling along copper wire or optic fibre. Although modern technology allows a very large number of such signals along a single cable, there is none the less a limit. Modern computers are also capable of sending a very large number of such signals in a very short space of time. The volume of these signals is what is meant by 'bandwidth'.

Because ultimately the University has to pay for the wires/fibres along which such signals are transmitted, it charges each College and Department for its use, based on the amount of data transmitted to or from sites external to the University. The termly charge for use of the College Network includes an allowance for externally transmitted data, but any use beyond a certain level (currently 8GB over 10 days) is charged separately (currently at the rate of 25p per GB over 4GB). If you exceed the limit, you will be charged a small amount each day, probably for several days, until your average usage falls below the limit.

In addition and quite separately, a record is kept of your bandwidth use, both internal to the University and external; if your total use is excessive according to certain criteria (currently 15 GB over 10 days), you will find that your connection is slowed down (auto-throttled). The purpose of this is not to cover any costs incurred by the College, but to ensure that the available bandwidth is not 'hogged' by a few individuals. Because overall use of the network is lighter at night time, any use between 2.00 a.m. and 7.00 a.m. is not counted towards this bandwidth limit, though charges will still be made for external traffic if those limits are exceeded.

If the bandwidth throttling interferes with your academic work, please discuss this with the IT Office.

Bandwidth Monitoring Tools

You can monitor your bandwidth uses with various programs which can be downloaded from the internet or from this web site. In particular, you could try Netmeter or Batch Bandwidth Monitor. You should configure these to reset at regular intervals.

You can also email it-office@sel to ask to be advised by a daily email of your bandwidth use (wired network only) for the last 10 days.

Using local copies (mirrors)

To help avoid bandwidth charging as a result of downloading large files, first make sure that there is no copy available locally. For example, the University Computing Service keeps mirrors or a variety of Linux distributions, updates and service packs for Windows, and an update service for Macs. Other items relevant to your studies may also be available via departmental sites.