2007/06/22 - Temporary Quota System Changes
As students go away for the June/July vacation we expect that the number of users competing for the University's bandwidth will drop. In order to allow the remaining users to make better use of the extra bandwidth available we've traditionally made changes to the quota values during the longer vacations. This year, the demand side management changes we made a few weeks ago allow us to do something slightly different.

From 10AM this morning (Friday 22nd June) until 23:00 on Saturday 21st July we're discounting bandwidth by a third between the hours of 7AM and midnight. This means that if you download 10MB of data at any time from 7AM to midnight, it will only count 6.6MB towards your quota (effectively increasing the per-user quota to 30MB/day). Between the hours of midnight and 7AM things remain as previously published.

The advantage of implementing the change this way is that we don't have to phase things out as we've done in previous vacs which makes the system easier to understand. At midnight on Sunday 22nd July, the quota system returns to normal; downloads prior to this won't be affected by the change back. Hopefully this will reduce the confusion we've seen in previous years.

The discount factor we've chosen (0.66) is based on the current utilisation of the University's Internet bandwidth, with the assumption that it'll drop slightly as the last of the students leave over the weekend. If it turns out that we've incorrectly predicted the demand, we may have to increase or decrease this factor to compensate. Any changes in this regard will be appended to this notice.
Given that the demand for bandwidth has been lower than we anticipated, we've changed the discount factor to 0.5. This means that instead of 6.6MB, your 10MB will now be billed to your quota as 5MB. This change has been backdated to Friday 22nd. We may have to change this again once conferences, etc start.
Just a reminder that the quota system returns to normal at 23:00 this evening. This means that 10MB of traffic downloaded during the day will be billed to your quota as 10MB, and 10MB downloaded during off peak times (midnight to 7AM) will be billed as 1MB.