Some colleges and universiteis, use very smart algorithmes and complex routing to manage their networks. For instance the univeristy I studied used a special policy.
They configed their network switches, routers and firewall that all campus (source) web and email traffic to university servers (dest) got priority and maximum bandwidth, then all other email and web traffic, and the last one other traffic. This was done to prevent the network to become congested due to heavy upload behavior and continous downstream and upstream saturation (P2P, online games,...). The logarithm let's you use all bandwidth available within a restricted limit / month for evey student, however when there is almost no traffic there are almost no restrictions and you get full speed, when users start to access priority servers (for example e-learning, ...) the bandwidht for other apps drops. This way the admins make the network do where it's meant for: university study and research purposes, still allowing entertainement on a certain scale.