Bandwidth Policy

A number of students currently living in the PSU dorms are using RESNET or RESNET2 services. These services provide access to the Internet and the PSU Campus network. A number of students, as customers of this service, have rightfully become curious and concerned about how bandwidth is managed. This document will explain the architecture of the Internet access and reasons for limited bandwidth available for certain applications.

The PSU Office of Information Technologies (OIT) currently manages the Campus network including the RESNET services and the Internet access for all campus residents.

The following diagram describes the current RESNET and RESNET2 architecture at a high level.

Both RESNET networks channel traffic through the Bandwidth shaper device to get to the Internet. The purpose of the B/W shaper is to assure that the proper amount of bandwidth is being used overall and individually as well as control the type of traffic that can flow through to the Internet.

Certain communications protocols are designed to use as much capacity as the physical link can provide. A few users using these protocols (peer-to-peer applications) can saturate the capacity of the physical link. This would starve other users of other less resource-hungry applications such as e-mail and web access. Overall, the fees collected from subscribers of RESNET pay for a certain amount of Internet access bandwidth. This bandwidth needs to be shared between all subscribers in a fair manner. OIT's goal is to make sure that each subscriber receives the best possible level of service. Hence, the bandwidth shaper is employed to de-prioritize certain bandwidth-hungry protocols to ensure that all users and protocols receive at least a minimum level of service. The decision to de-prioritize (but not filter or block) peer-to-peer traffic was made because that type of traffic is less sensitive to temporary slowdowns than other, more interactive applications. It was not a decision grounded in censorship or the desire to control content: OIT does not filter or block any type of application or traffic.

It should be noted that reducing the priority of peer-to-peer applications does not always impact their performance. If allowing all peer-to-peer traffic would not impact other, more sensitive applications, it is all allowed. However, if allowing peer-to-peer traffic would significantly slow down or stop other traffic, the other traffic is permitted first, and the peer-to-peer traffic is "shaped," or slowed down, so that it will no longer impact the other applications. The peer-to-peer traffic is never stopped or blocked.

In the end it's all about providing a cost-effective Internet access solution to students. The money collected can only pay for a certain amount of bandwidth. Rather than drastically raise prices in order to pay for the bandwidth required to support unmanaged peer-to-peer access, we chose to de-prioritize protocols that want to consume inordinate amounts of bandwidth. This will help ensure that all subscribers receive the best service possible at an affordable price.