Computing Services caps dormitory network transfers

When it comes to network bandwidth, nothing escapes the notice of tech-savvy Carnegie Mellon students. On Wednesday of last week, several people posted to the University bboard cmu.misc.market with complaints that the upload speed on the residential network was slow. Six hours later, a post to the official.computing-news bboard confirmed that Computing Services has capped the network traffic coming from the dorm network.

According to John Lerchey, computer and network security coordinator in Computing Services, the outbound residence hall connection has been limited to a total of 30 megabits per second. Carnegie Mellon pays for a 50 megabit per second outbound connection to the Internet for dorm and academic buildings combined. However, last week Computing Services was alerted by Pittsburgh Supercomputing Center (PSC), the provider of Internet bandwidth to the University community, that CMU was using more than 120 megabits per second.

Since the usage was more than twice the allotted bandwidth, PSC informed Computing Services that the connection was beginning to have a negative impact on other institutions, such as the University of Pittsburgh and the Pennsylvania State University, which also receive their bandwidth from PSC.

The bandwidth limit was implemented as a temporary solution to the overuse of upstream bandwidth. Computing Services believes that this problem is due to outbound traffic generated by file sharing programs such as KaZaa, Morpheus, and gnutella - which can be used to exchange music and video files.

"Most people install these search programs and don't realize it's setting them up to be a server," said Lerchey. The common file sharing programs allow people from outside the University to download large media files from computers on the campus network. Since CMU has a fast network connection, computers here that are serving large collections of mp3 or video files are popular choices for downloading.

If file sharing program users do not limit the number of uploads the program allows, then it can eat up a great deal of bandwidth. Lerchey said that in a scan of the campus network, it was determined that six residence hall machines were using up 10 megabits per second of the outgoing traffic. Nearly one-third of the current capped upstream bandwidth was being consumed by only six dorm computers. Last Friday, one computer running a gnutella program had over 1,500 simultaneous connections open to other computers, meaning that over 1,500 media files were being sent over the network.

In October of 1999, Computing Services cracked down on copyright violations by conducting a random search of computers for copyrighted media files. According to Lerchey, Computing Services received "a ridiculously large number of reports from the RIAA (Recording Industry Association of America)" in one week and this prompted them to investigate how common the files were. Computing Services only accessed computers that were using Windows Networking or a similar protocol to transfer files without being password protected.

A number of offenders were discovered and their network access was suspended for a specified period of time.

Local intra-campus bandwidth, which is used to transfer files between two computers on campus, is faster and more available than bandwidth to the commodity Internet. However, the 1999 crackdown may have pushed students towards bandwidth-greedy Internet file sharing programs, or may have simply motivated students to password protect shared files.

Computing Services still receives several emails each week from the RIAA, MPAA (Motion Picture Association of America), and other groups alerting them to copyright violations on the campus network. Lerchey said that the standard process is to send a warning email to the person implicated in the report. If the person is unresponsive and does not address the problems from the complaint, then network access from his or her dorm computer is suspended.

Although file sharing programs are often used to illegally distribute copyrighted material, the programs can also be used completely legitimately to distribute non-copyrighted media. Nevertheless, file sharing programs are believed to consume a disproportionate segment of the bandwidth and Computing Services is considering a variety of solutions to this problem.

"Is it really CMU's place to be providing this to people who aren't even part of our community?" questioned Lerchey in reference to the amount of bandwidth CMU provides for people outside the University to download files from computers here. Computing Services is looking for ways to reduce the bandwidth used by file sharing applications.

Perhaps the most obvious solution - simply increasing the bandwidth purchased - is not necessarily a smart choice. According to Lerchey, the University paid approximately $50,000 for Internet bandwidth in 1996. "We have steadily increased the bandwidth that we're buying over the years," said Lerchey. The bill for the network connection is now $370,000 per year. Currently CMU has enough bandwidth to handle the needs of the academic network and the dorm network, as long as mp3 servers do not consume exorbitant amounts.

However, Eric Fong, a senior electrical and computing engineering major, disagrees: "I am concerned that by focusing only on reducing network traffic, we might overlook valid reasons to increase our bandwidth purchases." He also pointed out that the cost of CMU's network connection when divided by the number of students here, costs less per person than a yearly subscription to a dialup service.

Joel Kraut, a freshman computer science major, expressed a similar opinion: "CMU spends $370,000 on Internet access per year. That's the tuition for 15 students. Is that such an awful price? If the bandwidth limit stays in effect, we don't get anything out of it."

One idea is to publish a list of the top network users/abusers to a webpage, in the hopes that peer-pressure would reduce network usage by the top abusers. However, Terrence Wong, a sophomore computer science major, said that idea would only spur more problems. "[M]any people not only don't care, but would try to get their names on the list by purposely abusing bandwidth further."

New equipment, which Computing Services is planning to purchase, will make it easy to enact bandwidth caps against specific computers, or against communication ports that only file sharing applications are known to use. These limits would only affect bandwidth abusers and would still allow regular use of other aspects of the Internet.

Lerchey said, "The big issue is if people can voluntarily cut back on file sharing, it would have a [positive] impact on everyone's ability to use the network."