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Campus Computing News

By Dr. Maurice Leatherbury, Senior Director of Academic Computing

Internet Bandwidth (Again!)

Many readers of Benchmarks Online vividly remember the slowness of UNT's Internet connections about two years ago. At that time, the University had about 9 Mbps (million bits per second) of bandwidth capacity to Internet 1 (the "commodity" Internet over which most of our traffic flows.) That capacity was full from very early in the morning until late at night, effectively slowing our Internet access to a crawl. To alleviate the constriction in Internet data carrying capacity, we installed a 45 Mbps connection to Internet 1 early in 2001, followed shortly by an Internet 2 connection of another 45 Mbps. Internet 2 only connects institutions of higher education in the U.S. (with some exceptions, but that's the primary participants in I2,) so most Internet data communications goes through I1 because that's where most of the Web sites to which we connect are located (sites such as the State of Texas one, K-12 schools, and commercial firms like Microsoft and Apple Computer.)

Running Out of Internet Bandwidth

It's clear that we're nearing the point at which we'll have to expand our Internet 1 capacity again - this chart shows the traffic for today (April 11, 2002):

                      Internet 1 Daily Average (bits per second)

The green area represents incoming traffic (i.e., bits flowing from off campus to UNT's local area network.)  The blue line show outgoing traffic. The chart graphically shows that we're nearing our 45 Mbps capacity several times during the day (and night.) The next chart demonstrates that today isn't an isolated instance of bandwidth congestion, because it shows a month's worth of traffic, and except for the weekends, our traffic peaks at our maximum capacity at some time each day.

                     Internet 1 Monthly Average (bits per second)

Internet2 and Bandwidth Utilization

Earlier, I said that Internet2 only connects institutions of higher education in the U.S., so is of limited help in solve our Internet 1 bandwidth problem. But that new research network does contribute significantly to our overall Internet bandwidth capacity, thus reducing our commodity Internet traffic somewhat.  Here's a graph of today's Internet2 bandwidth utilization:

                Internet 2 Daily Average (bits per second)

The monthly graph looks very similar to the Internet 1 monthly graph, although on a different scale:

               Internet 2 Monthly Average (bits per second)

In fact, calculating the total average bandwidth used over a month's period, we discover that Internet 1's average utilization was 18.2 Mbps inbound and 26.5 Mbps outbound while Internet2's average was 4.7316 Mbps inbound and 4.777 Mbps outbound. That means that Internet2 contributes 20% of our inbound Internet capacity and 15.3% of our outbound capacity utilization, not insignificant figures.

Future Bandwidth Plans

Because the campus is so heavily dependent upon Internet access, and our students, faculty, staff, alumni, general public, etc. need fast, reliable data communications to and from campus to perform their work and some leisure activities, the Computing Center is taking steps to expand our Internet 1 bandwidth.* We're exploring ways of funding the rather significant cost increase that will be required to expand our capacity to the next level, 155 Mbps. That expansion will cost about $200,000 per year more than we're current paying for our 45 Mbps connection. We're also talking to our local Internet2 partners, SMU, TCU, UTD, and UTA, about sharing an Internet 1 connection in order to reduce the per-institution costs.

We're near the end of our busiest semester as far as Internet bandwidth requirements go. The summer terms see a drastic drop-off in Internet utilization because fewer students are on campus, in the dorms, in the general access labs, etc. However, the Fall semester will undoubtedly bring an upsurge in bandwidth needs as even more students come to UNT. We in the Computing Center realize the importance of the Internet to much that we do and are doing everything we know how to be ready for the increasing demands on Internet bandwidth.

* For a "back to the basics" look at this issue, see Dr. Philip Baczewski's January 2002 Network Connection article "Back to the Basics: Bandwidth." For a discussion of bandwidth on the home front, see his Network Connection article "The Need for Speed," published last year.