UW-Madison wireless plan requires more net addresses – lots more

UW-Madison wireless plan requires more net addresses – lots more

The University of Wisconsin-Madison has been assigned 65,000 Internet addresses to boost its network capacity, allowing it to go forward with a planned expansion of its wireless network to blanket the campus.
A non-profit Internet management body, the American Registry for Internet Numbers, established the address block for the university, which is pushing 80 percent usage of its current allocation. The new block should also give the university some growing room.

Ubiquitous access

UW-Madison’s wireless network, which is available by secure login to students, staff and faculty, is expected to cover most of campus by the summer of 2006. “We hope to have well over 2000 wireless access points on campus,” said Brian Rust, a spokesperson for the university’s Division of Information Technology, or DoIT.
Each year, the university surveys students on their ownership and use of computers, mobile phones and other devices. This spring’s survey may go out as early as this week, Rust said.
In last year’s survey, 94 percent of students said they owned a computer, he said, and about half of those said they owned a laptop. Anecdotally, however, few bring their laptops to class.
An expanded wireless network may not give them much more reason to do so, as Internet access is considered a distraction in many classrooms and some may be left out.
“I think a lot of the wireless is still being installed so that it’s largely covering public areas, offices, lounges, stuff like that. … We’re not making a deliberate attempt to not cover lecture halls and classrooms, but they’re considered lower on the priority list,” Rust said.
Much of the university’s previous allocation of addresses went directly to DoIT and to the 6000 students living in dormitories, said Michael Hare, a UW network engineer, while the rest are spread out over numerous departments and other uses. The computer sciences department also has a large number of addresses, including some independent of DoIT’s management.

How many addresses?

IP addresses are a layer of the Internet just below domain names – such as the infamous dot-coms that have become such a part of the popular lexicon. But where domain names are meant for humans, IP addresses are meant for computers.
In the most widely used system today, they are represented as a set of four numbers, each from 0 to 255. For example, an address on a local network might be
The block of addresses that the university was just allocated includes every one from to That’s precisely 65,536 addresses in all. The university already had three similarly sized blocks and is using around 80 percent of them, according to the DoIT release.
Not only does each of the planned 2000 access points need its own IP, but there need to be enough for each computer that logs on, as well. Plans to give each building its own defined block of addresses will also push the number that needs to be allocated.
“With our current wireless network, you could get the same IP address sitting on the Memorial Union Terrace as you would sitting in Union South, but the large [Ethernet] network that this requires won’t scale reliably to such a large scale,” Hare said.
And the new addresses won’t go only to the wireless network.
“We should also have enough free IP space to grow into new applications without requesting more for quite a while,” Hare said.

Jason Stitt is a WTN editor and can be reached at jason@wistechnology.com.