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A Publication Featuring The Information Services Technology of Maine State Government

By Karl Beiser

This project is part of Maine libraries’ continuing effort to broaden access to on-line information resources. In doing so, it aims to:

• provide a community Internet access point for use by students with Maine Learning Technology Initiative laptops;
• enable libraries to make more efficient use of their own desktop and laptop public access computers; and
• meet the growing demand of library users for Internet connectivity for their own notebook computer hardware.
• In addition, development of a familiarity with wireless technology will prepare library staffs to evaluate and make better use of future generations of this rapidly evolving technology.

All sites were provided with a Linksys WRT54G access point / router supporting both 802.11g and 802.11b wireless communication. In those few cases where a single unit could not deliver a satisfactory signal to major public areas, a second was provided. Three wireless interface cards were offered, with a choice of PC Card devices for notebook computers or PCI cards for desktop computers.

Security Protecting the existing wired network from wireless users is a major focus. The security of network communications by wireless hotspot users is another. Each library’s access point was connected to the existing wired network in as secure a manner as possible. What this meant in practice was dependent on the site’s existing network infrastructure.

Almost all sites use the Maine School and Library Network (MSLN) as Internet service provider, and thus have either a T-1 connection and a Cisco router, or a 56 Kbps Frame Relay connection terminated in a Frame Relay Access Device (FRAD). Some Cisco units had an unused second Ethernet port. In these cases, the MSLN enabled the port and assigned a small number of IP addresses to it, thereby constituting an entirely new network segment, to which one or more access points could be connected.

Other libraries had a router or FRAD linked to a firewall appliance or utility router, which was linked to a switch and through it to individual wired computers. A typical hookup involved inserting a utility switch between the Cisco router or FRAD at the building’s entrance point and the firewall/router device, and connecting the wireless access point to a port on the switch.

Some libraries had just the Cisco router or FRAD and a switch – no firewall device of any kind. In a few instances, Maine State Library (MSL) staff set up a switch and a utility router to provide enhanced protection for computers on the wired network, both from the Internet and from wireless users. This could only be done in cases where the network was small and simple, and individual workstations did not need to be reconfigured individually.

As to the security of wireless communications, almost all sites elected not to enable WEP (Wired Equivalency Protection) encryption on the access point. Ease of use for the public and for library staff were deciding factors. Instead, the access point is set up to allow essentially immediate connection to any wireless network card. Through signs and other means, libraries alert users that credit card numbers, usernames and passwords, and other confidential information is susceptible to "eavesdropping" unless one is dealing with a server that provides SSL (Secure Sockets Layer) or other encryption.

Wireless Configuration and Access Point Location First the area requiring maximum signal strength was identified. Then a candidate location was selected as close as possible to the center of that area, yet reachable from an existing network jack or cable. The site monitoring software in the project-provided wireless laptop was used to determine relative signal strength in the area of primary coverage, and to estimate the edges of the range given furniture, book stacks, walls and other obstacles. If coverage was not satisfactory – very rarely the case – other candidate locations were tried. Once established, permanent installation of Ethernet and power to the selected location was left to the library. If power was not available at the desired access point location, a power over Ethernet kit was provided with which to run electrical current over the last length of Ethernet cable from a wiring closet to the access point.

Access point signal strength was surprisingly great even when the unit was positioned far from the center of a large interior space, at a spot determined more by connection convenience than signal optimization. The signal diminishes little in passing through wood-frame walls, ceilings and floors. A foot or two of brick or masonry wall are not enough to stop a signal, though there is a noticeable drop off. Generally, it takes at least four or five double-faced metal book stacks to cause a serious drop off.

Beware of steel and aluminum framing sometimes used in new construction. At the Belgrade Public Library, a small room enclosed in such framing prevented a useable signal from reaching a laptop just outside the room. Conversely, we got acceptable signal strength through at least 6 feet of brick and masonry in the basement of Lewiston Public Library.

The bottom line on siting the access point – do an actual walk-around. Moreover, use both site monitoring software that estimates signal strength, and pull up actual web pages to confirm that actual behavior tracks what the moving graphs report. Expect the unexpected – both surprisingly good reception in remote locations and the occasional blind spot. Determine a final access point location on your observations.