Print

Review: 3Com's Wireless Workgroup Bridge

by Glenn Fleishman
02/01/2002

Wireless networking using 802.11b (or Wi-Fi) is really taking off, but until now it's been only the newer machines that could take advantage of it. Laptops and some PDAs can take an 802.11b PC card and communicate wirelessly with an access point (the routed or bridged intersection of the wireless network and Ethernet), which carries that communication on out to the wired Internet.

But even in the most unwired environments, there's plenty of legacy equipment that isn't able to make the jump. Desktop PCs may feature built-in Ethernet, but they may not have free PCI slots or run an operating system that's too old. Printers connect to Ethernet easily, but few have wireless capability. Bluetooth may be the future of wireless connectivity for them and other peripherals, but it isn't here yet.

A few companies have offered half-hearted solutions, such as expensive Ethernet-to-Wi-Fi devices that run at 2 Mbps and work only with one computer.

Newer USB-to-Wi-Fi entries, such as Proxim's latest, are more promising, but they require special drivers that must be installed and configured on each machine. The cost is relatively high, too: $150 for each of these USB devices, versus $75 to $100 for a PC card.

Wireless bridges offer a better solution for this older equipment. In an article last year on O'Reilly Network, I described using a pair of Linksys WAP11s, which totaled $300. Or you could use more expensive gear that can attach as a solo wireless bridge to existing access points. Either way, that's a lot of configuration and a lot of money. (And the WAP11s need to be babied.)

Four machines, one wireless net

Enter 3Com's 11-Mbps Wireless Workgroup Bridge. 3Com's bridge supports up to four Ethernet devices, of any kind, plugged into its Ethernet port. The bridge creates a simple, single-client connection to any Wi-Fi access point using its one built-in radio.

You don't need to reconfigure your access point, nor do you need to install new drivers or otherwise reconfigure any of the connected equipment beyond what you would do or have already done for a wired Ethernet connection. Once you install it, you can administer the bridge through a Web interface from any machine on the LAN, or elsewhere on the Internet.

The secret to this $350 (street price) device is that it acts both like a plain old Wi-Fi client, creating a single connection to the access point, and a bridge, by piggybacking up to five MAC (Media Access Control layer) Ethernet device addresses on top of that signal. The five MAC addresses represent four other Ethernet devices plus itself.

Other strictly defined bridges perform much more complicated Ethernet packet and broadcast monitoring tricks; This device just bundles it all on a single transmission. It's an elegant way to reach its goal, which is to configure once, plug in the devices, and walk away. The only time you should have to touch it is when your access point changes, or if you take it on the road to connect ad-hoc networks.

Comment on this articleWireless is like any other luxury: once acquired, it's a necessity. Are you running a wireless LAN in your office? Let us know how it's going.
Post your comments

Setting up

The software interface is straightforward. It requires a Windows box running a later incarnation (or any subsequent version) of Windows 95. You install the software, reboot, select the bridge via its client software, and configure an IP. It can work as a DHCP client or attach to a static address.

The software installer intelligently reminds you that if you assign an address other than one of your subnets, you won't be able to reach it to administer it again. Because the address is set by IP number, not a broadcast protocol, you must be on the same subnet to reach that number unless the device is on an alternate subnet that's separately routable. If you use DHCP and your DHCP server has a short lease period and/or reassigns addresses frequently, you'll have to use the 3Com bridge's client to scan the network to find its current number.

If you assign a static address or have an option to keep DHCP assignment of NAT addresses static or long-term, you can simply use the IP address and any Web browser to reach it.

Unfortunately, you cannot set the port number for the bridge (default is 80), which would be handy for keeping Code Red viruses and their ilk from overwhelming the little feller. It does require a password for access, of course.

After assigning or configuring the IP address, a browser launches, allowing configuration of the individual settings. (You can also change IP values under the IP Settings panel using a Web browser after your initial setup.) This same configuration tool is used to connect to the device on subsequent administrations if you don't use a static IP for the bridge.

The product manager for the bridge said in email that the company may make a Linux version of the connection and configuration tool available on the 3Com Web site as a free download. 3Com has also received quite a lot of feedback from Macintosh users, and it is considering what approach to take.

It's hard to find enough good things to say about this Web-based interface. It's clearly laid out, well designed, and the menu options are written with an intelligent, but not necessarily experienced, user in mind. Advanced options are a click away: not hidden, but not exposed to helpless neophytes.

Help is available for each panel. Help files can even be configured to work over the Web or through a local cache on the machine on which you installed the configuration software.

The Wireless Network panel has already performed network discovery when you first select that panel. I found all of my local, open networks accessible as selections in the Wireless LAN Service Area popup menu. You can also choose for it to associate with private networks that do not broadcast their names by changing an option under Access Point Privacy Mode and entering the ESSID (network name) of that network.

Joining networks

You can force the bridge to attach to a specific network, or it can be promiscuous, finding any local, open network to connect to. The device can handle both peer-to-peer connections, which could be very handy in non-networked situations for sharing resources, as well as the more typical infrastructure mode. You can even turn off Wi-Fi compatibility for greater speed, throughput, or signal clarity through an advanced mode reached through a link at the bottom of panel. I haven't done enough testing to know how this non-Wi-Fi mode works with other devices.

Security options are found in the Security Settings panel. The bridge supports all of the various WEP modes: 40 bit, 128 bit, passphrases, and hex keys. One small flaw: We have a single WEP key on our network, and I was required to enter it four times, one for each possible key value. The bridge software wouldn't allow the other three hex keys all to be set to zero.

The Tools section of its configuration is a joy to those who administer systems on a regular basis. It sports several neat options in each settings panel: restart the unit (necessary but not forced after changing system options); upload new firmware via TFTP; reset factory defaults; save a disk image of the current setup; and restore such a disk image.

Administrators will note that in setting-up multiple versions of the same bridge, this save-and-restore image feature will save substantial time, as well as offer a safe backup of settings.

The System Status panels offer simple status information: MAC addresses for attached Ethernet devices, speed and signal quality, and a summary of settings.

The actual setup of this device is fiendishly simple. Plug in, install drivers, connect to device. Set IP, open Web browser, select ESSID from list, add WEP key, restart bridge.

And that's it.

Is it a bargain?

3Com's Wireless Workgroup Bridge is definitely a bargain for the right applications. For small, existing networks, running a length of Cat5 Ethernet wire is better than spending $350 on this unit. But for many other applications, especially where wireless is the connection option of choice, it's cheaper to spend $350 on this flexible gateway than that much or more on individual Wi-Fi cards. It also reduces load on your access point by bundling traffic into one client transmission instead of four separate network signals.

The lack of configuration required on the individual devices is a plus, too, reducing staff time (or your own) and bypassing the inevitable system problems that come when installing new network drivers. Out of four machines, you know that one will take hours or days to get back to normal.

Add into the mix old devices that don't support Wi-Fi: printers, all-in-one computers, machines with no additional expansion, and machines made for point-of-sale or other prefab operations with no chance to change configuration. Mac users with older, non-compatible devices (older systems, early iMacs, and so on) might find the bridge a particularly nice solution, despite the initial Windows setup required.

It's clear for anyone administering a medium to large network, especially one where distance or the ability to drill through a wall is an issue, the 3Com bridge is a cheap, simple, practically zero-administration method of getting more mileage out of existing access points.

I just wish I knew about this bridge before I festooned my house with five new holes (two of them, the right ones) after buying an Ethernet-only ReplayTV.

Glenn Fleishman is a freelance technology journalist contributing regularly to The New York Times, The Seattle Times, Macworld magazine, and InfoWorld. He maintains a wireless weblog at wifinetnews.com.


Return to the Wireless DevCenter.