Although the CBL-II adheres to Ethernet standards for communications on the wired side, the manufacturer decided to use a proprietary protocol, known as 10BaseRadio, on the radio side. In this respect, the CBL-II differs from some of its competitors, which generally use standards such as 802.11b on the radio side. However, it has long been felt that, for point-to-point applications, adherence to wireless standards isn't critical because the products won't be interoperating with other products.

RadioLAN's Campus Bridgelink-ii, (screen view) Click here to enlarge

The CBL-II provides well-rounded administration utilities and can be configured via SNMP, Web and serial console interfaces. For the bulk of my testing, I used both the console and Web interfaces and found them functional and intuitive. I appreciated that RadioLAN kept the Web interface simple, with most configuration and management functions available from the main interface screen. One feature lacking in the administration utility is an event-handling capability that would let the administrator set up notification schemes regarding possible events. I'd like to be able to arrange for admin e-mail notification or an entry to an error log on a remote server if the frame success rate drops below a certain threshold, for example.

Nuts and Bolts

The CBL-II's rich feature set demonstrates an impressive attention to detail. In particular, I was pleased to see an autosensing MDI/IX (Media Dependent Interface/Interface Crossover) Ethernet port, the beauty of which is that the product will sense automatically whether it is connected to a hub/switch or to a PC. The CBL-II also includes full support for the 802.1d Spanning Tree protocol, and some packet-filtering options, such as filtering by MAC (Media Access Control) address and the ability to filter on Layer 3 protocol type. For an additional $75 per bridge, RadioLAN also offers an optional security feature called SecureLink, which lets you run 40- or 128-bit encryption.

The CBL-II comes in two models--the 367 and the 377--which are chiefly differentiated by the length of the coaxial cable supplied with the kit. The 377 has a longer range but includes only 15 feet of coaxial cable. By increasing the length of the cable, you reduce the amount of gain, subsequently reducing your range. The 367 comes with 47 feet of coaxial cable, but the recommended range is no more than half a mile. Given the loss of gain, many deployments will require the CPU and CRM to be located within 15 feet of the antenna. This would make power over Ethernet highly feasible, yet this is something I felt the product lacked. Some installations might attempt to mount the CPU and CRM in different locations because they are physically separate components, but this CPU was designed specifically to have the CRM mounted in a cradle, which doubles as a wall-mounting bracket.

Overall, the CBL-II's features are comparable to those of its competitors. The biggest difference between this product and those from vendors such as Cisco Systems and Western Multiplex Corp. is the range: RadioLAN markets the CBL-II as a product for campus connectivity, which it defines as a distance of 1 mile or less, while some of its competitors designed their products for longer distances.

Spanning the Campus

Many wireless-bridge vendors boast data rates of 10 Mbps or higher, but often their products' throughputs are as much as 50 percent lower than advertised. To assess performance of the CBL-II, we compared it with a typical switched Ethernet connection. First we mounted the two antennas in our lab at a distance of a little more than 15 feet, adding 24 db (decibels) of inline attenuation to simulate a typical link. For the throughput tests, I used NetIQ's Chariot to transfer files of various sizes across the wireless connection between two 500-MHz Pentium PC computers running Microsoft Windows 2000. I ran identical tests using an isolated Ethernet switch between the two systems. Although I was able to achieve throughput of 8.6 Mbps using the Ethernet link, the CBL-II yielded throughput of 7.9 Mbps, or 92 percent of the Ethernet's performance.

Vendor Information Campus BridgeLINK-II (CBL-II), $2,499 per side. Available: Now. RadioLAN Marketing Group, (408) 365-6200; fax (408) 365-7675. www.radiolan.com

To evaluate ease of deployment, I conducted field tests over a .6-mile link between two buildings on the Syracuse University campus. For one building, I mounted the antenna outside, and at the second location I mounted the antenna on a tripod inside a mechanical room that had a large window. The entire installation and configuration of the CBL-II took about four hours. I used the antenna-alignment tool in the Web interface, and the tool revealed I had a 97 percent frame success rate on the first try. I was now ready to access the lab network from the remote side, and did so without a hitch. I was able to browse the Web, stream video and download software from the Internet. In fact, the performance was equivalent to what I could have achieved while sitting at my desktop in the lab. I found the antennas very easy to install and aim, though many organizations may prefer to contract with an experienced antenna installer to ensure safety and reliability.

RadioLAN Marketing Group is a small company that was formed after last year's bankruptcy of RadioLAN Corp. RadioLAN Corp. was the first company to introduce a 5-GHz wireless LAN product, but its offerings in that arena never proved profitable. The new RadioLAN Marketing Group is using that technology to focus on the point-to-point wireless bridge market, in which it has much better potential for success. With the CBL-II, the company may just have found its niche.