To the test
eWEEK labs tested the roaming performance of a pair of VOW phones: Zyxel Communications Corp.s P-2000W v2 and Hitachi Cable Ltd.s WirelessIP5000. We invited Zultys Technologies and SpectraLink Corp. to submit products for testing, but we were unable to acquire and install their products in time for this project. Using testing equipment provided by Azimuth Systems Inc. , we tested each devices roaming performance in a Cisco Systems Inc. Aironet-based wireless network. For comparison, we also tested the roaming capabilities of a Dell Inc. Inspiron 600m notebook computer configured with Intel Corp.s Pro/Wireless LAN 2100A wireless adapter and the X-Lite soft phone, a free SIP-based telephony application from CounterPath Solutions Inc. (formerly Xten Networks Inc.).We were pleasantly surprised by the outstanding roaming performance turned in by Zyxels P-2000W v2. The P-2000W v2 far surpassed the other devices in our tests, turning in an average roam time of just more than 17 ms. According to Zyxel officials, this outstanding performance is due to a proprietary implementation of several operations, including the phones association with the access point, authentication and prekeying, as well as a quick-scan mechanism that finds the best access point to connect to. (The prekeying capabilities did not affect our testing because we tested without encryption.) You cant knock the Zyxel phones performance, but because it is so hasty in looking for stronger signals from other access points, we have some concern about the excessive amounts of client beacons that would be generated with a large number of phones in the same space. Hitachi Cables WirelessIP5000 has a nice ergonomic design and a strong feature set, making it among the most highly recommended of the limited number of Wi-Fi phones on the market today. The WirelessIP5000 is also the first SIP phone certified with ShoreTel Inc.s ShoreTel 6 telephony platform. During our tests, the WirelessIP5000 performed acceptably, averaging 163 ms per roam. This throughput could cause noticeable delay in a standard wireless network as a user roams, but the performance we saw was in line with Hitachi Cables expectations: The WirelessIP5000 systems engineer manual estimates 100 to 300 ms for a Layer 2 handoff, depending on the type of access points used. We also performed a base-line test on a PC with an integrated Intel Pro/Wireless LAN 2100A wireless adapter and the popular X-Lite soft phone application. Known for being a little sticky in roaming situations (Intel adapters have a tendency to stay associated with a single access point, regardless of signal strength), the Intel wireless adapter turned in horrible performance, with average roam times of 1.7 seconds and a maximum time of 3.4 seconds. Fortunately, its the rare user who will wander office corridors talking on a laptop-based soft phone. Next Page: Network issues.
To read more about eWEEK Labs tests using Azimuth gear, click here.