Colleagues, In today's wireless LANs, with power limited by the Federal Communications Commission, performance drops markedly as the distance between access points and adapter cards increases. Under the best conditions, 802.11b has a range of about 300 feet; 802.11a goes about one-third of that. At maximum distances, throughput can drop from the typical actual throughput of 5M to 7M bit/sec for 802.11b and 18M to 21M bit/sec for 802.11a to mere kilobits per second if loads of users are linked to one access point.
While vendors are trying to address the distance issue through creation of advanced silicon and better antenna designs, one of the more intriguing solutions is the use of mesh networks that provide a new way for wireless LAN radios to interact. Wireless LANs today are based on client adapter cards that wirelessly link to an access point, which is then wired into the corporate LAN. Technically, 802.11 clients can create ad hoc connections to one another, but this isn't widely used. MeshNetworks is one of several companies building software to create a mesh instead of a hierarchical wireless LAN (others include SkyPilot, Ember and CoWave Networks). The software loads on the wireless adapter card and turns every adapter into a repeater-router, instead of an endpoint looking for an access point. This means your wireless PDA can hop through someone else's wireless laptop, or through several, to finally reach an access point to the corporate network. There are two results. One is the wireless LAN can extend wherever mesh clients exist. Second, because you're connecting to the nearest wireless LAN radio instead of a more distant access point, radio physics dictates that your throughput will be higher. You'll be able to run at closer to the 5M to 7M bit/sec that's typical of an 802.11b LAN. MeshNetworks has acquired exclusive rights, including patents, to mesh technology originally created by the Defense Advanced Research Projects Agency. The company's software is essentially a routing layer, which vendors will load on their wireless LAN adapter cards and access points. The company is developing ASICs to move this processing into silicon, instead of firmware, for faster performance, according to Rick Rotondo, director of disruptive technologies. MeshNetworks engineers have created algorithms to minimize the power used in each hop and the latency each creates. Rotondo says each hope is less than 5msec. The software is in beta test with a half-dozen adapter card vendors. Rotondo says the initial version of the software, called MeshLAN, will ship this fall. Alan Levy [EMAIL PROTECTED] ===== Iustum et tenacem propositi virum si fractus inlabatur orbis impavidum ferient ruinae ------------ ***GKD is solely supported by EDC, a Non-Profit Organization*** To post a message, send it to: <[EMAIL PROTECTED]> To subscribe or unsubscribe, send a message to: <[EMAIL PROTECTED]>. In the 1st line of the message type: subscribe gkd OR type: unsubscribe gkd Archives of previous GKD messages can be found at: <http://www.edc.org/GLG/gkd/>
