Meru is a company which likes to make news. At last year's Interop it offered "single channel WLANs" (together with Extricom). This year, the big new idea seems to be wireless backbones--systems in which wireless links push the wires one step further back toward the wiring closet. And, yes, Meru is pushing it with a system which bonds channels to make a 100 Mbps back haul from APs to distribution switches. Not only Meru: Xirrus also talked of a bonded back haul for enterprise WLANs, in the form of a software upgrade--Release 2.0--of its Integrated Access Point, which bonds three radios together for links which it claims are up to 162 Mbps. The software will be available at the end of May.
The Meru and Xirrus systems offer a bonded channel, with greater capacity than a normal WiFi link, and both offer features above and beyond what we typically see in a regular mesh. Meru's system offers a full-duplex link with quality of service, which Meru's director of product management says is different from a mesh. Xirrus' system appears to be faster, but the 162 Mbps may well be based on multiplying the theoretical 54 Mbps rate of three 802.11g channels by three. The actual throughput is likely to be half of what the company claims it to be.
Note also that Meru uses a "blanket" architecture, in which the APs all use the same WLAN channel(s). The bonded back channel benefits from the fact that with all the APs using specific channels, other channels are free for back haul. Xirrus, on the other hand, uses a sectorized architecture in which one AP contains up to 16 radios, which use directional antennas to reach a wedge of the building. The Xirrus sectorized architecture thus makes it possible to bond channels together without danger of their interfering with radios which are beaming out in a different direction.
For more on bonded channels for back haul:
- see Peter Judge's Techworld report