Opinion Supply Chain
enables enterprises to deploy 802.11a/b/g/n channels at every AP, creating multiple overlapping ‘Channel Blankets’ that leverage each of the radios in the multi-radio UltraThin AP. Each channel's bandwidth is delivered across the blanket's service area (i.e. the combined coverage of all APs connected to the switch), with interference-free operation and consistent capacity throughout. As the Wi-Fi client moves, different APs will be in the best position to serve it at different times. The switch always chooses the best uplink and downlink path to serve the client. While this is taking place ‘behind the scenes’, the client never experiences an AP-to- AP handoff (i.e. de-association and re-association), resulting in seamless mobility. And with the inter-AP handoffs eliminated, the mobility problem of ‘sticky’ clients goes away. An organisation now has the flexibility to choose any mix of clients, with the confidence that they will all operate with consistent behaviour on the same network.
Wire-like connectivity with seamless mobility
Within each Channel Blanket, the switch avoids co-channel interference by permitting multiple APs to simultaneously transmit on the same channel but only if they won't interfere with each other. At the same time, the diversity receiver inherent in the channel blanket means that the communications link is rock-solid, virtually eliminating the problem of frequent disconnections common in all other systems. The link robustness of Extricom is said to ensure that Wi-Fi communications succeed even in the toughest of environments. The ultimate challenge to Enterprise WLAN is how to support multiple applications with conflicting system requirements, such as voice and data. Extricom reports that it has resolved this problem by separating the applications on different Channel Blankets. The result is an integrated system that delivers predictable grade of service, by enabling different applications to operate in parallel, without contention, on the same physical infrastructure. In addition, the multiple concurrent Channel Blanket capability ensures Extricom is able to support both 802.11n and legacy 802.11a/b/g at full performance and without necessitating a radical cutover from what the user has today.
The self-adapting network
The Extricom contribution to Kiva’s MFS extends to operational and deployment considerations. “The Extricom wireless network self- adapts to a constantly changing RF environment created by pods and drive units in continuous motion,” said Verminski, “so there’s no need to tune APs and client transmission power levels. This also makes installation and support easier, since the channel cell planning and tuning step is eliminated.” Reliability is also a factor. Since all Kiva MFSs operate on a high-availability basis with service-level guarantees for its customers, completely redundant WLANs are deployed. Extricom’s architecture allows independent Channel Blankets on each redundant system to be tuned to separate channels, so that the two WLANs are physically separate right down to the airwaves. There is no interference between Channel Blankets operating on different channels, and the Extricom Switch eliminates co-channel interference within the blankets.
www.logisticsit.com
July 2011
MANUFACTURING &LOGISTICS
IT 53
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