* Wi-Fi architectures evolve to match traffic patterns
Within the past five years, the trend in wireless LANs has been toward centralized architectures that allow for scalable configuration, administration, and management. The idea has been basically that the controller contains the systems smarts and the radio access points have grown fairly dumb.
More recently, however, some architectures are finding a more middle ground. Newer companies and some existing thin-AP/controller companies are moving certain process-intensive functions, such as encryption, switching and QoS, back to a more distributed model.
The reason is the growing potential for latency and increased traffic loads on the back end. The traffic volumes associated with forthcoming 802.11n networks and growing data and voice traffic over time will place more processing demands on the back-end wireless and wired infrastructures. Controllers could become a bottleneck if all traffic streams must make a pit stop there.
Here are some of the current WLAN systems vendor architecture strategies:
* Aruba Wireless Networks
Retaining primarily centralized architecture, but will move QoS – such as Wi-Fi Multimedia (WMM) prioritization and call admission control – into distributed APs.
* Bluesocket
Retaining fully centralized architecture in order to support multivendor APs.
* Cisco
Retaining fully centralized architecture with AP1000s and Wireless Control System. Distributed functions are available in older Cisco Aironet 1100 and 1200 APs, with which customers can use the Wireless LAN Services Engine for centralized management.
* Colubris
Distributed APs switch client traffic and enforce security and QoS; centralized controller handles configuration, administration, and management only.
* Extricom
Offers a fully centralized architecture; uses “channel blanket” technology that avoids inter-AP handoffs, interference and cell planning.
* Meru Networks
Moving to distribute certain high-intensity processing functions with 802.11n APs and 802.11n controller.
* Motorola (formerly Symbol)
Retains fully centralized architecture with its AP300 thin AP and Wi-Fi controllers for large deployments. Distributed functions are available in older Motorola AP-5131 and AP-5181 radios without centralized management capabilities.
* Xirrus
APs and controller function are bundled together in a common housing and then distributed throughout the enterprise environment. So while forwarding, encryption and QoS still run between AP and controller, the controller is local to the AP.
* Trapeze Networks
Moving from fully centralized to partially distributed “Smart Mobile” architecture, which enables all or select application traffic to be switched within the distributed APs.
