Motorola Enterprise WLAN Controller Buyer's Guide - Page 2

• The AirDefense Infrastructure Management solution provides centralized IT firmware and configuration provisioning, change control, and auditing.
• The AirDefense Network Assurance solution provides centrally-initiated trouble-shooting and spectrum analysis, using either APs or sensors as remote "ears" and "eyes."
• The AirDefense Security and Compliance solution takes a similar centrally-managed, distributed AP/sensor approach to Wireless Intrusion Prevention (WIPS).

"We build our APs to be leveraged by AirDefense in order to reduce TCO," said Lopez. Cost analysis data and comparisons are posted on Motorola's website.

Pushing control to the edge

According to Sankhavaram, policies relating to network services, quality of service, security, and availability are managed by controllers, pushed from controllers to APs, and enforced by APs. During loss of communication, adaptive APs become a virtual controller for their site by performing all control plane functions, using local copies of policies.

For example, Motorola controllers include network services such as DHCP, DNS, and RADIUS servers. Every adaptive AP maintains a synchronized copy of the centrally-defined RADIUS user database. In case of WAN outage, an adaptive AP can automatically turn into a virtual controller, using its copy of the user database to authenticate new sessions without disruption.

A similar split exists for dynamic radio resource management. "SMART RF is available on all controller models," said Sankhavaram. "If an adaptive AP loses communication with a controller, APs still coordinate among themselves. If one AP fails, others increase power to cover dead spots or can change channels to mitigate interference."

However, there are some advanced application services that adaptive APs cannot perform. "One example would be geo-fencing. Both controllers and adaptive APs can deny or limit WLAN access based on user location. But advanced application services are available only on [dedicated] controllers, such as Ekahau location based services and RFID management," she said.

Finally, Motorola argues that its controller portfolio delivers cost-effective scalability. "Up to 12 controllers can be clustered for a single point of policy enforcement, and cluster members can talk to each other to load-balance APs across the entire WLAN," said Sankhavaram. "For redundancy, you can add a zero-AP-license controller. If another controller fails, it can adopt not only those APs, but also its AP licenses."

Bottom line

Ultimately, Motorola believes that its WiNG5 architecture, mix and match deployment model, integrated network services, and support for clustering create a cost effective, scalable solution. To learn more, visit Motorola's WLAN products page or download this portfolio overview [PDF].

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Lisa Phifer owns Core Competence, a consulting firm focused on business use of emerging network and security technologies. An avid fan of all things wireless and frequent contributor to Wi-Fi Planet, Lisa has reviewed, deployed, and tested 802.11 products for nearly a decade.