Cisco is making noise in the spectrum analysis arena this week at the Interop trade show in Las Vegas, announcing a new line of Wi-Fi access points that embed the capabilities directly into radio ASICs.
The move delivers a revamped iteration of Cisco's laptop-based spectrum analyzer, Spectrum Expert, which the company acquired with its purchase of Cognio in 2007. The ASIC capabilities are called CleanAir and run full time while still serving client traffic, according to David Stiff, product marketing manager in Cisco's Wireless Networking Business Unit.
Spectrum analyzers detect and identify wireless devices in the air space and measure their effect on a Wi-Fi network's performance. They differ from general RF monitoring tools in that they identify specifically what kind of device is causing the interference and where it is. In some cases, they allow the network to take automated action to self-heal.
For example, Cisco says its $1095 (internal) and $1,495 (external) Aironet 3500 APs with CleanAir technology and a Cisco Wireless LAN Controller (WLC) detect and classify 20 unique interference sources, such as cordless phones, wireless video cameras, microwave ovens and Bluetooth devices.
CleanAir requires Cisco Unified Wireless Network Software Release 7.0 on the WLCs and in the new APs. If you add the Cisco Mobility Services Engine (MSE) location appliance with CleanAir to the configuration, you can find out where these interferers are and track historically what's been interfering and where for improved channel planning. And, finally, running CleanAir in Cisco's master Wireless Control System (WCS) adds mapping, indexing, device de-duplication and other capabilities to the mix, Stiff says.
The University of South Florida is beta testing the capabilities and intends to purchase 700 Aironet 3500s over time, says Joe Rogers, network administrator, who adds that the university is currently upgrading its entire Wi-Fi infrastructure to 802.11n.
The university has been a Spectrum Expert shop, but the embedded nature of the latest solution "lets you do [persistent] analysis all the time" and see interferers and their locations centrally "as if you were sitting in the location with your laptop," Rogers says. He points to a growing population of wireless video cameras that "obliterate four to to six channels" as particularly troublesome.
Cisco's announcement comes at a time when vendors are pulling out all the stops to try to gain control of the airspace, as 802.11n begins to displace wired Ethernet connections, particularly in new deployments. Getting wireless to perform as reliably as wired Ethernet remains an industry challenge.
Atheros, which supplies Wi-Fi chips to most of Cisco's wireless LAN competitors, has demonstrated spectrum analysis embedded into its chipset as recently as the Consumer Electronics Show in January, though no availability time frame has been made public. Meanwhile, other vendors, including Motorola and Xirrus, offer spectrum analyzers in their APs with a centralized view, and Aruba has announced similar software capabilities to ship later this year.
Paul DeBeasi, research vice president at Gartner, acknowledges that wireless APs need to be more deterministic, which requires visibility into the physical layer that Cisco and others now provide.
But "Cisco is pushing the notion that its spectrum analysis is better [than software-based approaches]…with a greater degree of accuracy," he says. The company needs to provide more specifics about that "or it becomes a technical argument that's in the weeds," he says.