Four vendors placed in the "leaders" section of Gartner's magic quadrant for WAN optimization controllers: Riverbed Technology, Juniper, Blue Coat Systems and Expand Networks. Just what makes their gear so special?

As I mentioned in the last newsletter, Gartner’s magic quadrant, which was written by analysts Andy Rolfe and Joe Skorupa, rates vendors according to the completeness of their technology vision and their ability to execute on that vision. The firm reserves the leaders quadrant of the matrix for those WOC vendors that excel in both areas.

Here is just a small sample of the positive things Gartner analysts had to say about the vendors in the leaders quadrant:

Riverbed's Steelhead family “is the broadest lineup of appliances on the market, ranging from a low-cost entry model to a high-end cluster,” Gartner reports. Expand stands out for offering “the best mix of QoS, reporting and acceleration features,” while Blue Coat “has strong market understanding, demonstrated through its broad WOC range and feature set.” Gartner calls Juniper an “early compression innovator,” and says its WX and WXC WOC products “have a broad feature set, including User Datagram Protocol (UDP) and MAPI acceleration.”

Those aren’t the only standout products, however. “Challengers” Cisco and Packeteer, as well as “visionaries” F5 Networks and Citrix Systems also excel in key areas, as do “niche players” like Silver Peak Systems, Ipanema Technologies, Exinda Networks, Certeon, Intelligent Compression Technologies and Stampede Technologies.

Certeon offers encrypted disks in its WOC appliance, for example, and Exinda “offers the lowest-entry-cost disk-based appliances on the market,” Gartner reports. Silver Peak “has shown particularly good understanding of the acceleration needs of data replication and backup,” and Packeteer “has excellent QoS, reporting and application visibility.”

Still, none are perfect for every enterprise scenario -- even the leaders. Juniper lacks a SoftWOC, for example, and Riverbed has “less-capable QoS and reporting features than some leading vendors,” Gartner points out. Blue Coat’s Mach5 WOC “has weaker reporting and monitoring capabilities than some other leading vendors' products,” Gartner warns, and Expand “has limited WAN capacity at high end.”

Ann Bednarz is associate news editor at Network World.