As with similar initiatives from Cisco and 3Com, Riverbed's long-term aim is to replace servers with networking appliances: Virtualization decouples software from hardware, so why bother with physical servers?
Riverbed is so far the only vendor to propose running virtual servers on a WAN optimization box, but the concept makes a lot of sense. Server consolidation is most useful in branch offices, which also happens to be where most of its Steelhead boxes are installed. Virtualizing services on those could theoretically avoid either supporting servers at the remote office or consuming WAN bandwidth sending client requests to the data center.
But right now, much of the vision is still theoretical. Though Riverbed says the Steelhead will eventually be able to run multiple servers of any type through VMware, each box can currently run only one third-party server at a time. And customers have to choose from three officially supported applications: DNS/DHCP from Infoblox, video from Wowza, or Riverbed's own print server. Riverbed is also working with Secure Computing on unified threat management, but doesn't know when this will be available.
For the moment, the platform seems designed to counter all-in-one boxes from competitors like Cisco and Blue Coat, which already combine WAN optimization with their own security services. Riverbed argues that its approach will offer much more flexibility, giving customers a choice of best-of-breed products, though this will depend on signing up more partners or giving customers the option to run other software.
The overall strategy seems very similar to 3Com's, which can already run VMware and other applications on some of its routers. The main difference is that routers are based on specialized hardware, so 3Com customers need to plug in a separate blade for server apps. Steelhead appliances all use standard PC hardware and Linux so they can support server apps directly, isolated from Riverbed's own code using the Kernel-based Virtual Machine, a virtualization technology built into Linux.