Roberts was able to keep development costs low by relying on off-the-shelf chips, something startups couldn't necessarily do circa 1999. The heart of the FR-1000 is an FPGA programmed with Anagran's algorithms, alongside what Roberts describes as an inexpensive routing chip. All told, the box lists for $70,000.

    Anagran isn't just an exercise in pinching pennies, though. Roberts says he's spent the last few years expanding on what he started with Caspian, coming up with a more powerful way to use flow-based networking.

    So, what is the FR-1000?

    Inside the box

    Anagran's router was conceived as an add-on to live networks, something that would be deployed as an aggregation box at the network edge.

    Like Caspian, Anagran uses flow-based routing, where the router processes traffic in terms of flows and not just by individual packets. But this time, Anagran adds the wrinkle of being able to control the bandwidth used by each flow.

    The goal is to avoid the high packet loss that comes when the network gets overloaded. Put differently, Anagran claims to turn TCP into a better juggler, letting the network maintain high throughput on a higher number of flows.

    When a normal router reaches overcapacity, it starts discarding packets, often in a round-robin fashion, sometimes affecting traffic flows that aren't contributing to the problem. "The result is, everybody slows down at once. Then, they all start speeding up at once," Roberts says. To avoid this oscillatory behavior and the congestion that comes with it, carriers run their routers at around 30 percent of capacity, to leave enough headroom for surges in traffic, according to Roberts.