Routing Startup Tackles Internet Congestion

Anagran believes flow-based routing supports more efficient traffic control.

A small startup hopes to turn how routing is done in the Internet on its head, thanks to breakthroughs the company achieved in the new flow-based router it launched Aug. 6.

Anagran, founded by one of the four pioneers credited with creating the Internet, introduced on the Aug. 6 its Anagran FR-1000 Flow Router, which can economically bring a greater level of control over traffic flows to better serve latency-sensitive traffic such as voice and video.

Although company founder Larry Roberts attempted to develop intelligent flow routing in the past, recent advancements in the market and patent-pending techniques developed at Anagran have made it possible now to perform more efficient flow-based routing.

"When you do flow routing, you have to keep track of each flow, and that cost came way down," said Roberts, in Redwood City, Calif. "Its 1 percent of the product now, but it used to be much more. Once you keep track of the flow once, you dont have to route every time you get a packet. You can get rid of 80 percent of the old router. You dont need it anymore because you have already kept track of everything you need to in your flow table. So you can save a lot of money."

Although Anagrans FR-1000 Flow Router is compatible with existing Layer 3 routers, it differs from those in its ability to observe and evaluate all flows passing through it. While existing routers process and route individual packets, the Fast Flow Routing architecture used in the FR-1000 looks at packets in the context of their higher level flow. It can then apply priorities to more mission-critical or latency-sensitive flows to ensure they are not compromised by congestion caused by large peer-to-peer file transfers.

/zimages/1/28571.gifClick here to read more about Roberts earlier research on Internet congestion.

The flow router performs a fast lookup of information in the packet that identifies the flow. It maintains a flow state table based on that information. "If it hasnt seen [the packet] before, it sends it to the routing chip, which does normal routing to find out where to send it," Roberts said. "But it also has load information from the output port it chooses and makes a decision at what rate the new flow can travel at. It meters it to that rate carefully over time."

Rather than discard packets on the output port when congestion fills up queues, Anagran developed an Intelligent Flow Discard technique applied on a per-flow basis on the input port. "So it can control the flow and tell TCP at what rate to send it. Then we send the packet to the output port [without overloading the queues], so theres no need for an expensive [application-specific integrated circuit] there."

The FR-1000 Flow Router also uses a proprietary Behavioral Traffic Control technique to "take out long-lived, high-volume file transfers that shouldnt be using up all the bandwidth. We can sort out the traffic even as we watch it over time," he said.

Because packet-oriented routers experience significant packet loss, they typically only operate at about 25 percent utilization. "With the flow router we can operate at the 95 percent range and just slow down the big file transfers," said Roberts.

Although some level of control is now exerted by existing packet-oriented routers using quality-of-service techniques such as Diffserv, they are less efficient because they perform prioritization based on individual packets. "This does that by whole flows, so it makes it a much more efficient way to do it," said Joe Mambretti, director at the International Center for Advanced Internet Research at Northwestern University in Chicago. Mambrettis organization is beta testing the new routers.

/zimages/1/28571.gifClick here to read how Cisco pulled together advanced routing services into a single box.

"I think the big improvement is a capability for fine-grained segmentation. You can basically give attributes to certain streams in a very detailed way. It wont mean a lot to general network users, but it will to people who run networks," added Mambretti.

Anagran in fact is targeting the FR-1000 Flow Router at carriers for the edge of their networks as well as in peering links, and it is targeting data centers in large enterprises.

It can be used "at the edge layer to improve utilization of [network] trunks to [digital subscriber line access multiplexers], make sure traffic going to data servers is not overloaded, and doesnt send too much P2P traffic," said Roberts. "You can keep the [Multiprotocol Label Switching] core and use it more efficiently. And you can manage quality and make sure video works."

The FR-1000 Flow Router architecture reduces routing by a factor of 10-to-1, while providing the same capacity as existing router architectures. It also uses 80 percent less power than conventional Layer 3 routers and has a much smaller footprint, Roberts claimed.

The special sauce in Anagrans routers is implemented in FPGAs (Fully Programmable Gate Arrays) instead of proprietary ASICs, allowing Anagran to respond faster to changing market requirements. And it is encrypted to prevent reverse engineering.

Although other networking companies talk about handling flows, they only sample flows and dont reduce the costs associated with existing routers, Roberts said. "Others say that they do flows, but it isnt the same thing. They arent switching based on flows," he said.

The 1 Rack Unit router supports 48 Gigabit Ethernet ports or four 10 Gigabit Ethernet ports, or a mix of both. Multiple units can be linked to create a larger system. The FR-1000 Flow Router is available now and lists for $70,000.

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