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Note 14
BBN was in a position to make the multi-processor router a reality. Another team in the company was completing an innovative multi-processor computer called the Butterfly—which interconnected processors and peripherals through a time slotted banyan switch. So BBN built a next-generation router on the Butterfly platform. The team was led by Hinden and included Eric Rosen, Brescia, Sheltzer, and Linda Seamonson.
As a research activity, the Butterfly router was an important innovation. The software, in C, was the first demonstration that a high performance router could be implemented in a higher-level language. The router team also learned a number of painful lessons, most notably that the Butterfly was rich in processing power but weak in bandwidth between peripherals and that this balance was exactly the reverse of what a router would want. Indeed, performance issues led Rosen and Seamonson to invent an early version of label switching.
A little later, between 1992 and 1996, a BBN team led by Craig Partridge, Josh Seeger, Walter Milliken and Phil Carvey (Carvey and Milliken were members of the Butterfly team) designed and built a prototype of the world's first 40 gigabit per second router. The router design reflected BBN's painful experience with the Butterfly gateway. It including a switch designed specifically to move IP datagrams from arbitrary input interfaces to arbitrary output interfaces. (One of the lessons of the Butterfly experience was that IP traffic tended to include bursts of datagrams to a single destination, which could overload switches that assumed balanced traffic). Variants of this router architecture are now standard, and BBN's journal paper on the router is required reading at many corporations. BBN remains a center of expertise in the design and implementation of high-end router and router-like devices (for example, packet switches, firewalls and encryptors) today.
As a research activity, the Butterfly router was an important innovation. The software, in C, was the first demonstration that a high performance router could be implemented in a higher-level language. The router team also learned a number of painful lessons, most notably that the Butterfly was rich in processing power but weak in bandwidth between peripherals and that this balance was exactly the reverse of what a router would want. Indeed, performance issues led Rosen and Seamonson to invent an early version of label switching.
A little later, between 1992 and 1996, a BBN team led by Craig Partridge, Josh Seeger, Walter Milliken and Phil Carvey (Carvey and Milliken were members of the Butterfly team) designed and built a prototype of the world's first 40 gigabit per second router. The router design reflected BBN's painful experience with the Butterfly gateway. It including a switch designed specifically to move IP datagrams from arbitrary input interfaces to arbitrary output interfaces. (One of the lessons of the Butterfly experience was that IP traffic tended to include bursts of datagrams to a single destination, which could overload switches that assumed balanced traffic). Variants of this router architecture are now standard, and BBN's journal paper on the router is required reading at many corporations. BBN remains a center of expertise in the design and implementation of high-end router and router-like devices (for example, packet switches, firewalls and encryptors) today.
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