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PART III Playing with Routers > CHAPTER 15 Routers as Distributed Systems - Pg. 362

C H A P T E R 15 Routers as Distributed Systems Come now and let us reason together. -- Isaiah 1:18, The Bible Distributed systems are clearly evil things. They are subject to a lack of synchrony, a lack of assurance, and a lack of trust. Thus in a distributed system the time to receive messages can vary widely; messages can be lost and servers can crash; and when a message does arrive it could even contain a virus. In Lamport's well-known words a distributed system is "one in which the failure of a computer you didn't even know existed can render your own computer unusable." Of course, the main reason to use a distributed system is that people are distributed. It would perhaps be unreasonable to pack every computer on the Internet into an efficiency apartment in upper Manhattan. But a router? Behind the gleaming metallic cage and the flashing lights, surely there lies an orderly world of synchrony, assurance, and trust. On the contrary, this chapter argues that as routers (recall routers includes general inter-