3.4. Implementation and Performance

So far, we have talked about what switches and routers must do without discussing how to do it. There is a very simple way to build a switch or router: Buy a general-purpose processor and equip it with a number of network interfaces. Such a device, running suitable software, can receive packets on one of its interfaces, perform any of the switching or forwarding functions described above, and send packets out another of its interfaces. This is, in fact, a popular way to build experimental routers and switches when you want to be able to do things like develop new routing protocols because it offers extreme flexibility and a familiar programming environment. It is also not too far removed from the architecture ...

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