Chapter 11: Prefix-match lookups

You can look it up.



Prefixes have been used to compress a large database, but at the cost of a more complex longest-matching-prefix lookup. As described in Chapter 2, the Internet uses the same idea. In the year 2022, core routers stored only around 900,000 prefixes, instead of potentially billions of entries for each possible Internet address. For example, to a core router all the computers within a university, such as UCLA, will probably be reachable by the same next hop. If all the computers within UCLA are given the same initial set of bits (the network number, or prefix), then the router can store one entry for UCLA instead of thousands of entries for each computer in UCLA.

The world has ...

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