untangling_the_web

DID: 4046925
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ISP (AS3) in Chicago because there is no direct connection between Regional ISP
(AS1) in Baltimore and Regional ISP (AS2) in Los Angeles and going through
multiple third party networks would be both slow and costly. Does this look familiar?
It is the same principle that was at work in the way routers handle IP addresses.
Think of the routing of Internet packets as analogous to airline travel. Imagine you
need to fly from Dallas to Damascus, Syria. There is no direct flight, so you must first
fly to Washington Dulles Airport, change planes and carriers, then fly to Nicosia,
Cyprus. Once there, you must again change planes and carriers to get to
Damascus.
Internet traffic moves in much the same way. The airline is analogous to an
Autonomous System. Each AS has a limited number of other AS's with which they
exchange data, just as American Airlines does not have a direct connection with
Syrian Airlines. Similarly, Dulles Airport is analogous to MAE-East, a major Internet
Exchange Point along the East Coast of the US.
Internet Exchange Points
Internet Exchange Points are physical locations where different networks exchange
traffic, much like large airport hubs such as Washington's Dulles or London's
147 "Border Gateway Protocol," Cisco Documentation, Cisco.com,
(14 November 2006).
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