Brian Carpenter writes to Anthony Atkielski:
| > The telephone company figured out how to avoid problems decades ago. Why
| > the computer industry has to rediscover things the hard way mystifies me.
|
| The telephone company has milliseconds to seconds to resolve an address
| into a route. The Internet has microseconds to nanoseconds to do so.
You are missing the difference between "what" and "where".
The telephone company takes milliseconds to translate the equivalent
of 6.6.9.9.9.6.6.8.6.4.e164.net into the equivalent of 192.36.143.3.
That is, the phone number is merely an identity name, which is converted
into a location name by a database lookup.
The principal difference between hop-by-hop packet-based networks and
circuit-based networks is that in the former the location name does
not require negotiations among the intermediate systems, or between
the first-hop IS and the originating end system. There is a simple
assumption that each hop will be able to make a reasonable forwarding
decision on any location address, even if the location address is
"unexpected". In circuit-based networks, this is not generally the case.
The means and costs of translating a "what" address into a "where"
address are often strikingly similar in both circuit-based and
hop-by-hop packet-based networks.
Sean.