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Re: Why IPv6 is a must?

2001-11-12 16:50:02
| at present our locators are AS numbers.

No, Keith, they are not.

The AS number does not describe a location in any sort of topology.
It is simply a representation of a set of routers with the same
routing policy, that should not receive via eBGP NLRI which 
have originated from or passed through said routers.

The AS number is otherwise completely meaningless, although
the AS path itself is a funny sort of non-scalar metric.
(See the work of Ahuja and Labovitz for details on that).

A locator by definition must describe a precise location within 
a network, such that any router will be able to forward traffic
towards that network using only the information in locator.

In IPv4, the locator *is* the IPv4 address, independent of
what inter- or intra-domain routing system is being used.

| if we change the system to use a different kind of locator we still
| need stable addresses, we still have to maintain the mapping 
| function from addresses to locators, and we still need that mapping
| function to be current and reliable.

End-to-end/globally-unique identifiers are very convenient indeed.
However, identifiers and locators are different.
There is no reason to overload them, and it's a bad habit.
It's also a bad habit to think that locators need to be
end-to-end or globally (rather than contextually) unique.

| what we are arguing about is the appropriate granularity of the 
| mapping function, and the appropriate place to maintain that mapping.

No, we are not arguing about that, but these are indeed issues.

        Sean.



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