Re: That routing/redirection thing: mapping (?)

[Markus Hofmann <hofmann@bell-labs.com>]

Gary Tomlinson wrote:

> The term mapping works well.  I assume the term is then "Request Mapping"?

Well, I don't like the term "Request Mapping" in this context, because
mapping only refers to the process of finding the "best" surrogate for
a specific client (i.e. mapping the client to a surrogate). But it
does NOT include the acutal forwarding / direction / redirection /
navigation / steering, because different mechanisms can be used here
(e.g. DNS based, URL rewriting, etc.).

Every DIRECTION system consists of two parts:
  (a) the mapper (i.e. finding the best surrogate), and
  (b) the actual redirection mechanisms, i.e. the "client
      front end" that makes use of the mapper result and
      makes sure that the client request ends up at the
      correct surrogate.
We can use the same mapper module with different "front ends", for
example use the mapper module with a DNS front end or with URL
rewriting.

Therefore, it is important to distinguish between the actual MAPPING
(i.e. determining the best surrogate) and the process of telling the
client the best surrogate (the DIRECTION or whatever). In the IP
context, the correspinding terms are "routing" (i.e. mapping in the
CDN context) and "forwarding" - and what we really want to describe
corresponds to "forwarding"....

-Markus