[e2e] a means to an end

Noel Chiappa jnc at mercury.lcs.mit.edu
Sun Nov 9 06:48:21 PST 2008


    > From: "David P. Reed" <dpreed at reed.com>
    > Date: Sun, 09 Nov 2008 07:31:00 -0500

    > why not multiple competing "routing" layers?
    > ...
    > Rather than a "single routing strategy to rule them all" perhaps they
    > should compete for business, overlaid on a universal world-wide "dumb"
    > fabric that they use in creative ways?

By "routing", do you mean 'forwarding of user traffic', or 'selection of paths'?

If the former, the whole concept of MPLS was to allow a single fabric to be
used to simultaneously support multiple different traffic handling paradigms;
so one could have, for want of a better term (connection-based drags in too
many other concepts), a flow-based paradigm running simultaneously with a
pure datagram model (i.e. no setup, no concept or recognition of traffic
aggregates).

If the latter, some previous work I did tried to bring in the concept of
allowing competing path-selection algorithms. The design did share a single
underlying database of information about the network between them (of
connectivity), but it seemed to me that that level of commonality didn't
unduly burden the ability to go different ways, and having that common
underlying database had advantages that offset its disadvantages. I know
there is a position that there are some connectivity models which can't be
represented in the model we picked (a graph), but the architecture did allow
non-graph connectivity models in localized areas, and I still think that for
the overall representation of the global network, the graph model is best.

	Noel


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