[e2e] e2e principle..where??....

[Jon Crowcroft]

In message <200106041507.LAA19141 at ginger.lcs.mit.edu>, "J. Noel Chiappa" typed:

 >>    > this .. does reduce the responsiveness since you ONLY get to react
 >>    > edge-to-edge to local outages instead of having local recovery
 
 >>Not so. People have designed explicit-routing systems which allowed local
 >>repair. The trick is to have intermediate entities advertise higher-level
 >>topology abstractions. If one component which is being used to provide
 >>that abstraction fails, as long as the entity can reconstitute an
 >>equivalent "implementation" of the abstraction from other resources,
 >>nobody needs to know. The process can recurse, of course.

yes so:-
when you do this, you give up control - i.e. you are landmark or 
loose source routing - for the intermediate entites to "abstract" (just once, or
recursively, or iteratively, or telepathically) they have to do routing exchanges 
to tell each other "metrics" of equivalence for comparison and to make such decisions 
on what to advertise - aint no such thing as a free lunch
 
 >>Of course, if it's a long-lived flow, you can move some of the information
 >>into the switches - but let's not go down that rathole!
 
gumpless? (or is it mumble-ized general-protocol label switching? :-)

if its a long lived flow, you can move some information out of the switch into the header, as it s less
surprising that way.

 cheers

   jon