In hope of maybe clearing out some of the confusion:
Brian E Carpenter wrote:
> > I fail to understand how either would break if they simply intrepret the
> > flow label semantics as 'the source has identified this set of packtes
> > as related'. In either case there is an out-of-band mechansim to
> > translate the value to a router task.
This could include "behavior aggregate flows"?
> But in the diffserv case, which is stateless (no signalling,
> no soft state)
> the only out-of-band mechanism that works is if the flow label has
> intrinsic semantics. The fact that the packet belongs to a class is
> useless information on its own; you need to know what that
> class means,
> and that can only be conveyed by an encoded field, since there is no
> signalling or state.
A PHB-ID in the flow label is NOT the semantics, but a pointer to the
semantics. The actual semantics are found from the respective specification,
and since all the possible (future) PHB-ID pointed semantics cannot be
hard-coded into the router, they need to be delivered to the router by some
out-of-band mechanism. This out-of-band mechanism will indeed establish
state at the router, not source specific state, but behavior aggregate flow
specific state. One could even imagine establishing this state with an
end-to-end signaling mechanism, which would result in a kind of host-to-host
specific behavior aggregate flow (RFC 2460 App.A could be read this way
already). Could be useful for e.g. experimental use??
Jarno
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