The MPLS WG Archive

[neil.2.harrison@bt.com]

	Eric...see below:

> Neil> With all due respect Eric, I  think your comments as regarding MPLS
> as
> Neil> an extension  to IP  is the root  of many  of the problems  people
> are
> Neil> expressing with MPLS 
> 
> I would say  to the contrary that the folks who  tend to express
> unhappiness
> are just the ones who fail to see that MPLS is simply an extension of IP.
	NH=> I am not unhappy with MPLS and I don't see it just as an
extension of IP.  Indeed, I see it as a possible (indeed the only possible)
way to unify CO/CNLS transfer modes (for application a priori selection)
that may be needed one day to properly solve QoS and reduce unecessary
network complexity and/or ineffectiveness (which arises if one tries to do
everything in either a CO or CNLS mode only).  I am not going to explain
this again here as I have done so before.  

> If you try to think of MPLS as a different, independent layer, then you
> will
> inevitably end  up confusing yourself.   This confusion manifests  itself
> in
> several forms:
	NH=> I don't 'think' of MPLS as a new layer network and I can assure
you I am not confused.  It is a layer network by definition.  If you add
overhead to some payload (from a higher client layer, eg IP or indeed a
higher LSP) at point X and remove it at point Y then that constitutes a
trail in functional architecture (see G.805).  I, and many others,
understand these issues very well......and they are people who are not
confused.  Indeed, the main confusion I see directly stems from 2 facts:
	(a) that functional architecture is not understood/applied by many
people (usually those who only subscribe to there being only one L3
network.....that OSI model has a lot to answer for)
	(b) that MPLS user-plane functionality (ie the overhead applied to a
payload to create a trail entity) is quite a different/disjoint issue from
GMPLS where the (user-plane) trail OH is untouched but the goal is a common
control-plane across all forms of user-plane trail technologies.
	<snip>

> I think this  misunderstanding of MPLS can be found  both in "bellheads"
> and
> in "IP bigots", though it comes out in different ways.
	NH=> I agree sadly. But if we keep talking and are prepared to
listen we will (I hope) reach a better common understanding one day.