RE: Comment on draft-shiomoto-ccamp-gmpls-mrn-reqs-00.txt

[<neil.2.harrison@bt.com>]

John,

<snipped>
> > .....in fact a large supplier of ours recently admitted 
> (after 3 years 
> > of trying to persuade us otherwise) that they now agree with us on 
> > this.
> <John Drake>
> 
> It's not unusual for a vendor that is incapable of building 
> <something> to assert that <something> is a Bad IdeaTM.
NH=> Well, one could also look at this differently.....given we worked
out the facts several years ago on our own and nothing has happened
since to show we were wrong, then one could say that we know this vendor
is now at least trying to be honest with us on this issue.
> 
> > Those who think they can 'create topology on the fly' can 
> believe in 
> > this stuff if they like.....you will convince me the day I see a 
> > routing protocol lay a duct and light some fibre, till then we'll 
> > stick with what we know is true.
> <John Drake>
> 
> We never said that GMPLS had a backhoe option.
NH=> Try this logic.....and this is only one example of a given layered
network sequence:
-	to run the ducts we need the back-hoe
-	to run the fibre we need the ducts in place
-	to run the SDH MS/RS we need the fibre in place
-	to run the SDH VC4 layer network we need the SDH MS/RS in place
-	to run IP/MPLS layer networks we need the VC4 layer network in
place.

Do you see the logical dependency?  Put simply, one cannot create
topology on the fly....at some point in the above you are going have to
assume some 'already in place/fixed' topology.  But it's not even as
simple as that.......

Let's consider some of the commercial issues here as they are rather
important.  Ever tried figuring out the design rules required in some
co-cs transport network (like SDH VC4 or OTNs say) so that one can
'create a trail at will' (an SVC by any other name)....or at least to
some acceptable GoS (Grade of Service), ie probability of capacity being
available within an acceptable (to the client) time period post making
demand?

Folks should try it some time as the results are rather illuminating.
We did this with our traffic engineering maths group at the labs a few
years ago.  Without going into the detail, if you want to be able to
'turn-up' seriously large BW trails on demand between various locations
you are going to have a build a network that runs largely empty for most
of its working life....now try getting a business case for this past the
products/services/financial people ;-).

And once one turns up a trail in some lower layer network, do you
seriously expect we operators will turn it off?

Bottom-line...as one gets closer to the duct the holding time of
trails/topology must increase.

Note - These issues are over/above the requirement for
commercial/functional isolation between different operating parties in a
client/server layer network relationship.

regards, Neil