Is the advertisement (IGP) of available BW at each pre-emption level is a DS-TE- requirement ?

["Choudhury, Sanjaya" <Sanjaya.Choudhury@marconi.com>]

	Hi! I have few questions related to the LSP pre-emption in a DS-TE
	environment. I will appreciate, your help with these questions.

	Q1. If we support pre-emption _across_ different DiffServ classes,
	then what is the advantage in advertising available bandwidth for
each
	class at _each pre-emption level_ ?

	Q2. In general, does the advertisement of available of bandwidth
	at each pre-emption priority level, help in building/managing a 
	TE network ? 

	[Considering that at time t1 , there is might be enough BW for 
	class-x/priority-3, however at time t1+2min another LSP with	
	priority-2 might preempt the previous LSP.]

	Q3. In a DiffServ TE domain, where the network administrator
	initiates the creation the TE tunnels (using MPLS-TE-MIB ),
	when/how can he take advantage of the following pre-emption 
	scheme:
		a) Preemption within the same DiffServ traffic class 
		b) Preemption across different DiffServ traffic classes 

	Thanks,
	sanjay