1. Immediate-request vs. scheduled calls Short-duration vs
Immediate-request vs. scheduled calls Short-duration vs. long-duration calls
Malathi Veeraraghavan
University of Virginia
Control-plane solution offered by industry: GMPLS
Purpose of GMPLS signaling/routing/LMP
Distribute bandwidth (BW) management functionality to switches

2. Steps executed by a signaling engine at a switch for call setup
Path message
(requesting BW)
(to next switch
on path)
Route lookup 
Path message
(requesting BW)
Check BW availability (CAC)  
Select timeslots//ports/labels 
Program switch fabric
These 4 functions are distributed:
i.e, they are executed at each switch

3. Extent of CAC algorithm implemented
First-Come First-Serve (FCFS)
Simple Complete Sharing mechanism
Keep giving out BW until you run out.
Then block calls

4. Suitability for long- vs. short-duration calls
Fine answer for short-duration calls
Not so, for long-duration calls
Why?
Basic queueing theory
Mean waiting time related to mean call duration

5. Implication
If science apps. require a rate-guaranteed connection to be set up and left in place for a long duration, then
Cannot use this simplisitic Complete Sharing CAC mechanism

6. Direction headed by this community
Build a scheduler
What is the job of the scheduler?
BW management!
With a time parameter – when to schedule
Now, didn’t we just say that BW management is function of the GMPLS engine distributed at each switch?

7. Takes us partially “backwards” towards a centralized solution
Route lookup/computation 
A new protocol (BW requested + time)
Scheduler
Answer
Check BW availability (CAC)
(across multiple links) 
Third-party Path message with ERO
(just before scheduled time)
Path message 
Select timeslots//ports/labels 
Program switch fabric

8. My answer Short-term: Long-term: Partition BW on interfaces between
centralized scheduler control, and
distributed GMPLS signaling engine control
Long-term:
Make proposals to add parameters related to future scheduling (time of request, duration of request) to GMPLS protocols

9. Why this long-term answer?
Volume of literature on multi-class CAC
CBR, VBR, ABR
Upper Limit Guaranteed Minimum (ULGM)
or Virtual partitioning
Complete
partitioning
sharing
High efficiency
Poor service quality
Low efficiency
High service quality
Our problem: multiple classes but of new types!
Immediate-request/scheduled calls
Short-duration/long-duration calls
Long-path/short-path calls