presentation - University of Alberta

Comments

Transcription

presentation - University of Alberta
Exploiting Forcer Structure to Serve Uncertain
Demands and Minimize Redundancy
of p-Cycle Networks
Gangxiang Shen & Wayne D. Grover
TRLabs and University of Alberta
Edmonton, AB, Canada
web site for related research group:
http://www.ece.ualberta.ca/~grover
OptiComm 2003,
October 13-17, Dallas, Texas
Outline
• Conventional survivable network design
• What is a forcer and what is the meaning of a forcer in a
p-cycle network?
• Exploitation of forcer structure for a p-cycle network
• Experiments and results
• Conclusion
2
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Conventional Survivable Network Design
2
5
w=9
4
1
6 3
6
Node index
1
2
3
4
5
2 3 4
3 1 2
5 6
2 3
2 2
1
3 2
1 3
3 3
3
2
4
5
4
5
3
6
6
Network with working capacity
Network topology
1
6
1
3
5
2
Survivable network design
methods, e.g., span
restoration, path
restoration, p-cycle,
SBPP, flow p-cycle,
path-segment restoration…
?
Who forces this span to
require 5-unit spare capacity?
s=6
Here span restoration
method was employed
6
5
2
4
1
9 3
5
4
5
0
1
4
5
6
Network with protection capacity
Demand matrix
3
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
What is a Forcer?
“A forcer is any span for which an increase in network total
spare capacity is required (to retain restorability) if the span’s working capacity is increased.”
Have a look at the previous example again
w=9
5
2
1
6 3
6
2
4
5
4
5
6
s=6
4
1
3
9 3
6
Network with working capacity
5
2
5
4
5
0
1
4
5
6
Network with protection capacity
2
1
forcers
3
3
4
6
4
5
2
6
non-forcers
Network forcers
4
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Forcer in p-Cycle Networks
“A forcer is any span for which an increase in p-cycle spare capacity (corresponding to
total network spare capacity) is required (to retain restorability)
if the span’s working capacity is increased.”
0
1
0
3 3
5
6
3
7
6
4
w=6
1
3
2
2
3
Straddling span
1
3
5
8
4
6
9
1
3
A p-cycle with 3-unit spare capacity
2
3
6
3
10
11
On-cycle span
p-cycle
Forcer span
p-cycle protected envelope
12
5
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Forcing Chain in p-Cycle Networks
p-cycle 1 p-cycle 2
p-cycle 3
p-cycle 4
Span working capacity
p-cycle N
p-cycle spare capacity
Span protection capacity
How should we
deal with this gap?
p-cycle protected envelope
Protected working capacity envelope
Span working capacity
Span working capacity
6
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
How to Exploit the Gaps?
Forcer Filling: adding working capacity to non-forcers to make them forcers;
the added capacity can be used to serve future uncertain demands.
… the basic idea of this paper
Protected working capacity envelope
Span working capacity
Protected working capacity envelope
Just use it! No need to pay for
anything for protection
!
Extra protected span working capacity for
future uncertain demands
Span working capacity after forcer filling
7
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Forcer Maximized Design and its Relation to
Conventional Design
Regular design
Forcer maximized design
Totalspare
network
spare capacity
Span
capacity
budget
budget
Working demand pattern
Network
topology
Network
topology
Minimize required
spare capacity for
restorability
Maximize extra
servable protected
working channels
8
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Three ILP Models
•
Common ground of the three models
--Objective: Maximize total servable protected working channels
--Conditions: 1. Ensure the restorability of working capacity
2. Ensure spare capacity shall be within budgets
•
Forcer analyzer (FA) model
Maximize extra servable working channels, but disallowing to touch the existing working
channels
•
Forcer maximization-1 (FM-1)
Maximize servable working channels given span spare capacity budgets, but allowing to
change the existing working channels
•
Forcer maximization-2 (FM-2)
Maximize servable working channels given total network spare capacity budgets, but
allowing to change the existing working channels
9
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Test Methods and Network Topologies
1.
2.
3.
Two metrics: hop-based and physical distance-based
Dijkstra’s shortest path algorithm is used to find the route for a working path
Demand matrixes are randomly generated within the range [1-20] for each node pair
NSFNET
ARPA-2
COST239
SmallNet
10
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Test Methods and Network Topologies (cont’)
Level-3 network
11
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Percentages of extra servable working
channels without any increase in spare
capacity budget
Results of the FA Model for p-Cycle Networks
90
80
70
ARPA2
NSFNET
SmallNet
COST239
Level3
60
50
40
30
20
10
0
Hop-based
Distancebased
Percentages of extra working channels that can be served
in p-cycle networks without any increase in span spare capacity budget
12
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Redundancy Comparison between Various Survivable
Schemes
1: Conventional design 2: Forcer analyzer (FA)
3: Forcer maximization-1 (FM-1) 4: Forcer Maximization-2 (FM-2)
13
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
Concluding Discussion
• A simple but efficient forcer analyzer is developed
• Two forcer maximization design models are proposed
• Experiments show that there is a rich “protected working capacity
bank” under the forcer structure formed in the conventional survivable
network design
• The direct use of protected capacity in the “bank” to serve future
uncertain demands
……”Just use it! No need to pay any extra spare capacity
for protection! (Its already protected)”
• Neighbouring concept to this study is to use “protected working
capacity envelope (PWCE)” to serve dynamic protected demands for
efficiency and simplicity
Thanks!
14
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas
How to Deal with the Gaps?
--Clipping and Filling
Forcer Clipping: clipping forcers to make non-forcers become forcers as well
and to improve network spare capacity efficiency
Protected working capacity envelope
Span working capacity
Protected working capacity envelope
Ring covering
Remaining span working capacity
Clipped span working capacity
15
Gangxiang Shen and Wayne D. Grover
OptiComm ‘03 Dallas

Similar documents