university of alberta ece department network systems gangxiang shen, wayne d. grover extending the...
Post on 22-Dec-2015
213 views
TRANSCRIPT
University of AlbertaECE Department
Network Systems
Gangxiang Shen,Wayne D. Grover
Extending the p-Cycle Concept to Path-Segment Protection
Gangxiang Shen, Wayne D. Grover{gshen,[email protected]}
URL: http://hey.to/gxshen
2University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Outline
Background and MotivationConcept of Flow p-CyclesFlow p-Cycle Design ModelTest Methods and ResultsOperational Aspects and Potential
ApplicationsConclusions
3University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Basic Approaches to Transport Network Survivability
p-CycleSpan p-cycles (since 1998)Flow p-cycles (our topic)
MeshSpan PathSBPP
EfficiencySpeed
Ring1+1 UPSRBLSR
4University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Background: Span-Protecting p-Cycles
Characteristic: Ring-like switching speed and mesh-like capacity efficiency
0
1
42
378
9 6 5
10
Straddling span
0
1
42
3
78
96 5
10On-cycle span
5University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Comparison between Ring and p-Cycle Protection
Ring network: p-Cycle:
Spare Capacity
Protection
CoverageAble to restore 9
spansAble to restore 19
spans
6University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
The Unique Position Span p-Cycles Occupy
Redundancy
Speed
“50 ms”
100 %50 % 200 %
Path rest, SBPP
Span (link)rest.
BLSR
200 ms
p -cycles: BLSR speed
mesh efficiency
7University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Motivation
All the studies so far on p-cycles consider “span-protecting” p-cycles, so it is natural to ask: Q. is there is “a path protection
equivalent to p-cycles?” -- A. Yes the answer is “Flow p-Cycles” !
8University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Concept of Flow p-CyclesCharacteristic: Protect spans that span p-cycles can protect as well as spans that
span p-cycles cannot protect (example: span 6-7 below) Intermediate node failure restoration (example: node 7) Path restoration –like spare capacity efficiency, 1:1 path
protection –like switching speed
0
1
42
378
9 6 5
10On-cycle span
Straddling span
?
?0
1
42
3
78
96 5
10
Straddling flow
9University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
The Position Flow p-Cycles Occupy
Redundancy
Speed
“50 ms”
100 %50 % 200 %
Path rest, SBPP
Span (link)rest.
BLSR
200 ms
p -cycles: BLSR speed
mesh efficiency
Flow p-cycles
10University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Various Flow-to-Cycle Relationships
s
d
s
d
s
d
s
d
s
d
(a) (b) (c) (d) (e)
Related basic concepts•Intersecting and non-intersecting•Intersection nodes•Intersection flow segment•Straddling and on-cycle flow relationship
11University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Mutual Capacity Consideration
Single span-failure causes multiple flow-failures simultaneously
Flow-based restoration is required
0
1
42
3
78
96 5
10
Straddling flow
12University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Flow p-Cycle Design Model for 100% Span Failure Restoration
Objective: minimize total spare capacity
Constraints: Affected flows upon a span failure must be fully
restored Number of cycle copies to build is set by the
largest span failure-specific simultaneous use for unit copies of cycle
The spare capacity on a span must be enough to support the number of copies of each p-cycle that overlies the span
13University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Test Networks
NSFNET, N=14,S=21, |P|=139
ARPA2, N=21,S=25, |P|=18
Bellcore, N=15,S=28, |P|=976
SmallNet, N=10,S=22, |P|=833
14University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Result: Performance Comparison between Various Protection Schemes
0
0.2
0.4
0.6
0.8
1
1.2
1.4
SP SR flow p-cycles
PR (stubno release)
PR (stubrelease)
Protection schemes
Re
du
nd
an
cy NSFNET
ARPA2
SmallNet
Bellcore
15University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Operational Aspects and Protocol
s
f
Rtable:
Failedspan ID
Affectedconnection IDAIS
001 33 1 1 e?
Rtable
d
a
b
eg
p-cycle 1
p-cycle 2
Span ID=001
Connection ID = 33
Failedspan ID
Affectedconnection ID
p-cycleID
RequiredCapacity
FlagPeer node
IDOutlet
span1 IDOutlet
span2 ID
AIS 001 33
AIS 001 33
! !
c
16University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Applications of the General Concept
OXCOXC
OXC
OXCOXC
OXC
OXC
OXC
OXC
p
Regional expressflow - protecting
p-cycle(s)
Localspan - protecting
-cycles
17University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Conclusions
Flow p-cycle concept was proposed and evaluated
Flow p-cycle method achieves path restoration –like spare capacity efficiency and 1:1 path protection –like restoration speed
18University of AlbertaECE Department
Network Systems
Gangxiang Shen and Wayne D. GroverICC2003, Anchorage, Alaska
Future Work
Identify the impacts from the network details and demand patterns
Further consider operational aspects and develop control protocol
Implement some applications of the general concept
Consider an evolutional scheme, pre-configured segments: p-segments
Compare to “ordinary” node-encircling p-cycles for node protection.