Download - Topology Mapping
![Page 1: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/1.jpg)
Topology Mapping
Bo Sheng
Sept. 15
![Page 2: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/2.jpg)
Outline
Overview Solutions
LTM ACE
Problems and discussion Conclusion
![Page 3: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/3.jpg)
Introduction
Topology mapping Mismatch between overlay and physical
infrastructure Topology optimization
![Page 4: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/4.jpg)
Introduction
Traffic problem Facts
95% of any pairs of Gnutella nodes are within 7 hops 50,000 nodes generate 1G/second, 330T/month
Reasons Blind flooding
Cycles, merge of multiple paths, neighbors exchange Topology problem
Multiple times over a physical link
![Page 5: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/5.jpg)
Introduction
Perfect match
S S
Network infrastructure Overlay network
![Page 6: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/6.jpg)
Introduction
Mismatch
S S
N1
N2
N3
Network infrastructure Overlay network
23
4
5
52
4
![Page 7: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/7.jpg)
Topology Mismatch
Problems Randomly choosing neighbors Logically close, but physically far away
S PN1 N2
![Page 8: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/8.jpg)
Topology Mismatch
Problems Unnecessary traffic
Inefficient utilization of bandwidth Only 2%~5% Gnutella connections link nodes within a
single AS (autonomous system) More than 40% Gnutella nodes are located within top 10
AS Delayed response
Do we need long-distance neighbors?
![Page 9: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/9.jpg)
Topology Mismatch
Solutions to traffic problem Selective flooding Topology optimization
Avoid cycles Mapping
For each message, how many times it is delivered over a single physical link?
![Page 10: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/10.jpg)
Performance Metrics
Traffic cost Search scope Response time Overhead
![Page 11: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/11.jpg)
Approaches
Location-aware Topology Matching (LTM), INFOCOM 2004
Adaptive Connection Establishment (ACE), ICDCS 2004
![Page 12: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/12.jpg)
LTM
Three main operations1. TTL-2-detector flooding
Message format Short Source IP& timestamp Long Source IP& timestamp, TTL1 IP& timesta
mp d(i,S,v)
Link cost
S N1IP(S),T(S)
IP(S),T(S)N2
IP(N1),T(N1)
d(i,S,1) d(i,S,0)
![Page 13: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/13.jpg)
LTM
Three main operations2. Low productive connection cutting
1. Case1: P receives d(i,S,1) and d(i,S,0)
S
P
N
will-cut list
![Page 14: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/14.jpg)
LTM
Three main operations2. Low productive connection cutting
2. Case2: P receives multiple d(i,S,0)
S
P
N1
N2
![Page 15: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/15.jpg)
LTM
Three main operations2. Low productive connection cutting
3. Case3: P receives one d(i,S,1) and multiple d(i,S,0)
S
P
N1
N2
cut list
![Page 16: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/16.jpg)
LTM
Three main operations3. Source peer probing
S
P
N1
![Page 17: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/17.jpg)
LTM
S
P
N1
N2
Step2.case2 S
P
N1
Step3
![Page 18: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/18.jpg)
LTM
S
P
N1
N2
S
P
N1
N2
Step2.case2Step2.case3
Step2.case1
Step2.case3
![Page 19: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/19.jpg)
LTM
S
P
N1
S
P
N1
Step2.case1Step3
![Page 20: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/20.jpg)
LTM
States
Case1
Step3
Case3
Case2
![Page 21: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/21.jpg)
LTM
Performance Traffic Search scope Overhead
![Page 22: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/22.jpg)
ACE
Step1: Probe link costs with neighbors Build neighbor cost table Exchange neighbors cost table with neighbors
![Page 23: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/23.jpg)
ACE
Step2: Create a minimum spanning tree among each
peer and its neighbors
S
E
F
G
414
15
620
S
E
F
G
414
6
![Page 24: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/24.jpg)
ACE
Step3: Replace neighbors
S
E
F
G
414
6
H
Case1: SH<SG
Case2: GH>SH>SG
Case3: SH>SG,SH>GH
![Page 25: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/25.jpg)
ACE
Depth of optimization (h-neighbor closure)
10 1520
12 148
7
A
B
C
D
E
A->B=10A->D=15
B->E=8D->E=14
E->C=7E->D=14
Total:68
![Page 26: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/26.jpg)
ACE
2-neighbor closure
10 1520
12 148
A
B
C
D
E
A
B
C
D
E7
A->B=10B->E=8E->C=7E->D=14
Total:39
![Page 27: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/27.jpg)
Discussion
Measurement Link cost is not accurate
Link cutting and cycles Heuristic to theoretical support
f (Pn,Tn)=?
![Page 28: Topology Mapping](https://reader034.vdocuments.us/reader034/viewer/2022051402/568158da550346895dc620d1/html5/thumbnails/28.jpg)
Conclusion
Importance Effectiveness vs. cost Future work