IEEE SoftCOM 2010 Bol (Brac), 23-25 September 2010. MPR-based Pruning Techniques for Shortest Path Tree Computation. Juan Antonio Cordero Équipe Hipercom -- INRIA Saclay (France). 18 th International Conference on Software Telecommunications and Computer Networks.
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Bol (Brac), 23-25 September 2010
MPR-based Pruning Techniques for Shortest Path Tree Computation
Juan Antonio Cordero
Équipe Hipercom -- INRIA Saclay (France)
18th International Conference on Software Telecommunications and Computer Networks
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Agenda
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Motivation (1)
Flooding in Wireless Ad hoc Networks
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Motivation (2)
Multi-Point Relays (MPR)
MPR coverage criterion
Every 2-hop neighbor of the source is covered by (at least) one relay
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Agenda
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Topology
Advertisement 1
Topology
Advertisement 2
Topology
Acquisition
Shortest Path Tree
Computation
.
.
.
Topology
Advertisement n
Topology Pruning
Topology Pruning in Link State Routing
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Agenda
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Topology
Advertisement 1
Topology
Advertisement 2
Topology
Acquisition
Shortest Path Tree
Computation
.
.
.
Resulting overlay
Topology
Advertisement n
MPR for Topology Pruning (1)
Requirements
Rest of the network
Computing node
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
7
1
7
1
1
2
3
2
3
6
6
4
5
4
5
8
8
MPR for Topology Pruning (2)
Overlay Connection
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
MPR for Topology Pruning (3)
Preservation of Shortest Paths
(from a node s)
The local shortest path between two nodes x and y, reachable in 2 hops,
is the path in 2 or less hops between x and y with minimal cost.
local reverse shortest path to x
network-wide direct shortest path from s
4
2
network
1
min.cost
3
1
x
s
2
7
2
For an overlay that includes all links from s,
Preservation of links to 1-hop neighbors providing local reverse shortest paths to x, x
Preservation of network-wide direct shortest paths from s
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
MPR for Topology Pruning (and 4)
Summary of Results
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Agenda
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Path MPR (1)
Selection of links to advertise
Path MPR Selection
Cost-Coverage
Translation
MPR Selection
N(x)
N2(x)
N’(x)
N2’(x)
PathMPR(x)
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Path MPR (2)
Resulting Overlay
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
2
1
1
4
1
3
1
3
3
1
1
5
6
Path MPR (3)
(Non) Preservation of shortest paths
N(1)
N2(1)
N’(1)
N(1) = {2, 3, 6}
N2(1) = {4, 5}
N’2(1)
N’(1) = {2, 3}
N’2(1) = {4, 5}
PathMPR(1) = {3}
Shortest_Path(41) = 4-2-1
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Path MPR Selection
N(x)
N2(x)
E2x
N’(x)
N2’(x)
E2x’
Cost-Coverage
Translation
MPR Selection
PathMPR(x)
Path MPR (4)
Proposed correction
(E2x)’ = {Links taking part in local reverse shortest paths to x}
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
N’(1)
2
1
2
1
1
1
4
4
N’2(1)
1
1
3
1
3
3
1
3
3
1
1
3
1
1
5
6
5
6
Path MPR (and 5)
Proposed correction
N(1) = {2, 3, 6}
N2(1) = {4, 5}
N’(1) = {2, 3}
N’2(1) = {4, 5}
(E2x)’ = E2x \ {(6,1), (4,3)}
PathMPR(1) = {2, 3}
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Agenda
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
A first impact estimation (1)
Distance-based costs
+
Proposed modification
Path MPR (RFC 5449)
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
A first impact estimation (2)
Random costs
+
Proposed modification
Path MPR (RFC 5449)
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Conclusions & Future Work
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Questions ?
E-mail: [email protected]
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Multi-Point Relays Heuristics
Input: x, N(x), N2(x)
MPR = {}
MPR {n N(x) : m N2(x), m only covered by n}
while ( uncovered 2-hop neighbors)MPR n N(x) : covers max. # of uncovered 2-hop neighbors
Output: MPR(x, N(x), N2(x))
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
1
2
3
4
(k-1)
2k-1
2k
Examples of MPR overlay disconnection
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Path MPR Definitions
MPR-based Pruning Techniques for Shortest Path Tree Computation
IEEE SoftCOM 2010
Static Simulation Parameters