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CS710. INFOCOM 2007 Disjoint Multipath Routing to Two Distinct Drains in a Multi-Drain Sensor Network Preetha Thulasiraman, Srinivasan Ramasubramanian and Marwan Krunz University of Arizona. September 16, 2008. Shinae Woo. Multipath routing for WSN. Disjoint multipath routing!.
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CS710 INFOCOM 2007 Disjoint Multipath Routing to Two Distinct Drains in a Multi-Drain Sensor Network Preetha Thulasiraman, Srinivasan Ramasubramanian and Marwan Krunz University of Arizona September 16, 2008 Shinae Woo
Multipath routing for WSN Disjoint multipath routing! Sensor node Drain
Problem definition • DRMD-2 problem • Disjoint Routing in a Multi-Drain network • |D| trees, each rooted at a distinct drain • Every node has two node-disjoint path to two distinct drain 2 2 2 2 6 5 6 5 6 6 5 5 c 7 4 c 7 4 c c 7 7 4 4 3 3 3 3 b 8 b 8 b b 8 8 1 1 1 1 9 a 9 a 9 9 a a
Colored tree • Two trees rooted at a drain • Every node has a two disjoint path to the drain a b c a b c 7 8 9 7 8 9 4 5 6 4 5 6 1 1 2 3 2 3 Red tree Blue tree
Construction of colored tree 1 7 2 9 3 6 4 5 8 Theorem Graph G is 2-node connected -> G has a solution of colored tree
Removing backtracking 1 1 2 (1,3) • generalized low-point • Lowest DFS-index traversing a sequence of nodes increasing DFS-index with the exception of last hop • Value (GLPV), path , neighbor (GLPN) • Provide shorter path than low-point 7 (1,4) 3 2 (1,5) 4 9 3 6 Back edge 5 (1,6) 4 (1,7) (6,9) 6 8 5 8 (1,1) 7 9 (6,6)
Colored tree for two drains • Every node has a path to the two drains that are node-disjoint 2 2 7 8 7 8 3 6 9 3 6 9 4 5 a 4 5 a 1 1 c b c b
Solution for colored tree to two drains • Make a virtual drain d • Make a colored tree • One tree is rooted at drain 1, the other tree is rooted at drain 2 • Remove virtual drain 2 2 2 2 7 7 8 8 7 7 8 8 2 3 3 6 6 9 9 7 3 3 8 6 6 9 9 4 4 5 5 a a 3 6 4 4 9 5 5 a a d d d 1 1 1 1 c c b b 4 5 a c c b b 1 c b
Problem definition review • DRMD-2 problem • Pairs of two distinct drains |D|C2 O(|D|^2) 2 2 2 6 5 6 5 6 5 c 7 4 c 7 4 c 7 4 3 3 3 b 8 b 8 b 8 1 1 1 9 a 9 a 9 a
CTMP problem • |D| tree pairs • ( a primary drain, the other secondary drains) • (d1, {d2, d3}) , (d2, {d1, d3}) , (d3, {d1, d2}) • Every node has a tree pair • Two paths to a primary drain and one of the secondary drain are node-disjoint 2 2 2 6 5 6 6 5 5 c 7 4 c c 7 7 4 4 S S S 3 3 3 b 8 b b 8 8 1 1 1 9 a 9 9 a a
Integer programming V P S P S P S 2 2 2 6 5 6 5 6 5 c 7 4 c 7 4 c 7 4 3 3 3 b 8 b 8 b 8 1 1 1 9 a 9 a 9 a 6 5 c 7 4 b 8 9 a
Distributed Algorithm • Distributed DFS numbering • Distributed path augmentation • Node which has TOKEN initiate path search • Each node forwarding SEARCH message • To find a new path • If there are no neighbor to initiate path search, passing TOKEN to another node • If there are no more node to passing TOKEN, it complete. • Graph Selection • Choose a tree pair among |D| tree pairs
Distributed DFS numbering 3 Low-point table (to each drain) Example of node 4 4 – 7 – 8 – 9 – d1 4 – 7 – b – d2 4 – 7 – 8 – d3 4 5 2 2 6 5 6 1 c 7 4 7 3 b 8 8 1 9 a (1,7) 9 b (1,1) a c Back edge Forwarding edge
Distributed path augmentation • (d3, {d1, d2}) 2 2 2 6 5 6 5 6 5 c 7 4 c 7 4 c 7 4 token 3 3 3 b 8 b 8 b 8 1 1 1 9 a 9 a 9 a
Graph Selection • |D| tree pairs • Each has two tree • One is rooted at primary drain (red tree) • The other is rooted at one of secondary drains (blue tree) • Calculate the path length to each tree • Each node choose the tree pair which has the smallest average path length (of red tree and blue tree) • ⌈ log|D| ⌉ bits for choosing tree pairs • 1 bits for choosing red or blue tree
Comparing with optimal solution Average path lengths # of nodes
Distinct drains vs. Same drain Average path lengths # of nodes 50 100 300 1 out of n 2 out of n
Conclusion • Objective • Constructing multiple trees rooted at distinct drains • Every node has a path to two drains which are node-disjoint • Contributions • Solve CTMP problem • O(|L|) time complexity • O(|D||L|) message complexity • Significant path length reduction • Compared with sending to one out of multiple drain