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Region Topology Aware Routing for DTN. AsiaFI School on Mobile and Wireless Networks 2009. 01. 15 Presented by Dukhyun Chang (dhchang@mmlab.snu.ac.kr). Contents. Introduction Proposed Algorithm : RTAR Simulation Results Conclusion. Introduction.
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Region Topology Aware Routing for DTN AsiaFI School on Mobile and Wireless Networks 2009. 01. 15 Presented by Dukhyun Chang (dhchang@mmlab.snu.ac.kr)
Contents • Introduction • Proposed Algorithm : RTAR • Simulation Results • Conclusion
Introduction • Many routing protocols for DTNs are based on Flooding • Epidemic Routing, PRoPHET, Spray and Wait … • Epidemic Routing • Transfers messages that the encounter doesn’t have • Very high message overhead • Spray And Wait • Limits the number of message copies • L : max # of message copies • Consists of Spray phase and Wait phase • PRoPHET • Probabilistic Routing Protocol using History of Encounters and Transitivity • Uses delivery predictability • These are not proper when a network is divided into some groups
Introduction • In our proposal • Exploits network topology and mobility information • Network Topology • The networks consist of sub networks (“regions”) • Nodes move within regions or between regions • We propose • Region Topology Aware Routing (RTAR) for DTN
RTAR: Assumptions and Data Structures • Some assumptions • A node doesn’t know • Location of destination node • What regions are exists • A node knows • Region ID where I am located • Which region contacted node goes for • Data structures • Region vector: detected region information • Table mapping (region ID, # of tokens) to each messages
RTAR: Basic Operations • Controls the # of message relays with the region and mobility information • A source creates the limit of # of message relays (token) for known regions • All nodes having tokens handover tokens • Half of tokens for current region id to contacted intra-region nodes • All of tokens for other region to a first contacted node which goes for that region • Creates tokens for newly found regions
RTAR Example (1/2) Spread message with in region Hand over a half tokens Create message Allocate tokens Region 1 Region 2 Region 1 Region 2 Region 3 Region 3 C C E E I I D B D G G B A H A F M(R1:4,R2:4) F M(R1:2) H M(R1:2,R2:4) Message is spread to other region Hand over all tokens Region 1 Region 2 Region 3 Region 1 Region 2 Region 3 M(R1:1) M(R1:1) C C E I I B B M(R2:2) E M(R1:1) M(R1:1) M(R2:4) G D G D M(R2:2) H H A A F F M(R1:2) M(R1:2)
RTAR Example (2/2) Region 1 Region 2 Region 3 Region 1 Region 2 Region 3 M(R1:1) M(R1:1) C C M(R2:2, R3:2) I I M(R2:2) B M(R3:2) B E E G G M(R1:1) M(R1:1) D D M(R2:2) M(R2:2) H H A A Detect new region from region vector Allocate new tokens Hand over all tokens F F M(R1:2) M(R1:2) Message is arrived to the destination Message is spread to other region that A doesn’t know Region 1 Region 2 Region 3 Region 1 Region 2 Region 3 M(R1:1) M(R3:1) M(R1:1) C C I I M(R2:2) M(R2:2) B B E E H M(R1:1) M(R1:1) D D M(R2:2) M(R2:2) G G H A A F M(R3:1) F M(R3:1) M(R3:1) M(R1:2) M(R1:2)
Simulation Setting • Simulator: Opportunistic Network Environment (ONE) • Regions • Unit Region Size: 1 X 1km2 • 4 Regions in the network • Nodes • # of nodes in each region : 50 • Packets • Each node sends 6 packet for 6 hours • Packet size: 100kbytes
Conclusion • Region Topology Aware Routing protocol for DTN • Distributing messages achieves high delivery probability and low overhead using region information and mobility information • Future works • Analyzing appropriate number of tokens when all regions are known • Designing the mechanism controlling token numbers dynamically • And so on.
Q&A Thank You !
Message Relay • Add new tokens for regions not shown in messages R2 R1 R3