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Integration of Application-Layer Scheduling and Routing in Delay-Tolerant MANETs. José Brustoloni, Sherif Khattab , Christopher Santamaria, Brian Smyth, and Daniel Mossé C S @ P I T T. Mobile Ad-Hoc Networks (MANETs). Cell phone. Mobile Ad-Hoc Networks (MANETs).
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Integration of Application-Layer Scheduling and Routing in Delay-Tolerant MANETs José Brustoloni, Sherif Khattab, Christopher Santamaria, Brian Smyth, and Daniel Mossé CS@PITT
Mobile Ad-Hoc Networks (MANETs) Cell phone
Communication of First-Responders • Connecting handheld devices used to exchange data, images, video, voice, work orders, etc.
Need for MANETs • MANETs are needed if traditional communication infrastructure is damaged
Network Partitioning • MANETs may get partitioned: • Field characteristics • Noisy environments Packethop.com
Delay-Tolerant Networking • DTN research deals with routing of messages across network partitions • Our work proposes a new approach to DTN routing
Example Scenario Main Partition Subordinate Partition Leader EOC
Example Scenario Main Partition Subordinate Partition Work Order Leader EOC
Example Scenario Main Partition Subordinate Partition Work Order Courier Leader EOC
Work Order Model Execution Time Deadline Pre-emption Deadline Miss Time
Work Order Model Each task associated with a location Deadline
Courier Selection Problem Main Partition Subordinate Partition ? ? ? Work Order Courier Leader EOC
Metrics • Percentage of missed deadlines = • Average traveled distance per node Number of deadlines missed Total number of work orders
State-of-the-art • Dedicated mobile elements • Message Ferries [@GeorgiaTech] handle only message delivery • Minimize average delay • Trajectory modification of mobile users • @Dartmouth [Mobicom’00] • Minimize detour distance
Our Hypothesis • We can achieve better trade-off between missed deadlines and traveled distance if application-layer demand is taken into consideration in courier selection
Highest-Slack Courier Selection Main Partition Subordinate Partition Maximum Leeway
Compared Schemes • Closest • Select courier closest to work order destination • Dedicated • Set of nodes dedicated for message delivery (don’t execute any work) • Random
Common Assumption • Leader aware of current position of main-partition workers • GPS-enabled devices • Landmarks
Simulation Parameters • Rate of work orders (load) • main and sub-ordinate • default = 60% • Distance between partitions • default = 1200m • Number of dedicated couriers • default = 1 • Speed of dedicated couriers • default = 5 m/s (18 km/h)
Distance between Partitions 100% Dedicated Random Closest Highest-Slack 80% 60% Deadlines Missed 40% 20% 1200m 200m 400m 800m
Subordinate-partition Load 100% Random Closest Dedicated Highest-Slack 80% 60% Deadlines Missed 40% 20% 20% 40% 60% 80%
Why? Main Partition Subordinate Partition
Subordinate-partition Load 16km 12km Random Traveled Distance Per Node 8km Closest Highest-Slack 4km Dedicated 20% 40% 60% 80%
Main-partition Load 100% Dedicated Random Closest Highest-Slack 80% 60% Deadlines Missed 40% 20% 20% 40% 60% 80%
Dedicated-courier Speed 100% Random Closest Dedicated Highest-Slack 80% 60% Deadlines Missed 40% 20% 54 km/h 18 km/h 25 km/h
Number of Dedicated Couriers 100% Random Closest Dedicated Highest-Slack 80% 60% Deadlines Missed 40% 20% 5 1 10 15 20
Conclusions and Future Work • Courier Scheduling in partitioned ad-hoc networks • Integrated application- and network-layer scheduling • More realistic • models of work orders • metrics (e.g., rate of casualties) • frequency and structure of network partitions • Comparison with other schemes • communication bridges
Work Order Parameters • Average Deadline = 440 sec • Execution Time = 0.5 * Deadline • Enough to run back and forth across a 500m partition and still meet deadline
Simulation Time Cool-down Statistics Gathering Warm-up 10000 (~ 2.5 Hrs) 1000 10 9500 Time (Seconds)
When to return home? Main Partition Subordinate Partition