1	Adaptive Manet Routing: A Case Study Thomas Kunz Systems and Computer Engineering Carleton University
2	MANET Routing Protocols
3	Adaptive Routing for MANET Adaptive Routing: Mobile node adjusts its routing behavior based on its environment to improve routing performance Adjustment is on a per-node basis, not global Levels/Timescales of Possible Adjustments: Short term: change its routing parameters based on environment Mid-term: select stable route with enough bandwidth during Route Discovery Long-term: select adequate routing protocol based on application etc
4	Adaptive: What do I mean? “Environment” means many things Radio environment: could impact route stability and throughput Traffic pattern: which flows, between which nodes Mobility: topology changes, formation/destruction of links First step: adapt to mobility at short time-scales Identify mobility metric that Captures the mobility-driven impact of routing protocol performance Can easily be measured by a node, no extra hardware required Is true across a number of mobility scenarios (different patterns/mobility models) and independent of mobility model parameters (RWP: Max/min speed, pause time, …) Based on the metric, modify protocol to allow individual nodes to adapt their protocol behavior
5	First Simulations: Mobility Metrics
6	Simulation Results: PDR vs. Mobility
7	Simulation Results: Link Duration
8	Simulation Results: Link Duration as Performance Predictor
9	Simulation Results: Link Breaks
10	Mobility Metrics: Individual Nodes
11	Conclusions
12	OLSR Modifications OLSR has 4 control parameters Hello Interval TC Interval MPR Coverage TC Redundancy Idea is to set parameters “appropriately” for network They then apply to all nodes and for the whole time Our modifications: Monitor link breaks, define two thresholds (upper, lower) Choose appropriate Hello Interval more observed link breaks => higher mobility scenario => faster Hello Add states to OLSR nodes that govern processing of Hello messages/selection of MPRs Default OLSR, Fast OLSR, Fast Response
13	OLSR Node States
14	Simulation Setup Implemented Adaptive OLSR in NS2 and evaluated performance through experiments UM-OLSR version 0.8.8 for NS2 version 2.29 The simulation area is 1000x1000m 80 mobile nodes Default IEEE 802.11 configuration: 250 m transmission range, 11 Mbps data rate Traffic: 25 data sources, 4 packets/s, 64 byte packet size (CBR) Simulation time is 900 seconds Mobility model is “Random Trip Model” (avoids problems of RWP) 10-5-1-1 is a mobility scenario with mean node speed of 10m/s, speed variation of 5m/s, mean pause time of 1 second and pause time variation of 1 second
15	Simulation Results for Default OLSR
16	Adaptive OLSR vs. Default OLSR
17	Impact of Threshold Values
18	Some Analysis of Results
19	Adaptive OLSR also better in Packet Latency
20	Individual Node View
21	Conclusions/Future Work Improved OLSR performance, in particular in more mobile scenarios Idea of an adaptive protocol (nodes individually adjust their routing protocol behavior) has promise Future Work (in increasing order of difficulty, no student right now to do any of it…. J) Need more experimental validation Different mobility models, in particular group mobility models Different levels/type of offered load Consider further changes to OLSR TC Interval, MPR Selection, etc. Apply these insights/ideas to other routing protocols Consider additional avenues for adaptive behavior A node that is currently routing multiple flows may find it beneficial to spend more efforts in routing that a node that is currently not used