Multi-modal routing to tolerate failures

Multi-modal routing to tolerate failures Tiong Hoo Lim 1 , Iain Bate 1 , Jon Timmis 1

Department of Computer Science, 2 Department of Electronics,

University of York, U.K

ISSNIP 2011 December 8, 2011

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Outline

Introduction

Routing

Multi-modal Routing Protocol

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Outline Introduction Routing Routing in WSNs Reactive Routing Limitations Multi-modal Routing Protocol Design Properties Route Selection Process Evaluation of MRP Simulation Setup Results Conclusion QA

Evaluation of MRP

Conclusion

QA

Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Introduction Wireless Sensor Network Densely deployed and distributed. Multihop routing protocols Prone to permanent and non-permanent failures (Fault, Battery depletion, Attack, Obstacle, External interference) Motivation Different protocols are required to handle different failures Failures Attacks, Blocking Fault, Obstacle Obstacle, Interference

Routings AODV GD AODV LD NST-AODV

Switching Condition No forwarding nodes Next hop unavailable Intermittent next hop

Contribution A real-time route selection mechanism based on LLN feedback

QA

Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Routing in WSNs Proactive Routing Periodically monitors neighbouring node and update routing table Uses a simple (periodic) flooding mechanism consuming more energy resources Large routing table in large network Reactive Routing Query Based: Route is only established when required Sensor nodes always remain in idle state Uses control flooding mechanism On-demand: suitable for resource limited WSNs

QA

Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Reactive Routing Ad hoc On-Demand Distance Vector Routing (AODV) [Perkin and Rover, 1999] Originally proposed for Mobile Adhoc NETworks (MANET) to tolerate node movement Local and Global Route Discovery (RD) for route repair Sporadic and temporal link failure caused unnecessary RD Frequent RD − > Broadcast storm − > Consume resources− >Reduces network lifetime Not So Tiny-AODV [Gomez et al, 2006] Designed to tolerate sporadic transient failure Network layer performs additional single retransmission

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Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Limitations of Existing Routing Protocols

Existing Route Recovery Mechanism Design for specific network condition Focus on failure caused by fault or attacks but less on Radio Frequency Interference (RFI) or obstacle

No single protocol can handle multiple failures AODV:- Permanent or longer failure period NST-AODV:- Sporadic short transient failure

Hybrid routing is proposed [Fiqueredo et al, 2005] Single point of failure as decision is made by the destination (base station) Uses distribution mechanism to reach an agreement on the routing decision May cause service discontinuity due to switching

QA

Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Design of MRP Multi-mode Route Recovery System

External Interference

AODV

Link Failure Notification Link Layer

Route Selection Module

Local Discovery

Global Discovery

[If hopcnt < totalhop/2]

NST-AODV

Retransmit (retries=5)

Node Failure

Distribution approach to recover from network failure Integrates existing reactive routing features from AODV and NST-AODV Consists of Route Selection Module (RSM), a set of routing protocols, conditional rules set and threshold values

QA

Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Properties of MRP

Require at least one route available globally to forward the packet Localised routing decision is made independent of other nodes but relies on traffic condition reported by Link Layer Notification (LLN) Each routing feature is initially assigned with a cost NST-AODV with the lowest cost and GD with the highest cost Uses the LLN as feedback to tune the feature’s cost value Different routing protocol maybe used for the same packet or next packet received depending on the current cost of the routing feature

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Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Route Selection Process

[CostRT > LDMax]

Local Discovery

Global Discovery

Packet dropped [Costgd > GDMax]

[CostRT < RTmax] [CostLD > CostGD ] & [CostRT > RTmax]

LLN Failure

[CostRT > CostLD]

RSM

Packet forwarded

NST-AODV Retransmission

[CostRT < CostLD]

During packet failure, the RSM will select the routing feature using a set of rules based on the cost value The cost is either increased or decreased depending on the statistics of the feedback received over a sampling period

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Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Evaluation of MRPs Simulation Setup

NS-2 simulation of 51 nodes with redundant links Based on static indoor deployment (Fire detection systems) Each room periodically sends patient status to the sink Faults are injected at random nodes with different failure duration (fd ) to simulate interference from different devices 35 repeated simulations are run with different seeds for each duration with different number of failure.

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Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Performance Comparison Above 80% Packet Delivery Rate has been achieved by MRP (Up to 98% on average during transient failure) Energy Utilisation: MRP (2.39%) < NST (5.82%) < AODV (7.02%) Routing Overhead: MRP < NST-AODV < AODV Higher delay is observed in MRP than AODV but lower than NST-AODV when we increased the failure duration to 20 seconds Delay only increases when failure duration is greater than 10 seconds due to packets waiting to be transmitted in the queue The same delay is not observed in AODV as the packets are dropped during failure Graphs and source code can be obtained from my website http://www-users.cs.york.ac.uk/ thlim/sim/index.html.

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Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

Advantages of MRP It has a minimal switching overhead compared to hybrid approach Use of LLN Feedback Allows us to tune the cost of AODV and NST-AODV

Retransmission Increases the probabilities of packet being delivered Improves the packet delivery rate Energy efficient as less routing packets are being generated

No additional communication, processing and storage is needed to store the packet waiting to be transmitted Higher packet delivery rate at the cost of higher latency due to additional waiting time in the queue Robust to failure due to autonomous decision making Scalable with the network size Extendable to include other reactive routing protocols

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Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Thank You

Questions and Answers http://www-users.cs.york.ac.uk/ thlim/sim/index.html.

Conclusion

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Outline

Introduction

Routing

Multi-modal Routing Protocol

Evaluation of MRP

Conclusion

References

Perkins, C. E. and Royer, E. M.(1999), Ad-hoc on-demand distance vector routing, Proceedings of the 2nd IEEE Workshop on Mobile Computing Systems and Applications, 90 – 100 Gomez, C. and Salvatella, P. and Alonso, O. and Paradells, J. (2006) Adapting AODV for IEEE 802.15.4 Mesh Sensor Networks: Theoretical Discussion and Performance Evaluation in a Real Environment Proceedings of the International Symposium on on World of Wireless, Mobile and Multimedia Networks Figueredo, C. and Santos, A. and Loureiro, A. and Nogueira, J. (2005) Policy-Based Adaptive Routing in Autonomous WSNs Ambient Network: Lecture notes in computer science

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