Component-Based Routing for Mobile Ad Hoc Networks

Chunyue Liu, Tarek Saadawi & Myung Lee

CUNY, City College

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Outline

Motivation Objective Component analysis Current work Future work

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Motivation Existing research on evaluating

MANET routing performance is limited to predefined scenario;

The reasons of simulation results on MANET routing are not well understood and interpreted;

The shared similarities and specific properties of existing MANET routing protocols are never analyzed under a generalized structure.

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Objective

Develop a generalized component-based routing protocol that can cover most existing MANET routing protocols;

Analyze existing MANET routing protocols at component level;

Optimize component-based routing performance

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Component analysis

Route information representation Route information initialization Route discovery Route information management

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Our Focuses

How route information initialization affects the performance of on-demand MANET routing protocols;

How to improve MANET routing performance by introducing multipath mechanism.

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Route information initialization

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Argument

Pure on-demand is not the most efficient way to do ad hoc routing, some initial determination of necessary route information when a network is first deployed or a new routing domain is configured, may improve the total performance of pure on-demand routing.

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Definition We define route initialization as a

mechanism that allows source nodes to know of necessary route information before the transmission of real data packets.

Two ways of initialization: A-initialization, all nodes doing initialization; S-initialization, only source nodes doing initialization. For the situations without initialization, we call them No-initialization.

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Simulation Model

OPNET Modeler The MAC layer uses the IEEE 802.11 based

wireless radio with wireless LAN range of 250m

50 nodes, randomly distributed in 1500*300m2

Random waypoint mobility model Every result is an average of five runs of

simulation with different simulation seeds

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Performance Metrics Packet delivery rate, the ratio of the total data

packets successfully delivered to destinations to those generated by sources.

Average end-to-end delay of data packets, this includes all possible delays caused by buffering during route discovery, queuing delays at interface queues, retransmission delays at the MAC, and propagation and transfer times.

Normalized routing overhead, the number of routing packets transmitted per data packet successfully delivered to destinations.

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Results for DSR Fixed mobility, various duration of initialization time

     a) Average packet delivery rate vs. the duration of initialization time b) Normalized message overhead vs. the duration of initialization c) End-to-end delay vs. the duration of initialization

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A-initialization S-initialization

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Results for DSR (Cont.) Fixed duration of initialization time, various mobility

      a) Average packet delivery rate vs. pause time b) Normalized message overhead vs. pause time c) Average end-to-end delay vs. pause time

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S-initialization No initiliazation

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Results for AODV Fixed duration of initialization time, various mobility

     a) Average packet delivery rate vs. pause time b) Normalized message overhead vs. pause time c) Average end-to-end delay vs. pause time

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A-initialization No initialization

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Summary S-initialization is always more efficient than A-

initialization under the same traffic pattern.

An optimal value of the initialization duration exists for DSR to get the best average end-to-end delay, while AODV does not have this feature.

For lower mobility ad hoc network (pause time is greater than 100 seconds), the initialization brings more performance improvement to DSR than to AODV

For high mobility ad hoc network, we think initialization should not be applied to either DSR or AODV

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Future work

Identify quality factors of a route that may affect MANET routing performance

Improve routing performance by using multiple paths

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Technical Approaches

Operating conditions: network size, node density, mobility, link capacity, traffic patterns, fraction of unidirection links;

Route quality factors: bandwidth, freshness, security, energy Performance metrics: End-to-end data throughput, End-to-end delay,

Average delivery rate, Average message overhead, Energy consumption

Network OperatingConditions

Routing ProtocolPerformance

Multiple RoutesW\Quality Factors

external view

internal view

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Route quality factors

Why route quality factors What factors

number of routes distance (hop count or distance count) bandwidth (high or low) freshness (good or stale) security (secure or not) energy (node power high or low)

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Route Freshness We define Route Freshness Index

(RFI) as the probability that the route is valid, that is to say, all the links on the route are active.

Link Freshness Index (LFI) is defined to be the probability that the link is active.

RFI = Maintenance of LFI and RFI

i

iLFI )(

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Multipath routing

Multipath routing addresses the following components: Route information representation Multiple routes discovery Route cache management Route selection strategies

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Multiple routes discovery

How local discovery is put together to determine multiple paths

How to rank multiple paths How to handle route reply storm

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Route cache management

What kind of route information will be filled into cache

Methods to update of route quality factor information and how often

Methods to handle node join and leave

Performance effects of above schemes

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Route selection strategies

Shortest path Throughput Reliability Delay, jitter Freshness Energy conservation f(a,b,c,d…)

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THANK YOU!