Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 1 Carlos Cordeiro Philips Research North America Briarcliff Manor, NY Dharma P. Agrawal OBR Research Center for Distributed and Mobile Computing University of Cincinnati, OH

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 2

3 Table of Contents Chapters: 1.Introduction 2.Routing in Ad hoc Networks 3.Broadcasting, Multicasting and Geocasting 4.Wireless LANs 5.Wireless PANs 6.Directional Antenna Systems 7.TCP over Ad Hoc Networks 8.Wireless Sensor Networks 9.Data Retrieval in Sensor Networks 10.Security 11.Integrating MANETs, WLANs and Cellular Networks

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 4 Chapter 1: Introduction Introduction The Communication Puzzle Applications of MANETs Challenges  Scalability  Quality of Service  Client-Server Model Shift  Security  Interoperation with the Internet  Energy Conservation  Node (MH) Cooperation  Interoperation Book Organization Conclusions and Future Directions Homework Questions/Simulation Projects References

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 5 A Mobile Ad Hoc Network (MANET) MH2 MH3 MH2 MH4 MH1 MH5 MH6 MH7 Symmetric link Asymmetric link

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 6 Characteristics of a MANET An autonomous system of nodes (Mobile Hosts: MHs) connected by wireless links Same channel used by all nodes Lack of fixed infrastructure Absence of centralized authority Peer-to-peer connectivity Multi-hop forwarding to ensure network connectivity Topology may change dynamically Random Multi-hop Graph Energy-constrained Bandwidth-constrained, variable capacity links

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 7 Important characteristics of a MANET CharacteristicDescription Dynamic Topologies Nodes are free to move arbitrarily with different speeds; thus, the network topology may change randomly and at unpredictable times. Energy- constrained Operation Some or all of the nodes in an ad hoc network may rely on batteries or other exhaustible means for their energy. For these nodes, the most important system design optimization criteria may be energy conservation. Limited Bandwidth Wireless links continue to have significantly lower capacity than infrastructured networks. In addition, the realized throughput of wireless communications – after accounting for the effects of multiple access, fading, noise, and interference conditions, etc., is often much less than a radio’s maximum transmission rate. Security Threats Mobile wireless networks are generally more prone to physical security threats than fixed-cable nets. The increased possibility of eavesdropping, spoofing, and minimization of denial-of-service type attacks should be carefully considered.

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 8 The envisioned communication puzzle of 4G and beyond

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 9 The scope of various wireless technologies

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 10 Applications of MANETs Collaborative Work  Collaborative computing might be important outside office environments Crisis-management Applications  Natural disasters with entire communications infrastructure in disarray  Restoring communications quickly is essential  Infrastructure could be set up in hours instead of days/weeks Personal Area Networking  Short-range, localized network of nodes associated with a person  Nodes could be attached to someone’s cell phone, pulse watch, belt, etc.  Bluetooth is an example  Eliminates need of wires between devices such as printers, cell phones, PDAs, laptop computers, headsets, etc.  IEEE standard working group

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 11 Future Challenges in Ad hoc and Sensor Networks Scalability  Short-range Throughput per node decreases at a rate 1/, where N is the number of nodes  This cannot be fixed except by physical layer improvements, such as directional antennas Quality of service  Need to provide best-effort service only for Voice, live video and file transfer Client server model shift  There is no server, but demand for basic services still exists.  Address allocation, name resolution, authentication and service location are just examples of very basic services which are needed Security  Lack of any centralized network management or certification authority  Networks are particularly prone to malicious behavior Interoperation with the Internet  Networks require some Internet connection  Interface between the two are very different Energy conservation  Lifetime of a single battery and the whole network. Node cooperation  Why anyone should relay other people’s data Interoperation  What happens when two autonomous ad hoc networks move into same area

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 12 Book outline Chapter 2: Unicast routing over ad hoc networks Chapter 3: Multicasting, Broadcasting and geocasting in ad hoc networks Chapters 4 and 5: Most widely used MAC and physical layers for ad hoc networks Chapter 6: Use of directional antenna for increasing capacity, connectivity, and covertness of ad hoc networks Chapter 7: The issue of TCP (Transmission Control Protocol) over ad hoc networks Chapter 8: Introduction to sensor networks Chapter 9: Data retrieval in sensor networks Chapter 10: Security in ad hoc networks Chapter 11: Integration of heterogeneous wireless technologies in the context of ad hoc and sensor networks

Copyright © 2006, Dr. Carlos Cordeiro and Prof. Dharma P. Agrawal, All rights reserved. 13 Book Organization Application Transport Network LLC Physical MAC Data Link All chapters Chapters 7, 9 and 11 Chapters 4, 5, 6, and 11 Chapters 4, 5, 6, 8, 9, and 11 Chapters 2, 3, 6, 8, 9, 10, and 11