Ad Hoc Networks : Technologies and Protocols - University of ...

More documents

Recommendations

Info

Routing with Directional Antennas 217 based on which the schedules are formed are based on identifiers and not based on the traffic generated. 7.4 Routing with Directional Antennas The use of directional antennas can have an effect on routing. On-demand routing schemes can now scope their route queries in the direction in which the destination was last seen. With omni-directional antennas multi-path routing wherein (multiple paths are found between a source and a destination and used simultaneously) cannot be exploited very well since packets routed on one of the paths cause an interference zone that typically encompasses the other paths and thereby limits the number of packets routed on these paths. With directional antennas it is now possible to construct disjoint paths that do not interfere with each other [6]. The scheduling of transmissions (the directions in which antennas are to be pointed at different times) is tightly coupled with routing. However, current state of the art research has not looked at routing in great depth. It still remains an open area of research and possibilities for joint MAC/routing layer optimizations remain. In this section, we review the work on routing to date. 7.4.1 On Demand Routing Using Directional Antennas The first work on routing with directional antennas was by Nasipuri et al [2]. In this work, the authors examine the impact of directional antennas on the performance of on-demand routing protocols (such as the Ad hoc On Demand Distance Vector Routing or the Dynamic Source Routing [9]). On-demand routing protocols are based on searching for a route to a desired destination when the need arises. This search typically involves the flood of a route request or RREQ message. The key idea in [2] is to propagate this route request message in the direction of the desired destination with the help of directional transmissions by a restricted set of nodes. The authors assume the presence of simple switch beam or sectorized antennas. Two protocols are proposed. In the first protocol, when a source (say S) intends to compute a new route to a destination denoted by D, it broadcasts the route request query in the direction in which it had been communicating earlier with D. Any node that receives this query would then use the same technique, i.e., propagates the query in the same direction. This in effect, causes the query to be flooded in a conical section in the presumed direction of the destination. Clearly, the advantage of this process is to limit the scope of the flood. The scheme has been designed with the premise that the destination would not have moved too far from its initial position when it communicated with the originating node S. If this query were to fail, the query is re-initiated. The second time, it is flood throughout the network. The main drawback of this protocol is that it requires that the destination be in the
218 Use of Smart Antennas in Ad Hoc Networks same directional sector as the first hop on the path. If there exist circuitious routes wherein the destination is in a direction that is different from that of the preliminary search regime, then the preliminary search would fail. In the second proposed protocol in [2], the authors propose that when a particular route is found, the source should record the directions of the antennas used at each hop on the route. The relays that return the response from the route query from the destination add this information to the response packet header. This allows a node to get a rough estimate of the direction in which the destination is located depending upon the hop-count on the path and the number of times a particular direction was used. If a particular direction was used more than others, then the authors suggest that the particular direction be used in order to initiate the directional query. Clearly, the proposed schemes can lead to unsuccessful directional query floods. However, the authors show by simulations that the advantages in terms of the reduction in the quantum of overhead via successful directional floods outweigh the wasteful overhead due to unsuccessful floods. 7.4.2 The Impact of Directional Range on Routing The increased range of directional antennas can actually help in terms of reducing the number of hops needed in order to reach a destination i.e., can help in establishing shorter routes. Furthermore, in scenarios where omnidirectional transmissions may result in partitioned disjoint subnetworks, the extended range can help in bridging the sub-networks. In [5], Roy-Choudhury and Vaidya examine the impact of directional antennas on routing. The authors first perform simulations to understand the impact of directional antennas on routing. Based on their observations, they propose strategies that can exploit the presence of directional antennas and further analyze their new strategies via simulations. They assume that the DMAC protocol described earlier (proposed in [6]) is used in conjunction with the routing protocols. They then use the Dynamic Source Routing (DSR) protocol [8] over the DMAC protocol to study its performance. The DSR protocol is an on-demand routing protocol proposed for ad hoc networks. The protocol was designed with the premise that omni-directional transmissions and receptions are employed. We provide a very brief overview of DSR. A source broadcasts a route query message in order to find a destination. Nodes that hear the query broadcast it further; if they have a cached route to the destination they respond with a response instead of furthering the query. The destination upon receiving a query sends a response back to the source with a choice of the path. The identities of the relays on the entire route is recorded in the response packet. When a node wishes to use the route for sending data, it records the entire route in the packet header (hence the name
Page 2 and 3:
AD HOC NETWORKS Technologies and Pr
Page 4 and 5:
AD HOC NETWORKS Technologies and Pr
Page 6 and 7:
Contents List of Figures List of Ta
Page 8 and 9:
Contents vii 4.7. Conclusions and F
Page 10 and 11:
Contents ix 9.2. Potential Attacks
Page 12 and 13:
List of Figures 1.1 Internet in the
Page 14 and 15:
List of Figures xiii 6.3 COMPOW com
Page 16 and 17:
List of Figures xv 9.1 9.2 An IDS a
Page 18 and 19:
List of Tables 2.1 2.2 2.3 2.4 2.5
Page 20 and 21:
Contributing Authors Samir R. Das i
Page 22 and 23:
Preface Wireless mobile networks an
Page 24 and 25:
Acknowledgments xxiii We wish to ex
Page 26 and 27:
Chapter 1 AD HOC NETWORKS Emerging
Page 28 and 29:
Introduction and Definitions 3 coul
Page 30 and 31:
Introduction and Definitions 5 Secu
Page 32 and 33:
Ad Hoc Network Applications 7 tunis
Page 34 and 35:
Ad Hoc Network Applications 9 The d
Page 36 and 37:
Ad Hoc Network Applications 11 Figu
Page 38 and 39:
Design Challenges 13 example of cro
Page 40 and 41:
Evaluating Ad Hoc Network Protocols
Page 42 and 43:
Overview of the Chapters in this Bo
Page 44 and 45:
Overview of the Chapters in this Bo
Page 46 and 47:
Conclusions 21 1.6 Conclusions This
Page 48 and 49:
Chapter 2 COLLISION AVOIDANCE PROTO
Page 50 and 51:
Performance of collision avoidance
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Framework and Mechanisms for Fair A
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Conclusion 59 In the first part of
Page 86 and 87:
Conclusion 61 [13] [14] [15] [16] [
Page 88 and 89:
Chapter 3 ROUTING IN MOBILE AD HOC
Page 90 and 91:
Flooding 65 vector and link state p
Page 92 and 93:
Flooding 67 centralized approximati
Page 94 and 95:
Proactive Routing 69 status of each
Page 96 and 97:
Proactive Routing 71 Topology Broad
Page 98 and 99:
On-demand Routing 73 reply packets
Page 100 and 101:
On-demand Routing 75 during the lin
Page 102 and 103:
Proactive Versus On-demand Debate 7
Page 104 and 105:
Proactive Versus On-demand Debate 7
Page 106 and 107:
Location-based Routing 81 to find a
Page 108 and 109:
Location-based Routing 83 Figure 3.
Page 110 and 111:
Concluding Remarks 85 relative meri
Page 112 and 113:
Concluding Remarks 87 [14] [15] [16
Page 114 and 115:
Concluding Remarks 89 [42] [43] [44
Page 116 and 117:
Chapter 4 MULTICASTING IN AD HOC NE
Page 118 and 119:
Introduction 93 The mobility of the
Page 120 and 121:
Classifications of Protocols 95 red
Page 122 and 123:
Multicasting Protocols 97 this sect
Page 124 and 125:
Multicasting Protocols 99 as close
Page 126 and 127:
Multicasting Protocols 101 In ODMRP
Page 128 and 129:
Multicasting Protocols 103 hoc netw
Page 130 and 131:
Multicasting Protocols 105 A member
Page 132 and 133:
Multicasting Protocols 107 Figure 4
Page 134 and 135:
Broadcasting 109 “talk” to a ra
Page 136 and 137:
Broadcasting 111 broadcasted packet
Page 138 and 139:
Protocol Comparisons 113 are cluste
Page 140 and 141:
Overarching Issues 115 is user data
Page 142 and 143:
Overarching Issues 117 and RTS/CTS
Page 144 and 145:
Conclusions and Future Directions 1
Page 146 and 147:
Conclusions and Future Directions 1
Page 148 and 149:
Chapter 5 TRANSPORT LAYER PROTOCOLS
Page 150 and 151:
TCP and Ad-hoc Networks 125 Modifie
Page 152 and 153:
TCP and Ad-hoc Networks 127 mechani
Page 154 and 155:
TCP and Ad-hoc Networks 129 timeout
Page 156 and 157:
TCP and Ad-hoc Networks 131 to freq
Page 158 and 159:
TCP and Ad-hoc Networks 133 Figure
Page 160 and 161:
Transport Layer for Ad-hoc Networks
Page 162 and 163:
Modified TCP 137 MAC layers without
Page 164 and 165:
Modified TCP 139 Figure 5.6. TCP-EL
Page 166 and 167:
TCP-aware Cross-layered Solutions 1
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Ad-hoc Transport Protocol 147 in it
Page 174 and 175:
Ad-hoc Transport Protocol Figure 5.
Page 176 and 177:
Summary 151 References [1] [2] [3]
Page 178 and 179:
Chapter 6 ENERGY CONSERVATION Robin
Page 180 and 181:
Energy Consumption in Ad Hoc Networ
Page 182 and 183:
Energy Consumption in Ad Hoc Networ
Page 184 and 185:
Communication-Time Energy Conservat
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193: Communication-Time Energy Conservat
Page 200 and 201: Idle-time Energy Conservation 175 a
Page 202 and 203: Idle-time Energy Conservation 177 T
Page 204 and 205: Idle-time Energy Conservation 179 k
Page 206 and 207: Idle-time Energy Conservation 181 F
Page 210 and 211: Idle-time Energy Conservation 185 t
Page 212 and 213: Idle-time Energy Conservation 187 c
Page 216 and 217: Conclusion 191 [6] [7] [8] [9] [10]
Page 218 and 219: Conclusion 193 [33] [34] [35] [36]
Page 220 and 221: Conclusion 195 [59] [60] [61] [62]
Page 222 and 223: Chapter 7 USE OF SMART ANTENNAS IN
Page 224 and 225: Smart Antenna Basics and Models 199
Page 226 and 227: Medium Access Control with Directio
Page 244 and 245: Routing with Directional Antennas 2
Page 246 and 247: Routing with Directional Antennas 2
Page 248 and 249: Broadcast with Directional Antennas
Page 250 and 251: Broadcast with Directional Antennas
Page 252 and 253: Summary 227 [4] [5] [6] [7] [8] [9]
Page 254 and 255: Chapter 8 QOS ISSUES IN AD-HOC NETW
Page 256 and 257: Introduction 231 The concept of ad-
Page 258 and 259: Physical Layer 233 The 802.11a stan
Page 260 and 261: Medium Access Layer 235 neighbors,
Page 262 and 263: Medium Access Layer 237 Figure 8.5.
Page 264 and 265: QoS Routing 239 where is the number
Page 266 and 267: QoS at other Networking Layers 241
Page 268 and 269: Inter-Layer Design Approaches 243 8
Page 270 and 271: Conclusion 245 are specifically des
Page 272 and 273: Conclusion 247 [13] S. Mangold, S.
Page 274 and 275: Chapter 9 SECURITY IN MOBILE AD-HOC
Page 276 and 277: Potential Attacks 251 attacks, such
Page 278 and 279: Attack Prevention Techniques 253 9.
Page 280 and 281: Intrusion Detection Techniques 255
Page 290 and 291: Conclusion 265 an important and sti
Page 292 and 293:
Conclusion 267 [24] [25] [26] [27]
Page 294 and 295:
Index Ad hoc network multicast rout
show all

Ad Hoc Networks : Technologies and Protocols - University of ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?