07-03-2011, 12:34 PM
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Introduction
1.1 Ad hoc networks
Recent advances in portable computing and wireless technologies are opening up exciting possibilities for the future of wireless mobile networking. A mobile ad hoc network (MANET) is an autonomous system of mobile hosts connected by wireless links. Mobile networks can be classified into infrastructure networks and mobile ad hoc networks according to their dependence on fixed infrastructures. In an infrastructure mobile network, mobile nodes have wired access points (or base stations) within their transmission range. The access points compose the backbone for an infrastructure network. In contrast, mobile ad hoc networks are autonomously self-organized networks without infrastructure support. In a mobile ad hoc network, nodes move arbitrarily, therefore the network may experiences rapid and unpredictable topology changes. Additionally, because nodes in a mobile ad hoc network normally have limited transmission ranges, some nodes cannot communicate directly with each other. Hence, routing paths in mobile ad hoc networks potentially contain multiple hops, and every node in mobile ad hoc networks has the responsibility to act as a router.
Mobile ad hoc networks originated from the DARPA Packet Radio Network (PRNet) and SURAN project. Being independent on pre-established infrastructure, mobile ad hoc networks have advantages such as rapid and ease of deployment, improved flexibility and reduced costs.
Multicasting is the transmission of datagrams to a group of hosts identified by a single destination address and hence is intended for group-oriented computing. In MANETs, multicasting can support a variety of applications such as conferences, meetings, lecturers, traffic control, search and rescue, disaster recovery, and automated battlefield. In ad hoc networks, each host must act as a router since routes are mostly multihop.
Figure 1-1 shows an example of using MANET to hold conference meeting in a company. A group of mobile device users set up a meeting outside their normal office environment where the business network infrastructure is missing. The mobile devices automatically construct a mobile ad hoc network through wireless links and communicate with one another. The figure shows topology of the network and the available wireless links at a certain time. Suppose Susan wants to send data to Jerry. According to the network topology, Jerry’s PDA is not in the immediate radio transmission range of Susan’s laptop. The routing software on Susan’s laptop finds a route Susan
Introduction
1.1 Ad hoc networks
Recent advances in portable computing and wireless technologies are opening up exciting possibilities for the future of wireless mobile networking. A mobile ad hoc network (MANET) is an autonomous system of mobile hosts connected by wireless links. Mobile networks can be classified into infrastructure networks and mobile ad hoc networks according to their dependence on fixed infrastructures. In an infrastructure mobile network, mobile nodes have wired access points (or base stations) within their transmission range. The access points compose the backbone for an infrastructure network. In contrast, mobile ad hoc networks are autonomously self-organized networks without infrastructure support. In a mobile ad hoc network, nodes move arbitrarily, therefore the network may experiences rapid and unpredictable topology changes. Additionally, because nodes in a mobile ad hoc network normally have limited transmission ranges, some nodes cannot communicate directly with each other. Hence, routing paths in mobile ad hoc networks potentially contain multiple hops, and every node in mobile ad hoc networks has the responsibility to act as a router.
Mobile ad hoc networks originated from the DARPA Packet Radio Network (PRNet) and SURAN project. Being independent on pre-established infrastructure, mobile ad hoc networks have advantages such as rapid and ease of deployment, improved flexibility and reduced costs.
Multicasting is the transmission of datagrams to a group of hosts identified by a single destination address and hence is intended for group-oriented computing. In MANETs, multicasting can support a variety of applications such as conferences, meetings, lecturers, traffic control, search and rescue, disaster recovery, and automated battlefield. In ad hoc networks, each host must act as a router since routes are mostly multihop.
Figure 1-1 shows an example of using MANET to hold conference meeting in a company. A group of mobile device users set up a meeting outside their normal office environment where the business network infrastructure is missing. The mobile devices automatically construct a mobile ad hoc network through wireless links and communicate with one another. The figure shows topology of the network and the available wireless links at a certain time. Suppose Susan wants to send data to Jerry. According to the network topology, Jerry’s PDA is not in the immediate radio transmission range of Susan’s laptop. The routing software on Susan’s laptop finds a route Susan
