Biomedical Engineering Reference
In-Depth Information
Introduction
Wireless networks can be broadly classified into infrastructure-based wireless
network and infrastructure wireless networks or ad-hoc networks. In ad-hoc net-
works, the nodes are mobile and routing between source and destination node is
achieved by intermediate nodes acting as routers if it not in radio range. As ad-hoc
networks are highly dynamic, routing protocols play a crucial role to achieve
quality of service. Other important factors to be considered in ad-hoc networks are
dynamic networks topology, frequency of network updates, scalability, security,
and energy required. Basically MANET [
1
] is a group of wireless computing
devices like Laptop, mobile phone, personal digital assistant (PDA), or similar
devices. In ad-hoc networks routing protocols are broadly classified into proactive
(table driven) routing protocol, reactive (On-demand) routing protocols, and
hybrid protocols.
In proactive routing each node in the ad-hoc network maintains a table or tables
containing routing information of the network. Any node that needs to transmit
data can start transmitting data using routes already present in the routing table
enabling immediate data transmission. Popular proactive routing protocols include
destination sequence distance vector (DSDV) [
2
] routing protocol, wireless routing
protocol (WRP) [
3
], and optimized link state routing protocol (OLSR) [
3
]. The
advantages of proactive routing protocols update its routing table irrespective of
data traffic.
Unlike table-driven routing protocols, reactive protocols update routing infor-
mation only when a route is required by a source node to transmit data. Reactive
routing protocols reduce the control overhead which is advantageous in high
mobility networks, whereas periodic updates in routing information leads to sig-
nificant increase in networks overheads even when there is no data transmission
between nodes in the networks. Some of the popular ad-hoc routing protocols
falling in this category are dynamic source routing (DSR) [
4
], ad-hoc on-demand
distance vector (AODV) [
4
,
5
] routing and temporarily ordered routing protocols
(TORA) [
4
].
In this chapter, our major objective is to build the ADOV routing protocol in
such way that it can handle in a better way at the time of nodes or links failure.
This chapter will avoid the procedure taken by the data packet in case of nodes or
links fails in the AODV routing protocol thus they make it more efficient and faster
and improves certain characteristics.
ADOV Routing Protocols
AODV is an adaptation of destination sequenced distance vector (DSDV) protocol
used in wired networks and overcomes the shortcomings of DSDV in wireless
environment. AODV eliminates the counting to infinity problem faced in other
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