1,402 research outputs found
Analysis of Mobile Ad-hoc Network Routing Protocols in Random Graph Models
We analyze the performance of ad-hoc routing as defined in MANet IETF working group in the random graph model. In particular we analyze the performance of a reactive protocol DSR and of a pro-active protocol OLSR. The random graph model is defined by the number of nodes n, and link probabili- ty p. We give the asymptotic evaluation of the flooding distance which is used in DSR and the multi-point relay flooding used in OLSR
Modeling Routing Overhead Generated by Wireless Proactive Routing Protocols
In this paper, we present a detailed framework consisting of modeling of
routing overhead generated by three widely used proactive routing protocols;
Destination-Sequenced Distance Vector (DSDV), Fish-eye State Routing (FSR) and
Optimized Link State Routing (OLSR). The questions like, how these protocols
differ from each other on the basis of implementing different routing
strategies, how neighbor estimation errors affect broadcast of route requests,
how reduction of broadcast overhead achieves bandwidth, how to cope with the
problem of mobility and density, etc, are attempted to respond. In all of the
above mentioned situations, routing overhead and delay generated by the chosen
protocols can exactly be calculated from our modeled equations. Finally, we
analyze the performance of selected routing protocols using our proposed
framework in NS-2 by considering different performance parameters; Route
REQuest (RREQ) packet generation, End-to-End Delay (E2ED) and Normalized
Routing Load (NRL) with respect to varying rates of mobility and density of
nodes in the underlying wireless network
An analysis of the lifetime of OLSR networks
The Optimized Link State Routing (OLSR) protocol is a well-known route discovery protocol for ad-hoc networks. OLSR optimizes the flooding of link state information through the network using multipoint relays (MPRs). Only nodes selected as MPRs are responsible for forwarding control traffic. Many research papers aim to optimize the selection of MPRs with a specific purpose in mind: e.g., to minimize their number, to keep paths with high Quality of Service or to maximize the network lifetime (the time until the first node runs out of energy). In such analyzes often the effects of the network structure on the MPR selection are not taken into account. In this paper we show that the structure of the network can have a large impact on the MPR selection. In highly regular structures (such as grids) there is even no variation in the MPR sets that result from various MPR selection mechanisms. Furthermore, we study the influence of the network structure on the network lifetime problem in a setting where at regular intervals messages are broadcasted using MPRs. We introduce the ’maximum forcedness ratio’, as a key parameter of the network to describe how much variation there is in the lifetime results of various MPR selection heuristics. Although we focus our attention to OLSR, being a widely implemented protocol, on a more abstract level our results describe the structure of connected sets dominating the 2-hop neighborhood of a node
Simulation and Performance Analysis of MP-OLSR for Mobile Ad hoc Networks
Mobile ad hoc networks (MANETs) consist of a collection of wireless mobile
nodes which dynamically exchange data without reliance on a fixed base station
or a wired backbone network, which makes routing a crucial issue for the design
of a ad hoc networks. In this paper we discussed a hybrid multipath routing
protocol named MP-OLSR. It is based on the link state algorithm and employs
periodic exchange of messages to maintain topology information of the networks.
In the mean time, it updates the routing table in an on-demand scheme and
forwards the packets in multiple paths which have been determined at the
source. If a link failure is detected, the algorithm recovers the route
automatically. Concerning the instability of the wireless networks, the
redundancy coding is used to improve the delivery ratio. The simulation in NS2
shows that the new protocol can effectively improve the performance of the
networks
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