Impact of the Mobility Model on a Cooperative Caching Scheme for Mobile Ad Hoc Networks

Content Provider	Semantic Scholar
Author	Casilari, Eduardo
Copyright Year	2012
Abstract	In the last few years more and more mobile devices have been developed and they are now part of our lives. Cellular phones, PDAs and laptops are daily used in mobile environments such as airports or train stations. For many applications these terminals require access to data networks or the Internet. In order to share information among them the mobile nodes have to cooperate to forward and route the traffic from one node to another forming the socalled Mobile Ad Hoc Networks (MANETs). Due to the mobility of the nodes the mobile nodes can enter or leave the coverage area of other nodes forcing to recalculate the routes in order to make possible the packet forwarding. In addition, wireless networks have a more limited bandwidth and a greater error probability than the wired medium, since the radio medium is shared and prone to interferences and packet collisions. Moreover, the mobile devices have to be portable and hence the processing and battery capabilities also have important restrictions. Due to the limitations of the MANETs and the mobile devices, some caching mechanisms can be implemented in order to reduce the traffic in the network. Reducing the traffic along the network, and hence the number of forwarded packets, also reduces the battery consumption. Let us suppose a MANET with conectivity to an external network such as the Internet as depicted in Figure 1. The mobile nodes cooperate to route packets to the Access Routers that provide access to the external networks. As all the traffic in the MANET is routed to the Access Routers these devices can turn into a bottleneck. In addition, the Access Routers can become temporally inaccessible because they can be out of the coverage area of any mobile node in the network because of the nodes’ mobility. This situation causes temporal disconnections to the external networks. The caching mechanisms reduce the impact of the temporal disconnection to the Access Routers as the mobile nodes can cooperate to serve the documents they have previously cached to the rest of the nodes. On the other hand, since the mobile nodes also have the capability of serving information the bottleneck produced in the Access Routers is reduced as the traffic does not reaches them. As the mobility model influences the behaviour of the nodes in the MANET and the cooperative caching mechanisms depend on the connectivity among the mobile nodes this paper evaluates and compares the performance of a caching scheme under different mobility models. Consequently, in this paper we propose a cooperative caching mechanism and evaluate its performance using two different mobility models.
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://cdn.intechopen.com/pdfs-wm/12887.pdf
Alternate Webpage(s)	http://cdn.intechweb.org/pdfs/12887.pdf
Language	English
Access Restriction	Open
Subject Keyword	Airports Cache (computing) Cellular Phone Cooperative MIMO Epilepsy, Temporal Lobe Hoc (programming language) Internet Laptop Mobile device Network packet Node - plant part Personal digital assistant Router (computing) Routing Serial Experiments Lain collision
Content Type	Text
Resource Type	Article