MOBILE COMMUNICATION

Mobile Communication



Mobile Communication

An overview

A network of computers, also called computer network or computer network is a set of computers connected together by means of physical devices that send and receive electrical signals, electromagnetic waves or other means to transport data, in order to share information and resources and provide services. This term also covers those technical means of information sharing.

The main purpose for creating a computer network is to share resources and information on distance, ensuring the reliability and availability of information, increase the speed of data transmission and reduce the overall cost of these actions.

The structure and mode of operation of computer networks today are defined in various standards, the most important and widespread of the entire model TCP / IP based on the reference model OSI. The latter, each network structure of 7 layers with specific functions but related, in TCP / IP layers are reduced to 4 (Ki-Wan Kim et al, 2002, 1645). There are many scattered throughout each layer protocols, which are also governed by their respective standards.

TCP/IP3 Mobile Computing Architecture

The network protocols are described using the terminology TCP/IP model and were created by DARPA during the early phases of 1970. DARPA is the acronym for an agency of the of the Department of Defence of the United States. It has developed from ARPANET, which is known to be the precursor of WAN (Wide Area Network) and of the internet. The TCP/IP model is also popular as Model DoD, DARPA model or the internet model (Ki-Wan Kim et al, 2002, 1648).

The TCP/IP model is elaborated as a an array of formulated guidelines and execution of the particular network protocols to permit the computers to commune through the network. The TCP/IP model facilitate the end user with a resource to complete the connection by specifying the way in which data needs to be formatted, transmitted, addressed, routed and received by the receiver. The service of communication and networking between the computers has four different classes of protocols. There are four layers of TCP / IP abstraction which have been defined in RFC 1122. The seven layers of OSI model are frequently compared to this layered architecture (Perkins, 1996, 12). The Internet Engineering Task Force (IETF) maintains the protocols rekated to TCP/IP. To get a reliable exchange of data between two computers, you must perform many separate procedures. The result is that the communications software is complex. With a model in layers is easier to group related functions and implement modular communications software.

The layers are hierarchical. Each layer builds on its predecessor. The number of layers, each of them, their services and functions vary with each type of network. However, on any network, each layer's mission is to provide services to higher layers by making transparent the way in which those services are performed. Thus, each layer should deal exclusively with the level immediately below, who apply for services, and the next higher level, who returns results.

Layer 4 or application layer: Application, which is comparable to ...