08-16-2017, 09:04 PM
data communication and networking forouzan 2nd edition ppt
Abstract
As one of the fastest growing technologies in our culture today, data communications and networking presents a unique challenge for instructors. As both the number and types of students are increasing, it is essential to have a textbook that provides coverage of the latest advances, while presenting the material in a way that is accessible to students with little or no background in the field. Using a bottom-up approach, Data Communications and Networking presents this highly technical subject matter without relying on complex formulas by using a strong pedagogical approach supported by more than 700 figures. Now in its Fourth Edition, this textbook brings the beginning student right to the forefront of the latest advances in the field, while presenting the fundamentals in a clear, straightforward manner. Students will find better coverage, improved figures and better explanations on cutting-edge material. The "bottom-up" approach allows instructors to cover the material in one course, rather than having separate courses on data communications and networking.
Today the world scenario is changing. Data Communication and network have changed the way business and other daily affair works. Now, they rely on computer networks and internetwork. A set of devices often mentioned as nodes connected by media page link is called a Network. A node can be a device which is capable of sending or receiving data generated by other nodes on the network like a computer, printer etc. These links connecting the devices are called Communication channels.
Computer network is a telecommunication channel through which we can share our data. It is also called data network. The best example of computer network is Internet. Computer network does not mean a system with control unit and other systems as its slave. It is called a distributed system
A network must be able to meet certain criteria, these are mentioned below:
Performance
Reliability
Scalability
Performance
It can be measured in following ways :
Transit time : It is the time taken to travel a message from one device to another.
Response time : It is defined as the time elapsed between enquiry and response.
Other ways to measure performance are :
Efficiency of software
Number of users
Capability of connected hardware
Reliability
It decides the frequency at which network failure take place. More the failures are, less is the network's reliability.
Security
It refers to the protection of data from the unauthorised user or access. While travelling through network, data passes many layers of network, and data can be traced if attempted. Hence security is also a very important characteristic for Networks.
Properties of Good Network
Interpersonal Communication : We can communicate with each other efficiently and easily example emails, chat rooms, video conferencing etc.
Resources can be shared : We can use the resources provided by network such as printers etc.
Sharing files, data : Authorised users are allowed to share the files on the network.