Data Communication Fundamentals

In this module we shall discuss various aspects of data link control has been considered
. Lesson  deals with framing and synchronization along with how one can interface the machine to the media
. Error detection and error correction techniques are presented in Lesson 
. Lesson  introduces various protocols used for flow control and error control
. Finally, lesson  provides an overview of HDD, the most popular data link control protocol
. Module Switched Communication Networks In this module switched communication networks has been considered
. First, various switching techniques have been presented in Lesson . In this lesson various aspects of circuit switching and the operation of Public Switched Telephone Network (PST), which is based on circuit switching, have been discussed
. Various aspects of message switching, packet switching and virtual circuit switching have been addressed in Lesson Lesson  presents the Synchronous Optical Network (TONES) that defines a technology for carrying many signals of different capacities through a synchronous, flexible, optical hierarchy
. It utilizes the enormous bandwidth of optical fiber to achieve date transfer at a very high rate
. X.25 is a packet-switched network developed by ITS-T in 1976
. It defines how a packet-mode terminal can be interfaced to a packet network for data communication
. However, X.25 does not satisfy the present day requirements of higher data rate
. To overcome these limitations, a new standard, known as frame relay was introduced
. Lesson introduces these two packet switching networks
. In the last section of this module, ATM (Asynchronous transfer mode), which can be used both as a LAN or WAN standard has been introduced
. Various network devices used in ATM, concept of cell transfer and cell format have been discussed.