Data communication interview questions


36. What is Block Coding ?
Block coding refers to the technique of adding extra bits to a digital word in order to improve the reliability of transmission. The word consists of the message bits (often called information, or data) plus code bits. It may also, as in the present case, contain a frame synchronization bit. A block code adds bits to existing message bits, or blocks, independently of adjacent blocks.

37. Explain different framing algorithms ?
Framing can be of two types, fixed sized framing and variable sized framing. Here the size of the frame is fixed and so the frame length acts as delimiter of the frame. Consequently, it does not require additional boundary bits to identify the start and end of the frame.

38. What is data link layer ?
The data link layer is the protocol layer in a program that handles the moving of data into and out of a physical link in a network. The data link layer also determines how devices recover from collisions that may occur when nodes attempt to send frames at the same time.

39. What is transport layer ?
In computer networking, the transport layer is a conceptual division of methods in the layered architecture of protocols in the network stack in the Internet protocol suite and the OSI model. The protocols of this layer provide host-to-host communication services for applications.

40. What is Point-to-Point Connection ?
A point-to-point connection is a direct link between two devices such as a computer and a printer. It uses dedicated link between the devices. The entire capacity of the link is used for the transmission between those two devices. Most of today’s point-to-point connections are associated with modems and PSTN (Public Switched Telephone Network) communications. In point to point networks, there exist many connections between individual pairs of machines.

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