DCN VIVA QUESTIONS 1. What do you mean by data communication? Ans: It is the exchange of data between two devices via some form of transmission medium such as wire cable. The communicating system must be part of a communication system made up of a combination of hardware and software. The effectiveness of a data communication system depends on three fundamental characteristics: delivery, accuracy and timeliness. 2. What is simplex? Ans: It is the mode of communication between two devices in which flow of data is unidirectional. i.e. one can transmit and other can receive. E.g. keyboard and monitor. 3. What is half-duplex? Ans: It is the mode of communication between two devices in which flow of data is bidirectional but not at the same time. ie each station can transmit and receive but not at the same time. E.g walkie-talkies are half-duplex system. 4. What is full duplex? Ans: It is the mode of communication between two devices in which flow of data is bidirectional and it occurs simultaneously. Here signals going in either direction share the capacity of the link. E.g. telephone 5. What is a network? Ans: It is a set of devices connected by communication links. A node can be a computer or any other device capable of sending and/or receiving data generated by other nodes on the network. 6. What is distributed processing? Ans: It is a strategy in which services provided by the network reside at multiple sites. 7. What is point to point connection? Ans:It provides a dedicated link between two devices. The entire capacity of the link is reserved for transmission between the two devices e.g. when we change the TV channels by remote control we establish a point to point connection between remote control and TV control system. 8. What is multipoint connection? Ans: In multipoint connection more than two specific devices share a single link. Here the capacity of the channel is shared either separately or temporally. 9. What is a topology?
Ans: Topology of a network is defined as the geometric representation of the relationship of all the links and linking devices (node) to one another.Four basic topologies are star, bus, ring and mesh. Star – Here each device has a dedicated point to point link only to a central controller called hub. Bus -It is multipoint. One long cable acts as a backbone to link all the devices in the network. Ring -Here each device has a dedicated point to point connection only with the two devices on either side of it. Mesh -Here every device has a dedicated point to point link to every other device. 10. Define LAN, MAN and WAN. Ans: LAN- A local area network (LAN) is a privately owned and links the devices in a single office, building or campus. It allows resources to be shared between personal computers and work stations. MAN- A metropolitan-area network (MAN) spreads over an entire city. It may be wholly owned and operated by a private company, eg local telephone company. WAN – A wide area network (WAN) provides long distance transmission of data, voice, image and video information over large geographic areas that comprise a country, a continent or even whole world. 11.Define internet? Ans: It is a network of networks. 12.What is a protocol? Ans: It is a set of rules that governs data communication. A protocol defines what is communicated, how it is communicated, and when it is communicated. The key elements of protocol are syntax, semantics and timing. 13.What is TCP/IP protocol model? Ans: It is a five layered model which provides guidelines for the development of universally compatible networking protocols. The five layers are physical, data link, network, transport and application. 14.Describe the functions of five layers? Ans: Physical- It transmits raw bits over a medium. It provides mechanical and electrical specification. Data link- It organizes bits into frames. It provides hop to hop delivery. Network-It moves the packets from source to destination.It provide internetworking. Transport-It...
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