Basic CS-Networks [TCS Placement]: Sample Questions 6 - 7 of 133
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Question 6
Explanation
- Forward error correction (FEC) enhances data reliability by introducing redundant data, called error correcting code, prior to data transmission or storage.
- Destination (receiver) recognizes only the portion of the data that contains no apparent errors.
- Provides ability to correct errors without retransmission of data.
- The first FEC code, called a Hamming code, was introduced in the early 1950s.
- Forward error coding is also known as channel coding.
- FEC does not require handshaking between the source and the destination- can be used for broadcasting data to many destinations simultaneously.
Question 7
Explanation
- Beaconing allows a network to self-repair its problems.
- Beaconing is used in Token ring and FDDI networks; here stations on network notify the other stations when they are not receiving the transmissions.
- It is also used for signaling error conditions in wireless/LAN networks. On failure the packets are transmitted as beacons identifying neighboring active transmitters. This helps receivers in auto reconfiguration bypassing the failure.