41. What is Bridges?
They divide large network into smaller components.They can relay frames between two originally separated LANs.They provide security through partitioning traffic.They operate on physical and data link layer of OSI model.
42. What is ICMP?
ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages.
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43. What is FDM?
FDM is an analog technique that can be applied when the bandwidth of a link is greater than the combined bandwidths of the signals to be transmitted.
44. What is WDM?
WDM is conceptually the same as FDM, except that the multiplexing and demultiplexing involve light signals transmitted through fiber optics channel.
45. What is TDM?
TDM is a digital process that can be applied when the data rate capacity of the transmission medium is greater than the data rate required by the sending and receiving devices.
46. List the steps involved in creating the checksum.
a. Divide the data into sections
b. Add the sections together using 1’s complement arithmetic
c. Take the complement of the final sum, this is the checksum.
47. Compare Error Detection and Error Correction:
The correction of errors is more difficult than the detection. In error detection, checks only any error has occurred. In error correction, the exact number of bits that are corrupted and location in the message are known. The number of the errors and the size of the message are important factors.
48. What are the protocols in application layer ?
The protocols defined in application layer are
• TELNET
• FTP
• SMTP
• DNS
49. What are the protocols in transport layer ?
The protocols defined in transport layer are
• TCP
• UDP
50. What do you mean by client server model ?
In client server model ,the client runs a program to request a service and the server runs a program to provide the service.These two programs communicate with each other. One server program can provide services to many client programs.
