Intranets and extranets can use their network fire walls and other security features to establish secure Internet links within an enterprise or with its trading partners. Select the best fit for answer:

Protocols are

A. Agreements on how communication components and DTE

B. Logical communication channels used for transferri

C. Physical communication channels used for transferr

D. None of the above

The method of communication in which transmission takes place in both directions, but only one direction at a time is called

A. Simplex

B. Four wire circuit

C. Full Duplex

D. Half Duplex

Error detection at the data link level is achieved by

A. Bit Stuffing

B. Cyclic Redundancy Code

C. Hamming Code

D. Equalization

Which of the following is a wrong example of network layer?

A. Internet Protocol (IP) - ARPANET

B. X.25 Packet Level Protocol (PLP)-ISO

C. Source routing and domain naming-USENet

D. X.25 level 2-ISO