41. Which of the following is not a standard synchronous communication protocol?

A. SDLC
B. SMTP
C. SLIP
D. PAS
E. None of the above

42. The network layer, in reference to the OSI model, provide

A. data link procedures that provide for the exchange of data via frames that can be sent and received
B. the interface between the X.25 network and packet mode device
C. the virtual circuit interface to packet-switched service
D. All of the above
E. None of the above

43. In OSI network architecture, the routing is performed by

A. network layer
B. data link layer
C. transport layer
D. session layer
E. None of the above

44. Which of the following communications lines is best suited to interactive processing applications?

A. narrowband channels
B. simplex lines
C. full-duplex lines
D. mixed band channels
E. None of the above

45. What is the first octet range for a class B IP address?

A. 128 – 255
B. 1 – 127
C. 192 – 223
D. 128 – 191
E. 127 – 191