(电路交换)（(circuit switched)）.docVIP

(电路交换)（(circuit switched)） Morning exercises: When a large number of data transmission system between the need for high quality under the condition of exchange often used for ___ (1) __ way. In a circuit switched network, two devices using circuit switching connected by ___ in sending and receiving when (2) _; in a packet switched network, the information sent from the source node to the destination node in intermediate nodes to block ___ (3) _. Packet switching process, the data transfer between a source station before the destination station prior to setting up a path, the packet is ___ (4) _. The ATM switching technology is ___ (5) _ (1) A. B. virtual circuit switching packet switching C. circuit switched D. datagram (2) does not limit the rate of the same rate B. A. the sender of the sender and the receiver may be greater than the rate of C. is less than the rate of the sender receiver sender and receivers rate of D. (3) A. B. C. sent directly store and forward check error of D. flow control (4) A. B. circuit switched virtual circuit switching C. datagram exchange exchange D.ATM (5) A. B. C. virtual circuit switching packet switching circuit switching D. circuit switching and packet switching. Answer: CABBD In order to carry out error control, the transmitted data frames must be checked. Check the common technologies used in the LAN is ___ (6) __. CRC - CCITT is polynomial ___ (7) __; assume a CRC polynomial G (x) =x4+x+1, to send the place code is 101011, CRC is calculated for the ___ check code (8) __. Based on the hypothesis of the polynomial G (x) =x4+x2+x+1, to send the information code 1111101 to CRC encoding and transmission should be ___ (9) __, the cyclic redundancy codes in the form with information from the back, if the codeword by zero insertion (bit stuffing) after sending from left to right, then when sending bit order should be ___ (10) __. (6) A. CRC B. C. vertical horizontal parity check parity Hamming code D. (7) A. x16+x15+x+1 B. x16+x12+x5+1