A.TCP/IP transport layer protocols include TCP and UDP.

B.IP protocol is located in TCP/IP Internet layer.

C.UDP protocol provides unreliable transmission.

D.IP protocol provides reliable transmission.

32. The network topology suitable for CSMA/CD is (B).

A. star b ring

C. Bus type D. Grid type

33. The time slice allocation strategy in asynchronous time division multiplexing TDM technology is (A)

A. Pre-allocation but not fixed B. Pre-allocation is fixed.

C. dynamic allocation can be changed at any time. D. dynamic distribution is fixed.

34. When the destination address fields in the IEEE802.3MAC frame are all "1", it means (a).

A. Single address B. Group address

C. Broadcast address D. Local address

"Interception" is a form of network security attack, and the target of the attack is information (B).

A. Availability B. Confidentiality

C. Integrity D. Security

36. thirty-six The maximum downlink data transmission rate allowed by ADSL standard is (D).

A. 1Mbps B.2Mbps

4 Mbytes/sec and 8 Mbytes/sec

37. The device used to realize the physical layer interconnection of the network is (C)

A.b bridge repeater

C. Router D. Gateway

The length of Ethernet MAC address is (C).

A.4 bit B.32 bit

C.48 bit D. 128 bit

39. The port number used by SMTP is (d).

A.20 B.2 1

C.25 D. 1 10

40. The widely used digital signature method does not include (b).

A.RSA signature B. DSS signature

C. Hash signature