题库精选:CCNA考试自测题第1卷

　　26) Which statement is true of TLI (下面关于T L I的哪一句陈述是正确的)？

　　A. It is a layer in the OSI model

　　B. It is a layer in the TCP/IP model

　　C. It is a System V API

　　D. It is part of the UNIX Kernel

　　27) Which statement is true of Windows Name Server (WINS) (下面对于Windows 命名服务器( W I N S )的陈述中，哪一句是正确的)？

　　A. It is a protocol

　　B. It provides capability for name resolution

　　C. It is a network layer

　　D. It is a proprietary name server

　　E. A, B, and D only

　　F. B and D only

　　28) ICMP、I P、ARP and RARP of the IP protocol suite map to (IP协议套件的I C M P、I P、A R P和R A R P映射到)：

　　A. OSI layers 1 and 2

　　B. OSI layer 5

　　C. OSI layer 3

　　D. OSI layer 2

　　29) Which layer is most important in providing reliable data exchange between two systems(在两个系统之间提供可靠的数据交换中，哪一层是最重要的)？

　　A. Physical layer

　　B. Data link layer

　　C. Session layer

　　D. Transport layer

　　30) Which of the following does TCP provide (TCP提供了下面的哪一个功能)？

　　A. Unreliable data stream

　　B. Connectionless virtual circuit

　　C. Flow control

　　D. Structured byte stream movement

　　31) Of the following, which field is not a part of the TCP header (在下面各项中，哪一个字段不是T C P报头的一部分)？

　　A. Subnet mask

　　B. Sequence number

　　C. Data offset

　　D. Destination port