Certificates are 1 documents attesting to the 2 of a public key to an individual or other entity. They allow verification of the claim that a given public key does in fact belong to a given individual. Certificates help prevent someone from using a phony key to 3 someone else. In their simplest form, Certificates contain a public key and a name. As commonly used, a certificate also contains an 4 date, the name of the CA that issued the certificate, a serial number, and perhaps other information. Most importantly, it contains the digital 5 of the certificate issuer. The most widely accepted format for certificates is X.509, thus, Certificates can be read or written by any application complying with X.509.
WebSQL is a SQL-like 6 language for extracting information from the web. Its capabilities for performing navigation of web 7 makes it a useful tool for automating several web-related tasks that require the systematic processing of either all the links in a 8 , all the pages that can be reached from a given URL through 9 that match a pattern, or a combination of both. WebSQL also provides transparent access to index servers that can be queried via the Common 10 Interface.
Packet-switching wireless networks are preferable 11 when transmissions are 12 because of the way charges are 13 per packet. Circuit-switched networks are preferable for transferring large files or for other lengthy transmissions because customers are 14 for the 15 of time they use the network.
Open Shortest Path First (OSPF) is a 16 routing algorithm that 17 work done on the OSI IS-IS intradomain routing protocol. This routing, as compared to distance-vector routing, requires 18 processing power. The 19 algorithm is used to calculate routes. OSPF routing table updates only take place when necessary, 20 at regular intervals.
A socket is basically an end point of a communication link between two applications. Sockets that extend over a network connect two or more applications running on (61) computers attached to the network. A socket (62) two addresses: (63) . Sockets provide a (64) communication channel between one or more systems. There are (65) sockets separately using TCP and UDP.
21.
A.unique
B.separate
C.same
D.dependent
A B C D
B
22.
A.is made of
B.composed of
C.is composed Of
D.is consisted of
A B C D
C
23.
A.E-mail address and IP address
B.MAC address and port address
C.MAC address and IP address
D.port number and IP address
A B C D
D
24.
A.full-duplex
B.half-duplex
C.simplex
D.complex
A B C D
A
25.
A.message and packet
B.packet and frame
C.stream and datagram
D.flow and block
A B C D
C
[解析] 一个套接字基本上是两个应用程序间通信连接的一个终点。套接字可遍布一个网络，连接两个或多个运行在属于此网络的独立的(separate)计算机上的应用程序。一个套接字由两个地址组成(is composed of)：端口号和IP地址(port number and IP address)。套接字提供了一个介于两个或多个系统间的全双工的(full-duplex)通信通道。 套接字分为流套接字和数据报(stream and datagram)套接字，分别使用TCP和UDP协议。
Multipurpose Internet Mail Extension (MIME) is a 26 document messaging standard in the Internet environment. With MIME, users can send 27 E-mail messages that include audio, video, graphices, and text to any other user of a TCP/IP network. Richtext information can also be 28 into messages. It defines the fonts, formats, and 29 features of a document so the document can be easily 30 on many different types of systems.
DOM is a platform-and language- 31 API that allows programs and scripts to dynamically access and update the content, structure and style of WWW documents (currently ,definitions for HTML and XML documents are part of the specification). The document can be further processed and the results of that processing can be incorporated back into the presented 32 . DOM is a 33 -based AP1 to documents, which requires the whole document to be represented in 34 while processing it. A simpler alternative to DOM is the event-based SAX, which can be used to process very large 35 documents that do not fit info the memory available for processing.
Microwave communication uses high-frequency 36 waves that travel in straightlines through the air. Because the waves cannot 37 with the curvature of the earth, they can be 38 only over short distance. Thus, microwave is a good 39 for sending data between buildings in a city or on a large college campus. For longer distances, the waves must be relayed by means of "dishes" or 40 .These can be installed on towers, high buildings, and mountain tops.
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