Calculator network
First, concept
1. Hub (HUB): The wire jack seat on the original appliance control palette is centrally, from which lead wires can be transmitted. In the network, Hub is called a hub, and the site is set to "bus" to connect together.
2. Transferrs: Enlarge enhanced signals and forward to ensure reliable transmission.
3. Switch: It is a network interconnection device that interconnects multiple network segments in the LAN and can perform data link layers and physical layer protocols.
4. Bridge: It is a device that connects to each other in the data link layer. Its important function is the ability to "filter" for information, that is, saved each network segment connected in the bridge. The address of all sites. It is parsed in each packet of it to parsing the export node address, all source node addresses that do not belong to the network segment broadcast domain are filtered.
5. Routing: Yes, the process of discovering, selecting the path to the path to any destination IP address via the network. The router is characterized by providing interconnection of network layers, with routing and traffic control capability.
6. Gateway: It is actually a communication server. A device that is used to interconnect the application layer to realize the function of the protocol conversion between the network.
7. Firewall: It is a calculator system that runs specialized calculator security software, which combines software and hardware. It can construct a "protective layer" between the internal network of enterprises and external networks. So Communication between enterprises and outside networks must be checked and connected by this protective layer, and only authorized communication is allowed to pass the protective layer. In other words, it is prevented from attacking the external personnel, and it is also to prevent the interior from illegal access to the outside.
8. Domain: In a domain, you can include a batch of servers and work sites in the network. At least one is a domain server, and the domain server is responsible for the domain centralized management and security functions, that is, there is a system administrator control and Create a secure account management database.
9. ADSL: Abbreviation for asynchronous digital user loops. By two line encoding modulation techniques, the transmission rate of 6.1 Mbps can be performed under the conventional telephone line.
10. Active Directory --- "Active Directory" technology: It is a flexible enterprise directory service that is built with Internet standard technology to complete the integrated operating system level. It is a set of scalable, multi-purpose directory service technology, which simplifies the management of network users and resources, and allows users to use resources provided by internal networks.
Second, abbreviation
HTML: Hyper Text Markup Language, Hypertext Language
XML: EXTENSIBLE MARKUP LANGUAGE, scalable identity
HTTP: Hyper Text Transmission Protocol, Hypertext Transfer Protocol
URL: Uniform Resource Locator, the representation method for specifying the information location on the WWW service program on the Internet. (Unified resource locator)
CSS: Cascoding Style Sheet, Lama Platform
DHCP: Dynamic Host Config Protocol
POP3: Post Office Protocol 3
OLAP: ON LINE Analyze Peculiarity, Advanced Online Analysis Characteristics
Object oriented Analysis, object-oriented analysis
OOD: Object Oriented Design, object-oriented design
SSL: Secure Socket Layer, Safety Condom Layer
J2ee: Java 2 Enterprise Editor,
IIS: Internet Information ServerPws: Personal Web Server
Third, port number
SMTP: 25
POP3: 110
QQ: 8000
HTTP: 80
FTP: 21
Proxy server: 8080
Fourth, server / client mode
(1), Client / Server mode ---- C / S mode
1. C / S mode: client - function server or application server --- Database server.
2. Concept: Part related to data inventory is borne by DBMS Server, and the content related to the application's human-computer interface processing, input / output, or part of the logical function of the input / output or part of the application is borne by the Client end workstation.
3. The software of the application system is divided into three layers: 1. Remote user interface layer software in the client entity, responsible for the task of dialogue between users and applications. 2. Functional server entity stores business logic software to respond to client requests, complete the corresponding business processing or complex calculations. 3. Database service layer software resident in the database server entity is used to perform the SQL statement sent by the functional layer, responsible for managing tasks such as reading and writing, database query and update. The user returned to the client on the client after completion.
4. Benefits: 1. Fully mobilize the processing capabilities of Server and Client in the LAN. 2. greatly reduce information flow on the network. 3. Effectively send the server's hardware and software execution efficiency, centrally manage the safe and convenient convenience of the database, or take advantage of the advantages of the user interface and local I / O using the PC client. The 4.c / s architecture is likely to provide an open-oriented distributed computing environment, and protecting hardware.
(2) Browser / Server mode --- B / S mode:
1. B / S mode: B / S mode-based information systems typically use three or more layers of structures: browser-web server - database server.
2. Network computing in the Internet environment will be based on web technology, using the Browser / Server structure, combine database technology to form information services and database services with multimedia application features across platform openness.
3. Working principle: As the core of the system as the system, the client proposes a query request to the web server via Browser, and the web server issues a data request to the database server as needed. The database server returns the corresponding information results to the web server based on the search and query conditions, and the final web translates the results into the corresponding format of HTML or various Scripts languages. The user browses the desired results via Browser.
4. Benefits: High-efficiency and low cost, suitable for the full use of the Internet to provide a type of solution.
