Review of computer network--concept carding

Chapter I.

Computer network: The location of the different cutting function of the relatively independent computer systems through the communication lines connected together, follow the common network protocol, by the specialized network operating system management, in order to realize the resource sharing system.

Network topology: In order to facilitate the research and design of computer network structure, computers, terminals, communication processing machine, such as the abstract as a point, the connection of these devices to the line of communication lines, and the topology of these points and lines are called the network topology structure.

LAN: A limited range of (a floor, a building, a campus, etc.) computer interconnection into the network. The local area network has three, the obvious characteristic: 1, the range is small, several meters to thousands of meters. 2, high transmission rate (generally up to 10G bps), low error rates, lower latency. 3, the local area network is usually unit-owned, the establishment of maintenance and expansion are more convenient.

Metropolitan Area Network: The coverage range between the WAN and the local area network, to meet the urban, suburban networking needs. It can achieve a large number of users of data, voice, graphics and video and other information transmission function.

Wide Area Network: Achieve a wide range of resource sharing and information transfer, tens kilometers meters to by meters. It connects tens of thousands of LANs, metropolitan areas and WANs across the globe into a vast Internet network.

Communication subnet: is responsible for the resource subnet to provide data transmission and forwarding and other communication processing capacity, mainly by the communication control processor, communication links and other communication equipment, such as modems.

Resource subnet: Responsible for the entire network of data processing services, and to network users with a variety of network resources and Internet services. Mainly by the computer, the terminal and the corresponding input, various software resources and data resources constitute.

Chapter II

Network architecture: Under the premise of introducing layered model, the set of layers, protocols and interfaces between layers in computer network system is called Computer network architecture.

Entities: in layers of a layered model, the activity elements used to implement this layer are called entities, including all hardware and software that actually exists on that layer, such as functional circuits or terminals, control software, software protocols, applications, processes, and so on.

Protocol: A convention on how to exchange information about how peers communicate with each other.

Services: In the network tiering model, each layer provides functionality called services for the adjacent upper layer.

Interface:

Peer communication:

Protocol Data Unit:

Data encapsulation:

Data unpacking:

Chapter III

Review of computer network--concept carding