According to the function and structure of the network, computer networks can be divided into: resource subnets and communication subnets. The equipment in the communication subnet works at the physical layer, data link layer, network layer and transport layer of the TCP/IP protocol; the equipment in the resource subnet works at the application layer of the TCP/IP protocol.
As the computer network structure continues to improve, people logically separate the data processing function and the data communication function, and the data processing part is called the resource subsystem. network, and the communication function part is called the communication subnet.
Network hosts, terminals and their ancillary equipment (including hardware, system software and application software, etc.), which constitute the basic resources of the network and are mainly responsible for data processing tasks, are called resource subnets.
The resource subnet refers to the user-side system (intra-office dispatch automation network, MIS network and substation LAN), including user application resources, such as servers, fault collection computers, peripherals, system software and application software.
Communication subnet refers to the collection of equipment and software that implement network communication functions in the network. Communication equipment, network communication protocols, communication control software, etc. belong to the communication subnet, which is the inner layer of the network and is responsible for information. transmission.
The data processing part is called the resource subnet, and the communication part is called the communication subnet. There are two technologies used in communication subnets: one is circuit switching and the other is packet switching. The automatic data processing network of civil aviation adopts the latter, which is more in line with the bursty characteristics of air traffic control data.
The resource subnet is responsible for network-wide data processing and providing resources and network services to network users, including network data processing resources and data storage resources.
The communication subnet mainly provides users with data transmission, transfer, processing, transformation, etc. The task of the communication subnet is to transmit messages between end nodes, and it mainly consists of transfer points and communication links. In the ARPA network, the transfer point is commonly called the interface processor (IMP).
Extended information:
As far as the local area network is concerned, the communication subnet consists of network cards, cables, hubs, repeaters, bridges, routers, switches and other equipment and Related software components. The resource subnet consists of networked servers, workstations, shared printers and other devices, and related software.
In a wide area network, the communication subnet consists of some dedicated communication processors (i.e. node switches) and the software they run, concentrators and other equipment, and communication links connecting these nodes. The resource subnet consists of all hosts connected to the Internet and their external devices.
The devices in the communication subnet work at the physical layer, data link layer, network layer and transport layer of the TCP/IP protocol, and the devices in the resource subnet work at the application layer of the TCP/IP protocol.
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