concept
A computer network is a system that connects scattered computer systems with independent functions through communication equipment and lines , and realizes resource sharing and information transmission by software with complete functions.
Computer systems include : IOS, Android, Windows, macOS, etc., also called end systems
Communication equipment includes : switches, routers
A computer network is an interconnected, autonomous collection of computers
Interconnection - interconnection and intercommunication link
Autonomy - no master-slave relationship
Five functions of computer network
1. Data communication (connectivity)
2. Resource sharing (hardware, software, data)
3. Distributed processing (multiple computers each undertake different parts of the same task: Hodoop platform)
4. Improve reliability (replacement machine)
5. Load balancing (closer between computers)
Components of a computer network
1. Component hardware, software, protocol
2. Working method
Edge part: direct use by users (C/S mode, P2P mode)
The Core: Serving the Edge
3. Functional composition (data communication, resource sharing)
Communication subnet for data communication
Resource subnet for resource sharing/data processing
Classification of Computer Networks
1. According to the scope of distribution: wide area network WAN (switching technology), metropolitan area network MAN, local area network LAN (broadcasting technology), personal area network PAN
2. According to users: public network (China Telecom, China Mobile), private network (military, bank, public security)
3. According to switching technology: circuit switching, message switching, packet switching
4. According to topology
5. According to transmission technology
Broadcast Network Shared Common Communication Channel
Point-to-point networks use packet store-and-forward and routing mechanisms