1.1 Definition and function of computer networks
1, resource sharing
2, information transmission and centralized treatment
3, load balancing and distributed processing
4, integrated information service
1.2 evolution of computer networks
The first stage: single terminal system with multi-terminal system
The second stage: computer network - multi-machine system
The third stage: the Internet - multi-network system
Phase IV: the future - and other things to the Internet as the core of the network
1.3 Classification of computer networks
1, a local area network (LAN)
Features: ①: limited coverage
②: sharing resources, shared services
③: simple maintenance
④: low network overhead
⑤: The main transmission medium is twisted pair, and optical fiber in small amounts
2, a metropolitan area network (MAN)
Features: ①: networking is relatively complex
②: large network overhead
③: Internet resources can be achieved
④: The main transmission medium is fiber optic cable
⑤: we can provide high-speed, high-quality data transmission
3, wide area network (WAN)
Features: ①: adapt to large-capacity requirements and bursty
②: adapt to the requirements of Integrated Services
③: has a complete communications service and network management
④: can provide high-speed, high-quality data transmission
⑤: The main transmission medium is optical cable, the optical fiber
⑥: has a heavyweight redundancy measures
1.4 computer network performance indicators
1, the rate
2, the bandwidth
3, throughput
4, delay
5, round trip time
Computer network topology 1.5
1, star network
2, Tree Network
3, distributed network
4, bus network
5, ring network
6, the composite web
1.6 computer network-related standardization organizations
International Organization for Standardization (ISO)
The International Telecommunication Union (ITU)
Institute of Electrical and Electronics Engineers (IEEE)
American National Standards Institute (ANSI)
Electronic Industries Association (EIA / TIA)
Internet Engineering Task Force (IETF)
Internet Architecture Board (IAB)
IP address numbering structure (IANA) on the Internet