Computer Network

Computer Network

Overview

• Formal definition: interconnected collection of computing devices.
• End systems(host）:
  e.g.pc’s, workstation,servers.
  e.g.PDA’s, phone, toasters
  run network application program :WWW.,e-mail
• Computer network: provide communication services to allow data transfer between systems.

Computer Network uses

• Resource sharing
• Highly reliability
• Cost saving
• New way of communication
  1. Access to remote information(WWW,FTP…
  2. Exchange of information(Email,Wechat…
  3. Interactive entertainment(Video-on-demand,network gaming , Mp3,…

The Internet

• Global scale, general purpose, heterogeneous-technologies, public, Com.Net.
• Internet Protocol
  1.Open standard
  2.Technical basis for other types of networks
• Developed by the research community

History

…

• Everyone is selfish and aggressive, wanna the max ratio of transmission -> conjunction
• Common language -> interconnecting network

Cerf and Kahn’s internetworking principles:

• minimalism, autonomy-no internet changes required to interconnect networks
• best effort service model
• stateless route
• decentralized control
  define today’s Internet architecture