Computer network Learning Note _1

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Starting with David Weatherall's computer Networks, the first lesson is about goals and Motivation,focus of the course is networking, discussing packets and The internet, the bottom communications and the upper distributed systems, is how the network is built and what the top apps can do. The main point is learning how the Internet works, TCP/IP,DNS,HTTP,NAT,VPNS,802.11ETC et acronym, and learn the fundamentals of computer networks. While the web is evolving, the fundamentals of learning are constant, helping to understand the latest technology. The feeling is that David's slides is doing very well, the lectures are vivid, and many examples. Knowing why to build networks and what to do will help us build more efficient networks in the future.

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There is an important concept, statical multiplexing. How to have more users under the same bandwidth. Also introduces an important concept, the Value of Connectivity. 1980 Metcalfe proposed that the larger the network, the greater the value, the network value of n nodes is close to the square of N.

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Introduces some acronym,host,router,link,app of parts of a network. The app is using network. Host is a network terminal, such as a laptop computer. Router to the links between the transmission of information, such as CABLE/DSL modem. Link connects nodes, such as Wired, wireless. Types of links There are three kinds: Full-duplex dual work, both sides can communicate at the same time, Half-duplex half-duplex, both sides of the non-simultaneous communication; simplex single-work, one-way communication. Networks named according to scale: PAN, LAN, man, WAN, the Internet. Network boundaries:router and link indicate that isp,host, router, and link represent the network. Key interfaces:network-application Interfaces Define how apps Use the Network:sockets;network-network Interfaces define H OW nodes work Together:traceroute can peek in the network;

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Learn how to write a application and use the network. Do some understanding of network-application interface. Apps through the socket API and network communication. Sockets is a data structure sockets let apps attach to the local network at different ports. Ports is the address. Socket API functions are socket, BIND, LISTEN, ACCEPT, CONNECT, SEND, RECEIVE, CLOSE. Use the socket API function to complete the client and server program (outline). One should a answer, like a phone call. But one side first accept or recv the other side again connect or send. Another getaddrinfo () means translation, such as translating www.haha.com into a digital address.

Computer network Learning Note _1