tailieunhanh - Understanding the Internet as an Infrastructure

Hiểu biết về Internet như là cơ sở hạ tầng một Bạn đã nghe tất cả các hype về Internet, và vì vậy không ai trong số đó sẽ được lặp đi lặp lại ở đây. Tuy nhiên, bạn nên xem xét một vài điểm. Internet là một mạng lưới lớn (alright-một mạng lưới thực sự lớn) | Understanding the Internet as an Infrastructure You have heard all the hype about the Internet and so none of it will be repeated here. However you should consider a few points. The Internet is a big network alright a really big network and as a result the information and data that you can access over it can be quite remote. This should have an impact on the way you design your applications. For example you might get away with locking data in a database while a user browses it in a small local desktop application but this strategy will not be feasible for an application accessed over the Internet. Resource use impacts scalability much more for the Internet than for local applications. Network bandwidth itself is also a scarce resource that should be used sparingly. You might notice variations in the performance of your own local network according to the time of day networks always seem to slow down on a Friday afternoon just when you are trying to get everything done before the weekend the applications that users in your company are running and many other factors. But no matter how variable the performance of your own local network is the Internet is far more unpredictable. You are dependent on any number of servers routing your requests from your Web browser to the site you are trying to access and the replies can get passed back along an equally tortuous route. The network protocols and data presentation mechanisms that underpin the Internet reflect the fact that networks can be and at times most certainly will be unreliable and that an application running on a server can be accessed by a user running one of many different Web browsers on one of many different operating systems. Understanding Web Server Requests and Responses A user gaining access to an application over the Internet by using a Web browser uses the Hypertext Transfer Protocol HTTP to communicate with the application. Applications are usually hosted by some sort of Web server that reads HTTP .