Câu trả lời nằm trong kiểm tra hồi quy. Trong quá trình thử nghiệm hồi quy chỉ có những khía cạnh của thiết kế thành phần đã bị ảnh hưởng bởi một hành động khắc phục được tái xác nhận. Hình thức, phù hợp, và kiểm tra chức năng của UUT đã được hoàn tất thành công và không bị ảnh hưởng bởi bất kỳ hành động khắc phục không tái xác nhận. | Exercises 7 Applications TCP sockets TCP ports IP Figure Sockets protocols and ports. Figure depicts the logical relationships among applications socket abstractions protocols and port numbers within a single host. Note that a single socket abstraction can be referenced by multiple application programs. Each program that has a reference called a descriptor to a particular socket can communicate through that socket. Earlier we said that a port identifies an application on a host. Actually a port identifies a socket on a host. Figure shows that multiple programs on a host can access the same socket. In practice separate programs that access the same socket would usually belong to the same application . multiple copies of a Web server program although in principle they could belong to different applications. Exercises 1. Can you think of a real-life example of communication that does not fit the clientserver model 2. To how many different kinds of networks is your home connected How many support two-way communication 3. IP is a best-effort protocol requiring that information be broken down into datagrams which may be lost duplicated or reordered. TCP hides all of this providing a reliable service that takes and delivers an unbroken stream of bytes. How might you go about providing TCP service on top of IP Why would anybody use UDP when TCP is available ThisPagelntentionallyLeftBlank chap Basic ter 2 Sockets You are now ready to learn to write your own socket applications in C . One of the advantages of the C programming language is its use of Microsoft s .NET framework which provides a powerful library of APIs for programming. Among the class libraries provided are the and namespaces and most of this book is dedicated to how to use the socket APIs provided there. In this chapter we begin by demonstrating how C applications identify network hosts. Then we describe the creation of TCP and UDP clients and servers. The
