"网络程序设计1：Socket概述与协议栈实现"

: The 6th chapter of Network Program Design 1 at the School of Computer Science, Beijing University of Posts and Telecommunications, taught by Jiang Yanjun, focuses on Socket overview, protocol stack implementation, and user-space and kernel-space implementation of transport layer and network interconnection layer protocols. Socket Overview: - Protocol stack implementation - The transport layer and above are implemented by user-space applications - The transport layer and network interconnection layer protocols are implemented in the kernel (routing protocols are implemented by user-space processes) - The first and second layers are generally implemented by hardware UNIX methods for providing network functionality to applications: - BSD organizes devices and communication channels in a file-like manner, with different creation methods but similar access methods - Terminal devices - Pipes - Communication services Socket is a key concept in network programming and refers to the endpoint of a bidirectional communication flow across a network. It can be identified by an IP address and a port number and provides a method for communication between applications on different devices. The BSD method for creating and accessing network communications mirrors the traditional file system, allowing for a familiar and consistent approach to interacting with network devices and services. This approach simplifies the process for developers and users, as they can employ similar methods for network communications as they would for manipulating files and directories. In summary, this chapter covers the fundamentals of network programming, including the role of sockets, the implementation of protocols across different layers, and the methods provided by UNIX for utilizing network functionality in applications. Understanding these concepts is essential for developing and maintaining efficient and reliable networked systems.