NAD-chapter4-6.pdf

文档介绍：Chapter 4: Server Software Design Chapter 4: Server Software Design
Chapter goal: Chapter goal:
„ Algorithm and issues „ Algorithm and issues
„ Iterative servers „ Iterative servers
„ Concurrent, connection-oriented „ Concurrent, connection-oriented
servers servers
„ Singly-threaded, concurrent „ Singly-threaded, concurrent
servers servers
„ Multiprotocol servers „ Multiprotocol servers
„ Multiservice servers „ Multiservice servers
„ Uniform, efficient management „ Uniform, efficient management
of server concurrency of server concurrency
哈工大计算机学院 work Application Development Server Software Design 1 哈工大计算机学院 work Application Development Server Software Design 2
Concurrent vs. Iterative
The conceptual server algorithm Servers
„ Each server follows a simple algorithm: „ Iterative server
„ Creates a socket „ Process one request at a time
„ Binds port „ Unnecessary delays
„ Enters infinite loop „ Easier to build
„ Accepts request „ Poor performance
„ Processes request „ Concurrent server
„ Responses „ Handles multiple requests at one time
„ But only suffices for only the most trivial „ More difficult to design and build
services „ Better performance
哈工大计算机学院 work Application Development Server Software Design 3 哈工大计算机学院 work Application Development Server Software Design 4
Connection-oriented vs. Connection-oriented vs.
Connectionless Servers Connectionless Servers
„ Depend on the application protocol „ Connectionless servers
„ Connection-oriented servers „ Advantages:
„ Do not suffer from the problem of resource
„ Advantages:
depletion
„ Ease of programming
„ Can supply broadcast or munication
„ TCP provides reliability
„ Disadvantages:
„ Disadvantages:
„ Can not depend on underlying transport for
„ Require a separate socket for each connection reliable delivery
„ Overhead of 3-way handshaking
„ Application protocols respond for reliability
„ TCP does not send any packets over an idl