NAD-chapter4.pdf

文档介绍：Chapter 4: Server Software Design
Chapter goal:
„ Algorithm and issues
„ Iterative servers
„ Concurrent, connection-oriented
servers
„ Singly-threaded, concurrent
servers
„ Multiprotocol servers
„ Multiservice servers
„ Uniform, efficient management
of server concurrency
哈工大计算机学院 work Application Development Server Software Design 1
Chapter 4: Server Software Design
Chapter goal:
„ Algorithm and issues
„ Iterative servers
„ Concurrent, connection-oriented
servers
„ Singly-threaded, concurrent
servers
„ Multiprotocol servers
„ Multiservice servers
„ Uniform, efficient management
of server concurrency
哈工大计算机学院 work Application Development Server Software Design 2
The conceptual server algorithm
„ Each server follows a simple algorithm:
„ Creates a socket
„ Binds port
„ Enters infinite loop
„ Accepts request
„ Processes request
„ Responses
„ But only suffices for only the most trivial
services
哈工大计算机学院 work Application Development Server Software Design 3
Concurrent vs. Iterative
Servers
„ Iterative server
„ Process one request at a time
„ Unnecessary delays
„ Easier to build
„ Poor performance
„ Concurrent server
„ Handles multiple requests at one time
„ More difficult to design and build
„ Better performance
哈工大计算机学院 work Application Development Server Software Design 4
Connection-oriented vs.
Connectionless Servers
„ Depend on the application protocol
„ Connection-oriented servers
„ Advantages:
„ Ease of programming
„ TCP provides reliability
„ Disadvantages:
„ Require a separate socket for each connection
„ Overhead of 3-way handshaking
„ TCP does not send any packets over an idle
connection- run out of resources
哈工大计算机学院 work Application Development Server Software Design 5
Connection-oriented vs.
Connectionless Servers
„ Connectionless servers
„ Advantages:
„ Do not suffer from the problem of resource
depletion
„ Can supply bro