Chapter 4: Server Software Design Chapter 4: Server Software Design Algorithm and issues Algorithm and issues Iterative Iterative servers a Concurrent connection-oriented Concurrent connection-oriented servers servers Singly-threaded,concurrent a Singly-threaded, concurrent servers servers a Multiprotocol servers Multiprotocol servers a Multiservice servers Multiservice servers Uniform, efficient management Uniform, efficient management of server concurrency of server concurrency Concurrent vs. Iterative The conceptual server algorithm Servers Each server follows a simple algorithm a Iterative server Process one request at a time Enters infinite lo Easier to build Accepts request Poor performance Processes request a Concurrent Handles multiple requests at one time But only suffices for only the most trivial More difficult to design and build services Better performance Connection-oriented vs Connection-oriented vs Connectionless Servers Connectionless servers Depend on the application protocol Connectionless servers n Connection-oriented servers Advantages Advantages Do not suffer from the problem of resource Ease of programming TCP provides reliability Can supply broadcast or multicast communication Disadvantages Disadvantages: Require a separate socket for each connection Can not depend on underlying transport for Overhead of 3-way handshaking TCP does not send any packets over an idle Application protocols respond for reliability connection- run out of resources1 哈工大计算机学院 李全龙 Network 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 李全龙 Network Application Development Server Software Design 2 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 李全龙 Network Application Development Server Software Design 3 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 李全龙 Network Application Development Server Software Design 4 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 李全龙 Network Application Development Server Software Design 5 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 李全龙 Network Application Development Server Software Design 6 Connection-oriented vs. Connectionless Servers „ Connectionless servers „ Advantages: „ Do not suffer from the problem of resource depletion „ Can supply broadcast or multicast communication „ Disadvantages: „ Can not depend on underlying transport for reliable delivery „ Application protocols respond for reliability