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Lecture Business data communications and networking (8th edition): Chapter 2 - Jerry Fitzgerald, Alan Dennis

Lecture Business data communications and networking (8th edition): Chapter 2 - Application layer. In this chapter, the following content will be discussed: Application architectures, world wide web, electronic mail, other applications. | Business Data Communications and Networking 8th Edition Jerry Fitzgerald and Alan Dennis John Wiley & Sons, Inc Prof. M. Ulema Manhattan College Computer Information Systems 2 - Copyright 2005 John Wiley & Sons, Inc Chapter 2 Application Layer 2 - Copyright 2005 John Wiley & Sons, Inc Outline Application Architectures Host-Based, Client-Based, and Client-Server Architectures, Choosing Architectures World Wide Web How the Web Works, Inside an HTTP Request & HTTP Response Electronic Mail How E-Mail Works, Inside an SMTP Packet Listserv, Attachments in MIME Other Applications Ftp, Telnet, Instant Messaging, Videoconferencing 2 - Copyright 2005 John Wiley & Sons, Inc Application Layer - Introduction Application Layer Network Layer Transport Layer Applications (e.g., email, web, word processing) Functions of Applications Data storage Storing of data generated by programs (e.g., files, records) Data access logic Processing required to access stored data (e.g., SQL) . | Business Data Communications and Networking 8th Edition Jerry Fitzgerald and Alan Dennis John Wiley & Sons, Inc Prof. M. Ulema Manhattan College Computer Information Systems 2 - Copyright 2005 John Wiley & Sons, Inc Chapter 2 Application Layer 2 - Copyright 2005 John Wiley & Sons, Inc Outline Application Architectures Host-Based, Client-Based, and Client-Server Architectures, Choosing Architectures World Wide Web How the Web Works, Inside an HTTP Request & HTTP Response Electronic Mail How E-Mail Works, Inside an SMTP Packet Listserv, Attachments in MIME Other Applications Ftp, Telnet, Instant Messaging, Videoconferencing 2 - Copyright 2005 John Wiley & Sons, Inc Application Layer - Introduction Application Layer Network Layer Transport Layer Applications (e.g., email, web, word processing) Functions of Applications Data storage Storing of data generated by programs (e.g., files, records) Data access logic Processing required to access stored data (e.g., SQL) Application logic Business logic Presentation logic Presentation of info to user and acceptance of user commands 2 - Copyright 2005 John Wiley & Sons, Inc Application Architectures Determined by how functions of application programs are spread among clients and servers Host-based Architectures Server performs almost all functions Client-based architectures Client performs most functions Client-server architectures Functions shared between client and server 2 - Copyright 2005 John Wiley & Sons, Inc Host-Based Architectures captures key strokes then sends them to the mainframe displays information according to the server’s instructions or a PC running a terminal emulation program 2 - Copyright 2005 John Wiley & Sons, Inc Problems with Host-based Arch. Host becoming a bottleneck All processing done by the host, which can severely limit network performance Upgrades typically expensive and “lumpy” Available upgrades require big jumps in processing and memory $$$ Network demand grows .