Chapter 2 Application Layer Computer Networking A Top Down Approach The powerpoint slides are based on Featuring the Internet 2nd edition the material provided by Jim Kurose, Keith Ros JF Kurose and K.W. ross Addison-Wesley, Juf 2002 2: Application Layer 1
2: Application Layer 1 Chapter 2 Application Layer Computer Networking: A Top Down Approach Featuring the Internet, 2nd edition. Jim Kurose, Keith Ross Addison-Wesley, July 2002. The PowerPoint Slides are based on the material provided by J.F Kurose and K.W. Ross
Chapter 2: Application Layer Our goals: D learn about protocols o conceptual by examining popular implementation application-level aspects of network protocols application protocols O Http o transport-layer O FTP service models O SMTP/POP3/ IMAP o client-server O DNS paradigm o programming network o peer-to-peer applications paradigm o socket aPI 2: Application Layer 2
2: Application Layer 2 Chapter 2: Application Layer Our goals: conceptual, implementation aspects of network application protocols transport-layer service models client-server paradigm peer-to-peer paradigm learn about protocols by examining popular application-level protocols HTTP FTP SMTP / POP3 / IMAP DNS programming network applications socket API
Chapter 2 outline 口21 Principles of layer protoco/∞ 口26S0 cket programming with tCp o clients and servers 0 2.7 Socket programming o app requirements with UDP 02.2 Web and Http 02.8 Building a Web 口2.3FTP server 口24E| ectronic mail 02.9 Content distribution O SMTP POP3, IMAP o Network Web caching 0 25DNS o Content distribution networks o P2P file sharing 2: Application Layer 3
2: Application Layer 3 Chapter 2 outline 2.1 Principles of app layer protocols clients and servers app requirements 2.2 Web and HTTP 2.3 FTP 2.4 Electronic Mail SMTP, POP3, IMAP 2.5 DNS 2.6 Socket programming with TCP 2.7 Socket programming with UDP 2.8 Building a Web server 2.9 Content distribution Network Web caching Content distribution networks P2P file sharing
Network applications: some jargon Process: program running user agent: interfaces within a host with user above"and 口 within same host,two network" below processes communicate o implements user using interprocess interface communication(defined application-level by Os) proToco o processes running o eb: browser different hosts o E-mail: mail reader communicate with an o streaming audio/video application-layer media player rotoco 2: Application Layer 4
2: Application Layer 4 Network applications: some jargon Process: program running within a host. within same host, two processes communicate using interprocess communication (defined by OS). processes running in different hosts communicate with an application-layer protocol user agent: interfaces with user “above” and network “below”. implements user interface & application-level protocol Web: browser E-mail: mail reader streaming audio/video: media player
Applications and application-layer protocols Application: communicating, plication distributed processes o e.g., e-mail, Web, P2P file physical sharing, instant messaging o running in end systems (hosts ●●● o exchange messages to implement application Application-layer protocols 受 o one plece of an app o define messages transport exchanged by apps and hysical actions taken o use communication services provided by lower layer protocols(TCP UDP 2: Application Layer 5
2: Application Layer 5 Applications and application-layer protocols Application: communicating, distributed processes e.g., e-mail, Web, P2P file sharing, instant messaging running in end systems (hosts) exchange messages to implement application Application-layer protocols one “piece” of an app define messages exchanged by apps and actions taken use communication services provided by lower layer protocols (TCP, UDP) application transport network data link physical application transport network data link physical application transport network data link physical