This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Chapter 3 Application Layer Functionality and Protocols Protocols: Define processes on either end of the communication Define the types of messages Define the syntax of messages Define the meaning of any informational fields Define how messages are sent and the expected response Define interaction with the next lower layer Examples: Domain Name Service Protocol (DNS) Used to resolve internet names to IP addresses Hypertext Transfer Protocol (HTTP) Used to transfer files that make up the Web pages of the World Wide Web Simple Mail Transfer Protocol (SMTP) Used for the transfer of mail messages and attachments Telnet Used to provide remote access to servers and networking devices File Transfer Protocol (FTP) Used for interactive file transfer between systems Two forms of software programs or processes Network-Aware Applications Software used by people to communicate over the network Application Layer Services The programs that interface with the network and prepare the data for transfer The Client/Server Model The device requesting the information is called a client and the device responding to the request is called a server Data transfer from a client to a server is referred to as an upload Data transfer from a server to a client is referred to as a download Servers In a general networking context, any device that responds to requests from client applications is functioning as a server The server runs a service, or process sometimes called a server daemon Daemons run in the background...
View Full Document
This note was uploaded on 04/29/2008 for the course ICTN 2154 taught by Professor Khoury during the Spring '08 term at East Carolina University .
- Spring '08