1.7. Application Layer
At the top of the TCP/IP protocol architecture is the Application Layer. This layer includes all processes that use the Transport Layer protocols to deliver data. There are many applications protocols. Most provide user services, and new services are always being added to this layer.
The most widely known and implemented applications protocols are:
While HTTP, FTP, SMTP, and Telnet are the most widely implemented TCP/IP applications, you will work with many others as both a user and a system administrator. Some other commonly used TCP/IP applications are:
Some protocols, such as Telnet and FTP, can be used only if the user has some knowledge of the network. Other protocols, like OSPF, run without the user even knowing that they exist. As the system administrator, you are aware of all these applications and all the protocols in the other TCP/IP layers. And you're responsible for configuring them!
Copyright © 2002 O'Reilly & Associates. All rights reserved.