Application layer

The Internet protocol suite (TCP/IP) and the Open Systems Interconnection model (OSI model) of computer networking each specify a group of protocols and methods identified by the name application layer.

In TCP/IP, the application layer contains all protocols and methods that fall into the realm of process-to-process communications across an Internet Protocol (IP) network. Application layer methods use the underlying transport layer protocols to establish host-to-host connections.

In the OSI model, the definition of its application layer is narrower in scope, explicitly distinguishing additional functionality above the transport layer at two additional levels, the session layer and the presentation layer. OSI specifies strict modular separation of functionality at these layers and provides protocol implementations for each layer.

Internet protocol suite
Application layer
Transport layer
Internet layer
Link layer
The OSI model
7 Application layer
6 Presentation layer
5 Session layer
4 Transport layer
3 Network layer
2 Data link layer
1 Physical layer

Contents

TCP/IP protocols

The following protocols are explicitly mentioned in RFC 1123 (1989), describing the application layer of the Internet protocol suite.[1]

Other protocol examples

References

  1. ^ Robert Braden, ed (October 1989). "RFC 1123: Requirements for Internet Hosts – Application and Support". Network Working Group of the IETF. http://tools.ietf.org/html/rfc1123. 

External links