#readwise # Application layer - Wikipedia  ## Metadata - Author: [[wikipedia.org]] - Full Title: Application layer - Wikipedia - URL: https://en.wikipedia.org/wiki/Application_layer#Internet_protocol_suite ## Summary An application layer is an abstraction layer that specifies the shared communications protocols and interface methods used by hosts in a communications network. ## Highlights In the Internet protocol suite, the application layer contains the communications protocols and interface methods used in process-to-process communications across an [[Internet Protocol - Wikipedia|Internet Protocol]] (IP) computer network. The application layer only standardizes communication and depends upon the underlying [[Transport layer - Wikipedia|transport layer]] protocols to establish host-to-host data transfer channels and manage the data exchange in a [client–server](https://en.wikipedia.org/wiki/Client%E2%80%93server) or [peer-to-peer](https://en.wikipedia.org/wiki/Peer-to-peer) networking model. Though the TCP/IP application layer does not describe specific rules or data formats that applications must consider when communicating, the original specification (in [RFC 1123](https://datatracker.ietf.org/doc/html/rfc1123)) does rely on and recommend the [robustness principle](https://en.wikipedia.org/wiki/Robustness_principle) for application design. ([View Highlight](https://read.readwise.io/read/01jhtg0z9c2abe77w6p6m7ga86)) ^xawf29 --- The IETF definition document for the application layer in the Internet Protocol Suite is RFC 1123. It provided an initial set of protocols that covered the major aspects of the functionality of the early [Internet](https://en.wikipedia.org/wiki/Internet): - Hypertext documents: [Hypertext Transfer Protocol](https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol) (HTTP) - Remote login to hosts: [Telnet](https://en.wikipedia.org/wiki/Telnet), [Secure Shell](https://en.wikipedia.org/wiki/Secure_Shell) - File transfer: [File Transfer Protocol](https://en.wikipedia.org/wiki/File_Transfer_Protocol) (FTP), [Trivial File Transfer Protocol](https://en.wikipedia.org/wiki/Trivial_File_Transfer_Protocol) (TFTP) - Electronic mail transport: [Simple Mail Transfer Protocol](https://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol) (SMTP) - Networking support: [Domain Name System](https://en.wikipedia.org/wiki/Domain_Name_System) (DNS) - Host initialization: [BOOTP](https://en.wikipedia.org/wiki/BOOTP) - Remote host management: [Simple Network Management Protocol](https://en.wikipedia.org/wiki/Simple_Network_Management_Protocol) (SNMP), [Common Management Information Protocol](https://en.wikipedia.org/wiki/Common_Management_Information_Protocol) over TCP (CMOT) ([View Highlight](https://read.readwise.io/read/01jhtg20tz2d5dtfksn438n89m)) ---