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Different protocols often describe different aspects of a single communication; taken together, these form a protocol stack. The terms "protocol" and "protocol stack" also refer to the software that implements a protocol.

Most recent protocols are assigned by the IETF for internet communications, and the IEEE, or the ISO organizations for other types. The ITU-T handles telecommunications protocols and formats.

Index page for network protocols and protocol layers, categorised by the nearest matching layers of the OSI seven layer model.

1 Protocol families

Various protocol stacks or families

• AppleTalk
• DECnet
• IPX/SPX
• Open Systems Interconnect (OSI)
• Systems Network ArchitectureSystems Network Architecture (SNA) is IBM's proprietary networking architecture created in 1974. It is a complete protocol stack for interconnecting computers and their resources. SNA is still used intensively in banks and other financial transaction netw (SNA)
• Internet protocol suiteThe Internet protocol suite is the set of protocols that implement the protocol stack on which the Internet runs. It is sometimes called the TCP/IP protocol suite, after the two most important protocols in it: the Transmission Control Protocol (TCP) and t

There are many articles about network protocols. One of the sites with high quality protocol information is by Javvin (www.javvin.com [1]).

2 Individual protocols

2.1 Layer 1 protocols (physical layer)The physical layer is level one in the seven level OSI model of computer networking. It performs services requested by the data link layer. This level is referring to network hardware, physical cabling or a wireless electromagnetic connection. It also dea

• ISDNISDN is also short for isosorbide dinitrate Integrated Services Digital Network ISDN is a type of telephone network system, designed to allow digital (as opposed to analogue) transmission of voice and data over ordinary telephone copper wires, resulting i Integrated Services Digital Network
• PDH Plesiochronous Digital Hierarchy
  • T-carrierIn telecommunications, T-carrier is the generic designator for any of several digitally multiplexed telecommunications carrier systems originally developed by Bell Labs and used in North America and Japan. The E-carrier system, where 'E' stands for Europe (T1, T3 etc)
• RS-232, a serial line interface originally developed to connect modems and computer terminals
• SDH Synchronous Digital Hierarchy
• SONET Synchronous Optical NETworking