ISO Protocol Family

The ISO family of protocols isn't widely used, as the InternetProtocolFamily is much more common today.

Specifications of all of these protocols can be found in the ISO documents, which are (with some exceptions) not available free of charge. They can be found in the catalog of ISO standards.

A simplified overview of the core ISO protocols could look like this:

7 Application layer (FTAM, …)
6 Presentation Protocol
5 Session Protocol
4 COTP (connections) or CLTP (connectionless)
3 Internet (CLNP, ES-IS)
2 Link layer (LLC, …)


The ISO family consists of (at least) the following protocols:

Link layer:

  • LLC: ISO 8802-2 Logical Link Control (also an IEEE protocol standard, 802.2)

Network layer:

  • CLNP: ISO 8473 ConnectionLess network protocol: transfer IP packets from one host to another, similar to IP

Network layer (routing):

  • -: ISO 8348 Network Service Definition

  • ES-IS: ISO 9542 ESIS Routing Information Exchange Protocol

  • IS-IS: ISO 10589 ISIS InTRA Domain Routing Information Exchange Protocol

  • IDRP: ISO 10747 IDRP Inter Domain Routing Protocol, similar to BGP

Transport Layer:

  • -: ISO 8072 ISO Transport Service Definition

  • COTP: ISO 8073 COTP Connection-Oriented Transport Protocol, similar to TCP (spec. available as RFC905)

  • CLTP: ISO 8602 CLTP ConnectionLess Transport Protocol, similar to UDP

Transport layer (emulated by TCP/UDP):

  • TPKT: RFC1006 "ISO transport services on top of the TCP: Version 3", updated by RFC2126

  • TPKT: RFC2126 "Transport Service on top of TCP (ITOT)"

  • -: RFC1240 "OSI Connectionless Transport Services on top of UDP Version: 1"

Session layer:

  • SES: ISO 8327-1 OSI Session Protocol

Presentation layer:

  • PRES: ISO 8823/ITU-T X.226 OSI Presentation Protocol

Application layer:

Core Services:

  • ACSE: ISO/IEC 9594-2, ITU-T X.227 Application Control Service Element protocol

  • RTSE: ISO/IEC 9066-2, ITU-T X.228 Reliable Transfer Service Element protocol

  • ROSE: ISO/IEC 13712-1, ITU-T X.880 Remote Operations Service Element protocol

Messaging Services:

  • X411: ISO/IEC 10021-4, ITU-T X.411 Message Transfer System: Abstract Service, equivalent to SMTP

  • X413: ISO/IEC 10021-5, ITU-T X.413 Message Store: Abstract Service, equivalent to IMAP

  • X420: ISO/IEC 10021-7, ITU-T X.420 Interpersonal Messaging System

  • S4406: STANAG 4406 Miltary Messaging

Directory Services:

  • DAP: ISO/IEC 9594-3, ITU-T X.511 Directory Access Protocol, equivalent to LDAP

  • DSP: ISO/IEC 9594-4, ITU-T X.518 Directory System Protocol

  • DISP: ISO/IEC 9594-9, ITU-T X.525 Directory Information Shadowing Protocol

  • DOP: ISO/IEC 9594-8, ITU-T X.501 Directory Operational Management Binding Protocol


  • FTAM: ISO 8571 FTAM Protocol, similar to FTP

  • CMIP: ISO 8571-4 CMIP Protocol, similar to SNMP

  • MMS: ISO 9506 Manufacturing Message Specification (MMS)


  • ICAO standards for air/ground datalink in civil aviation (ICAO doc9705 "Aeronautical Telecommunication Network", ATN) are derived from ISO standards:

  • ICS: ICAO doc 9705 Ed.2 SV5, ATN Internet Connection Service, equivalent to CLNP/COTP/ISIS/ESIS/IDRP protocols

  • ULCS: ICAO doc 9705 Ed.2 SV4, ATN Upper Layer Service, based on SES/PRES/ACSE (PER encoding)

  • CM: ICAO doc 9705 Ed.2 SV2, Context Management Application, used for log on/registration

  • CPDLC: ICAO doc 9705 Ed.2 SV2, Controller Pilot Data Link Communication Application, including ammendements for PM CPDLC


XXX - add a brief description of ISO protocol history?

External links


Imported from on 2020-08-11 23:15:30 UTC