RFC 1136 (rfc1136) - Page 2 of 10
Administrative Domains and Routing Domains: A model for routing in the Internet
Alternative Format: Original Text Document
RFC 1136 A Model for Routing in the Internet December 1989 the present and future Internet, and to show how the model can aid in the construction of well-engineered routing environments. 4) Terminology The following is a brief glossary of OSI terminology. Formal definitions can be found in the OSI Basic Reference Model [4], the Internal Organization of the Network Layer [5], and the OSI Routeing Framework [1]. "Routeing" is the official ISO spelling of what is more commonly spelled "routing." In this paper, the ISO spelling will be used wherever directly quoted from ISO documents, and the common spelling used otherwise. End System (ES) An OSI system on which applications run. An End System has full seven-layer OSI functionality. Basically equivalent to an Internet Host. Intermediate System (IS) An OSI system that performs routing and relaying functions in order to provide paths between End Systems. Intermediate Systems have no functionality above the Network Layer (although a practical realization of an OSI router will have some amount of End System functionality for network management functions, among other things). Basically equivalent to an Internet Router. Subnetwork (SN) A communications medium that provides a "direct" path between Network Layer entities. This can be realized via a point-to- point link, a LAN, a Public Data Network, and so forth. This is essentially equivalent to an Internet Subnet. It is worth noting that, unlike Internet Subnets, OSI Subnetworks are not necessarily reflected in the addressing hierarchy, so the double meaning of the Internet term "Subnet" (a single IP hop; a part of the address hierarchy) does not hold in the OSI world. Open Systems Interconnection Environment (OSIE) The global collection of Open Systems. Basically equivalent to the Internet. Hares & Katz
