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