RFC 1139 (rfc1139) - Page 1 of 6


Echo function for ISO 8473



Alternative Format: Original Text Document



Network Working Group                             IETF-OSI Working Group
Request for Comments: 1139                                     R. Hagens
                                                            January 1990


                     An Echo Function for ISO 8473

Status of this Memo

   This memo defines an echo function for the connection-less network
   layer protocol.  This memo is not intended to compete with an ISO
   standard.  This is a Proposed Elective Standard for the Internet.
   Distribution of this memo is unlimited.

Abstract

   This memo defines an echo function for the connection-less network
   layer protocol.  Two mechanisms are introduced that may be used to
   implement the echo function.  The first mechanism is recommended as
   an interim solution for the Internet community.  The second mechanism
   will be progressed to the ANSI X3S3.3 working group for consideration
   as a work item.

   When an ISO standard is adopted that provides functionality similar
   to that described by this memo, then this memo will become obsolete
   and superceded by the ISO standard.

1.  Introduction

   The OSI Connection-less network layer protocol (ISO 8473) defines a
   means for transmitting and relaying data and error report PDUs
   through an OSI internet.  Unfortunately, the world that these packets
   travel through is imperfect.  Gateways and links may fail.  This memo
   defines an echo function to be used in the debugging and testing of
   the OSI network layer.

   Network management protocols can be used to determine the state of a
   gateway or link.  However, since these protocols themselves utilize a
   protocol that may experience packet loss, it cannot be guaranteed
   that the network management applications can be utilized.  A simple
   mechanism in the network layer is required so that systems can be
   probed to determine if the lowest levels of the networking software
   are operating correctly.  This mechanism is not intended to compete
   with or replace network management; rather it should be viewed as an
   addition to the facilities offered by network management.

   There are three important issues to consider when defining an echo
   extension to ISO 8473: complexity, code-path divergence, and backward



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