Browse Prior Art Database

High-level Entity Management System (HEMS) (RFC1021) Disclosure Number: IPCOM000001825D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2019-Feb-15
Document File: 5 page(s) / 8K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

C. Partridge: AUTHOR [+1]

Related Documents

10.17487/RFC1021: DOI


This memo provides a general overview of the High-level Entity management system (HEMS). This system is experimental, and is currently being tested in portions of the Internet.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 28% of the total text.

Network Working Group C. Partridge Request For Comment: 1021 BBN/NNSC G. Trewitt Stanford October 1987



An overview of the RFCs which comprise the High-Level Entity Management System is provided. This system is experimental, and is currently being tested in portions of the Internet. It is hoped that this work will help lead to a standard for IP internetwork management. Distribution of this memo is unlimited.


Until recently, a majority of critical components in IP networks, such as gateways, have come from a very small set of vendors. While each vendor had their own set of management protocols and mechanisms, the collection was small, and a knowledgeable system administrator could be expected to learn them all.

Now, however, the number of vendors has grown quite large, and the lack of an accepted standard for management of network components is causing severe management problems. Compounding this problem is the explosive growth of the connected IP networks known as the Internet. The combination of increased size and heterogeneity is making internetwork management extremely difficult. This memo discusses an effort to devise a standard protocol for all devices, which should help alleviate the management problem.

The RFCs that currently define the High-Level Entity Management System are this memo along with RFC-1022, 1024, and 1023. This list is expected to change and grow over time, and readers are strongly encouraged to check the RFC Index to find the most current versions.


Historically, the IP community has divided network management into two distinct types of activities: monitoring and control. Monitoring is the activity of extracting or collecting data from the network or a part of the network to observe its behavior. Control is the activity of taking actions to effect changes in the behavior of the network or a part of the network in real-time, typically in an attempt to improve the network’s performance.

Partridge & Trewitt [Page 1]

RFC 1021 HEMS Overview October 1987

Note that the ability to control presupposes the ability to monitor. Changing the behavior of the network without being able to observe the effects of the changes is not useful. On the other hand, monitoring without control makes some sense. Simply understanding what is causing a network to misbehave can be useful.

Control is also a more difficult functionality to define. Control operations other than the most generic, are usually device-specific. The problem is not just a matter of providing a mechanism for control, but also defining a set of control operations which are generally applicable across a diverse set of devices. Permitting remote applications to exercise control over an entity also implies the need for a suite of safeguards to ensure that unauthorized applications cannot harm the network.

Because monitoring is the key first step, in this initial design of the sys...