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HEMS monitoring and control language (RFC1023)

IP.com Disclosure Number: IPCOM000001827D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2019-Feb-15
Document File: 17 page(s) / 24K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

G. Trewitt: AUTHOR [+1]

Related Documents

10.17487/RFC1023: DOI


This RFC specifies the High-Level Entity Management System (HEMS) Monitoring and Control Language. This language defines the requests and replies used in HEMS. This memo assumes knowledge of the HEMS system described in RFC-1021, and of the ISO data encoding standard, ASN.1.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 9% of the total text.

Network Working Group G. Trewitt Request for Comments: 1023 Stanford C. Partridge BBN/NNSC October 1987

HEMS Monitoring and Control Language

This RFC specifies the design of a general-purpose, yet efficient, monitoring and control language for managing network entities. The data in the entity is modeled as a hierarchy and specific items are named by giving the path from the root of the tree. Most items are read-only, but some can be "set" in order to perform control operations. Both requests and responses are represented using the ISO ASN.1 data encoding rules.


The purpose of this RFC is provide a specification for monitoring and control of network entities in the Internet. This is an experimental specification and is intended for use in testing the ideas presented here. No proposals in this memo are intended as standards for the Internet at this time. After sufficient experimentation and discussion, this RFC will be redrafted, perhaps as a standard. Distribution of this memo is unlimited.

This language is a component of the High-Level Entity Monitoring System (HEMS) described in RFC-1021 and RFC-1022. Readers may want to consult these RFCs when reading this memo. RFC-1024 contains detailed assignments of numbers and structures used in this system. This memo assumes a knowledge of the ISO data encoding standard, ASN.1.


The basic model of monitoring and control used in this proposal is that a query is sent to a monitored entity and the entity sends back a response. The term query is used in the database sense -- it may request information, modify things, or both. We will use gateway- oriented examples, but it should be understood that this query- response mechanism can be applied to other entities besides just gateways.

In particular, there is no notion of an interactive "conversation" as in SMTP [RFC-821] or FTP [RFC-959]. A query is a complete request that stands on its own and elicits a complete response.

Trewitt & Partridge [Page 1]

RFC 1023 HEMS Language October 1987

It is not necessary for a monitored entity to be able to store the complete query. It is quite possible for an implementation to process the query on the fly, producing portions of the response while the query is still being received.

Other RFCs associated with HEMS are: RFC-1021 -- Overview; RFC-1022 -- transport protocol and message encapsulation; RFC-1024 -- precise data definitions. These issues are not dealt with here. It is assumed that there is some mechanism to transport a sequence of octets to a query processor within the monitored entity and that there is some mechanism to return a sequence of octets to the entity making the query.


Both queries and responses are encoded using the representation defined in ISO Standard ASN.1 (Abstract Syntax Notation 1). ASN.1 represents data as sequences of <tag,length,contents> triples that are encoded as a stream of octets. The data tuples may be recursively...