HEMS variable definitions (RFC1024)
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
C. Partridge: AUTHOR [+1]
This memo assigns instruction codes, defines object formats and object semantics for use with the High-Level Monitoring and Control Language, defined in RFC-1023. A general system has been described in previous memos (RFC-1021, RFC-1022). This system is called the High-Level Entity Management System (HEMS). This memo is provisional and the definitions are subject to change. Readers should confirm with the authors that they have the most recent version. This RFC assumes a working knowledge of the ISO data encoding standard, ASN.1, and a general understanding of the IP protocol suite.
Network Working Group C.Partridge Request For Comment: 1024 BBN/NNSC G. Trewitt Stanford October 1987
HEMS VARIABLE DEFINITIONS
STATUS OF THIS MEMO
This memo assigns instruction codes, defines object formats and object semantics for use with the High-Level Monitoring and Control Language, defined in RFC-1023.
This memo is provisional and the definitions are subject to change. Readers should confirm that they have the most recent version of the memo.
The authors assume a working knowledge of the ISO data encoding standard, ASN.1, and a general understanding of the IP protocol suite.
Distribution of this memo is unlimited.
In other memos [RFC-1021, RFC-1022] the authors have described a general system for monitoring and controlling network entities; this system is called the High-Level Entity Management System (HEMS). This system permits applications to read and write values in remote entities which support a simple query processor.
In this memo we standardize the language instruction codes, the objects which can be read or written, and the meanings of any constants stored in the objects. There are three parts to this standardization: (1) the assignment of an ASN.1 tag to each value, (2) the definition of the external representation of the value (e.g., INTEGER, OCTETSTRING, etc.), and (3) the definition of the meaning, or semantics of a value (e.g., what types of packets a particular packet counter actually tracks).
This definition is provisional, and the authors hope that it will be expanded and improved as the community becomes more experienced with HEMS. Readers with suggestions for additional object definitions, or improved definitions are encouraged to contact the authors.
Partridge & Trewitt [Page 1]
RFC 1024 HEMS Definitions October 1987
All HEMS values are conveyed between applications and entities using the High-Level Entity Management Protocol (HEMP) specified in RFC- 1022. All values specified in this memo are passed in the data sections of HEMP messages. For all message types, the data section is a SEQUENCE of objects. For requests, these objects are operations and their operands. Replies contain a sequence of objects retrieved by a request. Events contain an initial event object followed by an optional number of objects related to the event.
Messages conforming to this memo should set the link field in the HEMP CommonHeader to 1, to indicate version 1 of HEMS. The resourceId field should be set to NULL.
CONTROL LANGUAGE INSTRUCTIONS
The HEMS Monitoring and Control Language defines a suite of operations which the query processor must be able to perform. These operations and their operands are ASN.1 objects which are passed to the query processor over a network connection. The operations and operands are sent in postfix form (the operation follows the operands). Operands are pushed onto a stack and are processed when the operation is encountered.
To ensure that operations are easily recognized in the inpu...