RFC 1076 (rfc1076) - Page 2 of 42
HEMS monitoring and control language
Alternative Format: Original Text Document
RFC 1076 HEMS Monitoring and Control Language November 1988 This language is a component of the High-Level Entity Monitoring System (HEMS) described in RFC-1021 and RFC-1022. Readers may wish to consult these RFCs when reading this memo. RFC-1024 contains detailed assignments of numbers and structures used in this system. Portions of RFC-1024 that define query language structures are superceded by definitions in this memo. This memo assumes a knowledge of the ISO data encoding standard, ASN.1. Distribution of this memo is unlimited. INTRODUCTION 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. 2. OVERVIEW AND SCOPE The basic model of monitoring and control used in this memo 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 data, or both. We will use gateway- oriented examples, but it should be understood that this query- response mechanism is applicable to any IP entity. 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. In order to design the query language, we had to define a model for the data to be retrieved by the queries, which required some understanding of and assumptions to be made about the data. We ended up with a fairly flexible data model, which places few limits on the type or size of the data. Wherever possible, we give motivations for the design decisions or assumptions that led to particular features or definitions. Some of the important global considerations and assumptions are: - The query processor should place as little computational burden on the monitored entity as possible. - It should not be necessary for a monitored entity to store the complete query. Nothing in the query language should Trewitt & Partridge
