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Network Working Group M. MacFaden Request for Comments: 3512 Riverstone Networks, Inc. Category: Informational D. Partain Ericsson J. Saperia JDS Consulting, Inc. W. Tackabury Gold Wire Technology, Inc. April 2003 Configuring Networks and Devices with Simple Network Management Protocol (SNMP) Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document is written for readers interested in the Internet Standard Management Framework and its protocol, the Simple Network Management Protocol (SNMP). In particular, it offers guidance in the effective use of SNMP for configuration management. This information is relevant to vendors that build network elements, management application developers, and those that acquire and deploy this technology in their networks. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. The Internet Standard Management Framework. . . . . . . . 3 1.2. Configuration and the Internet Standard Management Frame-work. . . . . . . . . . . . . . . . . . . . . . . . 4 2. Using SNMP as a Configuration Mechanism. . . . . . . . . . . . 5 2.1. Transactions and SNMP . . . . . . . . . . . . . . . . . . 6 2.2. Practical Requirements for Transactional Control. . . . . 6 2.3. Practices in Configuration--Verification. . . . . . . . . 7 3. Designing a MIB Module . . . . . . . . . . . . . . . . . . . . 9 3.1. MIB Module Design - General Issues. . . . . . . . . . . . 10 3.2. Naming MIB modules and Managed Objects. . . . . . . . . . 11 3.3. Transaction Control And State Tracking. . . . . . . . . . 12 MacFaden, et al. Informational [Page 1]  RFC 3512 Configuring Networks and Devices with SNMP April 2003 3.3.1. Conceptual Table Row Modification Practices. . . . 12 3.3.2. Fate sharing with multiple tables. . . . . . . . . 13 3.3.3. Transaction Control MIB Objects. . . . . . . . . . 14 3.3.4. Creating And Activating New Table Rows . . . . . . 15 3.3.5. Summary Objects and State Tracking . . . . . . . . 15 3.3.6. Optimizing Configuration Data Transfer . . . . . . 18 3.4. More Index Design Issues. . . . . . . . . . . . . . . . . 22 3.4.1. Simple Integer Indexing. . . . . . . . . . . . . . 23 3.4.2. Indexing with Network Addresses. . . . . . . . . . 23 3.5. Conflicting Controls. . . . . . . . . . . . . . . . . . . 24 3.6. Textual Convention Usage. . . . . . . . . . . . . . . . . 25 3.7. Persistent Configuration. . . . . . . . . . . . . . . . . 26 3.8. Configuration Sets and Activation . . . . . . . . . . . . 28 3.8.1. Operational Activation Considerations. . . . . . . 28 3.8.2. RowStatus and Deactivation . . . . . . . . . . . . 30 3.9. SET Operation Latency . . . . . . . . . . . . . . . . . . 31 3.9.1. Subsystem Latency, Persistence Latency, and Activation Latency . . . . . . . . . . . . . . 33 3.10. Notifications and Error Reporting. . . . . . . . . . . . 33 3.10.1. Identifying Source of Configuration Changes . . . 34 3.10.2. Limiting Unnecessary Transmission of Notifications . . . . . . . . . . . . . . . . . . 34 3.10.3. Control of Notification Subsystem . . . . . . . . 36 3.11 Application Error Reporting . . . . . . . . . . . . . . . 36 3.12 Designing MIB Modules for Multiple Managers . . . . . . . 37 3.13 Other MIB Module Design Issues. . . . . . . . . . . . . . 39 3.13.1. Octet String Aggregations . . . . . . . . . . . . 39 3.13.2 Supporting multiple instances of a MIB Module. . . 40 3.13.3 Use of Special Optional Clauses. . . . . . . . . . 41 4. Implementing SNMP Configuration Agents . . . . . . . . . . . . 41 4.1. Operational Consistency . . . . . . . . . . . . . . . . . 41 4.2. Handling Multiple Managers. . . . . . . . . . . . . . . . 43 4.3. Specifying Row Modifiability. . . . . . . . . . . . . . . 44 4.4. Implementing Write-only Access Objects. . . . . . . . . . 44 5. Designing Configuration Management Software. . . . . . . . . . 44 5.1. Configuration Application Interactions with Managed Systems. . . . . . . . . . . . . . . . . . . 45 5.1.1. SET Operations . . . . . . . . . . . . . . . . . . 46 5.1.2. Configuration Transactions . . . . . . . . . . . . 46 5.1.3. Tracking Configuration Changes . . . . . . . . . . 47 5.1.4. Scalability of Data Retrieval. . . . . . . . . . . 48 6. Deployment and Security Issues . . . . . . . . . . . . . . . . 48 6.1. Basic assumptions about Configuration . . . . . . . . . . 48 6.2. Secure Agent Considerations . . . . . . . . . . . . . . . 49 6.3. Authentication Notifications. . . . . . . . . . . . . . . 49 6.4. Sensitive Information Handling. . . . . . . . . . . . . . 50 7. Policy-based Management. . . . . . . . . . . . . . . . . . . . 51 7.1. What Is the Meaning of 'Policy-based' . . . . . . . . . . 51 MacFaden, et al. Informational [Page 2]  RFC 3512 Configuring Networks and Devices with SNMP April 2003 7.2. Organization of Data in an SNMP-Based Policy System . . . 53 7.3. Information Related to Policy-based Configuration . . . . 54 7.4. Schedule and Time Issues. . . . . . . . . . . . . . . . . 56 7.5. Conflict Detection, Resolution and Error Reporting. . . . 56 7.5.1. Changes to Configuration Outside of the Policy System. . . . . . . . . . . . . . . . . . . 57 7.6. More about Notifications in a Policy System . . . . . . . 57 7.7. Using Policy to Move Less Configuration Data. . . . . . . 57 8. Example MIB Module With Template-based Data. . . . . . . . . . 58 8.1. MIB Module Definition. . . . . . . . . . . . . . . . . . 61 8.2. Notes on MIB Module with Template-based Data. . . . . . . 73 8.3. Examples of Usage of the MIB . . . . . . .. . . . . . . . 74 9. Security Considerations . . . . . . . . . . .. . . . . . . . . 77 10. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . 78 11. Normative References. . . . . . . . . . . . . . . . . . . . . 78 12. Informative References. . . . . . . . . . . . . . . . . . . . 79 13. Intellectual Property . . . . . . . . . . . . . . . . . . . . 81 14. Editors' Addresses. . . . . . . . . . . . . . . . . . . . . . 82 15. Full Copyright Statement. . . . . . . . . . . . . . . . . . . 83 1. Introduction 1.1. The Internet Standard Management Framework The Internet Standard Management Framework has many components. The purpose of this document is to describe effective ways of applying those components to the problems of configuration management. For reference purposes, the Internet Standard Management Framework presently consists of five major components: o An overall architecture, described in RFC 3411 [1]. o Mechanisms for desc