]> Everything OPS

benoit@everything-ops.net

Cisco

jclarke@cisco.com

Old Dog Consulting

adrian@olddog.co.uk

Nokia

samier.barguil_giraldo@nokia.com

Blue Fern Consulting

carlos@bluefern.consulting cpignata@gmail.com https://bluefern.consulting

ZTE

chen.ran@zte.com.cn

Operations and Management management operations operations and management ops considerations New Protocols or Protocol Extensions are best designed with due consideration of the functionality needed to operate and manage the protocols. Retrofitting operations and management is sub-optimal. The purpose of this document is to provide guidance to authors and reviewers of documents that define New Protocols or Protocol Extensions regarding aspects of operations and management that they should consider and include in their documents. This document obsoletes RFC 5706, replacing it completely and updating it with new operational and management techniques and mechanisms. It also introduces a requirement to include an "Operational Considerations" section in new RFCs in the IETF Stream.

Introduction Often when New Protocols or Protocol Extensions are developed, not enough consideration is given to how the protocol will be deployed, operated, and managed. Retrofitting operations and management mechanisms is often hard and architecturally unpleasant, and certain protocol design choices may make deployment, operations, and management particularly difficult. In order to make sure that protocols can be deployed and used, the operational environment and manageability of a protocol should be considered when New Protocols or Protocol Extensions are designed. This document provides guidelines to help Protocol Designers and working groups (WGs) consider the operations and management functionality for their New Protocol or Protocol Extension at an early phase in the design process. This document obsoletes and fully updates its content with new operational and management techniques and mechanisms. It also introduces a requirement for an "Operational Considerations" section in new RFCs in the IETF Stream. This document also removes outdated references and aligns with current practices, protocols, and technologies used in operating and managing devices, networks, and services. See for more details.

This Document This document provides a set of guidelines for considering operations and management in an IETF technical specification with an eye toward being flexible while also striving for interoperability. Entirely New Protocols may require significant consideration of expected operations and management, while Protocol Extensions to existing, widely deployed protocols may have established de facto operations and management practices that are already well understood. This document does not mandate a comprehensive inventory of all operational considerations. Instead, it guides authors to focus on key aspects that are essential for the technology's deployability, operation, and maintenance. Suitable management approaches may vary for different areas, working groups, and protocols in the IETF. This document does not prescribe a fixed solution or format in dealing with operational and management aspects of IETF protocols. However, these aspects should be considered for any IETF protocol, given the IETF's role in developing technologies and protocols to be deployed and operated in the real-world Internet. A WG may decide that its protocol does not need interoperable management or a standardized Data Model, but this should be a deliberate and documented decision, not the result of omission. This document provides some guidelines for those considerations. This document makes a distinction between "Operational Considerations" and "Management Considerations", although the two are closely related. The operational considerations apply to operating the protocol within a network, even if there were no management protocol actively being used. The section on manageability is focused on management technology, such as how to utilize management protocols and how to design management Data Models.

Audience The guidelines are intended to be useful to authors writing protocol specification, providing guidance about what to consider when thinking about the management and deployment of a new protocol, to provide guidance about documenting those considerations, and helping them provide a reasonably consistent format for such documentation. Protocol Designers should consider which operations and management needs are relevant to their protocol, document how those needs could be addressed, and suggest (preferably standard) management protocols and Data Models that could be used to address those needs. This is similar to a WG that considers which security threats are relevant to their protocol, documents (in the required Security Considerations section, per Guidelines for Writing RFC Text on Security Considerations ) how threats should be mitigated, and then suggests appropriate standard protocols that could mitigate the threats. This document does not impose a specific management or operational solution, imply that a formal Data Model is needed, or imply that using a specific management protocol is mandatory. If Protocol Designers conclude that the technology can be managed solely by using Proprietary Interfaces or that it does not need any structured or standardized Data Model, this might be fine, but it is a decision that should be explicit in a manageability discussion -- that this is how the protocol will need to be operated and managed. Protocol Designers should avoid deferring manageability to a later phase of the development of the specification. When a WG considers operation and management functionality for a protocol, the document should contain enough information for readers to understand how the protocol will be deployed, operated, and managed. The considerations do not need to be comprehensive and exhaustive; focus should be on key aspects. The WG should expect that considerations for operations and management may need to be updated in the future, after further operational experience has been gained. The OPS Directorate can use this document to inform their reviews. A list of guidelines and a checklist of questions to consider, which a reviewer can use to evaluate whether the protocol and documentation address common operations and management needs, is provided in . This document is also of interest to the broader community, who wants to understand, contribute to, and review Internet-Drafts, taking operational considerations into account.

Terminology This document does not describe interoperability requirements. As such, it does not use the capitalized keywords defined in . This section defines key terms used throughout the document to ensure clarity and consistency. Some terms are drawn from existing RFCs and IETF Internet-Drafts, while others are defined here for the purposes of this document. Where appropriate, references are provided for further reading or authoritative definitions.

• Anomaly: See .
• Cause: See .
• CLI: Command Line Interface. A human-oriented interface, typically a Proprietary Interface, to hardware or software devices (e.g., routers or operating systems). The commands, their syntax, and the precise semantics of the parameters may vary considerably between different vendors, between products from the same vendor, and even between different versions or releases of a single product. No attempt at standardizing CLIs has been made by the IETF.
• Data Model: A set of mechanisms for representing, organizing, storing and handling data within a particular type of data store or repository. This usually comprises a collection of data structures such as lists, tables, relations, etc., a collection of operations that can be applied to the structures such as retrieval, update, summation, etc., and a collection of integrity rules that define the legal states (set of values) or changes of state (operations on values). A Data Model may be derived by mapping the contents of an Information Model or may be developed ab initio. Further discussion of Data Models can be found in , , and .
• Fault: See .
• Fault Management: The process of interpreting fault notifications and other alerts and alarms, isolating faults, correlating them, and deducing underlying Causes. See for more information.
• Information Model: An abstraction and representation of the entities in a managed environment, their properties, attributes and operations, and the way that they relate to each other. The model is independent of any specific software usage, protocol, or platform . See Sections and for further discussion of Information Models.
• New Protocol and Protocol Extension: These terms are used in this document to identify entirely new protocols, new versions of existing protocols, and extensions to protocols.
• OAM: Operations, Administration, and Maintenance is the term given to the combination of:
  1. Operation activities that are undertaken to keep the network running as intended. They include monitoring of the network.
  2. Administration activities that keep track of resources in the network and how they are used. They include the bookkeeping necessary to track networking resources.
  3. Maintenance activities focused on facilitating repairs and upgrades. They also involve corrective and preventive measures to make the managed network run more effectively.
  The broader concept of "operations and management" that is the subject of this document encompasses OAM, in addition to other management and provisioning tools and concepts.
• Probable Root Cause: See
• Problem: See .
• Proprietary Interface: An interface to manage a network element that is not standardized. As such, the user interface, syntax, and semantics typically vary significantly between implementations. Examples of proprietary interfaces include Command Line Interface (CLI), management web portal and Browser User Interface (BUI), Graphical User Interface (GUI), and vendor-specific application programming interface (API).
• Protocol Designer: An individual, a group of people, or an IETF WG involved in the development and specification of New Protocols or Protocol Extensions.

Documentation Requirements for IETF Specifications

"Operational Considerations" Section All Internet-Drafts that document a technical specification and are advanced for publication as IETF RFCs are required to include an "Operational Considerations" section. Internet-Drafts that do not document technical specifications such as process, policy, or administrative Internet-Drafts are not required to include such a section. After evaluating the operational () and manageability aspects () of a New Protocol, a Protocol Extension, or an architecture, the resulting practices and requirements should be documented in an "Operational Considerations" section within a specification. Since protocols are intended for operational deployment and management within real networks, it is expected that such considerations will be present. It is also recommended that operational and manageability considerations be addressed early in the protocol design process. Consequently, early revisions of Internet-Drafts are expected to include an "Operational Considerations" section. An "Operational Considerations" section should include discussion of the management and operations topics raised in this document, and when one or more of these topics is not relevant, it would be useful to include a simple statement explaining why the topic is not relevant or applicable for the New Protocol or Protocol Extension. Of course, additional relevant operational and manageability topics should be included as well. Existing protocols and Data Models can provide the management functions identified in the previous section. Protocol Designers should consider how using existing protocols and Data Models might impact network operations.

"Operational Considerations" Section Boilerplate When No New Considerations Exist After a Protocol Designer has considered the manageability requirements of a New Protocol or Protocol Extension, they may determine that no management functionality or operational best-practice clarifications are needed. It would be helpful to reviewers, those who may update or write extensions to the protocol in the future, or to those deploying the protocol, to know the rationale regarding the decisions on manageability of the protocol at the time of its design. If there are no new manageability or deployment considerations, "Operations Considerations" section must contain the following simple statement, followed by a brief explanation of why that is the case. " ]]> The presence of such a section would indicate to the reader that due consideration has been given to manageability and operations. In cases where the specification is a Protocol Extension and the base protocol already addresses the relevant operational and manageability considerations, it is helpful to reference the considerations section in the base document.

Placement of the "Operational Considerations" Section It is recommended that the section be placed immediately before the Security Considerations section. Reviewers interested in such sections will find it easily, and this placement could simplify the development of tools to detect the presence of such a section.

How Will the New Protocol Fit into the Current Environment? Designers of a New Protocol should carefully consider the operational aspects. To ensure that a protocol will be practical to deploy in the real world, it is not enough to merely define it very precisely in a well-written document. Operational aspects will have a serious impact on the actual success of a protocol. Such aspects include bad interactions with existing solutions, a difficult upgrade path, difficulty of debugging problems, difficulty configuring from a central database, or a complicated state diagram that operations staff will find difficult to understand. BGP flap damping is an example. It was designed to block high-frequency route flaps; however, the design did not consider the existence of BGP path exploration / slow convergence. In real operations, path exploration caused false flap damping, resulting in loss of reachability. As a result, many networks turned flap damping off.

Operations Protocol Designers can analyze the operational environment and mode of work in which the New Protocol and Protocol Extension will work. Such an exercise need not be reflected directly by text in their document but could help in visualizing how to apply the protocol in the Internet environments where it will be deployed. A key question is how the protocol can operate "out of the box". If implementers are free to select their own defaults, the protocol needs to operate well with any choice of values. If there are sensible defaults, these need to be stated. There may be a need to support both a human interface (e.g., for troubleshooting) and a programmatic interface (e.g., for automated monitoring and Cause analysis). The application programming interfaces (APIs) and the human interfaces might benefit from being similar to ensure that the information exposed by both is consistent when presented to an operator. It is also relevant to identify consistent methods for determining information, such as what is counted in specific counters. Protocol Designers should consider what management operations are expected to be performed as a result of the deployment of the protocol -- such as whether write operations will be allowed on routers and on hosts, or whether notifications for alarms or other events will be expected.

Installation and Initial Setup Anything that can be configured can be misconfigured. "Architectural Principles of the Internet" , Section 3.8, states: "Avoid options and parameters whenever possible. Any options and parameters should be configured or negotiated dynamically rather than manually". To simplify configuration, Protocol Designers should consider specifying reasonable defaults, including default modes and parameters. For example, it could be helpful or necessary to specify default values for modes, timers, default state of logical control variables, default transports, and so on. Even if default values are used, it must be possible to retrieve all the actual values or at least an indication that known default values are being used. Protocol Designers should consider how to enable operators to concentrate on the configuration of the network as a whole rather than on individual devices. Of course, how one accomplishes this is the hard part. It is desirable to discuss the background of chosen default values, or perhaps why a range of values makes sense. In many cases, as technology changes, the values in an RFC might make less and less sense. It is very useful to understand whether defaults are based on best current practice and are expected to change as technologies advance or whether they have a more universal value that should not be changed lightly. For example, the default interface speed might be expected to change over time due to increased speeds in the network, and cryptographical algorithms might be expected to change over time as older algorithms are "broken". It is extremely important to set a sensible default value for all parameters. Default values should generally favor the conservative side over the "optimizing performance" side (e.g., the initial RTT and RTTVAR values of a TCP connection ). For those parameters that are speed-dependent, instead of using a constant, try to set the default value as a function of the link speed or some other relevant factors. This would help reduce the chance of problems caused by technology advancement. For example, where protocols involve cryptographic keys, Protocol Designers should consider not only key generation and validation mechanisms but also the format in which private keys are stored, transmitted, and restored. Designers should specify any expected consistency checks (e.g., recomputing an expanded key from the seed) that help verify correctness and integrity. Additionally, guidance should be given on data retention, restoration limits, and cryptographic module interoperability when importing/exporting private key material. See for an example of how such considerations are incorporated.

Migration Path If the New Protocol is a new version of an existing one, or if it is replacing another technology, the Protocol Designer should consider how deployments should transition to the New Protocol or Protocol Extensions. This should include coexistence with previously deployed protocols and/or previous versions of the same protocol, management of incompatibilities between versions, translation between versions, and consideration of potential side effects. A key question becomes: Are older protocols or versions disabled, or do they coexist in the network with the New Protocol? Many protocols benefit from being incrementally deployable -- operators may deploy aspects of a protocol before deploying the protocol fully. In those cases, the design considerations should also specify whether the New Protocol requires any changes to the existing infrastructure, particularly the network. If so, the protocol specification should describe the nature of those changes, where they are required, and how they can be introduced in a manner that facilitates deployment.

Requirements on Other Protocols and Functional Components Protocol Designers should consider the requirements that the new protocol might put on other protocols and functional components and should also document the requirements from other protocols and functional components that have been considered in designing the new protocol. These considerations should generally remain illustrative to avoid creating restrictions or dependencies, or potentially impacting the behavior of existing protocols, or restricting the extensibility of other protocols, or assuming other protocols will not be extended in certain ways. If restrictions or dependencies exist, they should be stated. For example, the design of the Resource ReSerVation Protocol (RSVP) required each router to look at the RSVP PATH message and, if the router understood RSVP, add its own address to the message to enable automatic tunneling through non-RSVP routers. But in reality, routers cannot look at an otherwise normal IP packet and potentially take it off the fast path! The initial designers overlooked that a new "deep packet inspection" requirement was being put on the functional components of a router. The "router alert" option (, ) was finally developed to solve this problem, for RSVP and other protocols that require the router to take some packets off the fast-forwarding path. Yet, Router Alert has its own problems in impacting router performance.

Impact on Network Operation The introduction of a New Protocol or Protocol Extensions may have an impact on the operation of existing networks. Protocol Designers should outline such impacts (which may be positive), including scaling benefits or concerns, and interactions with other protocols. Protocol Designers should describe the scenarios in which the New Protocol or its extensions are expected to be applicable or beneficial. This includes any relevant deployment environments, network topologies, usage constraints such as limited domains , or use cases that justify or constrain adoption. For example, a New Protocol that doubles the number of active, reachable addresses in a network might have implications for the scalability of interior gateway protocols, and such impacts should be evaluated accordingly. If the protocol specification requires changes to end hosts, it should also indicate whether safeguards exist to protect networks from potential overload. For instance, a congestion control algorithm must comply with to prevent congestion collapse and ensure network stability. A protocol could send active monitoring packets on the wire. Without careful consideration, active monitoring might achieve high accuracy at the cost of generating an excessive number of monitoring packets. The Protocol Designer should consider the potential impact on the behavior of other protocols in the network and on the traffic levels and traffic patterns that might change, including specific types of traffic, such as multicast. Also, consider the need to install new components that are added to the network as a result of changes in the configuration, such as servers performing auto-configuration operations. The Protocol Designer should consider also the impact on infrastructure applications like DNS , the registries, or the size of routing tables. For example, Simple Mail Transfer Protocol (SMTP) servers use a reverse DNS lookup to filter out incoming connection requests. When Berkeley installed a new spam filter, their mail server stopped functioning because of overload of the DNS cache resolver. The impact on performance may also be noted -- increased delay or jitter in real-time traffic applications, or increased response time in client-server applications when encryption or filtering are applied. It is important to minimize the impact caused by configuration changes. Given configuration A and configuration B, it should be possible to generate the operations necessary to get from A to B with minimal state changes and effects on network and systems.

Verifying Correct Operation The Protocol Designer should consider techniques for testing the effect that the protocol has had on the network by sending data through the network and observing its behavior (a.k.a., active monitoring). Protocol Designers should consider how the correct end- to-end operation of the New Protocol or Protocol Extension in the network can be tested actively and passively, and how the correct data or forwarding plane function of each network element can be verified to be working properly with the New Protocol. Which metrics are of interest? Having simple protocol status and health indicators on network devices is a recommended means to check correct operation.

How Will the Protocol Be Managed? The considerations of manageability should start from identifying the entities to be managed, as well as how the managed protocol is supposed to be installed, configured, and monitored. Considerations for management should include a discussion of what needs to be managed, and how to achieve various management tasks. Where are the managers and what type of interfaces and protocols will they need? The "write a MIB module" approach to considering management often focuses on monitoring a protocol endpoint on a single device. A MIB module document typically only considers monitoring properties observable at one end, while the document does not really cover managing the *protocol* (the coordination of multiple ends) and does not even come near managing the *service* (which includes a lot of stuff that is very far away from the box). This scenario reflects a common operational concern: the inability to manage both ends of a connection effectively. As noted in , "MIB modules can often be characterized as a list of ingredients without a recipe". The management model should take into account factors such as:

• What type of management entities will be involved (agents, network management systems)?
• What is the possible architecture (client-server, manager-agent, poll-driven or event-driven, auto-configuration, two levels or hierarchical)?
• What are the management operations (initial configuration, dynamic configuration, alarm and exception reporting, logging, performance monitoring, performance reporting, debugging)?
• How are these operations performed (locally, remotely, atomic operation, scripts)? Are they performed immediately or are they time scheduled, or event triggered?

Protocol Designers should consider how the New Protocol or Protocol Extension will be managed in different deployment scales. It might be sensible to use a local management interface to manage the New Protocol on a single device, but in a large network, remote management using a centralized server and/or using distributed management functionality might make more sense. Auto-configuration and default parameters might be possible for some New Protocols. Management needs to be considered not only from the perspective of a device, but also from the perspective of network and service management. A service might be network and operational functionality derived from the implementation and deployment of a New Protocol. Often an individual network element is not aware of the service being delivered. WGs should consider how to configure multiple related/co-operating devices and how to back off if one of those configurations fails or causes trouble. NETCONF addresses this in a generic manner by allowing an operator to lock the configuration on multiple devices, perform the configuration settings/changes, check that they are OK (undo if not), and then unlock the devices. Techniques for debugging protocol interactions in a network must be part of the network-management discussion. Implementation source code should be debugged before ever being added to a network, so asserts and memory dumps do not normally belong in management data models. However, debugging on-the-wire interactions is a protocol issue: while the messages can be seen by sniffing, it is enormously helpful if a protocol specification supports features that make debugging of network interactions and behaviors easier. There could be alerts issued when messages are received or when there are state transitions in the protocol state machine. However, the state machine is often not part of the on-the-wire protocol; the state machine explains how the protocol works so that an implementer can decide, in an implementation-specific manner, how to react to a received event. In a client/server protocol, it may be more important to instrument the server end of a protocol than the client end, since the performance of the server might impact more nodes than the performance of a specific client.

Available Management Technologies The IETF provides several standardized management protocols suitable for various operational purposes, for example as outlined in . Broadly, these include core network management protocols, purpose-specific management protocols, and network management Data Models. A non-exhaustive list of such protocols is provided below:

• Remote Authentication Dial In User Service (RADIUS)
• The Syslog Protocol
• Packet Sampling (PSAMP) Protocol Specifications
• Network Configuration Protocol (NETCONF)
• Diameter Base Protocol
• Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of Flow Information
• BGP Monitoring Protocol (BMP)
• RESTCONF Protocol
• Network Telemetry Framework

The IETF previously also worked on the Simple Network Management Protocol (SNMP) and the Structure of Management Information (SMI) , but further use of this management protocol in new IETF documents has been constrained to maintenance of existing MIB modules and development of MIB modules for legacy devices that do not support more resent management protocols . This section is not intended to offer in-depth definitions or explanations; readers seeking more detail should consult the referenced materials.

Interoperability Just as when deploying protocols that will inter-connect devices, management interoperability should be considered -- whether across devices from different vendors, across models from the same vendor, or across different releases of the same product. Management interoperability refers to allowing information sharing and operations between multiple devices and multiple management applications, often from different vendors. Interoperability allows for the use of third-party applications and the outsourcing of management services. Some product designers and Protocol Designers assume that if a device can be managed individually using a command line interface or a web page interface, that such a solution is enough. But when equipment from multiple vendors is combined into a large network, scalability of management may become a Problem. It may be important to have consistency in the management protocol support so network-wide operational processes can be automated. For example, a single switch might be easily managed using an interactive web interface when installed in a single-office small business, but when, say, a fast-food company installs similar switches from multiple vendors in hundreds or thousands of individual branches and wants to automate monitoring them from a central location, monitoring vendor- and model-specific web pages would be difficult to automate. The primary goal is the ability to roll out new useful functions and services in a way in which they can be managed in a scalable manner, where one understands the network impact (as part of the total cost of operations) of that service. Getting everybody to agree on a single syntax and an associated protocol to do all management has proven to be difficult. So, management systems tend to speak whatever the boxes support, whether the IETF likes this. The IETF is moving from support for one schema language for modeling the structure of management information (SMIv2) and one simple network management protocol (SNMP) towards support for additional schema languages and additional management protocols suited to different purposes. Other Standard Development Organizations (e.g., the Distributed Management Task Force - DMTF, the Tele-Management Forum - TMF) also define schemas and protocols for management and these may be more suitable than IETF schemas and protocols in some cases. Some of the alternatives being considered include:

• XML Schema Definition

and

• NETCONF Configuration Protocol
• the IP Flow Information Export (IPFIX) Protocol for usage accounting
• the syslog protocol for logging

Interoperability needs to be considered on the syntactic level and the semantic level. While it can be irritating and time-consuming, application designers, including operators who write their own scripts, can make their processing conditional to accommodate syntactic differences across vendors, models, or releases of product. Semantic differences are much harder to deal with on the manager side -- once you have the data, its meaning is a function of the managed entity. Information Models help focus interoperability on the semantic level by defining what information should be gathered and how it might be used, regardless of the underlying management protocol or vendor implementation. The use of an Information Model might help improve the ability of operators to correlate messages in different protocols where the data overlaps, such as a YANG Data Model and IPFIX Information Elements about the same event. An Information Model might identify which error conditions should be counted separately, and which error conditions can be recorded together in a single counter. Then, whether the counter is gathered via, e.g., NETCONF or exported via IPFIX, the counter will have the same meaning. Protocol Designers must consider what operational, configuration, state, or statistical information will be relevant for effectively monitoring, controlling, or troubleshooting a New Protocol and its Protocol Extensions. This includes identifying key parameters that reflect the protocol’s behavior, performance metrics, error indicators, and any contextual data that would aid in diagnostic, troubleshooting, or lifecycle management.

Information Models（IMs）and Data Models（DMs） conceptual/abstract model | for designers & operators +----------+---------+ | | | DM DM DM --> concrete/detailed model for implementers ]]>

"On the Difference between Information Models and Data Models" is helpful in determining what information to consider regarding Information Models (IMs), as compared to Data Models (DMs). Protocol Designers may directly develop Data Models without first producing an Information Model. For example, such a decision can be taken when it is given that the data component is not used by distinct protocols (e.g., IPFIX-only). Alternatively, Protocol Designers may decide to use an Information Model to describe the managed elements in a protocol or Protocol Extension. The protocol Designers then use the Information Model to develop Data Models that will be used for managing the protocol. Specifically, Protocol Designers should develop an Information Model if multiple Data Model representations (e.g., YANG and/or IPFIX ) are to be produced, to ensure lossless semantic mapping. Protocol Designers may create an Information Model if the resulting Data Models are complex or numerous. Information models should come from the protocol WGs and include lists of events, counters, and configuration parameters that are relevant. There are several Information Models contained in protocol WG RFCs. Some examples:

• - Policy Core Information Model -- Version 1 Specification
• - An Informal Management Model for Diffserv Routers
• - Policy Core Information Model (PCIM) Extensions
• - IPsec Configuration Policy Information Model
• - Policy Quality of Service (QoS) Information Model
• - Information Model for Describing Network Device QoS Datapath Mechanisms

Management protocol standards and management Data Model standards often contain compliance clauses to ensure interoperability. Manageability considerations should include discussion of which level of compliance is expected to be supported for interoperability.

Management Information Languages used to describe an Information Model can influence the nature of the model. Using a particular data modeling language, such as YANG, influences the model to use certain types of structures, for example, hierarchical trees, groupings, and reusable types. YANG, as described in and , provides advantages for expressing network information, including clear separation of configuration data and operational state, support for constraints and dependencies, and extensibility for evolving requirements. Its ability to represent relationships and dependencies in a structured and modular way makes it an effective choice for defining management information models. Although this document recommends using English text (the official language for IETF specifications) to describe an Information Model, including a complementary YANG module helps translate abstract concepts into implementation-specific Data Models. This ensures consistency between the high-level design and practical deployment. A management Information Model should include a discussion of what is manageable, which aspects of the protocol need to be configured, what types of operations are allowed, what protocol-specific events might occur, which events can be counted, and for which events an operator should be notified. Operators find it important to be able to make a clear distinction between configuration data, operational state, and statistics. They need to determine which parameters were administratively configured and which parameters have changed since configuration as the result of mechanisms such as routing protocols or network management protocols. It is important to be able to separately fetch current configuration information, initial configuration information, operational state information, and statistics from devices; to be able to compare current state to initial state; and to compare information between devices. So, when deciding what information should exist, do not conflate multiple information elements into a single element. What is typically difficult to work through are relationships between abstract objects. Ideally, an Information Model would describe the relationships between the objects and concepts in the information model. Is there always just one instance of this object or can there be multiple instances? Does this object relate to exactly one other object, or may it relate to multiple? When is it possible to change a relationship? Do objects (such as instances in lists) share fate? For example, if an instance in list A must exist before a related instance in list B can be created, what happens to the instance in list B if the related instance in list A is deleted? Does the existence of relationships between objects have an impact on fate sharing? YANG's relationships and constraints can help express and enforce these relationships.

Information Model Design This document recommends keeping the Information Model as simple as possible by applying the following criteria:

1. Start with a small set of essential objects and make additions only as further objects are needed with the objective of keeping the absolute number of objects as small as possible while still delivering the required function such that there is no duplication between objects and where one piece of information can be derived from the other pieces of information, it is not itself represented as an object.
2. Require that all objects be essential for management.
3. Consider evidence of current use of the managed protocol, and the perceived utility of objects added to the Information Model.
4. Exclude objects that can be derived from others in this or other information models.
5. Avoid causing critical sections to be heavily instrumented. A guideline is one counter per critical section per layer.
6. When defining an Information Model using YANG Data Structure Extensions (thereby keeping it abstract and implementation-agnostic per ) ensure that the Information Model remains simple, modular, and clear by following the authoring guidelines in .
7. When illustrating the abstract Information Model, use YANG Tree Diagrams to provide a simple, standardized, and implementation-neutral model structure.

YANG Data Model Considerations When considering YANG Data Models for a new specification, there are multiple types of Data Models that may be applicable. The hierarchy and relationship between these types is described in . A new specification may require or benefit from one or more of these YANG Data Model types.

• Device Models - Also called Network Element Models, represent the configuration, operational state, and notifications of individual devices. These models are designed to distinguish between these types of data and support querying and updating device-specific parameters. Consideration should be given to how device-level models might fit with broader network and service Data Models.
• Network Models - Also called Network Service Models, define abstractions for managing the behavior and relationships of multiple devices and device subsystems within a network. As described in , these models are used to manage network-wide. These abstractions are useful to network operators and applications that interface with network controllers. Examples of network models include the L3VPN Network Model (L3NM) and the L2VPN Network Model (L2VPN) .
• Service Models - Also called Customer Service Models, defined in , are designed to abstract the customer interface into a service. They consider customer-centric parameters such as Service Level Agreement (SLA) and high-level policy (e.g., network intent). Given that different operators and different customers may have widely-varying business processes, these models should focus on common aspects of a service with strong multi-party consensus. Examples of service models include the L3VPN Service Model (L3SM) and the L2VPN Service Model (L2SM) .

A common challenge in YANG Data Model development lies in defining the relationships between abstract service or network constructs and the underlying device models. Therefore, when designing YANG modules, it is important to go beyond simply modeling configuration and operational data (i.e., leaf nodes), and also consider how the status and relationships of abstract or distributed constructs can be reflected based on parameters available in the network. For example, the status of a service may depend on the operational state of multiple network elements to which the service is attached. In such cases, the YANG Data Model (and its accompanying documentation) should clearly describe how service-level status is derived from underlying device-level information. Similarly, it is beneficial to define events (and relevant triggered notifications) that indicate changes in an underlying state, enabling reliable detection and correlation of service-affecting conditions. Including such mechanisms improves the robustness of integrations and helps ensure consistent behavior across implementations. Specific guidelines to consider when authoring any type of YANG modules are described in .

Fault Management The Protocol Designer should document the basic Faults and health indicators that need to be instrumented for the New Protocol or Protocol Extension, as well as the alarms and events that must be propagated to management applications or exposed through a Data Model. The Protocol Designer should consider how fault information will be propagated. Will it be done using asynchronous notifications or polling of health indicators? If notifications are used to alert operators to certain conditions, then the Protocol Designer should discuss mechanisms to throttle notifications to prevent congestion and duplications of event notifications. Will there be a hierarchy of Faults, and will the Fault reporting be done by each Fault in the hierarchy, or will only the lowest Fault be reported and the higher levels be suppressed? Should there be aggregated status indicators based on concatenation of propagated Faults from a given domain or device? SNMP notifications and syslog messages can alert an operator when an aspect of the New Protocol fails or encounters an error or failure condition, and SNMP is frequently used as a heartbeat monitor. Should the event reporting provide guaranteed accurate delivery of the event information within a given (high) margin of confidence? Can we poll the latest events in the box?

Liveness Detection and Monitoring Protocol Designers should always build in basic testing features (e.g., ICMP echo, UDP/TCP echo service, NULL RPCs (remote procedure calls)) that can be used to test for liveness, with an option to enable and disable them. Mechanisms for monitoring the liveness of the protocol and for detecting Faults in protocol connectivity are usually built into protocols. In some cases, mechanisms already exist within other protocols responsible for maintaining lower-layer connectivity (e.g., ICMP echo), but often new procedures are required to detect failures and to report rapidly, allowing remedial action to be taken. These liveness monitoring mechanisms do not typically require additional management capabilities. However, when a system detects a Fault, there is often a requirement to coordinate recovery action through management applications or at least to record the fact in an event log.

Fault Determination It can be helpful to describe how Faults can be pinpointed using management information. For example, counters might record instances of error conditions. Some Faults might be able to be pinpointed by comparing the outputs of one device and the inputs of another device, looking for anomalies. Protocol Designers should consider what counters should count. If a single counter provided by vendor A counts three types of error conditions, while the corresponding counter provided by vendor B counts seven types of error conditions, these counters cannot be compared effectively -- they are not interoperable counters. How do you distinguish between faulty messages and good messages? Would some threshold-based mechanisms, such as Remote Monitoring (RMON) events/alarms or the EVENT-MIB, be usable to help determine error conditions? Are SNMP notifications for all events needed, or are there some "standard" notifications that could be used? Or can relevant counters be polled as needed?

Probable Root Cause Analysis Probable Root Cause analysis is about working out where the foundational Fault or Problem might be. Since one Fault may give rise to another Fault or Problem, a probable root cause is commonly meant to describe the original, source event or combination of circumstances that is the foundation of all related Faults. For example, if end-to-end data delivery is failing (e.g., reported by a notification), Probable Root Cause analysis can help find the failed link or node, or mis-configuration, within the end-to-end path.

Fault Isolation It might be useful to isolate or quarantine Faults, such as isolating a device that emits malformed messages that are necessary to coordinate connections properly. This might be able to be done by configuring next-hop devices to drop the faulty messages to prevent them from entering the rest of the network.

Configuration Management A Protocol Designer should document the basic configuration parameters that need to be instrumented for a New Protocol or Protocol Extensions, as well as default values and modes of operation. What information should be maintained across reboots of the device, or restarts of the management system? "Requirements for Configuration Management of IP-based Networks" discusses requirements for configuration management, including discussion of different levels of management, high-level policies, network-wide configuration data, and device-local configuration. Network configuration extends beyond simple multi-device push or pull operations. It also involves ensuring that the configurations being pushed are semantically compatible across devices and that the resulting behavior of all involved devices corresponds to the intended behavior. Is the attachment between them configured compatibly on both ends? Is the IS-IS metric the same? ... Now answer those questions for 1,000 devices. Several efforts have existed in the IETF to develop policy-based configuration management. "Terminology for Policy-Based Management" was written to standardize the terminology across these efforts. Implementations should not arbitrarily modify configuration data. In some cases (such as access control lists (ACLs)), the order of data items is significant and comprises part of the configured data. If a Protocol Designer defines mechanisms for configuration, it would be desirable to standardize the order of elements for consistency of configuration and of reporting across vendors and across releases from vendors. There are two parts to this:

1. A Network Management System (NMS) could optimize ACLs for performance reasons.
2. Unless the device or NMS is configured with adequate rules and guided by administrators with extensive experience, reordering ACLs can introduce significant security risks.

Network-wide configurations may be stored in central master databases and transformed into readable formats that can be pushed to devices, either by generating sequences of CLI commands or complete textual configuration files that are pushed to devices. There is no common database schema for network configuration, although the models used by various operators are probably very similar. Many operators consider it desirable to extract, document, and standardize the common parts of these network- wide configuration database schemas. A Protocol Designer should consider how to standardize the common parts of configuring the New Protocol, while recognizing that vendors may also have proprietary aspects of their configurations. It is important to enable operators to concentrate on the configuration of the network as a whole, rather than individual devices. Support for configuration transactions across several devices could significantly simplify network configuration management. The ability to distribute configurations to multiple devices, or to modify candidate configurations on multiple devices, and then activate them in a near-simultaneous manner might help. Protocol Designers can consider how it would make sense for their protocol to be configured across multiple devices. Configuration templates might also be helpful. Consensus of the 2002 IAB Workshop was that textual configuration files should be able to contain international characters. Human-readable strings should utilize UTF-8, and protocol elements should be in case-insensitive ASCII. A mechanism to dump and restore configurations is a primitive operation needed by operators. Standards for pulling and pushing configurations from/to devices are desirable. Given configuration A and configuration B, it should be possible to generate the operations necessary to get from A to B with minimal state changes and effects on network and systems. It is important to minimize the impact caused by configuration changes. A Protocol Designer should consider the configurable items that exist for the control of function via the protocol elements described in the protocol specification. For example, sometimes the protocol requires that timers can be configured by the operator to ensure specific policy-based behavior by the implementation. These timers should have default values suggested in the protocol specification and may not need to be otherwise configurable.

Verifying Correct Operation An important function that should be provided is guidance on how to verify the correct operation of a protocol. A Protocol Designer could suggest techniques for testing the impact of the protocol on the network before it is deployed as well as techniques for testing the effect that the protocol has had on the network after being deployed. Protocol Designers should consider how to test the correct end-to-end operation of the service or network, how to verify the correct functioning of the protocol, and whether that is verified by testing the service function and/or by testing the forwarding function of each network element. This may be achieved through status and statistical information gathered from devices.

Accounting Management A Protocol Designer should consider whether it would be appropriate to collect usage information related to this protocol and, if so, what usage information would be appropriate to collect. "Introduction to Accounting Management" discusses a number of factors relevant to monitoring usage of protocols for purposes of capacity and trend analysis, cost allocation, auditing, and billing. The document also discusses how some existing protocols can be used for these purposes. These factors should be considered when designing a protocol whose usage might need to be monitored or when recommending a protocol to do usage accounting.

Performance Management From a manageability point of view, it is important to determine how well a network deploying the protocol or technology defined in the document is doing. In order to do this, the network operators need to consider information that would be useful to determine the performance characteristics of a deployed system using the target protocol. The IETF, via the Benchmarking Methodology WG (BMWG), has defined recommendations for the measurement of the performance characteristics of various internetworking technologies in a laboratory environment, including the systems or services that are built from these technologies. Each benchmarking recommendation describes the class of equipment, system, or service being addressed; discusses the performance characteristics that are pertinent to that class; clearly identifies a set of metrics that aid in the description of those characteristics; specifies the methodologies required to collect said metrics; and lastly, presents the requirements for the common, unambiguous reporting of benchmarking results. Search for "benchmark" in the RFC search tool. Performance metrics may be useful in multiple environments and for different protocols. The IETF, via the IP Performance Monitoring (IPPM) WG, has developed a set of standard metrics that can be applied to the quality, performance, and reliability of Internet data delivery services. These metrics are designed such that they can be performed by network operators, end users, or independent testing groups. The existing metrics might be applicable to the new protocol. Search for "metric" in the RFC search tool. In some cases, new metrics need to be defined. It would be useful if the protocol documentation identified the need for such new metrics. For performance monitoring, it is often more important to report the time spent in a state rather than just the current state. Snapshots alone are typically of less value. There are several parts to performance management to be considered: protocol monitoring, device monitoring (the impact of the new protocol / service activation on the device), network monitoring, and service monitoring (the impact of service activation on the network).

Monitoring the Protocol Certain properties of protocols are useful to monitor. The number of protocol packets received, the number of packets sent, and the number of packets dropped are usually very helpful to operators. Packet drops should be reflected in counter variable(s) somewhere that can be inspected -- both from the security point of view and from the troubleshooting point of view. Counter definitions should be unambiguous about what is included in the count and what is not included in the count. Consider the expected behaviors for counters -- what is a reasonable maximum value for expected usage? Should they stop counting at the maximum value and retain the maximum value, or should they rollover? How can users determine if a rollover has occurred, and how can users determine if more than one rollover has occurred? Consider whether multiple management applications will share a counter; if so, then no one management application should be allowed to reset the value to zero since this will impact other applications. Could events, such as hot-swapping a blade in a chassis, cause discontinuities in counter? Does this make any difference in evaluating the performance of a protocol? The protocol specification should clearly define any inherent limitations and describe expected behavior when those limits are exceeded. These considerations should be made independently of any specific management protocol or data modeling language. In other words, focus on what makes sense for the protocol being managed, not the protocol used for management. If a constraint is not specific to a management protocol, then it should be left to Data Model designers of that protocol to determine how to handle it. For example, VLAN identifiers are defined by standard to range from 1 to 4094. Therefore, a YANG "vlan-id" definition representing the 12-bit VLAN ID used in the VLAN Tag header uses a range of "1..4094".

Monitoring the Device Consider whether device performance will be affected by the number of protocol entities being instantiated on the device. Designers of an Information Model should include information, accessible at runtime, about the maximum number of instances an implementation can support, the current number of instances, and the expected behavior when the current instances exceed the capacity of the implementation or the capacity of the device. Designers of an Information Model should model information, accessible at runtime, about the maximum number of protocol entity instances an implementation can support on a device, the current number of instances, and the expected behavior when the current instances exceed the capacity of the device.

Monitoring the Network Consider whether network performance will be affected by the number of protocol entities being deployed. Consider the capability of determining the operational activity, such as the number of messages in and the messages out, the number of received messages rejected due to format Problems, and the expected behaviors when a malformed message is received. What are the principal performance factors that need to be considered when measuring the operational performance of a network built using the protocol? Is it important to measure setup times, end-to-end connectivity, hop-by-hop connectivity, or network throughput?

Monitoring the Service What are the principal performance factors that need to be considered when measuring the performance of a service using the protocol? Is it important to measure application-specific throughput, client-server associations, end-to-end application quality, service interruptions, or user experience (UX)?

Security Management Protocol Designers should consider how to monitor and manage security aspects and vulnerabilities of the New Protocol or Protocol Extension. There will be security considerations related to the New Protocol. To make it possible for operators to be aware of security-related events, it is recommended that system logs should record events, such as failed logins, but the logs must be secured. Should a system automatically notify operators of every event occurrence, or should an operator-defined threshold control when a notification is sent to an operator? Should certain statistics be collected about the operation of the new protocol that might be useful for detecting attacks, such as the receipt of malformed messages, messages out of order, or messages with invalid timestamps? If such statistics are collected, is it important to count them separately for each sender to help identify the source of attacks? Manageability considerations that are security-oriented might include discussion of the security implications when no monitoring is in place, the regulatory implications of absence of audit-trail or logs in enterprises, exceeding the capacity of logs, and security exposures present in chosen/recommended management mechanisms. Consider security threats that may be introduced by management operations. For example, Control and Provisioning of Wireless Access Points (CAPWAP) breaks the structure of monolithic Access Points (APs) into Access Controllers and Wireless Termination Points (WTPs). By using a control protocol or management protocol, internal information that was previously not accessible is now exposed over the network and to management applications and may become a source of potential security threats. The granularity of access control needed on management interfaces needs to match operational needs. Typical requirements are a role- based access control model and the principle of least privilege, where a user can be given only the minimum access necessary to perform a required task. Some operators wish to do consistency checks of access control lists across devices. Protocol Designers should consider information models to promote comparisons across devices and across vendors to permit checking the consistency of security configurations. Protocol Designers should consider how to provide a secure transport, authentication, identity, and access control that integrates well with existing key and credential management infrastructure. It is a good idea to start with defining the threat model for the protocol, and from that deducing what is required. Protocol Designers should consider how access control lists are maintained and updated. Standard SNMP notifications or syslog messages might already exist, or can be defined, to alert operators to the conditions identified in the security considerations for the new protocol. For example, you can log all the commands entered by the operator using syslog (giving you some degree of audit trail), or you can see who has logged on/off using the Secure Shell (SSH) Protocol and from where; failed SSH logins can be logged using syslog, etc. An analysis of existing counters might help operators recognize the conditions identified in the security considerations for the new protocol before they can impact the network. Different management protocols use different assumptions about message security and data-access controls. A Protocol Designer that recommends using different protocols should consider how security will be applied in a balanced manner across multiple management interfaces. SNMP authority levels and policy are data-oriented, while CLI authority levels and policy are usually command-oriented (i.e., task-oriented). Depending on the management function, sometimes data-oriented or task-oriented approaches make more sense. Protocol Designers should consider both data-oriented and task- oriented authority levels and policy.

Operational and Management Tooling Considerations The operational community's ability to effectively adopt and use new specifications is significantly influenced by the availability and adaptability of appropriate tooling. In this context, "tools" refers to software systems or utilities used by network operators to deploy, configure, monitor, troubleshoot, and manage networks or network protocols in real-world operational environments. While the introduction of a new specification does not automatically mandate the development of entirely new tools, careful consideration must be given to how existing tools can be leveraged or extended to support the management and operation of these new specifications. The workshop highlighted a consistent theme applicable beyond network management protocols: the "ease of use" and adaptability of existing tools are critical factors for successful adoption. Therefore, a new specification should provide examples using existing, common tooling, or running code that demonstrate how to perform key operational tasks. Specifically, the following tooling-related aspects should be considered, prioritizing the adaptation of existing tools:

• Leveraging Existing Tooling: Before considering new tools, assess whether existing tooling, such as monitoring systems, logging platforms, configuration management systems, and/or orchestration frameworks, can be adapted to support the new specification. This may involve developing plugins, modules, or drivers that enable these tools to interact with the new specification.
• Extending Existing Tools: Identify areas where existing tools can be extended to provide the necessary visibility and control over the new specification. For example, if a new transport protocol is introduced, consider whether existing network monitoring tools can be extended to track its performance metrics or whether existing security tools can be adapted to analyze its traffic patterns.
• New Tools: Only when existing tools are demonstrably inadequate for managing and operating the elements of the new specification should the development of new tools be considered. In such cases, carefully define the specific requirements for these new tools, focusing on the functionalities that cannot be achieved through adaptation or extension of existing solutions.
• IETF Hackathons for Manageability Testing: IETF Hackathons provide an opportunity to test the functionality, interoperability, and manageability of New Protocols. These events can be specifically leveraged to assess the operational (including manageability) implications of a New Protocol by focusing tasks on:
  • Adapting existing tools to interact with the new specification.
  • Developing example management scripts or modules for existing management platforms.
  • Testing the specification's behavior under various operational conditions.
  • Identifying potential tooling gaps and areas for improvement.
  • Creating example flows and use cases for manageability.
• Open-Source for Tooling: If new tools are deemed necessary, or if significant adaptations to existing tools are required, prioritize open-source development with community involvement. Open-source tools lower the barrier to entry, encourage collaboration, and provide operators with the flexibility to customize and extend the tools to meet their specific needs.

IANA Considerations This document does not have any IANA actions required.

Operational Considerations Although this document focuses on operations and manageability guidance, it does not define a New Protocol, a Protocol Extension, or an architecture. As such, there are no new operations or manageability requirements introduced by this document.

Security Considerations This document provides guidelines for considering manageability and operations. It introduces no new security concerns. The provision of a management portal to a network device provides a doorway through which an attack on the device may be launched. Making the protocol under development be manageable through a management protocol creates a vulnerability to a new source of attacks. Only management protocols with adequate security apparatus, such as authentication, message integrity checking, and authorization, should be used. While a standard description of a protocol's manageable parameters facilitates legitimate operation, it may also inadvertently simplify an attacker's efforts to understand and manipulate the protocol. A well-designed protocol is usually more stable and secure. A protocol that can be managed and inspected offers the operator a better chance of spotting and quarantining any attacks. Conversely, making a protocol easy to inspect is a risk if the wrong person inspects it. If security events cause logs and/or notifications/alerts, a concerted attack might be able to be mounted by causing an excess of these events. In other words, the security-management mechanisms could constitute a security vulnerability. The management of security aspects is important (see ).

Informative References IETF IESG IAB New protocols or protocol extensions are best designed with due consideration of the functionality needed to operate and manage the protocols. Retrofitting operations and management is sub-optimal. The purpose of this document is to provide guidance to authors and reviewers of documents that define new protocols or protocol extensions regarding aspects of operations and management that should be considered. This memo provides information for the Internet community. All RFCs are required to have a Security Considerations section. Historically, such sections have been relatively weak. This document provides guidelines to RFC authors on how to write a good Security Considerations section. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Poor selection of transient numerical identifiers in protocols such as the TCP/IP suite has historically led to a number of attacks on implementations, ranging from Denial of Service (DoS) or data injection to information leakages that can be exploited by pervasive monitoring. Due diligence in the specification of transient numeric identifiers is required even when cryptographic techniques are employed, since these techniques might not mitigate all the associated issues. This document formally updates RFC 3552, incorporating requirements for transient numeric identifiers, to prevent flaws in future protocols and implementations. In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. Ciena Old Dog Consulting Swisscom Huawei Huawei Technologies This document sets out some terms that are fundamental to a common understanding of network fault and problem management within the IETF. The purpose of this document is to bring clarity to discussions and other work related to network fault and problem management, in particular to YANG data models and management protocols that report, make visible, or manage network faults and problems. There has been ongoing confusion about the differences between Information Models and Data Models for defining managed objects in network management. This document explains the differences between these terms by analyzing how existing network management model specifications (from the IETF and other bodies such as the International Telecommunication Union (ITU) or the Distributed Management Task Force (DMTF)) fit into the universe of Information Models and Data Models. This memo documents the main results of the 8th workshop of the Network Management Research Group (NMRG) of the Internet Research Task Force (IRTF) hosted by the University of Texas at Austin. This memo provides information for the Internet community. At first glance, the acronym "OAM" seems to be well-known and well-understood. Looking at the acronym a bit more closely reveals a set of recurring problems that are revisited time and again. This document provides a definition of the acronym "OAM" (Operations, Administration, and Maintenance) for use in all future IETF documents that refer to OAM. There are other definitions and acronyms that will be discussed while exploring the definition of the constituent parts of the "OAM" term. This memo documents an Internet Best Current Practice. Blue Fern Consulting Old Dog Consulting Huawei As the IETF continues to produce and standardize different Operations, Administration, and Maintenance (OAM) protocols and technologies, various qualifiers and modifiers are prepended to the OAM abbreviation. While, at first glance, the most used appear to be well understood, the same qualifier may be interpreted differently in different contexts. A case in point is the qualifiers "in-band" and "out-of-band" which have their origins in the radio lexicon, and which have been extrapolated into other communication networks. This document considers some common qualifiers and modifiers that are prepended, within the context of packet networks, to the OAM abbreviation and lays out guidelines for their use in future IETF work. This document updates RFC 6291 by adding to the guidelines for the use of the term "OAM". It does not modify any other part of RFC 6291. CMCC Telefonica Huawei Ciena A network incident refers to an unexpected interruption of a network service, degradation of a network service quality, or sub-health of a network service. Different data sources including alarms, metrics, and other anomaly information can be aggregated into a few of network incidents through data correlation analysis and the service impact analysis. This document defines a YANG Module for the network incident lifecycle management. This YANG module is meant to provide a standard way to report, diagnose, and help resolve network incidents for the sake of network service health and probable cause analysis. A usage of the BGP routing protocol is described which is capable of reducing the routing traffic passed on to routing peers and therefore the load on these peers without adversely affecting route convergence time for relatively stable routes. [STANDARDS-TRACK] The Internet and its architecture have grown in evolutionary fashion from modest beginnings, rather than from a Grand Plan. While this process of evolution is one of the main reasons for the technology's success, it nevertheless seems useful to record a snapshot of the current principles of the Internet architecture. This is intended for general guidance and general interest, and is in no way intended to be a formal or invariant reference model. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. This document defines the standard algorithm that Transmission Control Protocol (TCP) senders are required to use to compute and manage their retransmission timer. It expands on the discussion in Section 4.2.3.1 of RFC 1122 and upgrades the requirement of supporting the algorithm from a SHOULD to a MUST. This document obsoletes RFC 2988. [STANDARDS-TRACK] AWS AWS sn3rd Cloudflare Digital signatures are used within X.509 certificates, Certificate Revocation Lists (CRLs), and to sign messages. This document specifies the conventions for using FIPS 204, the Module-Lattice- Based Digital Signature Algorithm (ML-DSA) in Internet X.509 certificates and certificate revocation lists. The conventions for the associated signatures, subject public keys, and private key are also described. This memo describes version 1 of RSVP, a resource reservation setup protocol designed for an integrated services Internet. RSVP provides receiver-initiated setup of resource reservations for multicast or unicast data flows, with good scaling and robustness properties. [STANDARDS-TRACK] This memo describes a new IP Option type that alerts transit routers to more closely examine the contents of an IP packet. [STANDARDS-TRACK] This memo describes a new IPv6 Hop-by-Hop Option type that alerts transit routers to more closely examine the contents of an IP datagram. [STANDARDS-TRACK] There is a noticeable trend towards network behaviors and semantics that are specific to a particular set of requirements applied within a limited region of the Internet. Policies, default parameters, the options supported, the style of network management, and security requirements may vary between such limited regions. This document reviews examples of such limited domains (also known as controlled environments), notes emerging solutions, and includes a related taxonomy. It then briefly discusses the standardization of protocols for limited domains. Finally, it shows the need for a precise definition of "limited domain membership" and for mechanisms to allow nodes to join a domain securely and to find other members, including boundary nodes. This document is the product of the research of the authors. It has been produced through discussions and consultation within the IETF but is not the product of IETF consensus. RFC 5033 discusses the principles and guidelines for standardizing new congestion control algorithms. This document obsoletes RFC 5033 to reflect changes in the congestion control landscape by providing a framework for the development and assessment of congestion control mechanisms, promoting stability across diverse network paths. This document seeks to ensure that proposed congestion control algorithms operate efficiently and without harm when used in the global Internet. It emphasizes the need for comprehensive testing and validation to prevent adverse interactions with existing flows. This RFC is the revised basic definition of The Domain Name System. It obsoletes RFC-882. This memo describes the domain style names and their used for host address look up and electronic mail forwarding. It discusses the clients and servers in the domain name system and the protocol used between them. This document is a specification of the basic protocol for Internet electronic mail transport. It consolidates, updates, and clarifies several previous documents, making all or parts of most of them obsolete. It covers the SMTP extension mechanisms and best practices for the contemporary Internet, but does not provide details about particular extensions. Although SMTP was designed as a mail transport and delivery protocol, this specification also contains information that is important to its use as a "mail submission" protocol for "split-UA" (User Agent) mail reading systems and mobile environments. [STANDARDS-TRACK] This document gives an overview of the IETF network management standards and summarizes existing and ongoing development of IETF Standards Track network management protocols and data models. The document refers to other overview documents, where they exist and classifies the standards for easy orientation. The purpose of this document is, on the one hand, to help system developers and users to select appropriate standard management protocols and data models to address relevant management needs. On the other hand, the document can be used as an overview and guideline by other Standard Development Organizations or bodies planning to use IETF management technologies and data models. This document does not cover Operations, Administration, and Maintenance (OAM) technologies on the data-path, e.g., OAM of tunnels, MPLS Transport Profile (MPLS-TP) OAM, and pseudowire as well as the corresponding management models. This document is not an Internet Standards Track specification; it is published for informational purposes. This document describes a protocol for carrying authentication, authorization, and configuration information between a Network Access Server which desires to authenticate its links and a shared Authentication Server. [STANDARDS-TRACK] This document describes the syslog protocol, which is used to convey event notification messages. This protocol utilizes a layered architecture, which allows the use of any number of transport protocols for transmission of syslog messages. It also provides a message format that allows vendor-specific extensions to be provided in a structured way. This document has been written with the original design goals for traditional syslog in mind. The need for a new layered specification has arisen because standardization efforts for reliable and secure syslog extensions suffer from the lack of a Standards-Track and transport-independent RFC. Without this document, each other standard needs to define its own syslog packet format and transport mechanism, which over time will introduce subtle compatibility issues. This document tries to provide a foundation that syslog extensions can build on. This layered architecture approach also provides a solid basis that allows code to be written once for each syslog feature rather than once for each transport. [STANDARDS-TRACK] This document specifies the export of packet information from a Packet SAMPling (PSAMP) Exporting Process to a PSAMP Collecting Process. For export of packet information, the IP Flow Information eXport (IPFIX) protocol is used, as both the IPFIX and PSAMP architecture match very well, and the means provided by the IPFIX protocol are sufficient. The document specifies in detail how the IPFIX protocol is used for PSAMP export of packet information. [STANDARDS-TRACK] The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] The Diameter base protocol is intended to provide an Authentication, Authorization, and Accounting (AAA) framework for applications such as network access or IP mobility in both local and roaming situations. This document specifies the message format, transport, error reporting, accounting, and security services used by all Diameter applications. The Diameter base protocol as defined in this document obsoletes RFC 3588 and RFC 5719, and it must be supported by all new Diameter implementations. [STANDARDS-TRACK] This document specifies the IP Flow Information Export (IPFIX) protocol, which serves as a means for transmitting Traffic Flow information over the network. In order to transmit Traffic Flow information from an Exporting Process to a Collecting Process, a common representation of flow data and a standard means of communicating them are required. This document describes how the IPFIX Data and Template Records are carried over a number of transport protocols from an IPFIX Exporting Process to an IPFIX Collecting Process. This document obsoletes RFC 5101. This document defines the BGP Monitoring Protocol (BMP), which can be used to monitor BGP sessions. BMP is intended to provide a convenient interface for obtaining route views. Prior to the introduction of BMP, screen scraping was the most commonly used approach to obtaining such views. The design goals are to keep BMP simple, useful, easily implemented, and minimally service affecting. BMP is not suitable for use as a routing protocol. This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). Network telemetry is a technology for gaining network insight and facilitating efficient and automated network management. It encompasses various techniques for remote data generation, collection, correlation, and consumption. This document describes an architectural framework for network telemetry, motivated by challenges that are encountered as part of the operation of networks and by the requirements that ensue. This document clarifies the terminology and classifies the modules and components of a network telemetry system from different perspectives. The framework and taxonomy help to set a common ground for the collection of related work and provide guidance for related technique and standard developments. The purpose of this document is to provide an overview of the third version of the Internet-Standard Management Framework, termed the SNMP version 3 Framework (SNMPv3). This Framework is derived from and builds upon both the original Internet-Standard Management Framework (SNMPv1) and the second Internet-Standard Management Framework (SNMPv2). The architecture is designed to be modular to allow the evolution of the Framework over time. The document explains why using SNMPv3 instead of SNMPv1 or SNMPv2 is strongly recommended. The document also recommends that RFCs 1157, 1441, 1901, 1909 and 1910 be retired by moving them to Historic status. This document obsoletes RFC 2570. This memo provides information for the Internet community. It is the purpose of this document, the Structure of Management Information Version 2 (SMIv2), to define that adapted subset, and to assign a set of associated administrative values. [STANDARDS-TRACK] It is the purpose of this document to define the initial set of textual conventions available to all MIB modules. [STANDARDS-TRACK] Collections of related objects are defined in MIB modules. It may be useful to define the acceptable lower-bounds of implementation, along with the actual level of implementation achieved. It is the purpose of this document to define the notation used for these purposes. [STANDARDS-TRACK] YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF). This document presents the object-oriented information model for representing policy information developed jointly in the IETF Policy Framework WG and as extensions to the Common Information Model (CIM) activity in the Distributed Management Task Force (DMTF). [STANDARDS-TRACK] This document proposes an informal management model of Differentiated Services (Diffserv) routers for use in their management and configuration. This model defines functional datapath elements (e.g., classifiers, meters, actions, marking, absolute dropping, counting, multiplexing), algorithmic droppers, queues and schedulers. It describes possible configuration parameters for these elements and how they might be interconnected to realize the range of traffic conditioning and per-hop behavior (PHB) functionalities described in the Diffserv Architecture. This memo provides information for the Internet community. This document specifies a number of changes to the Policy Core Information Model (PCIM, RFC 3060). Two types of changes are included. First, several completely new elements are introduced, for example, classes for header filtering, that extend PCIM into areas that it did not previously cover. Second, there are cases where elements of PCIM (for example, policy rule priorities) are deprecated, and replacement elements are defined (in this case, priorities tied to associations that refer to policy rules). Both types of changes are done in such a way that, to the extent possible, interoperability with implementations of the original PCIM model is preserved. This document updates RFC 3060. [STANDARDS-TRACK] This document presents an object-oriented information model of IP Security (IPsec) policy designed to facilitate agreement about the content and semantics of IPsec policy, and enable derivations of task- specific representations of IPsec policy such as storage schema, distribution representations, and policy specification languages used to configure IPsec-enabled endpoints. The information model described in this document models the configuration parameters defined by IPSec. The information model also covers the parameters found by the Internet Key Exchange protocol (IKE). Other key exchange protocols could easily be added to the information model by a simple extension. Further extensions can further be added easily due to the object-oriented nature of the model. This information model is based upon the core policy classes as defined in the Policy Core Information Model (PCIM) and in the Policy Core Information Model Extensions (PCIMe). [STANDARDS-TRACK] This document presents an object-oriented information model for representing Quality of Service (QoS) network management policies. This document is based on the IETF Policy Core Information Model and its extensions. It defines an information model for QoS enforcement for differentiated and integrated services using policy. It is important to note that this document defines an information model, which by definition is independent of any particular data storage mechanism and access protocol. The purpose of this document is to define an information model to describe the quality of service (QoS) mechanisms inherent in different network devices, including hosts. Broadly speaking, these mechanisms describe the properties common to selecting and conditioning traffic through the forwarding path (datapath) of a network device. This selection and conditioning of traffic in the datapath spans both major QoS architectures: Differentiated Services and Integrated Services. This document should be used with the QoS Policy Information Model (QPIM) to model how policies can be defined to manage and configure the QoS mechanisms (i.e., the classification, marking, metering, dropping, queuing, and scheduling functionality) of devices. Together, these two documents describe how to write QoS policy rules to configure and manage the QoS mechanisms present in the datapaths of devices. This document, as well as QPIM, are information models. That is, they represent information independent of a binding to a specific type of repository This document describes YANG mechanisms for defining abstract data structures with YANG. YumaWorks Orange Huawei This document provides guidelines for authors and reviewers of specifications containing YANG data models, including IANA-maintained modules. Recommendations and procedures are defined, which are intended to increase interoperability and usability of Network Configuration Protocol (NETCONF) and RESTCONF Protocol implementations that utilize YANG modules. This document obsoletes RFC 8407. Also, this document updates RFC 8126 by providing additional guidelines for writing the IANA considerations for RFCs that specify IANA-maintained modules. This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. The YANG data modeling language is currently being considered for a wide variety of applications throughout the networking industry at large. Many standards development organizations (SDOs), open-source software projects, vendors, and users are using YANG to develop and publish YANG modules for a wide variety of applications. At the same time, there is currently no well-known terminology to categorize various types of YANG modules. A consistent terminology would help with the categorization of YANG modules, assist in the analysis of the YANG data modeling efforts in the IETF and other organizations, and bring clarity to the YANG- related discussions between the different groups. This document describes a set of concepts and associated terms to support consistent classification of YANG modules. As a complement to the Layer 3 Virtual Private Network Service Model (L3SM), which is used for communication between customers and service providers, this document defines an L3VPN Network Model (L3NM) that can be used for the provisioning of Layer 3 Virtual Private Network (L3VPN) services within a service provider network. The model provides a network-centric view of L3VPN services. The L3NM is meant to be used by a network controller to derive the configuration information that will be sent to relevant network devices. The model can also facilitate communication between a service orchestrator and a network controller/orchestrator. This document defines an L2VPN Network Model (L2NM) that can be used to manage the provisioning of Layer 2 Virtual Private Network (L2VPN) services within a network (e.g., a service provider network). The L2NM complements the L2VPN Service Model (L2SM) by providing a network-centric view of the service that is internal to a service provider. The L2NM is particularly meant to be used by a network controller to derive the configuration information that will be sent to relevant network devices. Also, this document defines a YANG module to manage Ethernet segments and the initial versions of two IANA-maintained modules that include a set of identities of BGP Layer 2 encapsulation types and pseudowire types. The IETF has produced many modules in the YANG modeling language. The majority of these modules are used to construct data models to model devices or monolithic functions. A small number of YANG modules have been defined to model services (for example, the Layer 3 Virtual Private Network Service Model (L3SM) produced by the L3SM working group and documented in RFC 8049). This document describes service models as used within the IETF and also shows where a service model might fit into a software-defined networking architecture. Note that service models do not make any assumption of how a service is actually engineered and delivered for a customer; details of how network protocols and devices are engineered to deliver a service are captured in other modules that are not exposed through the interface between the customer and the provider. This document defines a YANG data model that can be used for communication between customers and network operators and to deliver a Layer 3 provider-provisioned VPN service. This document is limited to BGP PE-based VPNs as described in RFCs 4026, 4110, and 4364. This model is intended to be instantiated at the management system to deliver the overall service. It is not a configuration model to be used directly on network elements. This model provides an abstracted view of the Layer 3 IP VPN service configuration components. It will be up to the management system to take this model as input and use specific configuration models to configure the different network elements to deliver the service. How the configuration of network elements is done is out of scope for this document. This document obsoletes RFC 8049; it replaces the unimplementable module in that RFC with a new module with the same name that is not backward compatible. The changes are a series of small fixes to the YANG module and some clarifications to the text. This document defines a YANG data model that can be used to configure a Layer 2 provider-provisioned VPN service. It is up to a management system to take this as an input and generate specific configuration models to configure the different network elements to deliver the service. How this configuration of network elements is done is out of scope for this document. The YANG data model defined in this document includes support for point-to-point Virtual Private Wire Services (VPWSs) and multipoint Virtual Private LAN Services (VPLSs) that use Pseudowires signaled using the Label Distribution Protocol (LDP) and the Border Gateway Protocol (BGP) as described in RFCs 4761 and 6624. The YANG data model defined in this document conforms to the Network Management Datastore Architecture defined in RFC 8342. This memo discusses different approaches to configure networks and identifies a set of configuration management requirements for IP-based networks. This memo provides information for the Internet community. This document is a glossary of policy-related terms. It provides abbreviations, explanations, and recommendations for use of these terms. The intent is to improve the comprehensibility and consistency of writing that deals with network policy, particularly Internet Standards documents (ISDs). This memo provides information for the Internet community. This document provides an overview of a workshop held by the Internet Architecture Board (IAB) on Network Management. The workshop was hosted by CNRI in Reston, VA, USA on June 4 thru June 6, 2002. The goal of the workshop was to continue the important dialog started between network operators and protocol developers, and to guide the IETFs focus on future work regarding network management. This report summarizes the discussions and lists the conclusions and recommendations to the Internet Engineering Task Force (IETF) community. This memo provides information for the Internet community. This document describes and discusses the issues involved in the design of the modern accounting systems. The field of Accounting Management is concerned with the collection the collection of resource consumption data for the purposes of capacity and trend analysis, cost allocation, auditing, and billing. This memo provides information for the Internet community. The Secure Shell (SSH) Protocol is a protocol for secure remote login and other secure network services over an insecure network. This document describes the architecture of the SSH protocol, as well as the notation and terminology used in SSH protocol documents. It also discusses the SSH algorithm naming system that allows local extensions. The SSH protocol consists of three major components: The Transport Layer Protocol provides server authentication, confidentiality, and integrity with perfect forward secrecy. The User Authentication Protocol authenticates the client to the server. The Connection Protocol multiplexes the encrypted tunnel into several logical channels. Details of these protocols are described in separate documents. [STANDARDS-TRACK] The "Next Era of Network Management Operations (NEMOPS)" workshop was convened by the Internet Architecture Board (IAB) from December 3-5, 2024, as a three-day online meeting. It builds on a previous 2002 workshop, the outcome of which was documented in RFC 3535, identifying 14 operator requirements for consideration in future network management protocol design and related data models, along with some recommendations for the IETF. Much has changed in the Internet’s operation and technological foundations since then. The NEMOPS workshop reviewed the past outcomes and discussed any operational barriers that prevented these technologies from being widely implemented. With the industry, network operators and protocol engineers working in collaboration, the workshop developed a suggested plan of action and network management recommendations for the IETF and IRTF. Note that this document is a report on the proceedings of the workshop. The views and positions documented in this report were expressed during the workshop by participants and do not necessarily reflect IAB's views and positions. This document updates RFC 3535 as the report of the follow-up IAB workshop on Network Management.

Changes Since RFC 5706 The following changes have been made to the guidelines published in :

• Change intended status from Informational to Best Current Practice
• Move the "Operational Considerations" Appendix A to a Checklist maintained in GitHub
• Add a requirement for an "Operational Considerations" section in all new Standard Track RFCs, along with specific guidance on its content.
• Update the operational and manageability-related technologies to reflect over 15 years of advancements
  • Provide focus and details on YANG-based standards, deprioritizing MIB Modules.
  • Add a "YANG Data Model Considerations" section
  • Update the "Available Management Technologies" landscape
• Add an "Operational and Management Tooling Considerations" section

TO DO LIST See the list of open issues at https://github.com/IETF-OPSAWG-WG/draft-opsarea-rfc5706bis/issues

Acknowledgements The authors wish to thank the following individuals and groups.

The IETF Ops Directorate:

The IETF Ops Directorate reviewer team, who has been providing document reviews for over a decade, and its Chairs, Gunter Van de Velde, Carlos Pignataro, and Bo Wu.

The AD championing the update:

Med Boucadair initiated the effort to refresh RFC 5706, 15 years after its publication, building on an idea originally suggested by Carlos Pignataro.

The author of RFC 5706:

David Harrington

Acknowledgments from RFC 5706:

This document started from an earlier document edited by Adrian Farrel, which itself was based on work exploring the need for Manageability Considerations sections in all Internet-Drafts produced within the Routing Area of the IETF. That earlier work was produced by Avri Doria, Loa Andersson, and Adrian Farrel, with valuable feedback provided by Pekka Savola and Bert Wijnen.

Some of the discussion about designing for manageability came from private discussions between Dan Romascanu, Bert Wijnen, Jürgen Schönwälder, Andy Bierman, and David Harrington.

Thanks to reviewers who helped fashion this document, including Harald Alvestrand, Ron Bonica, Brian Carpenter, Benoît Claise, Adrian Farrel, David Kessens, Dan Romascanu, Pekka Savola, Jürgen Schönwälder, Bert Wijnen, Ralf Wolter, and Lixia Zhang.

Contributors Swisscom

thomas.graf@swisscom.com