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Versions: 00 01 02 03 04 05 06 07 08 09 RFC 5706

Network Working Group                                      D. Harrington
Internet-Draft                                   Huawei Technologies USA
Intended status: BCP                                    October 27, 2008
Expires: April 30, 2009

 Guidelines for Considering Operations and Management of New Protocols

Status of This Memo

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   New protocols or protocol extensions are best designed with due
   consideration of functionality needed to operate and manage the
   protocol.  Retrofitting operations and management is sub-optimal.
   The purpose of this document is to provide guidance to authors and
   reviewers of documents defining new protocols or protocol extensions,
   about covering aspects of operations and management that should be

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Design for Operations and Management . . . . . . . . . . . . .  4
     2.1.  IETF Management Framework  . . . . . . . . . . . . . . . .  5
   3.  Operational Considerations . . . . . . . . . . . . . . . . . .  6
     3.1.  Operations Model . . . . . . . . . . . . . . . . . . . . .  6
     3.2.  Installation and Initial Setup . . . . . . . . . . . . . .  7
     3.3.  Migration Path . . . . . . . . . . . . . . . . . . . . . .  8
     3.4.  Requirements on Other Protocols and Functional
           Components . . . . . . . . . . . . . . . . . . . . . . . .  8
     3.5.  Impact on Network Operation  . . . . . . . . . . . . . . .  9
     3.6.  Verifying Correct Operation  . . . . . . . . . . . . . . .  9
   4.  Management Considerations  . . . . . . . . . . . . . . . . . . 10
     4.1.  Interoperability . . . . . . . . . . . . . . . . . . . . . 11
     4.2.  Management Information . . . . . . . . . . . . . . . . . . 13
     4.3.  Fault Management . . . . . . . . . . . . . . . . . . . . . 14
       4.3.1.  Liveness Detection and Monitoring  . . . . . . . . . . 15
       4.3.2.  Fault Determination  . . . . . . . . . . . . . . . . . 15
       4.3.3.  Fault Isolation  . . . . . . . . . . . . . . . . . . . 16
     4.4.  Configuration Management . . . . . . . . . . . . . . . . . 16
       4.4.1.  Verifying Correct Operation  . . . . . . . . . . . . . 18
       4.4.2.  Control of Function and Policy . . . . . . . . . . . . 18
     4.5.  Accounting Management  . . . . . . . . . . . . . . . . . . 18
     4.6.  Performance Management . . . . . . . . . . . . . . . . . . 19
     4.7.  Security Management  . . . . . . . . . . . . . . . . . . . 20
   5.  Documentation Guidelines . . . . . . . . . . . . . . . . . . . 22
     5.1.  Recommended Discussions  . . . . . . . . . . . . . . . . . 22
     5.2.  Null Manageability Considerations Sections . . . . . . . . 22
     5.3.  Placement of Operations and Manageability
           Considerations Sections  . . . . . . . . . . . . . . . . . 23
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 23
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 23
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 23
   9.  Informative References . . . . . . . . . . . . . . . . . . . . 24
   Appendix A.  Operations and Management Review Checklist  . . . . . 27
     A.1.  Operational Considerations . . . . . . . . . . . . . . . . 27
     A.2.  Management Considerations  . . . . . . . . . . . . . . . . 28
     A.3.  Documentation  . . . . . . . . . . . . . . . . . . . . . . 29
   Appendix B.  Change Log  . . . . . . . . . . . . . . . . . . . . . 29

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1.  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 hard.  Since the ease of operations and
   management may impact the success of IETF protocols, this document
   provides guidelines to help protocol designers and working groups
   consider the operations and management functionality needed by their
   new IETF protocol or protocol extension at an earlier phase.

   This document suggests protocol designers consider operations and
   management needs and then recommend appropriate standard management
   protocols and data models to address the relevant operations and
   management needs.  This is similar to a WG considering which security
   threats are relevant to their protocol, and then recommending
   appropriate standard security protocols to mitigate the relevant

   The purpose of this document is to provide guidance about what to
   consider when thinking about the management and deployment of a new
   protocol, and to provide guidance about documenting the
   considerations.  The following guidelines are designed to help
   writers provide a reasonably consistent format for such
   documentation.  Separate manageability and operational considerations
   sections are desirable in many cases, but their structure and
   location is a decision that can be made from case to case.

   We want to avoid seeming to impose a solution by putting in place a
   strict terminology - for example implying that a formal data model,
   or even using a management protocol is mandatory.  If protocol
   designers conclude that its technology can be managed solely by using
   proprietary CLIs, and no structured or standardized data model needs
   to be in place, 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 having manageability pushed for a later/never phase of
   the development of the standard.

   Making a Management Considerations section a mandatory publication
   requirement for IETF documents is the responsibility of the IESG, or
   specific area directors, or working groups, and this document avoids
   recommending any mandatory publication requirements.  For a complex
   protocol, a completely separate draft on operations and management
   might be appropriate, or even a completely separate WG effort.

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   This document discusses the importance of considering operations and
   management.  Section 1 introduces the subject and section 2 describes
   the IETF Management Framework.  Section 3 discusses operational
   functionality to consider.  Section 4 discusses management
   functionality to consider.

   This document sets forth a list of subjective guidelines and a list
   of objective criteria by which a protocol designer can evaluate
   whether the protocol that he/she has developed addresses common
   operations and management needs.  Operations and management are
   highly dependent on their environment, so most guidelines are
   subjective rather than objective.

   We provide some objective criteria to promote interoperability
   through the use of standard management interfaces, such as "did you
   design counters in a MIB module for monitoring packets in/out of an
   interface?"  The Interfaces Group MIB [RFC2863], "did you write an
   XML-based data model for configuring your protocol with Netconf?"
   NETCONF Configuration Protocol [RFC4741], and "did you standardize
   syslog message content and structured data elements for reporting
   events that might occur when operating your protocol?"
   [I-D.ietf-syslog-protocol] and "did you consider appropriate
   notifications in case of failure situations??

1.1.  Terminology

   This document deliberately does not use the (capitalized) keywords
   described in RFC 2119 [RFC2119].  RFC 2119 states the keywords must
   only be used where it is actually required for interoperation or to
   limit behavior which has potential for causing harm (e.g., limiting
   retransmissions).  For example, they must not be used to try to
   impose a particular method on implementers where the method is not
   required for interoperability.  This document is a set of guidelines
   based on current practices of protocol designers and operators.  This
   document does not describe requirements, so the key words from
   RFC2119 have no place here.

   o  "new protocol" includes new protocols, protocol extensions, data
      models, or other functionality being designed.

   o  "protocol designer" represents individuals and working groups
      involved in the development of new protocols.

2.  Design for Operations and Management

   "Design for operations and management" means that the operational
   environment and manageability of the protocol should be considered
   from the start when new protocols are designed.

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   When a WG considers operation and management functionality for a
   protocol, the document should contain enough information to
   understand how the protocol will be deployed and managed, but 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.

2.1.  IETF Management Framework

   For years the IETF has stressed the use of the IETF Standard
   Management Framework and MIB modules [RFC2578] for managing new
   protocols.  The IETF designed these to permit multiple protocols to
   utilize the MIB data [RFC1052], but it became a common
   misunderstanding that a MIB module could only be used with the SNMP
   protocol (described in [RFC3410] and associated documents).

   In 2001, OPS Area design teams were created to document requirements
   related to configuration of IP-based networks.  One output was
   "Requirements for Configuration Management of IP-based Networks"

   In 2003, the Internet Architecture Board (IAB) held a workshop on
   Network Management [RFC3535] that discussed the strengths and
   weaknesses of some IETF network management protocols, and compared
   them to operational needs, especially configuration.

   One issue discussed was the user-unfriendliness of the binary format
   of SNMP and COPS Usage for Policy Provisioning (COPS-PR) [RFC3084],
   and it was recommended that the IETF explore an XML-based Structure
   of Management Information, and an XML-based protocol for

   Another conclusion was that the tools for event/alarm correlation and
   for root cause analysis and logging are not sufficient, and that
   there is a need to support a human interface and a programmatic
   interface.  The IETF decided to standardize aspects of the de facto
   standard for system logging security and programmatic support.

   In 2006, the IETF discussed whether the Management Framework should
   be updated to accommodate multiple IETF schema languages for
   describing the structure of management information, and multiple IETF
   standard protocols for doing network management.

   This document provides some initial guidelines for considering
   operations and management in an IETF Management Framework that
   consists of multiple protocols and multiple data models, with an eye
   toward being flexible while also striving for interoperability.

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3.  Operational Considerations

   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 [RFC2439] 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, most places turned flap damping
   off.  Regional Internet Registries even issued an official
   recommendation for turning it off.

3.1.  Operations Model

   Protocol designers can analyze the operational environment and mode
   of work in which the new protocol or extension will work.  Such an
   exercise need not be reflected directly by text in their document,
   but could help in visualizing the operational model related to the
   applicability of the protocol in the Internet environments where it
   will be deployed.  The operational model should take into account
   factors such as:

   o  what type of management entities will be involved (agents, network
      management systems)?

   o  what is the possible architecture (client-server, manager-agent,
      poll-driven or event-driven, autoconfiguration, two levels or

   o  what are the management operations - initial configuration,
      dynamic configuration, alarm and exception reporting, logging,
      performance monitoring, performance reporting, debugging?

   o  how are these operations performed - locally, remotely, atomic
      operation, scripts?  Are they performed immediately or time
      scheduled or event triggered?

   o  what are the typical user interfaces - Command line (CLI) or
      graphical user interface (GUI)?

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   Protocol designers should consider how the new protocol 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.

   There may be a need to support a human interface, e.g., for
   troubleshooting, and a programmatic interface, e.g., for automated
   monitoring and root cause analysis.  It might be important that the
   internal method routines used by the application programming
   interfaces and the human interfaces should be the same to ensure that
   data exchanged between these two interfaces is always consistent.
   Mixing methods leads to inconsistency, so identifying consistent
   methods of retrieving information is relevant.

   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.

3.2.  Installation and Initial Setup

   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.

   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 algoithms are "broken".

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      it is extremely important to set a sensible default value for all

      the default value should stay on the conservative side rather than
      on the "optimizing performance" side. (example: 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.

3.3.  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.  This should
   include co-existence with previously deployed protocols and/or
   previous versions of the same protocol, incompatibilities between
   versions, translation between versions, and side-effects that might
   occur.  Are older protocols or versions disabled or do they co-exist
   in the network with the new protocol?

3.4.  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 elements that have been considered in designing the new

   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.

   For example, the design of Resource ReSerVation Protocol (RSVP)
   [RFC2205] required each router to look at the RSVP PATH message, and
   if the router understood RSVP, to add its own address to the message
   to enable automatically 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 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.

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3.5.  Impact on Network Operation

   The introduction of a new protocol or extensions to an existing
   protocol may have an impact on the operation of existing networks.
   Protocol designers should outline such impacts (which may be
   positive) including scaling concerns and interactions with other
   protocols.  For example, a new protocol that doubles the number of
   active, reachable addresses in use within a network might need to be
   considered in the light of the impact on the scalability of the IGPs
   operating within the network.

   A protocol could send active monitoring packets on the wire.  If we
   don't pay attention, we might get very good accuracy, but at the cost
   of using all the available bandwidth.

   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 result of the changes in
   the operational model, such as servers performing auto-configuration

   The protocol designer should consider also the impact on
   infrastructure applications like DNS [RFC1034], the registries, or
   the size of routing tables.  For example, Simple Mail Transfer
   Protocol (SMTP) [RFC2821] 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 the DNS
   cache resolver overload.

   The impact on performance may also be noted - increased delay or
   jitter in real-time traffic applications, or 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.

3.6.  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 (aka active
   monitoring).  Protocol designers should consider how the correct end-
   to-end operation of the new protocol in the network can be tested
   actively and passively, and how the correct data or forwarding plane

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   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.

4.  Management Considerations

   The considerations of manageability should start from describing the
   operational model, which includes identifying the entities to be
   managed, how the respective protocol is supposed to be installed,
   configured and monitored, who are the managers and what type of
   management interfaces and protocols they would use.

   Considerations for management should include a discussion of what
   needs to be managed, and how to achieve various management tasks.
   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 is exactly what
   operators hate - you need to be able to manage both ends.  As
   [RFC3535] says, MIB modules can often be characterized as a list of
   ingredients without a recipe.

   Management needs to be considered not only from the perspective of a
   device, but also from the perspective of network and service
   management perspectives.  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: it is enormously helpful if a protocol has hooks to make
   debugging of network interactions easy, and/or is designed in such a

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   way that debugging protocol behaviors is easy.  Hand-waving this away
   is not something that operators like ...

   In a client/server protocol, it may be more important to instrument
   the server end of a protocol than the client end.

4.1.  Interoperability

   Just as when deploying protocols that will inter-connect devices, our
   primary goal in considering management should be interoperability,
   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 3rd 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 becomes a problem.  It is important to have consistency
   in the management interfaces 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.

   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 or not.  The IETF is moving from support for one
   schema language for modeling the structure of management information
   (Structure of Management Information Version 2 (SMIv2) [RFC2578]) and
   one simple network management protocol (Simple Network Management
   Protocol (SNMP) [RFC3410]) towards support for additional schema
   languages and additional management protocols suited to different
   purposes.  Other Standard Development Organizations (e.g.  DMTF, 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 [W3C.REC-xmlschema-0-20010502]

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      and others


      NETCONF Configuration Protocol [RFC4741]

      IP Flow Information Export (IPFIX) Protocol [RFC5101]) for usage

      The syslog Protocol [I-D.ietf-syslog-protocol] for logging

      and others

   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 differences
   across vendors or 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.  For example, 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

   Information models are helpful to try to focus interoperability on
   the semantic level - they establish standards for what information
   should be gathered, and how gathered information might be used
   regardless of which management interface carries the data or which
   vendor produces the product.  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 SYSLOG message
   and an SNMP notification about the same event.  An information model
   might identify which error conditions should be counted separately,
   and which error conditions can be counted together in a single
   counter.  Then, whether the counter is gathered via SNMP or a CLI
   command or a SYSLOG message, the counter will have similar meaning.

   Protocol designers should consider which information might be useful
   for managing the new protocol or protocol extensions.

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                IM                --> conceptual/abstract model
                 |                    for designers and operators
      |          |         |
      DM        DM         DM     --> concrete/detailed model
                                      for implementers

   Information Models and Data Models

                                 Figure 1

   On the Difference between Information Models and Data Models
   [RFC3444] may be useful in determining what information to consider
   regarding information models, as compared to data models.

   Information models should come from the protocol WGs and include
   lists of events, counters and configuration parameters that are
   relevant.  There are a number of information models contained in
   protocol WG RFCs.  Some examples:

   o  [RFC3060] - Policy Core Information Model version 1

   o  [RFC3290] - An Informal Management Model for DiffServ Routers

   o  [RFC3460] - Policy Core Information Model Extensions

   o  [RFC3585] - IPsec Configuration Policy Information Model

   o  [RFC3644] - Policy Quality of Service Information Model

   o  [RFC3670] - Information Model for Describing Network Device QoS
      Datapath Mechanisms

   o  [RFC3805] - Printer MIB v2 (contains both an IM and a DM

   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.

4.2.  Management Information

   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 should an
   operator be notified.

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   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 administrative configured and
   which parameters have changed since configuration as the result of
   mechanisms such as routing protocols.

   It is important to be able to separately fetch configuration data,
   operational state data, and statistics from devices, and to be able
   to compare current state to initial state, and to compare data
   between devices.

   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

   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

   Do objects (such as rows in tables) share fate?  For example, if a
   row in table A must exist before a related row in table B can be
   created, what happens to the row in table B if the related row in
   table A is deleted?  Does the existence of relationships between
   objects have an impact on fate sharing?

4.3.  Fault Management

   The protocol designer should document the basic faults and health
   indicators that need to be instrumented for the new protocol, and the
   alarms and events that must be propagated to management applications
   or exposed through a data model.

   The protocol designer should consider how faults 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

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   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 gyaranteed accurate delivery of
   the event information within a given (high) margin of confidence?
   Can we poll the latest events in the box?

4.3.1.  Liveness Detection and Monitoring

   Liveness detection and monitoring applies both to the control plane
   and the data plane.  Mechanisms for detecting faults in the control
   plane or for monitoring its liveness are usually built into the
   control plane protocols or inherited from underlying data plane or
   forwarding plane protocols.  These mechanisms do not typically
   require additional management capabilities.  However, when a system
   detects a control plane fault, there is often a requirement to
   coordinate recovery action through management applications or at
   least to record the fact in an event log.

   Where the protocol is responsible for establishing data or user plane
   connectivity, liveness detection and monitoring usually need to be
   achieved through other mechanisms.  In some cases, these mechanisms
   already exist within other protocols responsible for maintaining
   lower layer connectivity, but it will often be the case that new
   procedures are required to detect failures in the data path and to
   report rapidly, allowing remedial action to be taken.

   Protocol designers should always build in basic testing features
   (e.g.  ICMP echo, UDP/TCP echo service, NULL RPC calls) that can be
   used to test for liveness, with an option to enable and disable them.

4.3.2.  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.

   How do you distinguish between faulty messages and good messages?

   Would some threshold-based mechanisms, such as RMON events/alarms or
   the EVENT-MIB, be useable to help determine error conditions?  Are
   SNMP notifications for all events needed, or are there some
   "standard" notifications that could be used? or can the right
   counters that can be polled as needed?

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4.3.3.  Fault Isolation

   It might be useful to isolate faults, such as a system that emits
   malformed messages necessary to coordinate connections properly.
   Spanning tree comes to mind.  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.

4.4.  Configuration Management

   A protocol desoigners should document what the basic configuration
   parameters that need to be instrumented for a new protocol, 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"
   [RFC3139] discusses requirements for configuration management.  This
   document includes discussion of different levels of management,
   including high-level-policies, network-wide configuration data, and
   device-local configuration.

   A number of efforts have existed in the IETF to develop policy-based
   management.  "Terminology for Policy-Based Management" [RFC3198] was
   written to standardize the terminology across these efforts.  Some of
   the efforts resulted in proposals that are NOT RECOMMENDED, so a
   protocol designer should check the current recommendation status
   before depending on a specific protocol suggestion.

   It is highly desirable that text processing tools such as diff, and
   version management tools such as RCS or CVS or SVN, can be used to
   process configurations.  This approach simplifies comparing the
   current operational state to the initial configuration.  It is
   commonplace to compare configuration changes to e.g., last day, last
   week, last month, etc. -- having configuration in a text, and human-
   understandable format is very valuable for various reasons such as
   change control (or verification), configuration consistency checks,

   With structured text such as XML, simple text diffs may be found to
   be inadequate and more sophisticated tools may be needed to make any
   useful comparison of versions.

   To simplify such configuration comparisons, devices should not
   arbitrarily reorder data such as access control lists.  If a protocol
   designer defines mechanisms for configuration, it would be desirable
   to standardize the order of elements for consistency of configuration

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   and of reporting across vendors, and across releases from vendors.

   There are two parts to this: 1.  An NMS system could optimize ACLs
   for performance reasons 2.  Unless the device/NMS systems has correct
   rules/a lot of experience, reordering ACLs can lead to a huge
   security issue.

   Network wide configurations are ideally stored in central master
   databases and transformed into formats that can be pushed to devices,
   either by generating sequences of CLI commands or complete
   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.  It is 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 the vendors will likely have proprietary
   aspects of their configurations.

   It is important to distinguish between the distribution of
   configurations and the activation of a certain configuration.
   Devices should be able to hold multiple configurations.  NETCONF
   [RFC4741], for example, differentiates between the "running"
   configuration and "candidate" 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 a number of
   devices would significantly simplify network configuration
   management.  The ability to distribute configurations to multiple
   devices, or 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

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   minimize the impact caused by configuration changes.

   Many protocol specifications include timers that are used as part of
   operation of the protocol.  These timers may need default values
   suggested in the protocol specification and do not need to be
   otherwise configurable.

4.4.1.  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, and 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 network, and how to verify the correct data or
   forwarding plane function of each network element.  This may be
   achieved through status and statistical information from network

4.4.2.  Control of Function and Policy

   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.

4.5.  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" [RFC2975] discusses a number
   of factors relevant to monitoring usage of protocols for purposes of
   capacity and trend analysis, cost allocation, auditing, and billing.
   This document also discusses how Remote Authentication Dial In User
   Service (RADIUS) [RFC2865], Terminal Access Controller Access Control
   System (TACACS) [RFC1492], SNMP, IPFIX, and Packet Sampling (PSAMP)
   Protocol [I-D.ietf-psamp-protocol] 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.

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4.6.  Performance Management

   Consider information that would be useful when trying to determine
   the performance characteristics of a deployed system using the target

   There are several parts to performance management to be considered:
   protocol monitoring, services monitoring, and device monitoring (the
   impact of the new protocol/service activation on the device).

   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

   Consider scalability, such as whether performance will be affected by
   the number of protocol connections.  If so, then it might be useful
   to provide information about the maximum number of table entries that
   should be expected to be modeled, how many entries an implementation
   can support, the current number of instances, and the expected
   behavior when the current instances exceed the capacity of the
   implementation.  This should be considered in a data-modeling
   independent manner - what makes managed-protocol sense, not what
   makes management-protocol-sense.  If it is not managed-protocol-
   dependent, then it should be left for the management-protocol data
   modelers to decide.  For example, VLAN identifiers have a range of
   1..4095 because of the VLAN standards.  A MIB implementing a VLAN
   table should be able to support 4096 entries because the content
   being modeled requires it.

   Any recommendation in the document should be data-modeling language
   independent.  The protocol document should make clear the limitations
   implicit within the protocol and the behavior when limits are

   Consider the capability of determining the operational activity, such
   as the number of message in and the messages out, the number of
   received messages rejected due to format problems, the expected
   behaviors when a malformed message is received.

   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?

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   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 information?  Does this make any difference in
   evaluating the performance of a protocol?

   For performance monitoring, it is often important to report the time
   spent in a state rather than the current state.  Snapshots are of
   less value for performance monitoring.

   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
   recommendation describes the class of equipment, system, or service
   being addressed; discuss the performance characteristics that are
   pertinent to that class; clearly identify a set of metrics that aid
   in the description of those characteristics; specify the
   methodologies required to collect said metrics; and lastly, present
   the requirements for the common, unambiguous reporting of
   benchmarking results.

   What are the principal performance factors that need to be looked at
   when measuring the operational performance of the protocol
   implementations?  Is it important to measure setup times? throughput?
   quality versus throughput? interruptions? end-to-end throughput? end-
   to-end quality? hop-to-hop throughput?  In many cases the performance
   metrics are generic and already defined by work done in the IPPM WG,
   or BMWG for example, but in some cases new metrics need to be
   defined.  It would be useful if the document would identify the need
   for such new metrics.

4.7.  Security Management

   Protocol designers should consider how to monitor and to manage
   security aspects and vulnerabilities of the new protocol.

   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?

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   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, or 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 CAPWAP breaks the structure of monolithic
   Access Points (AP) into Access Controllers and Wireless Termination
   Points (WTP).  By using a management interface, 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.

   It must be possible 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 which 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
   [I-D.ietf-syslog-protocol] 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
   SSH from where, failed SSH logins can be logged using syslog, etc.

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   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.

   RADIUS and DIAMETER can provide authentication and authorization.  A
   protocol designer should consider which attributes would be
   appropriate for their protocol.

   Different 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 access
   control is data-oriented, while CLI access control is usually command
   (task) oriented.  Depending on the management function, sometimes
   data-oriented or task-oriented access control makes more sense.
   Protocol designers should consider both data-oriented and task-
   oriented access control.

5.  Documentation Guidelines

   This document is focused on what to think about, and how to document
   the considerations of the protocol designer.

5.1.  Recommended Discussions

   A Manageability 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 contain a simple statement explaining why the topic is not
   relevant for the new protocol.  Of course, additional relevant 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.

5.2.  Null Manageability Considerations Sections

   A protocol designer may seriously consider the manageability
   requirements of a new protocol, and determine that no management
   functionality is needed by the new protocol.  It would be helpful to
   those who may update or write extensions to the protocol in the
   future or to those deploying the new protocol to know the thinking of
   the working regarding the manageability of the protocol at the time
   of its design.

   If there are no new manageability or deployment considerations, it is

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   recommended that a Manageability Considerations section contain a
   simple statement such as "There are no new manageability requirements
   introduced by this document," and a brief explanation of why that is
   the case.  The presence of such a Manageability Considerations
   section would indicate to the reader that due consideration has been
   given to manageability and operations.

   In the case where the new protocol is an extension, and the base
   protocol discusses all the relevant operational and manageability
   considerations, it would be helpful to point out the considerations
   section in the base document.

5.3.  Placement of Operations and Manageability Considerations Sections

   If a protocol designer develops a Manageability Considerations
   section for a new protocol, it is recommended that the section be
   placed immediately before the Security Considerations section.
   Reviewers interested in such sections could find it easily, and this
   placement could simplify the development of tools to detect the
   presence of such a section.

6.  IANA Considerations

   This document does not introduce any new codepoints or name spaces
   for registration with IANA.  Note to RFC Editor: this section may be
   removed on publication as an RFC.

7.  Security Considerations

   This document is informational and provides guidelines for
   considering manageability and operations.  It introduces no new
   security concerns.

8.  Acknowledgements

   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, Juergen
   Schoenwaelder, Andy Bierman, and David Harrington.

   Thanks to reviewers who helped fashion this document, including David
   Kessens, Dan Romascanu, Ron Bonica, Bert Wijnen, Lixia Zhang, Ralf

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   Wolter, Benoit Claise, Brian Carpenter, Harald Alvestrand, Juergen
   Schoenwaelder, Pekka Savola

9.  Informative References

   [I-D.ietf-psamp-protocol]       Claise, B., "Packet Sampling (PSAMP)
                                   Protocol Specifications",
                                   draft-ietf-psamp-protocol-09 (work in
                                   progress), December 2007.

   [I-D.ietf-syslog-protocol]      Gerhards, R., "The syslog Protocol",
                                   draft-ietf-syslog-protocol-23 (work
                                   in progress), September 2007.

   [RFC1034]                       Mockapetris, P., "Domain names -
                                   concepts and facilities", STD 13,
                                   RFC 1034, November 1987.

   [RFC1052]                       Cerf, V., "IAB recommendations for
                                   the development of Internet network
                                   management standards", RFC 1052,
                                   April 1988.

   [RFC1492]                       Finseth, C., "An Access Control
                                   Protocol, Sometimes Called TACACS",
                                   RFC 1492, July 1993.

   [RFC2119]                       Bradner, S., "Key words for use in
                                   RFCs to Indicate Requirement Levels",
                                   BCP 14, RFC 2119, March 1997.

   [RFC2205]                       Braden, B., Zhang, L., Berson, S.,
                                   Herzog, S., and S. Jamin, "Resource
                                   ReSerVation Protocol (RSVP) --
                                   Version 1 Functional Specification",
                                   RFC 2205, September 1997.

   [RFC2439]                       Villamizar, C., Chandra, R., and R.
                                   Govindan, "BGP Route Flap Damping",
                                   RFC 2439, November 1998.

   [RFC2578]                       McCloghrie, K., Ed., Perkins, D.,
                                   Ed., and J. Schoenwaelder, Ed.,
                                   "Structure of Management Information
                                   Version 2 (SMIv2)", STD 58, RFC 2578,
                                   April 1999.

   [RFC2821]                       Klensin, J., "Simple Mail Transfer

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                                   Protocol", RFC 2821, April 2001.

   [RFC2863]                       McCloghrie, K. and F. Kastenholz,
                                   "The Interfaces Group MIB", RFC 2863,
                                   June 2000.

   [RFC2865]                       Rigney, C., Willens, S., Rubens, A.,
                                   and W. Simpson, "Remote
                                   Authentication Dial In User Service
                                   (RADIUS)", RFC 2865, June 2000.

   [RFC2975]                       Aboba, B., Arkko, J., and D.
                                   Harrington, "Introduction to
                                   Accounting Management", RFC 2975,
                                   October 2000.

   [RFC3060]                       Moore, B., Ellesson, E., Strassner,
                                   J., and A. Westerinen, "Policy Core
                                   Information Model -- Version 1
                                   Specification", RFC 3060,
                                   February 2001.

   [RFC3084]                       Chan, K., Seligson, J., Durham, D.,
                                   Gai, S., McCloghrie, K., Herzog, S.,
                                   Reichmeyer, F., Yavatkar, R., and A.
                                   Smith, "COPS Usage for Policy
                                   Provisioning (COPS-PR)", RFC 3084,
                                   March 2001.

   [RFC3139]                       Sanchez, L., McCloghrie, K., and J.
                                   Saperia, "Requirements for
                                   Configuration Management of IP-based
                                   Networks", RFC 3139, June 2001.

   [RFC3198]                       Westerinen, A., Schnizlein, J.,
                                   Strassner, J., Scherling, M., Quinn,
                                   B., Herzog, S., Huynh, A., Carlson,
                                   M., Perry, J., and S. Waldbusser,
                                   "Terminology for Policy-Based
                                   Management", RFC 3198, November 2001.

   [RFC3290]                       Bernet, Y., Blake, S., Grossman, D.,
                                   and A. Smith, "An Informal Management
                                   Model for Diffserv Routers",
                                   RFC 3290, May 2002.

   [RFC3410]                       Case, J., Mundy, R., Partain, D., and
                                   B. Stewart, "Introduction and

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                                   Applicability Statements for
                                   Internet-Standard Management
                                   Framework", RFC 3410, December 2002.

   [RFC3444]                       Pras, A. and J. Schoenwaelder, "On
                                   the Difference between Information
                                   Models and Data Models", RFC 3444,
                                   January 2003.

   [RFC3460]                       Moore, B., "Policy Core Information
                                   Model (PCIM) Extensions", RFC 3460,
                                   January 2003.

   [RFC3535]                       Schoenwaelder, J., "Overview of the
                                   2002 IAB Network Management
                                   Workshop", RFC 3535, May 2003.

   [RFC3585]                       Jason, J., Rafalow, L., and E.
                                   Vyncke, "IPsec Configuration Policy
                                   Information Model", RFC 3585,
                                   August 2003.

   [RFC3644]                       Snir, Y., Ramberg, Y., Strassner, J.,
                                   Cohen, R., and B. Moore, "Policy
                                   Quality of Service (QoS) Information
                                   Model", RFC 3644, November 2003.

   [RFC3670]                       Moore, B., Durham, D., Strassner, J.,
                                   Westerinen, A., and W. Weiss,
                                   "Information Model for Describing
                                   Network Device QoS Datapath
                                   Mechanisms", RFC 3670, January 2004.

   [RFC3805]                       Bergman, R., Lewis, H., and I.
                                   McDonald, "Printer MIB v2", RFC 3805,
                                   June 2004.

   [RFC4741]                       Enns, R., "NETCONF Configuration
                                   Protocol", RFC 4741, December 2006.

   [RFC5101]                       Claise, B., "Specification of the IP
                                   Flow Information Export (IPFIX)
                                   Protocol for the Exchange of IP
                                   Traffic Flow Information", RFC 5101,
                                   January 2008.

   [W3C.REC-xmlschema-0-20010502]  Fallside, D., "XML Schema Part 0:
                                   Primer", World Wide Web Consortium

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                                   FirstEdition REC-xmlschema-0-
                                   20010502, May 2001, <http://

Appendix A.  Operations and Management Review Checklist

   This appendix provides a quick checklist of issues that protocol
   designers should expect operations and management expert reviewers to
   look for when reviewing a document being proposed for consideration
   as a protocol standard.

A.1.  Operational Considerations

      Has the operations model been discussed? see section 3.1.

         Does the document include a description of the operational
         model - how is this protocol or technology going to be deployed
         and managed?

         Is the proposed specification deployable?  If not, how could it
         be improved?

         Does the solution scale well?  Does the proposed approach have
         any scaling issues that could affect usability for large scale

      Has installation and initial setup been discussed? see section 3.2

         Is the solution sufficiently configurable?

         are configuration parameters clearly identified?

         are configuration parameters normalized?

         does each configuration parameter have a reasonable default

         Will configuration be pushed to a device by a configuration
         manager, or pulled by a device from a configuration server?

         How will the devices and managers find and authenticate each

      Has the migration path been discussed? see section 3.3.

         Are there any backward compatibility issues?

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      Have the Requirements on Other Protocols and Functional Components
      been discussed? see section 3.4.

         What protocol operations are expected to be performed relative
         to the new protocol or technology, and what protocols and data
         models are expected to be in place or recommended to ensure for
         interoperable management?

      Has the Impact on Network Operation been discussed? see section

      Have suggestions for verifying correct operation been discussed?
      see section 3.6.

      Have suggestions for verifying correct operation been discussed?
      see section 4.1.

A.2.  Management Considerations

   Do you anticipate any manageability issues with the specification?

      Is Management interoperability discussed? see section 4.1.

         will it use centralized or distributed management?

         will it require remote and/or local management applications?

         Are textual or graphical user interfaces required?

         Is textual or binary format for management information

      Is Management Information discussed? see section 4.2.

         What is the minimal set of management (configuration, faults,
         performance monitoring) objects that need to be instrumented in
         order to manage the new protocol?

      Is Fault Management discussed? see section 4.3.

         Is Liveness Detection and Monitoring discussed?

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         Does the solution have failure modes that are difficult to
         diagnose or correct?  Are faults and alarms reported and

      Is Configuration Management discussed? see section 4.4.

         is protocol state information exposed to the user?  How? are
         significant state transitions logged?

      Is Accounting Management discussed? see section 4.5.

      Is Performance Management discussed? see section 4.6.

         Does the protocol have an impact on network traffic and network
         devices?  Can performance be measured?

         Is protocol performance information exposed to the user?

      Is Security Management discussed? see section 4.7.

         Does the specification discuss hwo to manage aspects of
         security, such as access controls, managing key distribution,

A.3.  Documentation

   Is an operational considerations and/or manageability section part of
   the document?

   Does the proposed protocol have a significant operational impact on
   the Internet.  If it does, and the document under review targets
   standards track, is their enough proof of implementation and/or
   operational experience to grant Proposed Standard status?

Appendix B.  Change Log

   Changes from opsawg-04 to opsawg-05

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      added bullets for appendix checklist

      aligned checklist order and guidelines order

      resolved all DISCUSS and TODO issues.

   Changes from opsawg-03 to opsawg-04

      improved wording in Introduction

      added a number of DISCUSS points raised during WG reviews

      added more wording on service management

      updated references and copyrights

   Changes from opsawg-02 to opsawg-03

   From reviews by Lixia Zhang and feedback from WG Chairs' Lunch.

      added discussion of impact on the Internet to checklist

      spell check

      added examples

      added discussion of default values

      added discussion of database-driven configuration

      fixed some references

      expanded the checklist

   Changes from opsawg-01 to opsawg-02

      moved survey of protocols and data models to separate document

      changed "working group" to "protocol designer" throughout, as

      modified wording from negative to positive spin in places.

      updated based on comments from Ralf Wolter and David Kessens

   Changes from opsawg-00 to opsawg-01

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      moved Proposed Standard data models to appendix

      moved advice out of data model survey and into considerations

      addressed comments from Adrian and Dan

      modified the Introduction and Section 2 in response to many

      expanded radius and syslog discussion, added psamp and VCCV,
      modified ipfix,

   Changes from harrington-01 to opsawg-00

      added text regarding operational models to be managed.

      Added checklist appendix (to be filled in after consensus is
      reached on main text )

   Changes from harrington-00 to harrington-01

      modified unclear text in "Design for Operations and Management"

      Expanded discussion of counters

      Removed some redundant text

      Added ACLs to Security Management

      Expanded discussion of the status of COPS-PR, SPPI, and PIBs.

      Expanded comparison of RADIUS and Diameter.

      Added placeholders for EPP and XCAP protocols.

      Added Change Log and Open Issues

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Author's Address

   David Harrington
   Huawei Technologies USA
   1700 Alma Dr, Suite 100
   Plano, TX  75075

   Phone: +1 603 436 8634
   EMail: dharrington@huawei.com

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Full Copyright Statement

   Copyright (C) The IETF Trust (2008).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an

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