NETMOD Working Group K. Watsen
Internet-Draft Juniper Networks
Intended status: Informational T. Nadeau
Expires: June 17, 2016 Brocade Networks
December 15, 2015
NETMOD Operational State Requirements
draft-ietf-netmod-opstate-reqs-01
Abstract
This document defines requirements for servers enabling better
visibility and control over the server's operational state. To
achieve this end, this document also defines terminology describing a
conceptual model enabling the requirements to be expressed.
Status of This Memo
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Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Relation to Terms Defined in Other Drafts . . . . . 7
Appendix B. Relation to Requirements in Other Drafts . . . . . . 7
Appendix C. Open Issues . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
The term "server" is used throughout this document to refer to what
is many times known as the "device", "system", or "network element".
This definition is intended to be consistent with the term "server"
defined in [RFC6241], Section 1.1, but free of any association to a
particular protocol.
This document defines the following terms:
Applied Configuration: This data represents the configuration state
that the server is actually in. That is, the configuration state
which is currently being used by server components (e.g., control
plane daemons, operating system kernels, line cards).
NOTE: The server's ability to report applied configuration
accurately may be limited in some cases, such as when the
configuration goes through an intermediate layer without an
ability to inspect the lower layer.
Asynchronous Configuration Operation: A configuration request to
update the running configuration of a server that is applied
asynchronously with respect to the client request. The server
MUST update its intended configuration (see term) before replying
to the client indicating whether the request will be processed.
This reply to the client only indicates whether there are any
errors in the original request. The server's applied
configuration state (see term) is updated after the configuration
change has been fully effected to all impacted components in the
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server. Once applied, there MUST be a mechanism for the client
to determine when the request has completed processing and
whether the intended config is now fully effective or there are
any errors from applying the configuration change, which could be
from an asynchronous notification or via a client operation.
Continue On Error: Continue to process configuration data on error;
error is recorded, and negative response is generated if any
errors occur.
Derived State: This data represents information which is generated
as part of the server's own interactions. For example, derived
state may consist of the results of protocol interactions (the
negotiated duplex state of an Ethernet link), statistics (such as
message queue depth), or counters (such as packet input or output
bytes).
Intended Configuration: This data represents the configuration state
that the network operator intends the server to be in, and that
has been accepted by the server as valid configuration.
Operational State: Operational State is the current state of the
system as known to the various components of the system (e.g.,
control plane daemons, operating system kernels, line cards).
The operational state includes both applied configuration and
derived state.
Rollback On Error: If an error condition occurs such that part of
applying the configuration fails, the server will stop processing
the configuration operation and restore the specified
configuration to its complete state at the start of this
configuration operation.
Synchronous Configuration Operation: A configuration request to
update the running configuration of a server that is applied
synchronously with respect to the client request (i.e. a blocking
call). The server MUST fully attempt to apply the configuration
change to all impacted components in the server, updating both
the server's intended and applied configuration (see terms),
before replying to the client. The reply to the client indicates
whether there are any errors in the request or errors from
applying the configuration change.
2. Requirements
1. Ability to interact with both intended and applied configuration
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A. The ability to ask the operational components of a server
(e.g., line cards) for the configuration that they are
currently using. This is the applied configuration (see
term).
B. Applied configuration is read-only
C. The data model for the applied configuration is the same as
the data model for the intended configuration (same leaves)
D. When a configuration change for any intended configuration
node has been successfully applied to the server (e.g. not
failed, nor deferred due to absent hardware) then the
existence and value of the corresponding applied
configuration node must match the intended configuration
node.
2. Support for both synchronous and asynchronous configuration
operations (see terms)
A. A server may support only synchronous configuration
operations, or only asynchronous configuration operations, or
both synchronous and asynchronous configuration operations on
a client-specified per-operation basis.
B. Servers that support asynchronous configuration operations
MAY also provide a verify operation that a client can request
from the server to return information regarding the
difference between the intended and applied configurations.
C. The configuration protocol MUST specify how configuration
errors are handled. Errors may be handled by "stop on
error", "continue on error" or "rollback on error" semantics
(see terms). Support for "rollback on error" SHOULD be
provided.
3. Separation of the applied configuration and derived state aspects
of operational state; ability to retrieve them independently and
together
A. Be able to retrieve only the applied configuration aspects of
operational state
B. Be able to retrieve only the derived state aspects of
operational state
C. Be able to retrieve both the applied configuration and
derived state aspects of operational state together
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4. Ability to relate configuration with its corresponding
operational state
A. Ability to map intended config nodes to corresponding applied
config nodes
B. Ability to map intended config nodes to associated derived
state nodes
C. The mappings needs to be programmatically consumable
5. Ability for distinct modules to leverage a common model-structure
A. Focus on the IETF-defined modules, and ideally provides
guidance to other SDOs
B. Multiple domain-specific model-structure trees are okay
C. Model-structures may be defined in multiple modules with
distinct namespaces
3. Security Considerations
None
4. IANA Considerations
None
5. Acknowledgements
The authors would like to thank the following for contributing to
this document (in alphabetic order): Acee Lindem, Andy Bierman, Anees
Shaikh, Benoit Claise, Carl Moberg, Dan Romascanu, Dean Bogdanovic,
Gert Grammel, Jonathan Hansford, Juergen Schoenwaelder, Lou Berger,
Mahesh Jethanandani, Martin Bjorklund, Phil Shafer, Randy Presuhn,
Rob Shakir, Robert Wilton, Sterne, Jason.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
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6.2. Informative References
[draft-openconfig-netmod-model-structure-00]
Shaikh, A., Shakir, R., D'Souza, K., and L. Fang,
"Operational Structure and Organization of YANG Models",
draft-openconfig-netmod-model-structure-00 (work in
progress), 2015, <https://tools.ietf.org/html/draft-
openconfig-netmod-model-structure-00>.
[draft-openconfig-netmod-opstate-01]
Shakir, R., Shaikh, A., and M. Hines, "Consistent Modeling
of Operational State Data in YANG", draft-openconfig-
netmod-opstate-01 (work in progress), 2015,
<https://tools.ietf.org/html/draft-openconfig-netmod-
opstate-01>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<http://www.rfc-editor.org/info/rfc6241>.
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Appendix A. Relation to Terms Defined in Other Drafts
The following terms were originally defined in [RFC6241], but since
modified by the NETMOD WG:
o continue-on-error
o stop-on-error
o rollback-on-error
The following terms were originally defined in
[draft-openconfig-netmod-opstate-01], but since modified by the
NETMOD WG:
o Intended Configuration
o Applied Configuration
o Derived State
Appendix B. Relation to Requirements in Other Drafts
The requirements in this document roughly map onto the requirements
listed in [draft-openconfig-netmod-opstate-01] and
[draft-openconfig-netmod-model-structure-00] as list below. Some
liberty was taken to adjust the requirements based on what looked
liked consensus from on list discussions:
1. draft-openconfig-netmod-opstate-01, Section 3
2. draft-openconfig-netmod-opstate-01, Section 4.2
3. draft-openconfig-netmod-opstate-01, Section 4.3
4. draft-openconfig-netmod-opstate-01, Section 4.5
5. draft-openconfig-netmod-model-structure-00 (no section)
Appendix C. Open Issues
All issues with this draft are tracked using GitHub issues. Please
see: https://github.com/netmod-wg/opstate-reqs/issues to see
currently opened issues.
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Authors' Addresses
Kent Watsen
Juniper Networks
EMail: kwatsen@juniper.net
Thomas Nadeau
Brocade Networks
EMail: tnadeau@lucidvision.com
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