draft-ietf-i2rs-ephemeral-state-16.txt   draft-ietf-i2rs-ephemeral-state-17.txt 
I2RS working group J. Haas I2RS working group J. Haas
Internet-Draft Juniper Internet-Draft Juniper
Intended status: Standards Track S. Hares Intended status: Standards Track S. Hares
Expires: March 2, 2017 Huawei Expires: March 24, 2017 Huawei
August 29, 2016 September 20, 2016
I2RS Ephemeral State Requirements I2RS Ephemeral State Requirements
draft-ietf-i2rs-ephemeral-state-16 draft-ietf-i2rs-ephemeral-state-17
Abstract Abstract
This document covers requests to the NETMOD and NETCONF Working The I2RS (interface to routing system) Architecture document
Groups for functionality to support the ephemeral state requirements (RFC7920) abstractly describes a number of requirements for ephemeral
to implement the I2RS architecture. state (in terms of capabilities and behaviors) which any protocol
suite attempting to meet I2RS needs has to provide. This document
describes in detail requirements for ephemeral state for those
implementing the I2RS higher-protocol.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 2, 2017. This Internet-Draft will expire on March 24, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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4. YANG Features for Ephemeral State . . . . . . . . . . . . . . 6 4. YANG Features for Ephemeral State . . . . . . . . . . . . . . 6
5. NETCONF Features for Ephemeral State . . . . . . . . . . . . 6 5. NETCONF Features for Ephemeral State . . . . . . . . . . . . 6
6. RESTCONF Features for Ephemeral State . . . . . . . . . . . . 6 6. RESTCONF Features for Ephemeral State . . . . . . . . . . . . 6
7. Requirements regarding Supporting Multi-Head Control via 7. Requirements regarding Supporting Multi-Head Control via
client Priority . . . . . . . . . . . . . . . . . . . . . . . 7 client Priority . . . . . . . . . . . . . . . . . . . . . . . 7
8. Multiple Message Transactions . . . . . . . . . . . . . . . . 8 8. Multiple Message Transactions . . . . . . . . . . . . . . . . 8
9. Pub/Sub Requirements Expanded for Ephemeral State . . . . . . 8 9. Pub/Sub Requirements Expanded for Ephemeral State . . . . . . 8
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
11. Security Considerations . . . . . . . . . . . . . . . . . . . 9 11. Security Considerations . . . . . . . . . . . . . . . . . . . 9
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
13.1. Normative References: . . . . . . . . . . . . . . . . . 10 13.1. Normative References: . . . . . . . . . . . . . . . . . 10
13.2. Informative References . . . . . . . . . . . . . . . . . 10 13.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
The Interface to the Routing System (I2RS) Working Group is chartered The Interface to the Routing System (I2RS) Working Group is chartered
with providing architecture and mechanisms to inject into and with providing architecture and mechanisms to inject into and
retrieve information from the routing system. The I2RS Architecture retrieve information from the routing system. The I2RS Architecture
document [RFC7921] abstractly documents a number of requirements for document [RFC7921] abstractly documents a number of requirements for
implementing the I2RS requirements. Section 2 reviews 10 key implementing the I2RS requirements. Section 2 reviews 10 key
requirements related to ephemeral state. requirements related to ephemeral state.
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The purpose of these requirements and the suggested protocol straw The purpose of these requirements and the suggested protocol straw
man is to provide a quick turnaround on creating the I2RS protocol. man is to provide a quick turnaround on creating the I2RS protocol.
Support for ephemeral state is an I2RS protocol requirement that Support for ephemeral state is an I2RS protocol requirement that
requires datastore changes (see section 3), YANG additions (see requires datastore changes (see section 3), YANG additions (see
section 4), NETCONF additions (see section 5), and RESTCONF additions section 4), NETCONF additions (see section 5), and RESTCONF additions
(see section 6). (see section 6).
Sections 7-9 provide details that expand upon the changes in sections Sections 7-9 provide details that expand upon the changes in sections
3-6 to clarify requirements discussed by the I2RS and NETCONF working 3-6 to clarify requirements discussed by the I2RS and NETCONF working
groups. Sections 7 provide additional requirements that detail how groups. Section 7 provided additional requirements that detail how
write-conflicts should be resolved if two I2RS client write the same write-conflicts should be resolved if two I2RS client write the same
data. Section 8 provides an additional requirement that details on data. Section 8 details an additional requirement that details on
I2RS support of multiple message transactions. Section 9 highlights I2RS support of multiple message transactions. Section 9 highlights
two requirements in the I2RS publication/subscription requirements two requirements in the I2RS publication/subscription requirements
[RFC7923] that must be expanded for ephemeral state. [RFC7923] that must be expanded for ephemeral state.
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
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changing or short lived operational state nodes, such as MPLS LSP-ID changing or short lived operational state nodes, such as MPLS LSP-ID
or a BGP IN-RIB. Ephemeral state constraints should be assessed when or a BGP IN-RIB. Ephemeral state constraints should be assessed when
the ephemeral state is written, and if any of the constraints change the ephemeral state is written, and if any of the constraints change
to make the constraints invalid after that time the I2RS agent should to make the constraints invalid after that time the I2RS agent should
notify the I2RS client. notify the I2RS client.
Ephemeral-REQ-04: Ephemeral state MUST be able to refer to non- Ephemeral-REQ-04: Ephemeral state MUST be able to refer to non-
ephemeral state as a constraint. Non-ephemeral state can be ephemeral state as a constraint. Non-ephemeral state can be
configuration state or operational state. configuration state or operational state.
Ephemeral-REQ-05: I2RS pub-sub [RFC7923], logging, RPC or other Ephemeral-REQ-05: I2RS pub-sub [RFC7923], tracing ([RFC7922], RPC or
mechanisms may lead to undesirable or unsustainable resource other mechanisms may lead to undesirable or unsustainable resource
consumption on a system implementing an I2RS agent. It is consumption on a system implementing an I2RS agent. It is
RECOMMENDED that mechanisms be made available to permit RECOMMENDED that mechanisms be made available to permit
prioritization of I2RS operations, when appropriate, to permit prioritization of I2RS operations, when appropriate, to permit
implementations to shed work load when operating under constrained implementations to shed work load when operating under constrained
resources. An example of such a work shedding mechanism is rate- resources. An example of such a work shedding mechanism is rate-
limiting. limiting.
3.3. Hierarchy 3.3. Hierarchy
Ephemeral-REQ-06: YANG MUST have the ability to do the following: Ephemeral-REQ-06: YANG MUST have the ability to do the following:
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Ephemeral-REQ-07: Local configuration MUST have a priority that is Ephemeral-REQ-07: Local configuration MUST have a priority that is
comparable with individual I2RS client priorities for making changes. comparable with individual I2RS client priorities for making changes.
This priority will determine whether local configuration changes or This priority will determine whether local configuration changes or
individual ephemeral configuration changes take precedence as individual ephemeral configuration changes take precedence as
described in RFC7921. The I2RS protocol MUST support this mechanism. described in RFC7921. The I2RS protocol MUST support this mechanism.
4. YANG Features for Ephemeral State 4. YANG Features for Ephemeral State
Ephemeral-REQ-08:In addition to config true/false, there MUST be a Ephemeral-REQ-08:In addition to config true/false, there MUST be a
way to indicate that YANG schema nodes represent ephemeral state. It way to indicate that YANG schema nodes represent ephemeral state. It
is desirable to allow for, and have to way to indicate, config false is desirable to allow for, and have a way to indicate, config false
YANG schema nodes that are writable operational state. YANG schema nodes that are writable operational state.
5. NETCONF Features for Ephemeral State 5. NETCONF Features for Ephemeral State
Ephemeral-REQ-09: The changes to NETCONF/RESTCONF must include: Ephemeral-REQ-09: The changes to NETCONF must include:
1. Support for communication mechanisms to enable an I2RS client to 1. Support for communication mechanisms to enable an I2RS client to
determine that an I2RS agent supports the mechanisms needed for determine that an I2RS agent supports the mechanisms needed for
I2RS operation. I2RS operation.
2. The ephemeral state MUST support notification of write conflicts 2. The ephemeral state MUST support notification of write conflicts
using the priority requirements defined in section 7 below in using the priority requirements defined in section 7 below in
requirements Ephemeral-REQ-11 through Ephemeral-REQ-14). requirements Ephemeral-REQ-11 through Ephemeral-REQ-14).
6. RESTCONF Features for Ephemeral State 6. RESTCONF Features for Ephemeral State
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7. Requirements regarding Supporting Multi-Head Control via client 7. Requirements regarding Supporting Multi-Head Control via client
Priority Priority
To support Multi-Headed Control, I2RS requires that there be a To support Multi-Headed Control, I2RS requires that there be a
decidable means of arbitrating the correct state of data when decidable means of arbitrating the correct state of data when
multiple clients attempt to manipulate the same piece of data. This multiple clients attempt to manipulate the same piece of data. This
is done via a priority mechanism with the highest priority winning. is done via a priority mechanism with the highest priority winning.
This priority is per-client. This priority is per-client.
Ephemeral-REQ-11: The I2RS Protocol (e.g. NETCONF/RESTCONF + yang) Ephemeral-REQ-11: The following requirements must be supported by the
MUST be able to support I2RS protocol I2RS Protocol (e.g. NETCONF/RESTCONF + yang) in order
to support I2RS client identity and priority:
o the data nodes MAY store I2RS client identity and not the o the data nodes MAY store I2RS client identity and not the
effective priority at the time the data node is stored. effective priority at the time the data node is stored.
o Per SEC-REQ-07 in section 3.1 of o Per SEC-REQ-07 in section 4.3 of
[I-D.ietf-i2rs-protocol-security-requirements], an identifier MUST [I-D.ietf-i2rs-protocol-security-requirements], an I2RS Identifier
have just one priority. The I2RS protocol MUST support the MUST have just one priority. The I2RS protocol MUST support the
ability to have data nodes store I2RS client identity and not the ability to have data nodes store I2RS client identity and not the
effective priority of the I2RS client at the time the data node is effective priority of the I2RS client at the time the data node is
stored. stored.
o The priority MAY be dynamically changed by AAA, but the exact o The priority MAY be dynamically changed by AAA, but the exact
actions are part of the protocol definition as long as collisions actions are part of the protocol definition as long as collisions
are handled as described in Ephemeral-REQ-12, Ephemeral-REQ-13, are handled as described in Ephemeral-REQ-12, Ephemeral-REQ-13,
and Ephemeral-REQ-14. and Ephemeral-REQ-14.
Ephemeral-REQ-12: When a collision occurs as two clients are trying Ephemeral-REQ-12: When a collision occurs as two clients are trying
to write the same data node, this collision is considered an error to write the same data node, this collision is considered an error
and priorities were created to give a deterministic result. When and priorities were created to give a deterministic result. When
there is a collision, a notification (which includes indicating data there is a collision, a notification (which includes indicating data
node the collision occurred on) MUST BE sent to the original client node the collision occurred on) MUST BE sent to the original client
to give the original client a chance to deal with the issues to give the original client a chance to deal with the issues
surrounding the collision. The original client may need to fix their surrounding the collision. The original client may need to fix their
state. state.
Note:RESTCONF and NETCONF posts can come in concurrently from Explanation: RESTCONF and NETCONF updates can come in concurrently
alternative sources (see ETag in [I-D.ietf-netconf-restconf] section from alternative sources. Therefore the collision detection and
3.4.1.2 usage). Therefore the collision detection and comparison of comparison of priority needs to occur for any type of update.
priority needs to occur both for both type of updates (POST or edit-
config) at the point of comparison. For example, RESTCONF tracks the source of configuration change via
the entity-Tag (section 3.5.2 of [I-D.ietf-netconf-restconf]) which
the server returns to the client along with the value in GET or HEAD
methods. RESTCONF requires that this resource entity-tag be updated
whenever a resource or configuration resource within the resource is
altered. In the RESTCONF processing, when the resource or a
configuration resource within the resource is altered, then the
processing of the configuration change for two I2RS clients must
detect an I2RS collision and resolve the collision using the priority
mechanism.
Ephemeral-REQ-13: Multi-headed control is required for collisions and Ephemeral-REQ-13: Multi-headed control is required for collisions and
the priority resolution of collisions. Multi-headed control is not the priority resolution of collisions. Multi-headed control is not
tied to ephemeral state. I2RS protocol MUST NOT mandate how AAA tied to ephemeral state. I2RS protocol MUST NOT mandate the internal
supports priority. Mechanisms which prevent collisions of two mechanism for how AAA protocols (E.g. Radius or Diameter) or
clients trying to modify the same node of data are the focus. mechanisms distribute priority per identity except that any AAA
protocols MUST operate over a secure transport layer (See Radius
[RFC6614] and Diameter [RFC6733]. distribute priority per identity.
Mechanisms which prevent collisions of two clients trying to modify
the same node of data are the focus.
Ephemeral-REQ-14: A deterministic conflict resolution mechanism MUST Ephemeral-REQ-14: A deterministic conflict resolution mechanism MUST
be provided to handle the error scenario that two clients, with the be provided to handle the error scenario that two clients, with the
same priority, update the same configuration data node. The I2RS same priority, update the same configuration data node. The I2RS
architecture gives one way that this could be achieved, by specifying architecture gives one way that this could be achieved, by specifying
that the first update wins. Other solutions, that prevent that the first update wins. Other solutions, that prevent
oscillation of the config data node, are also acceptable. oscillation of the config data node, are also acceptable.
8. Multiple Message Transactions 8. Multiple Message Transactions
Ephemeral-REQ-15: Section 7.9 of the [RFC7921] states the I2RS Ephemeral-REQ-15: Section 7.9 of the [RFC7921] states the I2RS
architecture does not include multi-message atomicity and roll-back architecture does not include multi-message atomicity and roll-back
mechanisms. The I2RS protocol implementation MUST not require the mechanisms. The I2RS protocol implementation MUST NOT require the
support of these features. As part of this requirement, the I2RS support of these features. As part of this requirement, the I2RS
protocol should support: protocol should support:
multiple operations in one or more messages; though errors in multiple operations in one or more messages; though errors in
message or operation will have no effect on other messages or message or operation will have no effect on other messages or
commands even they are related. commands even they are related.
No multi-message commands SHOULD cause errors to be inserted into No multi-message commands SHOULD cause errors to be inserted into
the I2RS ephemeral state. the I2RS ephemeral state.
skipping to change at page 9, line 28 skipping to change at page 9, line 41
[I-D.ietf-i2rs-security-environment-reqs]. [I-D.ietf-i2rs-security-environment-reqs].
12. Acknowledgements 12. Acknowledgements
This document is an attempt to distill lengthy conversations on the This document is an attempt to distill lengthy conversations on the
I2RS mailing list for an architecture that was for a long period of I2RS mailing list for an architecture that was for a long period of
time a moving target. Some individuals in particular warrant time a moving target. Some individuals in particular warrant
specific mention for their extensive help in providing the basis for specific mention for their extensive help in providing the basis for
this document: this document:
o Alia Atlas o Alia Atlas,
o Andy Bierman o Andy Bierman,
o Martin Bjorklund o Martin Bjorklund,
o Dean Bogdanavich o Dean Bogdanavich,
o Rex Fernando o Rex Fernando,
o Joel Halpern o Joel Halpern,
o Thomas Nadeau,
o Thomas Nadeau o Juergen Schoenwaelder,
o Juergen Schoenwaelder o Kent Watsen,
o Kent Watsen o Robert Wilton, and
o Robert Wilton o Joe Clark,
13. References 13. References
13.1. Normative References: 13.1. Normative References:
[I-D.ietf-i2rs-protocol-security-requirements] [I-D.ietf-i2rs-protocol-security-requirements]
Hares, S., Migault, D., and J. Halpern, "I2RS Security Hares, S., Migault, D., and J. Halpern, "I2RS Security
Related Requirements", draft-ietf-i2rs-protocol-security- Related Requirements", draft-ietf-i2rs-protocol-security-
requirements-09 (work in progress), August 2016. requirements-11 (work in progress), September 2016.
[I-D.ietf-i2rs-security-environment-reqs] [I-D.ietf-i2rs-security-environment-reqs]
Migault, D., Halpern, J., and S. Hares, "I2RS Environment Migault, D., Halpern, J., and S. Hares, "I2RS Environment
Security Requirements", draft-ietf-i2rs-security- Security Requirements", draft-ietf-i2rs-security-
environment-reqs-01 (work in progress), April 2016. environment-reqs-01 (work in progress), April 2016.
[I-D.ietf-netconf-restconf] [I-D.ietf-netconf-restconf]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", draft-ietf-netconf-restconf-16 (work in Protocol", draft-ietf-netconf-restconf-16 (work in
progress), August 2016. progress), August 2016.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<http://www.rfc-editor.org/info/rfc6241>. <http://www.rfc-editor.org/info/rfc6241>.
[RFC6614] Winter, S., McCauley, M., Venaas, S., and K. Wierenga,
"Transport Layer Security (TLS) Encryption for RADIUS",
RFC 6614, DOI 10.17487/RFC6614, May 2012,
<http://www.rfc-editor.org/info/rfc6614>.
[RFC6733] Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,
Ed., "Diameter Base Protocol", RFC 6733,
DOI 10.17487/RFC6733, October 2012,
<http://www.rfc-editor.org/info/rfc6733>.
[RFC7921] Atlas, A., Halpern, J., Hares, S., Ward, D., and T. [RFC7921] Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
Nadeau, "An Architecture for the Interface to the Routing Nadeau, "An Architecture for the Interface to the Routing
System", RFC 7921, DOI 10.17487/RFC7921, June 2016, System", RFC 7921, DOI 10.17487/RFC7921, June 2016,
<http://www.rfc-editor.org/info/rfc7921>. <http://www.rfc-editor.org/info/rfc7921>.
[RFC7922] Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to [RFC7922] Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to
the Routing System (I2RS) Traceability: Framework and the Routing System (I2RS) Traceability: Framework and
Information Model", RFC 7922, DOI 10.17487/RFC7922, June Information Model", RFC 7922, DOI 10.17487/RFC7922, June
2016, <http://www.rfc-editor.org/info/rfc7922>. 2016, <http://www.rfc-editor.org/info/rfc7922>.
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