draft-ietf-i2rs-ephemeral-state-14.txt   draft-ietf-i2rs-ephemeral-state-15.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: January 7, 2017 Huawei Expires: January 22, 2017 Huawei
July 6, 2016 July 21, 2016
I2RS Ephemeral State Requirements I2RS Ephemeral State Requirements
draft-ietf-i2rs-ephemeral-state-14 draft-ietf-i2rs-ephemeral-state-15
Abstract Abstract
This document covers requests to the NETMOD and NETCONF Working This document covers requests to the NETMOD and NETCONF Working
Groups for functionality to support the ephemeral state requirements Groups for functionality to support the ephemeral state requirements
to implement the I2RS architecture. to implement the I2RS architecture.
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
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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
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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 January 7, 2017. This Internet-Draft will expire on January 22, 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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3.2. Constraints . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. Constraints . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . 6 3.3. Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . 6
3.4. Ephemeral Configuration overlapping Local Configuration . 6 3.4. Ephemeral Configuration overlapping Local Configuration . 6
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 . . . . . . . . . . . . . . . . . . . . . 8 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
11. Security Considerations . . . . . . . . . . . . . . . . . . . 9 11. Security Considerations . . . . . . . . . . . . . . . . . . . 9
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
13.1. Normative References: . . . . . . . . . . . . . . . . . 9 13.1. Normative References: . . . . . . . . . . . . . . . . . 10
13.2. Informative References . . . . . . . . . . . . . . . . . 10 13.2. Informative References . . . . . . . . . . . . . . . . . 10
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 [I-D.ietf-i2rs-architecture] abstractly documents a number document [I-D.ietf-i2rs-architecture] abstractly documents a number
of requirements for implementing the I2RS requirements. Section 2 of requirements for implementing the I2RS requirements. Section 2
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running data store in NETCONF, running-config can be copied to a running data store in NETCONF, running-config can be copied to a
persistent data store, like startup config. I2RS ephemeral state persistent data store, like startup config. I2RS ephemeral state
MUST NOT be persisted. MUST NOT be persisted.
3.2. Constraints 3.2. Constraints
Ephemeral-REQ-02: Non-ephemeral state MUST NOT refer to ephemeral Ephemeral-REQ-02: Non-ephemeral state MUST NOT refer to ephemeral
state for constraint purposes; it SHALL be considered a validation state for constraint purposes; it SHALL be considered a validation
error if it does. error if it does.
Ephemeral-REQ-03: Ephemeral state may have constraints that refer to Ephemeral-REQ-03: Ephemeral state MUST be able to have constraints
operational state, this includes potentially fast changing or short that refer to operational state, this includes potentially fast
lived operational state nodes, such as MPLS LSP-ID or a BGP IN-RIB. changing or short lived operational state nodes, such as MPLS LSP-ID
Ephemeral state constraints should be assessed when the ephemeral or a BGP IN-RIB. Ephemeral state constraints should be assessed when
state is written, and if any of the constraints change to make the the ephemeral state is written, and if any of the constraints change
constraints invalid after that time the I2RS agent should notify the to make the constraints invalid after that time the I2RS agent should
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, logging, RPC or other mechanisms may Ephemeral-REQ-05: I2RS pub-sub, logging, RPC or other mechanisms may
lead to undesirable or unsustainable resource consumption on a system lead to undesirable or unsustainable resource consumption on a system
implementing an I2RS Agent. It is RECOMMENDED that mechanisms be implementing an I2RS Agent. It is RECOMMENDED that mechanisms be
made available to permit prioritization of I2RS operations, when made available to permit prioritization of I2RS operations, when
appropriate, to permit implementations to shed work load when appropriate, to permit implementations to shed work load when
operating under constrained resources. An example of such a work operating under constrained resources. An example of such a work
shedding mechanism is rate-limiting. shedding mechanism is rate-limiting.
3.3. Hierarchy 3.3. Hierarchy
Ephemeral-REQ-06: The ability to: Ephemeral-REQ-06: YANG MUST have the ability to:
1. to define a YANG module or submodule schema that only contains 1. to define a YANG module or submodule schema that only contains
data nodes with the property of being ephemeral, and data nodes with the property of being ephemeral, and
2. to augment a YANG data model with additional YANG schema nodes 2. to augment a YANG data model with additional YANG schema nodes
that have the property of being ephemeral. that have the property of being ephemeral.
3.4. Ephemeral Configuration overlapping Local Configuration 3.4. Ephemeral Configuration overlapping Local Configuration
Ephemeral-REQ-07: Ephemeral configuration state could override Ephemeral-REQ-07: Local configuration MUST have a priority that is
overlapping local configuration state, or vice-versa. comparable with individual I2RS client priorities for making changes.
Implementations MUST provide a mechanism to choose which takes This priority will determine whether local configuration changes or
precedence. This mechanism MUST include local configuration (policy) individual ephemeral configuration changes take precedence as
and MAY be provided via the I2RS protocol mechanisms. described in RFC7921. The I2RS protocol MUST support his 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 to 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 conceptual changes to NETCONF Ephemeral-REQ-09: The changes to NETCONF/RESTCONF 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
Ephemeral-REQ-10: The conceptual changes to RESTCONF are: Ephemeral-REQ-10: The conceptual changes to RESTCONF are:
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.
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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 data nodes MAY store I2RS client identity and Ephemeral-REQ-11: The I2RS Protocol (e.g. NETCONF/RESTCONF + yang)
not the effective priority at the time the data node is stored. Per MUST be able to support
SEC-REQ-07 in section 3.1 of
[I-D.ietf-i2rs-protocol-security-requirements], an identifier must o the data nodes MAY store I2RS client identity and not the
have just one priority. Therefore, the data nodes MAY store I2RS effective priority at the time the data node is stored.
client identity and not the effective priority of the I2RS client at
the time the data node is stored. The priority MAY be dynamically o Per SEC-REQ-07 in section 3.1 of
changed by AAA, but the exact actions are part of the protocol [I-D.ietf-i2rs-protocol-security-requirements], an identifier MUST
definition as long as collisions are handled as described in have just one priority. The I2RS protocol MUST support the
Ephemeral-REQ-12, Ephemeral-REQ-13, and Ephemeral-REQ-14. ability to have data nodes MAY store I2RS client identity and not
the effective priority of the I2RS client at the time the data
node is stored.
o The priority MAY be dynamically changed by AAA, but the exact
actions are part of the protocol definition as long as collisions
are handled as described in Ephemeral-REQ-12, Ephemeral-REQ-13,
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 Note:RESTCONF and NETCONF posts can come in concurrently from
alternative sources (see ETag in [I-D.ietf-netconf-restconf] section alternative sources (see ETag in [I-D.ietf-netconf-restconf] section
3.4.1.2 usage). Therefore the collision detection and comparison of 3.4.1.2 usage). Therefore the collision detection and comparison of
priority needs to occur both for both type of updates (POST or edit- priority needs to occur both for both type of updates (POST or edit-
config) at the point of comparison. config) at the point of comparison.
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 is not mandating how AAA supports tied to ephemeral state. I2RS protocol MUST NOT mandate how AAA
priority. Mechanisms which prevent collisions of two clients trying supports priority. Mechanisms which prevent collisions of two
to modify the same node of data are the focus. 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 [I-D.ietf-i2rs-architecture] Ephemeral-REQ-15: Section 7.9 of the [I-D.ietf-i2rs-architecture]
states the I2RS architecture does not include multi-message atomicity states the I2RS architecture does not include multi-message atomicity
and roll-back mechanisms. I2RS notes multiple operations in one or and roll-back mechanisms. The I2RS protocol implementation MUST not
more messages handling can handle errors within the set of operations require the support of these features. As part of this requirement,
in many ways. No multi-message commands SHOULD cause errors to be the I2SR protocol should support:
inserted into the I2RS ephemeral state.
multiple operations in one or more messages handling can handle
errors within the set of operations in many ways.
No multi-message commands SHOULD cause errors to be inserted into
the I2RS ephemeral state.
9. Pub/Sub Requirements Expanded for Ephemeral State 9. Pub/Sub Requirements Expanded for Ephemeral State
I2RS clients require the ability to monitor changes to ephemeral I2RS clients require the ability to monitor changes to ephemeral
state. While subscriptions are well defined for receiving state. While subscriptions are well defined for receiving
notifications, the need to create a notification set for all notifications, the need to create a notification set for all
ephemeral configuration state may be overly burdensome to the user. ephemeral configuration state may be overly burdensome to the user.
There is thus a need for a general subscription mechanism that can There is thus a need for a general subscription mechanism that can
provide notification of changed state, with sufficient information to provide notification of changed state, with sufficient information to
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environment-reqs-01 (work in progress), April 2016. environment-reqs-01 (work in progress), April 2016.
[I-D.ietf-i2rs-traceability] [I-D.ietf-i2rs-traceability]
Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to 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", draft-ietf-i2rs-traceability-11 (work Information Model", draft-ietf-i2rs-traceability-11 (work
in progress), May 2016. in progress), May 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-14 (work in Protocol", draft-ietf-netconf-restconf-15 (work in
progress), June 2016. progress), July 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>.
13.2. Informative References 13.2. Informative References
[I-D.hares-i2rs-protocol-strawman] [I-D.hares-i2rs-protocol-strawman]
Hares, S., Bierman, A., and a. amit.dass@ericsson.com, Hares, S. and a. amit.dass@ericsson.com, "I2RS protocol
"I2RS protocol strawman", draft-hares-i2rs-protocol- strawman", draft-hares-i2rs-protocol-strawman-03 (work in
strawman-02 (work in progress), May 2016. progress), July 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020, the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010, DOI 10.17487/RFC6020, October 2010,
<http://www.rfc-editor.org/info/rfc6020>. <http://www.rfc-editor.org/info/rfc6020>.
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