draft-ietf-i2rs-ephemeral-state-10.txt   draft-ietf-i2rs-ephemeral-state-11.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: December 23, 2016 Huawei Expires: December 27, 2016 Huawei
June 21, 2016 June 25, 2016
I2RS Ephemeral State Requirements I2RS Ephemeral State Requirements
draft-ietf-i2rs-ephemeral-state-10 draft-ietf-i2rs-ephemeral-state-11
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 December 23, 2016. This Internet-Draft will expire on December 27, 2016.
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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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Review of Requirements from I2RS architecture document . . . 3 2. Review of Requirements from I2RS architecture document . . . 3
3. Ephemeral State Requirements . . . . . . . . . . . . . . . . 5 3. Ephemeral State Requirements . . . . . . . . . . . . . . . . 5
3.1. Persistence . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Persistence . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Constraints . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. Constraints . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . 5 3.3. Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . 5
3.4. Ephemeral Configuration overlapping Local Configuration . 6 3.4. Ephemeral Configuration overlapping Local Configuration . 6
4. YANG Features for Ephemeral State for I2RS Protocol version 1 6 4. YANG Features for Ephemeral State . . . . . . . . . . . . . . 6
5. NETCONF Features for Ephemeral State for I2RS Protocol 5. NETCONF Features for Ephemeral State . . . . . . . . . . . . 6
version 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6. RESTCONF Features for Ephemeral State . . . . . . . . . . . . 6
6. RESTCONF Features for Ephemeral State for I2RS Protocol
version 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7. Requirements regarding Supporting Multi-Head Control via 7. Requirements regarding Supporting Multi-Head Control via
Client Priority . . . . . . . . . . . . . . . . . . . . . . . 6 Client Priority . . . . . . . . . . . . . . . . . . . . . . . 6
8. Multiple Message Transactions . . . . . . . . . . . . . . . . 7 8. Multiple Message Transactions . . . . . . . . . . . . . . . . 7
9. Pub/Sub Requirements Expanded for Ephemeral State . . . . . . 7 9. Pub/Sub Requirements Expanded for Ephemeral State . . . . . . 7
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
11. Security Considerations . . . . . . . . . . . . . . . . . . . 8 11. Security Considerations . . . . . . . . . . . . . . . . . . . 8
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
13.1. Normative References: . . . . . . . . . . . . . . . . . 9 13.1. Normative References: . . . . . . . . . . . . . . . . . 9
13.2. Informative References . . . . . . . . . . . . . . . . . 10 13.2. Informative References . . . . . . . . . . . . . . . . . 10
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agent. agent.
10. The I2RS protocol MUST support the use of a secure transport. 10. The I2RS protocol MUST support the use of a secure transport.
However, certain functions such as notifications MAY use a non- However, certain functions such as notifications MAY use a non-
secure transport. Each model or service (notification, logging) secure transport. Each model or service (notification, logging)
must define within the model or service the valid uses of a non- must define within the model or service the valid uses of a non-
secure transport. secure transport.
3. Ephemeral State Requirements 3. Ephemeral State Requirements
In requirements Ephemeral-REQ-01 to Ephemeral-05, Ephemeral state is
defined as potentially including both ephemeral configured state and
operational state.
3.1. Persistence 3.1. Persistence
Ephemeral-REQ-01: I2RS requires ephemeral state; i.e. state that does Ephemeral-REQ-01: I2RS requires ephemeral state; i.e. state that does
not persist across reboots. Ephemeral state may consists of not persist across reboots. If state must be restored, it should be
ephemeral configured state and operational state. If state must be done solely by replay actions from the I2RS client via the I2RS
restored, it should be done solely by replay actions from the I2RS agent.
client via the I2RS agent.
While at first glance this may seem equivalent to the writable- While at first glance this may seem equivalent to the writable-
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 must be able to utilized temporary Ephemeral-REQ-03: Ephemeral state may have constraints that refer to
operational state (e.g. MPLS LSP-ID or a BGP IN-RIB) as a operational state, this includes potentially fast changing or short
constraints. lived operational state nodes, such as MPLS LSP-ID or a BGP IN-RIB.
Ephemeral-REQ-04: Ephemeral state MAY refer to non-ephemeral state Ephemeral-REQ-04: Ephemeral state MUST be able to refer to non-
for purposes of implementing constraints. ephemeral state as a constraint.
Ephemeral-REQ-05: 2RS 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.
Note: Ephemeral-REQ-05 is part of the yang-push and event
notification technology drafts being worked out in NETCONF WG. It is
included here to indicate that these features are necessary for
ephemeral state.
3.3. Hierarchy 3.3. Hierarchy
Ephemeral-REQ-06: The ability to augment an object with appropriate Ephemeral-REQ-06: The ability to augment Yang schema nodes with
YANG structures that have the property of being ephemeral. An object additional Yang Schema nodes that have the property of being
defined as any one of the following: yang module, submodule or ephemeral.
components of submodule, or schema node.
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: Ephemeral configuration state could override
overlapping local configuration state, or vice-versa. overlapping local configuration state, or vice-versa.
Implementations MUST provide a mechanism to choose which takes Implementations MUST provide a mechanism to choose which takes
precedence. This mechanism MUST include local configuration (policy) precedence. This mechanism MUST include local configuration (policy)
and MAY be provided via the I2RS protocol mechanisms. and MAY be provided via the I2RS protocol mechanisms.
4. YANG Features for Ephemeral State for I2RS Protocol version 1 4. YANG Features for Ephemeral State
Ephemeral-REQ-08: Yang MUST have a way to indicate in a data model Ephemeral-REQ-08: Yang MUST have a way to indicate in a data model
that nodes have the following properties: ephemeral, writable/not- that schema nodes have the following properties: ephemeral, writable/
writable, and status/configuration. not-writable, and status/configuration.
5. NETCONF Features for Ephemeral State for I2RS Protocol version 1 5. NETCONF Features for Ephemeral State
Ephemeral-REQ-09: The conceptual changes to NETCONF Ephemeral-REQ-09: The conceptual changes to NETCONF
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 for I2RS Protocol version 1 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.
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).
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Ephemeral-REQ-11: The data nodes MAY store I2RS client identity and Ephemeral-REQ-11: The data nodes MAY store I2RS client identity and
not the effective priority at the time the data node is stored. Per not the effective priority at the time the data node is stored. Per
SEC-REQ-07 in section 3.1 of SEC-REQ-07 in section 3.1 of
[I-D.ietf-i2rs-protocol-security-requirements], an identifier must [I-D.ietf-i2rs-protocol-security-requirements], an identifier must
have just one priority. Therefore, the data nodes MAY store I2RS have just one priority. Therefore, the data nodes MAY store I2RS
client identity and not the effective priority of the I2RS client at client identity and not the effective priority of the I2RS client at
the time the data node is stored. The priority MAY be dynamically the time the data node is stored. The priority MAY be dynamically
changed by AAA, but the exact actions are part of the protocol changed by AAA, but the exact actions are part of the protocol
definition as long as collisions are handled as described in definition as long as collisions are handled as described in
Ephemeral-REQ-10, Ephemeral-REQ-11, and Ephemeral-REQ-12. 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 MUST BE sent to the original there is a collision, a notification MUST BE sent to the original
client to give the original client a chance to deal with the issues client 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.
Ephemeral-REQ-13: The requirement to support multi-headed control is Ephemeral-REQ-13: The requirement to support multi-headed control is
required for collisions and the priority resolution of collisions. required for collisions and the priority resolution of collisions.
Multi-headed control is not tied to ephemeral state. I2RS is not Multi-headed control is not tied to ephemeral state. I2RS is not
mandating how AAA supports priority. Mechanisms which prevent mandating how AAA supports priority. Mechanisms which prevent
collisions of two clients trying the same node of data are the focus. collisions of two clients trying the same node of data are the focus.
Ephemeral-REQ-14: If two clients have the same priority, the Ephemeral-REQ-14: If two clients have the same priority, the
architecture says the first one wins. The I2RS protocol has this architecture says the first one wins. The I2RS protocol has this
requirement to prevent was the oscillation between clients. If one requirement to prevent oscillations between clients. If one uses the
uses the last wins scenario, you may oscillate. That was our last wins scenario, you may oscillate. That was our opinion, but a
opinion, but a design which prevents oscillation is the key point. design which prevents oscillation is the key point.
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. I2RS notes multiple operations in one or
more messages handling can handle errors within the set of operations more messages handling can handle errors within the set of operations
in many ways. No multi-message commands SHOULD cause errors to be in many ways. No multi-message commands SHOULD cause errors to be
inserted into the I2RS ephemeral data-store. inserted into the I2RS ephemeral data-store.
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