draft-ietf-i2rs-ephemeral-state-09.txt   draft-ietf-i2rs-ephemeral-state-10.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 2, 2016 Huawei Expires: December 23, 2016 Huawei
May 31, 2016 June 21, 2016
I2RS Ephemeral State Requirements I2RS Ephemeral State Requirements
draft-ietf-i2rs-ephemeral-state-09 draft-ietf-i2rs-ephemeral-state-10
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 2, 2016. This Internet-Draft will expire on December 23, 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
4. YANG Features for Ephemeral State for I2RS Protocol version 1 6 4. YANG Features for Ephemeral State for I2RS Protocol version 1 6
5. NETCONF Features for Ephemeral State for I2RS Protocol 5. NETCONF Features for Ephemeral State for I2RS Protocol
version 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 6 version 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. RESTCONF Features for Ephemeral State for I2RS Protocol 6. RESTCONF Features for Ephemeral State for I2RS Protocol
version 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 7 version 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7. Requirements regarding Supporting Multi-Head Control via 7. Requirements regarding Supporting Multi-Head Control via
Client Priority . . . . . . . . . . . . . . . . . . . . . . . 9 Client Priority . . . . . . . . . . . . . . . . . . . . . . . 6
8. Multiple Message Transactions . . . . . . . . . . . . . . . . 10 8. Multiple Message Transactions . . . . . . . . . . . . . . . . 7
9. Pub/Sub Requirements Expanded for Ephemeral State . . . . . . 10 9. Pub/Sub Requirements Expanded for Ephemeral State . . . . . . 7
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
11. Security Considerations . . . . . . . . . . . . . . . . . . . 11 11. Security Considerations . . . . . . . . . . . . . . . . . . . 8
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
13.1. Normative References: . . . . . . . . . . . . . . . . . 12 13.1. Normative References: . . . . . . . . . . . . . . . . . 9
13.2. Informative References . . . . . . . . . . . . . . . . . 13 13.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 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
reviews 10 key requirements related to ephemeral state. reviews 10 key requirements related to ephemeral state.
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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
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. If state must be restored, it should be not persist across reboots. Ephemeral state may consists of
done solely by replay actions from the I2RS client via the I2RS ephemeral configured state and operational state. If state must be
agent. Ephemeral state may consist of ephemeral configuration or restored, it should be done solely by replay actions from the I2RS
ephemeral operational state, or both. 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 must be able to utilized temporary
operational state (e.g. MPLS LSP-ID or a BGP IN-RIB) as a operational state (e.g. MPLS LSP-ID or a BGP IN-RIB) as a
constraints. constraints.
Ephemeral-REQ-04: Ephemeral state MAY refer to non-ephemeral state Ephemeral-REQ-04: Ephemeral state MAY refer to non-ephemeral state
for purposes of implementing constraints. The designer of ephemeral for purposes of implementing constraints.
state modules are advised that such constraints may impact the speed
of processing ephemeral state commits and should avoid them when
speed is essential.
Ephemeral-REQ-05: Ephemeral state handling and notifications could Ephemeral-REQ-05: 2RS pub-sub, logging, RPC or other mechanisms may
increase need for CPU processing, data flow rates across a transport, lead to undesirable or unsustainable resource consumption on a system
or the rate of publication of data in a subscription or the logging implementing an I2RS Agent. It is RECOMMENDED that mechanisms be
for traceability. The I2RS Agent SHOULD have the ability to made available to permit prioritization of I2RS operations, when
constraints for OAM functions operating to limit CPU processing, data appropriate, to permit implementations to shed work load when
rate across a transport, the rate of publication of data in a operating under constrained resources. An example of such a work
subscription, and logging rates; and the I2RS Agent SHOULD have the shedding mechanism is rate-limiting.
ability to prioritize some of the management data flows between the
I2RS Agent and I2RS Client. In order to constrain resources needed, Note: Ephemeral-REQ-05 is part of the yang-push and event
the I2RS Agent MAY also schedule data flows or split data flows unto notification technology drafts being worked out in NETCONF WG. It is
multiple data flow streams. 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 an object with appropriate
YANG structures that have the property of being ephemeral. An object YANG structures that have the property of being ephemeral. An object
defined as any one of the following: defined as any one of the following: yang module, submodule or
components of submodule, or schema node.
o Yang module(and the module's schema tree),
o submodule or components of a submodule (e.g. derived types,
groupings, data node, RPCs, actions, and notifications), or
o a schema node (container, leaf, leaf-list, choice, case, rpc, 3.4. Ephemeral Configuration overlapping Local Configuration
input, output, notifications, and anyxml).
See [I-D.hares-i2rs-protocol-strawman] for examples of yang syntax. Ephemeral-REQ-07: Ephemeral configuration state could override
overlapping local configuration state, or vice-versa.
Implementations MUST provide a mechanism to choose which takes
precedence. This mechanism MUST include local configuration (policy)
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 for I2RS Protocol version 1
Ephemeral-REQ-07: 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 nodes have the following properties: ephemeral, writable/not-
writable, and status/configuration. Yang must also have a way to writable, and status/configuration.
specify on a module or submodule level whether the data MAY
optionally flow across an non-secure transport.
5. NETCONF Features for Ephemeral State for I2RS Protocol version 1 5. NETCONF Features for Ephemeral State for I2RS Protocol version 1
Ephemeral-REQ-08: The conceptual changes to NETCONF Ephemeral-REQ-09: The conceptual changes to NETCONF
1. protocol version support for I2RS modifications - (e.g. I2RS
version 1)
2. support for ephemeral model scope indication - which indicates
whether a module is an ephemeral-only module or mixed ephemeral
config (ephemeral + config), mixed derived state (ephemeral and
opstate).
3. multiple message support - supports the I2RS "all or nothing"
concept ([I-D.ietf-i2rs-architecture] section 7.9) which is the
same as NETCONF "roll-back-on-error".
4. support for the following transports protocol supported: "TCP",
"SSH", "TLS", and non-secure transport (see
[I-D.ietf-i2rs-protocol-security-requirements] section 3.2 in
requirements SEC-REQ-09 and SEC-REQ-11 for details). NETCONF
should be able to expand the number of secure transport protocols
supported as I2RS may add additional transport protocols.
5. ability to restrict non-secure transport support to specific
portions of a data models marked as valid to transfer via
insecure protocol.
6. ephemeral state overwriting of configuration state MUST be
controlled by the following policy knobs (as defined by
[I-D.ietf-i2rs-architecture] section 6.3 and 6.3.1):
* ephemeral configuration overwrites local configuration (true/
false; normal value: true), and
* Update of local configuration value supersedes and overwrites
the ephemeral configuration (true/false; normal value: false).
7. The ephemeral overwriting to local configuration described in (6) 1. Support for communication mechanisms to enable an I2RS client to
above is considered to be the composite of all ephemeral values determine that an I2RS agent supports the mechanisms needed for
by all clients. Some may consider this approach as a single pane I2RS operation.
of glass for ephemeral state.
8. 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-10 through Ephemeral-REQ-13). requirements Ephemeral-REQ-11 through Ephemeral-REQ-14).
9. Ephemeral data stores SHOULD not require support interactions
with writable-running, candidate data store, confirmed commit,
and a distinct start-up capability,
This list of requirements require the following the following
existing features are supported:
support for the following encodings: XML or JSON.
support for the following transports protocol supported: "TCP",
"SSH", "TLS".
all of the following NETCONF protocol [RFC6241] specifications:
* yang pub-sub push [I-D.ietf-netconf-yang-push],
* yang module library [I-D.ietf-netconf-yang-library],
* call-home [I-D.ietf-netconf-call-home], and
* server model [I-D.ietf-netconf-server-model] with the server
module must be augmented to support mutual authentication (see
[I-D.ietf-i2rs-protocol-security-requirements] section 3.1 in
requirements: SEC-REQ-01 to SEC-REQ-08).
6. RESTCONF Features for Ephemeral State for I2RS Protocol version 1 6. RESTCONF Features for Ephemeral State for I2RS Protocol version 1
Ephemeral-REQ-09: The conceptual changes to RESTCONF are: Ephemeral-REQ-10: The conceptual changes to RESTCONF are:
1. protocol version support for I2RS protocol modification (e.g.
I2RS-version 1).
2. ephemeral model scope allowed - ephemeral modules, mixed config
module (ephemeral and config), mixed derived state (ephemeral and
opstate).
3. support for both of the following transport protocol suites:
* HTTP over TLS (secure HTTP as defined in RESTCONF
[I-D.ietf-netconf-restconf] section 2),
* HTTP used in a non-secure fashion (See
[I-D.ietf-i2rs-protocol-security-requirements], section 3.2,
requirements SEC-REQ-09 and SEC-REQ-11 for details), and
* RESTCONF SHOULD be able to expand the transports supported as
as future I2RS protocol versions may support other transports.
4. The ability to restrict insecure transports to specific portions
of a data model marked as valid to transfer via an insecure
protocol.
5. Support for the development of a RESTCONF based yang pub-sub push
based on the requirements in [I-D.ietf-i2rs-pub-sub-requirements]
and equivalent to the netconf . [I-D.ietf-netconf-yang-push]
6. ephemeral state overwriting of configuration state MUST be
controlled by the following policy knobs (as defined by
[I-D.ietf-i2rs-architecture] section 6.3 and 6.3.1)
* Ephemeral configuration overwrites local configuration (true/
false; normal value:true), and
* Update of local configuration value supersedes and overwrites
the ephemeral configuration (true/false; normal value:false).
7. The ephemeral state overwriting a local configuration described
above is considered to be the composite of all ephemeral state
values by all clients. Some may consider this a single "pane of
glass" for the ephemeral values.
8. RESTCONF support ephemeral state MUST support notification of
write conflicts using the priority requirements (see section 7
below, specifically requirements Ephemeral-REQ-10 through
Ephemeral-REQ-13). Expansion of existing "edit-collision"
features (timestamp and Entity tag) to include I2RS client-
priorities is preferred since I2RS client-Agents exchange MAY
wish to use the existing edit-collision features in RESTCONF.
9. Ephemeral data stores SHOULD not require support for interactions
with writeable-running, candidate data stores, confirmed commit,
and a distinct start-up capability.
This requirement also requires that RESTCONF support all of the
following specifications:
1. support for the following encodings: XML or JSON.
2. all of the following current RESTCONF specifications:
1. RESTCONF [I-D.ietf-netconf-restconf],
2. the yang-patch features as specified in
[I-D.ietf-netconf-yang-patch],
3. yang module library [I-D.ietf-netconf-yang-library] as
defined in RESTCONF [I-D.ietf-netconf-restconf] section
3.3.3),
4. call-home [I-D.ietf-netconf-call-home],
5. zero-touch [I-D.ietf-netconf-zerotouch], and 1. Support for communication mechanisms to enable an I2RS client to
determine that an I2RS agent supports the mechanisms needed for
I2RS operation.
6. server modules [I-D.ietf-netconf-server-model] (server module 2. The ephemeral state must support notification of write conflicts
must be augmented to support mutual authentication). using the priority requirements defined in section 7 below in
requirements Ephemeral-REQ-11 through Ephemeral-REQ-14).
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-10: 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-10, Ephemeral-REQ-11, and Ephemeral-REQ-12.
Ephemeral-REQ-11: 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-12: 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-13: 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 was the oscillation between clients. If one
uses the last wins scenario, you may oscillate. That was our uses the last wins scenario, you may oscillate. That was our
opinion, but a design which prevents oscillation is the key point. opinion, but a design which prevents oscillation is the key point.
8. Multiple Message Transactions 8. Multiple Message Transactions
Ephemeral-REQ-14: 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.
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
skipping to change at page 13, line 17 skipping to change at page 10, line 22
Library", draft-ietf-netconf-yang-library-06 (work in Library", draft-ietf-netconf-yang-library-06 (work in
progress), April 2016. progress), April 2016.
[I-D.ietf-netconf-yang-patch] [I-D.ietf-netconf-yang-patch]
Bierman, A., Bjorklund, M., and K. Watsen, "YANG Patch Bierman, A., Bjorklund, M., and K. Watsen, "YANG Patch
Media Type", draft-ietf-netconf-yang-patch-08 (work in Media Type", draft-ietf-netconf-yang-patch-08 (work in
progress), March 2016. progress), March 2016.
[I-D.ietf-netconf-yang-push] [I-D.ietf-netconf-yang-push]
Clemm, A., Prieto, A., Voit, E., Tripathy, A., and E. Clemm, A., Prieto, A., Voit, E., Tripathy, A., and E.
Einar, "Subscribing to YANG datastore push updates", Nilsen-Nygaard, "Subscribing to YANG datastore push
draft-ietf-netconf-yang-push-02 (work in progress), March updates", draft-ietf-netconf-yang-push-03 (work in
2016. progress), June 2016.
[I-D.ietf-netconf-zerotouch] [I-D.ietf-netconf-zerotouch]
Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning
for NETCONF or RESTCONF based Management", draft-ietf- for NETCONF or RESTCONF based Management", draft-ietf-
netconf-zerotouch-08 (work in progress), April 2016. netconf-zerotouch-08 (work in progress), April 2016.
[I-D.ietf-netmod-yang-metadata] [I-D.ietf-netmod-yang-metadata]
Lhotka, L., "Defining and Using Metadata with YANG", Lhotka, L., "Defining and Using Metadata with YANG",
draft-ietf-netmod-yang-metadata-07 (work in progress), draft-ietf-netmod-yang-metadata-07 (work in progress),
March 2016. March 2016.
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