draft-ietf-i2rs-ephemeral-state-21.txt   draft-ietf-i2rs-ephemeral-state-22.txt 
I2RS working group J. Haas I2RS working group J. Haas
Internet-Draft Juniper Internet-Draft Juniper
Intended status: Informational S. Hares Intended status: Informational S. Hares
Expires: April 30, 2017 Huawei Expires: May 18, 2017 Huawei
October 27, 2016 November 14, 2016
I2RS Ephemeral State Requirements I2RS Ephemeral State Requirements
draft-ietf-i2rs-ephemeral-state-21.txt draft-ietf-i2rs-ephemeral-state-22.txt
Abstract Abstract
The I2RS (interface to the routing system) Architecture document The I2RS (interface to the routing system) Architecture document
(RFC7921) abstractly describes a number of requirements for ephemeral (RFC7921) abstractly describes a number of requirements for ephemeral
state (in terms of capabilities and behaviors) which any protocol state (in terms of capabilities and behaviors) which any protocol
suite attempting to meet the needs of I2RS has to provide. This suite attempting to meet the needs of I2RS has to provide. This
document describes, in detail, requirements for ephemeral state for document describes, in detail, requirements for ephemeral state for
those implementing the I2RS protocol. those implementing the I2RS protocol.
skipping to change at page 1, line 36 skipping to change at page 1, line 36
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 April 30, 2017. This Internet-Draft will expire on May 18, 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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
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. Architectural Requirements for Ephemeral State . . . . . . . 3
3. Ephemeral State Requirements . . . . . . . . . . . . . . . . 4 3. Ephemeral State Requirements . . . . . . . . . . . . . . . . 4
3.1. Persistence . . . . . . . . . . . . . . . . . . . . . . . 4 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 . 5 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 . . . . . . . . . . . . . . . . . . . . . . . 6 client Priority . . . . . . . . . . . . . . . . . . . . . . . 6
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
skipping to change at page 2, line 38 skipping to change at page 2, line 38
13.1. Normative References: . . . . . . . . . . . . . . . . . 10 13.1. Normative References: . . . . . . . . . . . . . . . . . 10
13.2. Informative References . . . . . . . . . . . . . . . . . 11 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 key implementing the I2RS, and defines ephemeral state as "state which
requirements related to ephemeral state. [RFC7921] defines ephemeral does not survive the reboot of a routing device or the reboot of the
state as "state which does not survive the reboot of a routing device software handling the I2RS software on a routing device" (see section
or the reboot of the software handling the I2RS software on a routing 1.1 of [RFC7921]). Section 2 describes the specific requirements
device" (see section 1.1 of [RFC7921]). which the I2RS Working group has identified based on the I2RS
architecture's abstract requirements.
The I2RS Working Group has chosen to use the YANG data modeling The I2RS Working Group has chosen to use the YANG data modeling
language [RFC7950] as the basis to implement its mechanisms. language [RFC7950] as the basis to implement its mechanisms.
Additionally, the I2RS Working group has chosen to re-use two Additionally, the I2RS Working group has chosen to re-use two
existing protocols, NETCONF [RFC6241] and its similar but lighter- existing protocols, NETCONF [RFC6241] and its similar but lighter-
weight relative RESTCONF [I-D.ietf-netconf-restconf], as the weight relative RESTCONF [I-D.ietf-netconf-restconf], as the
protocols for carrying I2RS. protocols for carrying I2RS.
What does re-use of a protocol mean? Re-use means that while YANG, What does re-use of a protocol mean? Re-use means that while the
NETCONF and RESTCONF are a good starting basis for the I2RS protocol, combination of the YANG modeling language, and the NETCONF and
the creation of the I2RS protocol implementations requires that the RESTCONF protocols is a good starting basis for the I2RS data
I2RS requirements modeling language and protocol, the creation of I2RS protocol
implementations requires that the I2RS requirements:
1. select features from YANG, NETCONF, and RESTCONF per version of 1. select features from the YANG modeling language, and the NETCONF
the I2RS protocol (See sections 4, 5, and 6) and RESTCONF protocols per version of the I2RS protocol (See
sections 4, 5, and 6)
2. propose additions to YANG, NETCONF, and RESTCONF per version of 2. propose additions to YANG, NETCONF, and RESTCONF per version of
the I2RS protocol for key functions (ephemeral state, protocol the I2RS protocol for key functions (ephemeral state, protocol
security, publication/subscription service, traceability), security, publication/subscription service, traceability),
The purpose of these requirements is to ensure clarity during I2RS The purpose of these requirements is to ensure clarity during I2RS
protocol creation. protocol creation.
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. Section 7 provided additional requirements that detail how groups. Section 7 provides 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 describes I2RS requirements for support of multiple data. Section 8 describes I2RS requirements for support of multiple
message transactions. Section 9 highlights two requirements in the message transactions. Section 9 highlights two requirements in the
I2RS publication/subscription requirements [RFC7923] that must be I2RS publication/subscription requirements [RFC7923] that must be
expanded for ephemeral state. 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].
2. Review of Requirements from I2RS architecture document 2. Architectural Requirements for Ephemeral State
The I2RS architecture defines important high-level requirements for The I2RS architecture [RFC7921] and the I2RS problem statement
the I2RS protocol. The following are requirements distilled from [RFC7920] define the important high-level requirements for the I2RS
[RFC7921] that provide context for the ephemeral data state protocol in abstract terms. This section distills this high level
requirements given in sections 3-8: abstract guidance into specific requirements for the I2RS protocol.
To aid the reader, there are references back to the abstract
descriptions in the I2RS architecture document and the I2RS problem
statement, but the reader should note the requirements below are not
explicitly stated in the I2RS architecture document [RFC7921] or in
the I2RS problem statement [RFC7920]/
Requirements:
1. The I2RS protocol SHOULD support an interface asynchronous 1. The I2RS protocol SHOULD support an asynchronous programmatic
programmatic interface interface with properties of described in interface with properties of described in section 5 of [RFC7920]
section 5 of [RFC7920] (e.g. high throughput) with support for (e.g. high throughput) with support for target information
target information streams, filtered evens, and thresholded streams, filtered events, and thresholded events (real-time
events (real-time events) sent by an I2RS agent to an I2RS Client events) sent by an I2RS agent to an I2RS client (from section 1.1
(Key points from section 1.1 of [RFC7921]). of [RFC7921]).
2. I2RS agent MUST record the client identity when a node is created 2. I2RS agent MUST record the client identity when a node is created
or modified. The I2RS agent SHOULD to be able to read the client or modified. The I2RS agent SHOULD to be able to read the client
identity of a node and use the client identity's associated identity of a node and use the client identity's associated
priority to resolve conflicts. The secondary identity is useful priority to resolve conflicts. The secondary identity is useful
for traceability and may also be recorded. (Key points from for traceability and may also be recorded. (from section 4 of
section 4 of [RFC7921].) [RFC7921].)
3. An I2RS Client identity MUST have only one priority for the 3. An I2RS client identity MUST have only one priority for the
client's identifier. A collision on writes is considered an client's identifier. A collision on writes is considered an
error, but the priority associated with each client identifier is error, but the priority associated with each client identifier is
utilized to compare requests from two different clients in order utilized to compare requests from two different clients in order
to modify an existing node entry. Only an entry from a client to modify an existing node entry. Only an entry from a client
which is higher priority can modify an existing entry (First which is higher priority can modify an existing entry (First
entry wins). Priority only has meaning at the time of use. (Key entry wins). Priority only has meaning at the time of use. (from
points from section 7.8 of [RFC7921].) section 7.8 of [RFC7921].)
4. I2RS Client's secondary identity data is read-only meta-data that 4. I2RS client's secondary identity data is read-only meta-data that
is recorded by the I2RS agent associated with a data model's node is recorded by the I2RS agent associated with a data model's node
is written. Just like the primary client identity, the secondary is written. Just like the primary client identity, the secondary
identity SHOULD only be recorded when the data node is written. identity SHOULD only be recorded when the data node is written.
(Key points from sections 7.4 of [RFC7921].) (from sections 7.4 of [RFC7921].)
5. I2RS agent MAY have a lower priority I2RS client attempting to 5. I2RS agent MAY have a lower priority I2RS client attempting to
modify a higher priority client's entry in a data model. The modify a higher priority client's entry in a data model. The
filtering out of lower priority clients attempting to write or filtering out of lower priority clients attempting to write or
modify a higher priority client's entry in a data model SHOULD be modify a higher priority client's entry in a data model SHOULD be
effectively handled and not put an undue strain on the I2RS effectively handled and not put an undue strain on the I2RS
agent. (See section 7.8 of [RFC7921] augmented by the resource agent. (See section 7.8 of [RFC7921] augmented by the resource
limitation language in section 8 [RFC7921].) limitation language in section 8 [RFC7921].)
3. Ephemeral State Requirements 3. Ephemeral State Requirements
skipping to change at page 6, line 32 skipping to change at page 6, line 43
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.
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 (see using the priority requirements defined in section 7 below (see
requirements Ephemeral-REQ-11 through Ephemeral-REQ-14). 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-11: The following requirements must be supported by the Ephemeral-REQ-11: The following requirements must be supported by the
I2RS protocol I2RS Protocol (e.g. NETCONF/RESTCONF + yang) in order I2RS protocol in order to support I2RS client identity and priority:
to support I2RS client identity and priority:
o the data nodes MAY store I2RS client identity and not the o the data nodes MUST store I2RS client identity and MAY store 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 4.3 of o Per SEC-REQ-07 in section 4.3 of
[I-D.ietf-i2rs-protocol-security-requirements], an I2RS Identifier [I-D.ietf-i2rs-protocol-security-requirements], an I2RS Identifier
MUST 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 I2RS clients are Ephemeral-REQ-12: When a collision occurs as two I2RS clients are
trying to write the same data node, this collision is considered an trying to write the same data node, this collision is considered an
error. The I2RS priorities are used to provide a deterministic error. The I2RS priorities are used to provide a deterministic
resolution to the conflict. When there is a collision, and the data resolution to the conflict. When there is a collision, and the data
node is changed, a notification (which includes indicating data node node is changed, a notification (which includes indicating data node
the collision occurred on) MUST BE sent to the original client to the collision occurred on) MUST be sent to the original client to
give the original client a chance to deal with the issues surrounding give the original client a chance to deal with the issues surrounding
the collision. The original client may need to fix their state. the collision. The original client may need to fix their state.
Explanation: RESTCONF and NETCONF updates can come in concurrently Explanation: RESTCONF and NETCONF updates can come in concurrently
from alternative sources. Therefore the collision detection and from alternative sources. Therefore the collision detection and
comparison of priority needs to occur for any type of update. comparison of priority needs to occur for any type of update.
For example, RESTCONF tracks the source of configuration change via 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 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 the server returns to the client along with the value in GET or HEAD
skipping to change at page 10, line 21 skipping to change at page 10, line 26
Related Requirements", draft-ietf-i2rs-protocol-security- Related Requirements", draft-ietf-i2rs-protocol-security-
requirements-17 (work in progress), September 2016. requirements-17 (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-17 (work in Protocol", draft-ietf-netconf-restconf-18 (work in
progress), September 2016. progress), October 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, [RFC6614] Winter, S., McCauley, M., Venaas, S., and K. Wierenga,
"Transport Layer Security (TLS) Encryption for RADIUS", "Transport Layer Security (TLS) Encryption for RADIUS",
RFC 6614, DOI 10.17487/RFC6614, May 2012, RFC 6614, DOI 10.17487/RFC6614, May 2012,
<http://www.rfc-editor.org/info/rfc6614>. <http://www.rfc-editor.org/info/rfc6614>.
skipping to change at page 11, line 16 skipping to change at page 11, line 26
for Subscription to YANG Datastores", RFC 7923, for Subscription to YANG Datastores", RFC 7923,
DOI 10.17487/RFC7923, June 2016, DOI 10.17487/RFC7923, June 2016,
<http://www.rfc-editor.org/info/rfc7923>. <http://www.rfc-editor.org/info/rfc7923>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016, RFC 7950, DOI 10.17487/RFC7950, August 2016,
<http://www.rfc-editor.org/info/rfc7950>. <http://www.rfc-editor.org/info/rfc7950>.
13.2. Informative References 13.2. Informative References
[I-D.hares-i2rs-protocol-strawman]
Hares, S. and a. amit.dass@ericsson.com, "I2RS protocol
strawman", draft-hares-i2rs-protocol-strawman-03 (work in
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>.
Authors' Addresses Authors' Addresses
Jeff Haas Jeff Haas
Juniper Juniper
 End of changes. 25 change blocks. 
50 lines changed or deleted 53 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/