Internet Working Group Y. Jiang, Ed. X. Liu Internet-Draft J. Xu Huawei Intended status: Standards Track R. Cummings, Ed. National Instruments Expires: May 2017 November 25, 2016 YANG Data Model for IEEE 1588v2 draft-ietf-tictoc-1588v2-yang-02 Abstract This document defines a YANG data model for the configuration of IEEE 1588-2008 devices and clocks, and also retrieval of the configuration information, data set and running states of IEEE 1588-2008 clocks. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on May 25, 2017. Copyright Notice Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. Jiang, et al Expires May 25, 2017 [Page 1] Internet-Draft 1588v2 YANG Model November 2016 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction .............................................. 2 1.1. Conventions used in this document ...................... 4 1.2. Terminology ............................................ 4 2. IEEE 1588-2008 YANG Model hierarchy ....................... 5 2.1. Interpretations from IEEE 1588 Working Group ........... 8 3. IEEE 1588-2008 YANG Module ................................ 9 4. Security Considerations .................................. 21 5. IANA Considerations ...................................... 22 6. References ............................................... 22 6.1. Normative References .................................. 22 6.2. Informative References ................................ 22 7. Acknowledgments .......................................... 23 Appendix A Transferring YANG Work to IEEE 1588 WG (Informational) ................................................................. 23 A.1. Assumptions for the Transfer .......................... 24 A.2. Intellectual Property Considerations .................. 25 A.3. Namespace and Module Name ............................. 25 A.4. IEEE 1588 YANG Modules in ASCII Format ................ 26 1. Introduction As a synchronization protocol, IEEE 1588-2008 (also known as IEEE 1588v2) [IEEE1588] is widely supported in the carrier networks, industrial networks, automotive networks, and many other applications. It can provide high precision time synchronization as fine as nano-seconds. The protocol depends on a Precision Time Protocol (PTP) engine to decide its own state automatically, and a PTP transportation layer to carry the PTP timing and various quality messages. The configuration parameters and state data sets of IEEE 1588-2008 are numerous. According to the concepts described in [RFC3444], IEEE 1588-2008 itself provides an information model in its normative Jiang, et al Expires May 25, 2017 [Page 2] Internet-Draft 1588v2 YANG Model November 2016 specifications for the data sets (in IEEE 1588-2008 clause 8). Some standardization organizations including the IETF have specified data models in MIBs (Management Information Bases) for IEEE 1588- 2008 data sets (e.g. [PTP-MIB], [IEEE8021AS]). These MIBs are typically focused on retrieval of state data using the Simple Network Management Protocol (SNMP), while configuration of PTP data sets is not considered. Some service providers and applications require that the management of the IEEE 1588-2008 synchronization network be flexible and more Internet-based (typically overlaid on their transport networks). Software Defined Network (SDN) is another driving factor, which demands an improved configuration capability of synchronization networks. YANG [RFC6020] is a data modeling language used to model configuration and state data manipulated by network management protocols like the Network Configuration Protocol (NETCONF) [RFC6241]. A small set of built-in data types are defined in [RFC6020], and a collection of common data types are further defined in [RFC6991]. Advantages of YANG include Internet based configuration capability, validation, rollback and so on. All of these characteristics make it attractive to become another candidate modeling language for IEEE 1588-2008. This document defines a YANG [RFC6020] data model for the configuration of IEEE 1588-2008 devices and clocks, and retrieval of the state data of IEEE 1588-2008 clocks. The data model is based on the PTP data sets as specified in [IEEE1588]. The technology specific IEEE 1588-2008 information, e.g., those specifically implemented by a bridge, a router or a telecom profile, is out of scope of this document. When used in practice, network products in support of synchronization typically conform to one or more IEEE 1588-2008 profiles. Each profile specifies how IEEE 1588-2008 is used in a given industry (e.g. telecom, automotive) and application. A profile can require features that are optional in IEEE 1588-2008, and it can specify new features that use IEEE 1588-2008 as a foundation. It is expected that the IEEE 1588-2008 YANG module will be used as follows: o The IEEE 1588-2008 YANG module can be used as-is for products that conform to one of the default profiles specified in IEEE 1588- 2008. Jiang, et al Expires May 25, 2017 [Page 3] Internet-Draft 1588v2 YANG Model November 2016 o When the IEEE 1588 standard is revised (e.g. the IEEE 1588 revision in progress scheduled to be published in 2017), it will add some new optional features to its data sets. The YANG module of this document can be revised and extended to add the new features (e.g. of IEEE 1588-2017). The YANG "revision" can be used to indicate changes to the YANG module. o A profile standard based on IEEE 1588-2008 may create a dedicated YANG module for its profile. The profile's YANG module may use YANG "import" to import the IEEE 1588-2008 YANG module as its foundation. Then the profile's YANG module can use YANG "augment" to add any profile-specific enhancements. o A product that conforms to a profile standard can also create its own YANG module. The product's YANG module can "import" the profile's module, and then use YANG "augment" to add any product- specific enhancements. 1.1. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 1.2. Terminology Most terminologies used in this document are extracted from [IEEE1588]. BC Boundary Clock DS Data Set E2E End-to-End EUI Extended Unique Identifier. GPS Global Positioning System IANA Internet Assigned Numbers Authority IP Internet Protocol NIST National Institute of Standards and Technology NTP Network Time Protocol Jiang, et al Expires May 25, 2017 [Page 4] Internet-Draft 1588v2 YANG Model November 2016 OC Ordinary Clock P2P Peer-to-Peer PTP Precision Time Protocol TAI International Atomic Time TC Transparent Clock UTC Coordinated Universal Time 2. IEEE 1588-2008 YANG Model hierarchy This section describes the hierarchy of an IEEE 1588-2008 YANG module. Query and configuration of device wide or port specific configuration information and clock data set is described for this version. Query and configuration of clock information include: - Clock data set attributes in a clock node, including: current-ds, parent-ds, default-ds, time-properties-ds, and transparent-clock- default-ds. - Port-specific data set attributes, including: port-ds and transparent-clock-port-ds. The readers are assumed to be familiar with IEEE 1588-2008. As all PTP terminologies and PTP data set attributes are described in details in IEEE 1588-2008 [IEEE1588], this document only outlines each of them in the YANG module. A simplified graphical representation of the data model is typically used by YANG modules as described in [REST-CONF]. This document uses the same representation and the meaning of the symbols in these diagrams is as follows: o Brackets "[" and "]" enclose list keys. o Abbreviations before data node names: "rw" means configuration data (read-write) and "ro" state data (read-only). o Symbols after data node names: "?" means an optional node, "!" means a presence container, and "*" denotes a list and leaf-list. Jiang, et al Expires May 25, 2017 [Page 5] Internet-Draft 1588v2 YANG Model November 2016 o Parentheses enclose choice and case nodes, and case nodes are also marked with a colon (":"). o Ellipsis ("...") stands for contents of subtrees that are not shown. o Arrow ("->") stands for a reference to a particular leaf instance in the tree. module: ietf-ptp-dataset +--rw instance-list* [instance-number] | +--rw instance-number uint8 | +--rw default-ds | | +--rw two-step-flag? boolean | | +--rw clock-identity? binary | | +--rw number-ports? uint16 | | +--rw clock-quality | | | +--rw clock-class? uint8 | | | +--rw clock-accuracy? uint8 | | | +--rw offset-scaled-log-variance? uint16 | | +--rw priority1? uint8 | | +--rw priority2? uint8 | | +--rw domain-number uint8 | | +--rw slave-only? boolean | +--rw current-ds | | +--rw steps-removed? uint16 | | +--rw offset-from-master? binary | | +--rw mean-path-delay? binary | +--rw parent-ds | | +--rw parent-port-identity | | | +--rw clock-identity? binary | | | +--rw port-number? uint16 | | +--rw parent-stats? boolean | | +--rw observed-parent-offset-scaled-log-variance? uint16 | | +--rw observed-parent-clock-phase-change-rate? int32 | | +--rw grandmaster-identity? binary | | +--rw grandmaster-clock-quality | | | +--rw grandmaster-clock-class? uint8 | | | +--rw grandmaster-clock-accuracy? uint8 | | | +--rw grandmaster-offset-scaled-log-variance? uint16 | | +--rw grandmaster-priority1? uint8 | | +--rw grandmaster-priority2? uint8 | +--rw time-properties-ds | | +--rw current-utc-offset-valid? boolean | | +--rw current-utc-offset? uint16 Jiang, et al Expires May 25, 2017 [Page 6] Internet-Draft 1588v2 YANG Model November 2016 | | +--rw leap59? boolean | | +--rw leap61? boolean | | +--rw time-traceable? boolean | | +--rw frequency-traceable? boolean | | +--rw ptp-timescale? boolean | | +--rw time-source? uint8 | +--rw port-ds-list* [port-number] | +--rw port-number -> ../port-identity/port-number | +--rw port-identity | | +--rw clock-identity? binary | | +--rw port-number? uint16 | +--rw port-state? uint8 | +--rw log-min-delay-req-interval? int8 | +--rw peer-mean-path-delay? int64 | +--rw log-announce-interval? int8 | +--rw announce-receipt-timeout? uint8 | +--rw log-sync-interval? int8 | +--rw delay-mechanism? enumeration | +--rw log-min-pdelay-req-interval? int8 | +--rw version-number? uint8 +--rw transparent-clock-default-ds | +--rw clock-identity? binary | +--rw number-ports? uint16 | +--rw delay-mechanism? enumeration | +--rw primary-domain? uint8 +--rw transparent-clock-port-ds-list* [port-number] +--rw port-number -> ../port-identity/port-number +--rw port-identity | +--rw clock-identity? binary | +--rw port-number? uint16 +--rw log-min-pdelay-req-interval? int8 +--rw faulty-flag? boolean +--rw peer-mean-path-delay? int64 Jiang, et al Expires May 25, 2017 [Page 7] Internet-Draft 1588v2 YANG Model November 2016 2.1. Interpretations from IEEE 1588 Working Group The preceding model and the associated YANG module have some subtle differences from the data set specifications of IEEE Std 1588-2008. These differences are based on interpretation from the IEEE 1588 Working Group, and are intended to provide compatibility with future revisions of the IEEE 1588 standard. In IEEE Std 1588-2008, a physical product can implement multiple PTP clocks (i.e. ordinary, boundary, or transparent clock). As specified in 1588-2008 subclause 7.1, each of the multiple clocks operates in an independent domain. However, the organization of multiple PTP domains was not clear in the data sets of IEEE Std 1588-2008. This document introduces the concept of PTP instance as described in the new revision of IEEE 1588. The instance concept is used exclusively to allow for optional support of multiple domains. The instance number has no usage within PTP messages. Based on statements in IEEE 1588-2008 subclauses 8.3.1. and 10.1, most transparent clock products have interpreted the transparent clock data sets to reside as a singleton at the root level of the managed product. Since 1588-2008 transparent clocks are domain independent, the instance concept is not applicable for domains. Jiang, et al Expires May 25, 2017 [Page 8] Internet-Draft 1588v2 YANG Model November 2016 3. IEEE 1588-2008 YANG Module file "ietf-ptp-dataset@2016-11-25.yang" module ietf-ptp-dataset{ namespace "urn:ietf:params:xml:ns:yang:ietf-ptp-dataset"; prefix "ptp-dataset"; organization "IETF TICTOC Working Group"; contact "WG Web: http://tools.ietf.org/wg/tictoc/ WG List: WG Chair: Karen O'Donoghue WG Chair: Yaakov Stein Editor: Yuanlong Jiang Editor: Rodney Cummings "; description "This YANG module defines a data model for the configuration of IEEE 1588-2008 clocks, and also for retrieval of the state data of IEEE 1588-2008 clocks."; revision "2016-11-25" { description "Version 2.0"; reference "draft-ietf-tictoc-1588v2-yang"; } grouping default-ds-entry { description "Collection of members of the default data set."; leaf two-step-flag { type boolean; description "When set, the clock is a two-step clock; otherwise, the clock is a one-step clock."; } leaf clock-identity { type binary { length "8"; } description "The clockIdentity of the local clock"; } Jiang, et al Expires May 25, 2017 [Page 9] Internet-Draft 1588v2 YANG Model November 2016 leaf number-ports { type uint16; description "The number of PTP ports on the device."; } container clock-quality { description "The clockQuality of the local clock. It contains clockClass, clockAccuracy and offsetScaledLogVariance."; leaf clock-class { type uint8; default 248; description "The clockClass denotes the traceability of the time or frequency distributed by the grandmaster clock."; } leaf clock-accuracy { type uint8; description "The clockAccuracy indicates the expected accuracy of a clock when it is the grandmaster."; } leaf offset-scaled-log-variance { type uint16; description "An estimate of the variations of the local clock from a linear timescale when it is not synchronized to another clock using the protocol."; } } leaf priority1 { type uint8; description "The priority1 attribute of the local clock."; } leaf priority2{ type uint8; description "The priority2 attribute of the local clock. "; } leaf domain-number { type uint8; description Jiang, et al Expires May 25, 2017 [Page 10] Internet-Draft 1588v2 YANG Model November 2016 "The domain number of the current syntonization domain."; } leaf slave-only { type boolean; description "When set, the clock is a slave-only clock."; } } grouping current-ds-entry { description "Collection of members of current data set."; leaf steps-removed { type uint16; default 0; description "The number of communication paths traversed between the local clock and the grandmaster clock."; } leaf offset-from-master { type binary { length "1..255"; } description "An implementation-specific representation of the current value of the time difference between a master and a slave clock as computed by the slave."; } leaf mean-path-delay { type binary { length "1..255"; } description "An implementation-specific representation of the current value of the mean propagation time between a master and a slave clock as computed by the slave."; } } grouping parent-ds-entry { description "Collection of members of the parent data set."; Jiang, et al Expires May 25, 2017 [Page 11] Internet-Draft 1588v2 YANG Model November 2016 container parent-port-identity { description "The portIdentity of the port on the master, which contains two members: clockIdentity and portNumber."; leaf clock-identity { type binary { length "8"; } description "The clockIdentity of the master clock."; } leaf port-number { type uint16; description "The portNumber for the port on the specific master."; } } leaf parent-stats { type boolean; default false; description "When set, the values of observedParentOffsetScaledLogVariance and observedParentClockPhaseChangeRate of parentDS have been measured and are valid."; } leaf observed-parent-offset-scaled-log-variance { type uint16; default 0xFFFF; description "An estimate of the parent clock's PTP variance as observed by the slave clock."; } leaf observed-parent-clock-phase-change-rate { type int32; description "An estimate of the parent clock's phase change rate as observed by the slave clock."; } leaf grandmaster-identity { type binary{ length "8"; } Jiang, et al Expires May 25, 2017 [Page 12] Internet-Draft 1588v2 YANG Model November 2016 description "The clockIdentity attribute of the grandmaster clock."; } container grandmaster-clock-quality { description "The clockQuality of the grandmaster clock. It contains clockClass, clockAccuracy and offsetScaledLogVariance."; leaf grandmaster-clock-class { type uint8; default 248; description "The clockClass attribute of the grandmaster clock."; } leaf grandmaster-clock-accuracy { type uint8; description "The clockAccuracy attribute of the grandmaster clock."; } leaf grandmaster-offset-scaled-log-variance { type uint16; description "The offsetScaledLogVariance of the grandmaster clock."; } } leaf grandmaster-priority1 { type uint8; description "The priority1 attribute of the grandmaster clock."; } leaf grandmaster-priority2 { type uint8; description "The priority2 attribute of the grandmaster clock."; } } grouping time-properties-ds-entry { description "Collection of members of the timeProperties data set."; Jiang, et al Expires May 25, 2017 [Page 13] Internet-Draft 1588v2 YANG Model November 2016 leaf current-utc-offset-valid { type boolean; description "When set, the current UTC offset is valid."; } leaf current-utc-offset { type uint16; description "The offset between TAI and UTC when the epoch of the PTP system is the PTP epoch, otherwise the value has no meaning."; } leaf leap59 { type boolean; description "When set, the last minute of the current UTC day contains 59 seconds."; } leaf leap61 { type boolean; description "When set, the last minute of the current UTC day contains 61 seconds."; } leaf time-traceable { type boolean; description "When set, the timescale and the currentUtcOffset are traceable to a primary reference."; } leaf frequency-traceable { type boolean; description "When set, the frequency determining the timescale is traceable to a primary reference."; } leaf ptp-timescale { type boolean; description "When set, the clock timescale of the grandmaster clock is PTP; otherwise the timescale is ARB (arbitrary)."; } leaf time-source { type uint8; description Jiang, et al Expires May 25, 2017 [Page 14] Internet-Draft 1588v2 YANG Model November 2016 "The source of time used by the grandmaster clock."; } } grouping port-ds-entry { description "Collection of members of the port data set."; container port-identity { description "The PortIdentity attribute of the local port. It contains two members: clockIdentity and portNumber."; leaf clock-identity { type binary { length "8"; } description "The clockIdentity of the local clock."; } leaf port-number { type uint16; description "The portNumber for a port on the local clock."; } } leaf port-state { type uint8; default 1; description "Current state associated with the port."; } leaf log-min-delay-req-interval { type int8; description "The base-two logarithm of the minDelayReqInterval (the minimum permitted mean time interval between successive Delay_Req messages)."; } leaf peer-mean-path-delay { Jiang, et al Expires May 25, 2017 [Page 15] Internet-Draft 1588v2 YANG Model November 2016 type int64; default 0; description "An estimate of the current one-way propagation delay on the link when the delayMechanism is P2P, otherwise it is zero."; } leaf log-announce-interval { type int8; description "The base-two logarithm of the mean announceInterval (mean time interval between successive Announce messages)."; } leaf announce-receipt-timeout { type uint8; description "The number of announceInterval that have to pass without receipt of an Announce message before the occurrence of the event ANNOUNCE_RECEIPT_TIMEOUT_ EXPIRES."; } leaf log-sync-interval { type int8; description "The base-two logarithm of the mean SyncInterval for multicast messages. The rates for unicast transmissions are negotiated separately on a per port basis and are not constrained by this attribute."; } leaf delay-mechanism { type enumeration { enum E2E { value 01; description "The port uses the delay request-response mechanism."; } enum P2P { value 02; description "The port uses the peer delay mechanism."; } Jiang, et al Expires May 25, 2017 [Page 16] Internet-Draft 1588v2 YANG Model November 2016 enum DISABLED { value 254; description "The port does not implement any delay mechanism."; } } description "The propagation delay measuring option used by the port in computing meanPathDelay."; } leaf log-min-pdelay-req-interval { type int8; description "The base-two logarithm of the minPdelayReqInterval (minimum permitted mean time interval between successive Pdelay_Req messages)."; } leaf version-number { type uint8; description "The PTP version in use on the port."; } } grouping transparent-clock-default-ds-entry { description "Collection of members of the transparentClockDefault data set (default data set for a transparent clock)."; leaf clock-identity { type binary { length "8"; } description "The clockIdentity of the transparent clock."; } leaf number-ports { type uint16; description "The number of PTP ports on the device."; } leaf delay-mechanism { type enumeration { Jiang, et al Expires May 25, 2017 [Page 17] Internet-Draft 1588v2 YANG Model November 2016 enum E2E { value 1; description "The port uses the delay request-response mechanism."; } enum P2P { value 2; description "The port uses the peer delay mechanism."; } enum DISABLED { value 254; description "The port does not implement any delay mechanism."; } } description "The propagation delay measuring option used by the transparent clock."; } leaf primary-domain { type uint8; default 0; description "The domainNumber of the primary syntonization domain."; } } grouping transparent-clock-port-ds-entry { description "Collection of members of the transparentClockPort data set (port data set for a transparent clock)."; container port-identity { description "This object specifies the portIdentity of the local port."; leaf clock-identity { type binary { length "8"; } description "The clockIdentity of the transparent clock."; Jiang, et al Expires May 25, 2017 [Page 18] Internet-Draft 1588v2 YANG Model November 2016 } leaf port-number { type uint16; description "The portNumber for a port on the transparent clock."; } } leaf log-min-pdelay-req-interval { type int8; description "The logarithm to the base 2 of the minPdelayReqInterval (minimum permitted mean time interval between successive Pdelay_Req messages)."; } leaf faulty-flag { type boolean; default false; description " When set, the port is faulty."; } leaf peer-mean-path-delay { type int64; default 0; description "An estimate of the current one-way propagation delay on the link when the delayMechanism is P2P, otherwise it is zero."; } } list instance-list { key "instance-number"; description "List of one or more PTP datasets in the device, one for each domain-number (see IEEE 1588-2008 subclause 6.3)"; leaf instance-number { type uint8; description "The instance number of the current PTP instance"; } container default-ds { Jiang, et al Expires May 25, 2017 [Page 19] Internet-Draft 1588v2 YANG Model November 2016 description "The default data set of the clock."; uses default-ds-entry; } container current-ds { description "The current data set of the clock."; uses current-ds-entry; } container parent-ds { description "The parent data set of the clock."; uses parent-ds-entry; } container time-properties-ds { description "The timeProperties data set of the clock."; uses time-properties-ds-entry; } list port-ds-list { key "port-number"; description "List of port data sets of the clock."; leaf port-number{ type leafref{ path "../port-identity/port-number"; } description "Refers to the portNumber memer of portDS.portIdentity."; } uses port-ds-entry; } } container transparent-clock-default-ds { description "The members of the transparentClockDefault Data Set"; uses transparent-clock-default-ds-entry; } list transparent-clock-port-ds-list { Jiang, et al Expires May 25, 2017 [Page 20] Internet-Draft 1588v2 YANG Model November 2016 key "port-number"; description "List of transparentClockPort data sets of the transparent clock."; leaf port-number { type leafref { path "../port-identity/port-number"; } description "Refers to the portNumber memer of transparentClockPortDS.portIdentity."; } uses transparent-clock-port-ds-entry; } } 4. Security Considerations YANG modules are designed to be accessed via the NETCONF protocol [RFC6241], thus security considerations in [RFC6241] apply here. Security measures such as using the NETCONF over SSH [RFC6242] and restricting its use with access control [RFC6536] can further improve its security, avoid injection attacks and misuse of the protocol. Some data nodes defined in this YANG module are writable, and any changes to them may adversely impact a synchronization network. Jiang, et al Expires May 25, 2017 [Page 21] Internet-Draft 1588v2 YANG Model November 2016 5. IANA Considerations This document registers a URI in the IETF XML registry, and the following registration is requested to be made: URI: urn:ietf:params:xml:ns:yang:ietf-ptp-dataset This document registers a YANG module in the YANG Module Names: name: ietf-ptp-dataset namespace: urn:ietf:params:xml:ns:yang:ietf- ptp-dataset 6. References 6.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF) ", RFC 6020, October 2010 [RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991, July 2013 [IEEE1588] IEEE, "IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems", IEEE Std 1588-2008, July 2008 6.2. Informative References [IEEE8021AS] IEEE, "Timing and Synchronizations for Time-Sensitive Applications in Bridged Local Area Networks", IEEE 802.1AS-2001, 2011 [PTP-MIB] Shankarkumar, V., Montini, L., Frost, T., and Dowd, G., "Precision Time Protocol Version 2 (PTPv2) Management Information Base", draft-ietf-tictoc-ptp-mib-11, Work in progress [REST-CONF] Bierman, A., Bjorklund, M., and Watsen, K., "RESTCONF protocol", draft-ietf-netconf-restconf-18, Work in progress [RFC3444] Pras, A. and J. Schoenwaelder, "On the Difference between Information Models and Data Models", RFC 3444, January 2003 Jiang, et al Expires May 25, 2017 [Page 22] Internet-Draft 1588v2 YANG Model November 2016 [RFC4663] Harrington, D., "Transferring MIB Work from IETF Bridge MIB WG to IEEE 802.1 WG", RFC 4663, September 2006 [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, June 2011 [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, March 2012 7. Acknowledgments The authors would like to thank Joe Gwinn, Mahesh Jethanandani and Tal Mizrahi for their valuable reviews and suggestions. Appendix A Transferring YANG Work to IEEE 1588 WG (Informational) This appendix describes a future plan to transition responsibility for IEEE 1588 YANG modules from the IETF TICTOC Working Group (WG) to the IEEE 1588 WG, which develops the time synchronization technology that the YANG modules are designed to manage. This appendix is forward-looking with regard to future standardization roadmaps in IETF and IEEE. Since those roadmaps cannot be predicted with significant accuracy, this appendix is informational, and it does not specify imperatives or normative specifications of any kind. The IEEE 1588-2008 YANG module of this standard represents a cooperation between IETF (for YANG) and IEEE (for 1588). For the initial standardization of IEEE-1588 YANG modules, the information model is relatively clear (i.e. IEEE 1588 data sets), but expertise in YANG is required, making IETF an appropriate location for the standards. The TICTOC WG has expertise with IEEE 1588, making it the appropriate location within IETF. The IEEE 1588 WG anticipates future changes to its standard on an ongoing basis. As IEEE 1588 WG members gain practical expertise with YANG, the IEEE 1588 WG will become more appropriate for standardization of its YANG modules. As the IEEE 1588 standard is Jiang, et al Expires May 25, 2017 [Page 23] Internet-Draft 1588v2 YANG Model November 2016 revised and/or amended, IEEE 1588 members can more effectively synchronize the revision of this YANG module with future versions of the IEEE 1588 standard. This appendix is meant to establish some clear expectations between IETF and IEEE about the future transfer of IEEE 1588 YANG modules to the IEEE 1588 WG. The goal is to assist in making the future transfer as smooth as possible. As the transfer takes place, some case-by-case situations are likely to arise, which can be handled by discussion on the IETF TICTOC WG mailing lists and/or appropriate liaisons. This appendix obtained insight from [RFC4663], an informational memo that described a similar transfer of MIB work from the IETF Bridge MIB WG to the IEEE 802.1 WG. A.1. Assumptions for the Transfer For the purposes of discussion in this appendix, assume that the IETF TICTOC WG has approved a standard YANG module for a published IEEE 1588 standard. As of this writing, this is IEEE Std 1588-2008, but it is possible that YANG for subsequent 1588 revisions could be published from the IETF TICTOC WG. For discussion in this appendix, we use the phrase "last IETF 1588 YANG" to refer to most recently published 1588 YANG from the IETF TICTOC WG. The IEEE-SA Standards Board New Standards Committee (NesCom) handles new Project Authorization Requests (PARs) (see http://standards.ieee.org/board/nes/). PARs are roughly the equivalent of IETF Working Group Charters and include information concerning the scope, purpose, and justification for standardization projects. Assume that IEEE 1588 has an approved PAR that explicitly specifies development of a YANG module. The transfer of YANG work will occur in the context of this IEEE 1588 PAR. For discussion in this appendix, we use the phrase "first IEEE 1588 YANG" to refer to the first IEEE 1588 standard for YANG. Assume that as part of the transfer of YANG work, the IETF TICTOC WG agrees to cease all work on standard YANG modules for IEEE 1588. Assume that the IEEE 1588 WG has participated in the development of the last IETF 1588 YANG module, such that the first IEEE 1588 YANG module will effectively be a revision of it. In other words, the transfer of YANG work will be relatively clean. Jiang, et al Expires May 25, 2017 [Page 24] Internet-Draft 1588v2 YANG Model November 2016 The actual conditions for the future transfer can be such that the preceding assumptions do not hold. Exceptions to the assumptions will need to be addressed on a case-by-case basis at the time of the transfer. This appendix describes topics that can be addressed based on the preceding assumptions. A.2. Intellectual Property Considerations During review of the legal issues associated with transferring Bridge MIB WG documents to the IEEE 802.1 WG (Section 3.1 and Section 9 of [RFC4663]), it was concluded that the IETF does not have sufficient legal authority to make the transfer to IEEE without the consent of the document authors. If the last IETF 1588 YANG is published as a RFC, the work is required to be transferred from the IETF to the IEEE, so that IEEE 1588 WG can begin working on the first IEEE 1588 YANG. When work on the first IEEE YANG module begins in the IEEE 1588 WG, that work derives from the last IETF YANG module of this RFC, requiring a transfer of that work from the IETF to the IEEE. In order to avoid having the transfer of that work be dependent on the availability of this RFC's authors at the time of its publication, the IEEE Standards Association department of Risk Management and Licensing provided the appropriate forms and mechanisms for this document's authors to assign a non-exclusive license for IEEE to create derivative works from this document. Those IEEE forms and mechanisms will be updated as needed during the development of this document and any future IETF YANG modules for IEEE 1588. This will help to make the future transfer of work from IETF to IEEE occur as smoothly as possible. As stated in the initial "Status of this Memo", the YANG module in this document conforms to the provisions of BCP 78. The IETF will retain all the rights granted at the time of publication in the published RFCs. A.3. Namespace and Module Name As specified in the "IANA Considerations" section, the YANG module in this document uses IETF as the root of its URN namespace and YANG module name. Use of IETF as the root of these names implies that the YANG module is standardized in a Working Group of IETF, using the IETF Jiang, et al Expires May 25, 2017 [Page 25] Internet-Draft 1588v2 YANG Model November 2016 processes. If the IEEE 1588 Working Group were to continue using these names rooted in IETF, the IEEE 1588 YANG standardization would need to continue in the IETF. The goal of transferring the YANG work is to avoid this sort of dependency between standards organizations. IEEE 802 has an active PAR (IEEE P802d) for creating a URN namespace for IEEE use (see http://standards.ieee.org/develop/project/802d.html). It is likely that this IEEE 802 PAR will be approved and published prior to the transfer of YANG work to the IEEE 1588 WG. If so, the IEEE 1588 WG can use the IEEE URN namespace for the first IEEE 1588 YANG module, such as: urn:ieee:Std:1588:yang:ieee1588-ptp-dataset where "ieee1588-ptp-dataset" is the registered YANG module name in the IEEE. Under the assumptions of section A.1, the first IEEE 1588 YANG module prefix can be the same as the last IETF 1588 YANG module prefix (i.e. "ptp-dataset"), since the nodes within both YANG modules are compatible. The result of these name changes are that for complete compatibility, a server (i.e. IEEE 1588 node) can choose to implement a YANG module for the last IETF 1588 YANG module (with IETF root) as well as the first IEEE 1588 YANG module (with IEEE root). Since the content of the YANG module transferred are the same, the server implementation is effectively common for both. From a client's perspective, a client of the last IETF 1588 YANG module (or earlier) looks for the IETF-rooted module name; and a client of the first IEEE 1588 YANG module (or later) looks for the IEEE-rooted module name. A.4. IEEE 1588 YANG Modules in ASCII Format Although IEEE 1588 can certainly decide to publish YANG modules only in the PDF format that they use for their standard documents, without publishing an ASCII version, most network management systems cannot import the YANG module directly from the PDF. Thus, not publishing an ASCII version of the YANG module would negatively impact implementers and deployers of YANG modules and would make potential IETF reviews of YANG modules more difficult. Jiang, et al Expires May 25, 2017 [Page 26] Internet-Draft 1588v2 YANG Model November 2016 This appendix recommends that the IEEE 1588 WG consider future plans for: o Public availability of the ASCII YANG modules during project development. These ASCII files allow IETF participants to access these documents for pre-standard review purposes. o Public availability of the YANG portion of published IEEE 1588 standards, provided as an ASCII file for each YANG module. These ASCII files are intended for use of the published IEEE 1588 standard. As an example of public availability during project development, IEEE 802 uses the same repository that IETF uses for YANG module development (see https://github.com/YangModels/yang). IEEE branches are provided for experimental work (i.e. pre-PAR) as well as standard work (post-PAR drafts). IEEE-SA has approved use of this repository for project development, but not for published standards. As an example of public availability of YANG modules for published standards, IEEE 802.1 provides a public list of ASCII files for MIB (see http://www.ieee802.org/1/files/public/MIBs/ and http://www.ieee802.org/1/pages/MIBS.html), and analogous lists are planned for IEEE 802.1 YANG files. Jiang, et al Expires May 25, 2017 [Page 27] Internet-Draft 1588v2 YANG Model November 2016 Authors' Addresses Yuanlong Jiang (Editor) Huawei Technologies Co., Ltd. Bantian, Longgang district Shenzhen 518129, China Email: jiangyuanlong@huawei.com Xian Liu Huawei Technologies Co., Ltd. Bantian, Longgang district Shenzhen 518129, China lene.liuxian@huawei.com Jinchun Xu Huawei Technologies Co., Ltd. Bantian, Longgang district Shenzhen 518129, China xujinchun@huawei.com Rodney Cummings (Editor) National Instruments 11500 N. Mopac Expwy Bldg. C Austin, TX 78759-3504 Email: Rodney.Cummings@ni.com Jiang, et al Expires May 25, 2017 [Page 28]