Network Working Group A. Bierman Internet-Draft YumaWorks, Inc. Intended status: Standards Track October 21, 2014 Expires: April 24, 2015 NETCONF Efficiency Extensions draft-bierman-netconf-efficiency-extensions-02 Abstract This document describes protocol extensions to improve the efficiency of the Network Configuration Protocol (NETCONF). Protocol capabilities and operations are defined to reduce network usage and transaction complexity. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on April 24, 2015. Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. 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. Bierman Expires April 24, 2015 [Page 1] Internet-Draft NETCONF-EX October 2014 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.1.1. NETCONF . . . . . . . . . . . . . . . . . . . . . . . 4 1.1.2. YANG . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1.3. RESTCONF . . . . . . . . . . . . . . . . . . . . . . . 5 1.1.4. YANG Patch . . . . . . . . . . . . . . . . . . . . . . 5 1.1.5. Terms . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1.6. Tree Diagrams . . . . . . . . . . . . . . . . . . . . 5 1.2. Problem Statement . . . . . . . . . . . . . . . . . . . . 6 1.2.1. Initial Configuration Retrieval . . . . . . . . . . . 6 1.2.2. Datastore Editing . . . . . . . . . . . . . . . . . . 6 1.2.3. Data Retrieval . . . . . . . . . . . . . . . . . . . . 8 1.3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.3.1. Configuration ID Advertisement . . . . . . . . . . . . 10 1.3.2. Operation . . . . . . . . . . . . . . . . . . 10 1.3.3. Operation . . . . . . . . . . . . . . . . . . . 10 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1. "config-id" Capability . . . . . . . . . . . . . . . . . . 11 2.1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . 11 2.1.2. Dependencies . . . . . . . . . . . . . . . . . . . . . 12 2.1.3. Capability Identifier . . . . . . . . . . . . . . . . 12 2.1.4. New Operations . . . . . . . . . . . . . . . . . . . . 12 2.1.5. Modifications to Existing Operations . . . . . . . . . 13 2.1.6. Interactions with Other Capabilities . . . . . . . . . 13 2.2. Protocol Operation . . . . . . . . . . . . . . . . 13 2.2.1. Input . . . . . . . . . . . . . . . . . . . . 13 2.2.2. Output . . . . . . . . . . . . . . . . . . . . 14 2.2.3. YANG Tree Diagram . . . . . . . . . . . . . . 14 2.2.4. Example . . . . . . . . . . . . . . . . . . . 16 2.3. Operation . . . . . . . . . . . . . . . 18 2.3.1. Input . . . . . . . . . . . . . . . 18 2.3.2. Output . . . . . . . . . . . . . . . 18 2.3.3. YANG Tree Diagram . . . . . . . . . 19 2.3.4. Example . . . . . . . . . . . . . . 19 2.4. Operation . . . . . . . . . . . . . . . . 19 2.4.1. Input . . . . . . . . . . . . . . . . 19 2.4.2. Output . . . . . . . . . . . . . . . . 19 2.4.3. YANG Tree Diagram . . . . . . . . . . 20 2.4.4. Example . . . . . . . . . . . . . . . 20 2.5. Protocol Operation . . . . . . . . . . . . . . . . 20 2.5.1. Depth Filters . . . . . . . . . . . . . . . . . . . . 20 2.5.2. Time Filters . . . . . . . . . . . . . . . . . . . . . 21 2.5.3. Input . . . . . . . . . . . . . . . . . . . . . 21 2.5.4. Output . . . . . . . . . . . . . . . . . . . . 22 2.5.5. YANG Tree Diagram . . . . . . . . . . . . . . . 23 2.5.6. Example . . . . . . . . . . . . . . . . . . . . 23 Bierman Expires April 24, 2015 [Page 2] Internet-Draft NETCONF-EX October 2014 2.6. NETCONF-EX YANG Module . . . . . . . . . . . . . . . . . . 24 2.7. XSD for NETCONF-EX Metadata . . . . . . . . . . . . . . . 40 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 43 3.1. NETCONF-EX XML Namespace . . . . . . . . . . . . . . . . . 43 3.2. NETCONF-EX XML Schema . . . . . . . . . . . . . . . . . . 43 3.3. NETCONF-EX YANG Module . . . . . . . . . . . . . . . . . . 43 4. Security Considerations . . . . . . . . . . . . . . . . . . . 44 5. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 45 5.1. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . . 45 5.1.1. Removed :encoding Capability . . . . . . . . . . . . . 45 5.2. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . . 45 5.2.1. Removed :capability-id Capability . . . . . . . . . . 45 5.2.2. RESTCONF Alignment . . . . . . . . . . . . . . . . . . 46 6. Normative References . . . . . . . . . . . . . . . . . . . . . 47 Appendix A. Open Issues . . . . . . . . . . . . . . . . . . . . . 48 A.1. resource-identifier-type . . . . . . . . . . . . . . . . . 48 A.2. no YANG for top-level message nodes . . . . . . . . . . . 48 A.3. config-id attribute . . . . . . . . . . . . . . . . . . . 48 A.4. nodeset retrieval . . . . . . . . . . . . . . . . . 48 Appendix B. Additional Examples . . . . . . . . . . . . . . . . . 49 B.1. YANG Module Used in Examples . . . . . . . . . . . . . . . 49 B.2. YANG Data Used in Examples . . . . . . . . . . . . . . . . 50 B.3. Examples . . . . . . . . . . . . . . . . . . . . . 51 B.3.1. Confirmed Commit on the "running" Datastore . . . . . 51 B.3.2. Conditional Editing with "if-match" Parameter . . . . 52 B.3.3. Bulk Editing with "target-resource" Parameter . . . . 55 B.3.4. Edit Validation with "test-only" Parameter . . . . . . 57 B.4. Examples . . . . . . . . . . . . . . . . . . . . . 58 B.4.1. If-Modified-Since Non-Empty Filter Retrieval . . . . . 58 B.4.2. If-Modified-Since Empty Filter Retrieval . . . . . . . 60 B.4.3. Keys Only Filter Retrieval . . . . . . . . . . . . . . 60 B.4.4. Test for Node Existence with Depth=1 . . . . . . . . . 62 B.4.5. Retrieve Only Non-Configuration Data Nodes . . . . . . 63 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 65 Bierman Expires April 24, 2015 [Page 3] Internet-Draft NETCONF-EX October 2014 1. Introduction There is a need for standard mechanisms to allow NETCONF [RFC6241] application designers to manage NETCONF servers more efficiently when used in network environments with poor connectivity, low bandwidth, and/or high latency. In such conditions, it is desirable to minimize network usage wrt/ the size of protocol messages and the number of protocol operations required to perform a network management function. 1.1. Terminology The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, [RFC2119]. 1.1.1. NETCONF The following terms are defined in [RFC6241]: o candidate configuration datastore o client o configuration data o datastore o configuration datastore o protocol operation o running configuration datastore o server o startup configuration datastore 1.1.2. YANG The following terms are defined in [RFC6020]: o container o data node Bierman Expires April 24, 2015 [Page 4] Internet-Draft NETCONF-EX October 2014 o key leaf o leaf o leaf-list o list 1.1.3. RESTCONF The following terms are defined in [RESTCONF]: o data resource o datastore resource 1.1.4. YANG Patch The following term is defined in [YANG-Patch]: o YANG Patch 1.1.5. Terms The following terms are defined: o config ID: An opaque string identifier that represents the state of the running datastore contents on the server. A new config ID is chosen by the server each time the server running configuration datastore is altered in any way. o depth filter: A mechanism implemented within the NETCONF server to allow a client to retrieve only a limited number of levels within the a subtree, instead of retrieving the entire subtree. o time filter: A mechanism implemented within the NETCONF server to allow a client to retrieve only data that has been modified since a specified data and time. 1.1.6. Tree Diagrams A simplified graphical representation of the data model is used in this document. The meaning of the symbols in these diagrams is as follows: o Brackets "[" and "]" enclose list keys. Bierman Expires April 24, 2015 [Page 5] Internet-Draft NETCONF-EX October 2014 o Abbreviations before data node names: "rw" means configuration (read-write) and "ro" state data (read-only). o Symbols after data node names: "?" means an optional node and "*" denotes a "list" and "leaf-list". 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. 1.2. Problem Statement This document attempts to address the following problems with NETCONF protocol procedures. 1.2.1. Initial Configuration Retrieval A client application often needs to retrieve the entire running configuration datastore contents, usually at the start of an editing session. The for this request can be very large (e.g., greater than 250,000 bytes). If a large number of server connections are lost and then restarted, the quantity of large messages from every server could severely impact network performance. It would be useful if the message exchange could be enhanced so an entity-tag value for the current running datastore configuration is included in the server message. A client can cache the server configuration identifier and omit an initial operation if the value from the server message matches the cached value. 1.2.2. Datastore Editing There are several deficiencies with the NETCONF editing procedures that could be improved. Multi-operation functions can be required. A single edit can take up to 9 operations. Several operations are required to complete a set of 1 or more edits on a NETCONF server. Each operation uses 1 request and 1 response message. If the candidate datastore is used, then 1 extra operation is required (for the operation) to activate the edit(s). If the startup datastore is used then 1 extra operation is required (for the operation) to save the running datastore contents in non-volatile storage. If global Bierman Expires April 24, 2015 [Page 6] Internet-Draft NETCONF-EX October 2014 locking is used, then 2 extra operations are required for each datastore involved (candidate, running, startup) Since the datastore is locked at the start and unlocked at the end of the entire edit operation, these extra roundtrip times are intervals in which the datastore is being locked, but no datastore access is being done. Obtaining locks can be expensive. If the server has more than 1 datastore (e.g., candidate + running or running + startup), then multiple lock requests are required, since the and operations on affect 1 datastore at a time. This can cause a long delay or even deadlock if multiple clients are attempting to obtain global locks at once. E.g., client 1 holds a lock on the candidate datastore and is trying to lock the running datastore. At the same time, client 2 holds a lock on the running datastore and is trying to lock the candidate datastore. Using locks can be brittle. NETCONF clients are intended to be programmatic, so is not likely that locks will be long-lived. Global locks are designed to be short-lived since they block write access to the entire datastore. If lock collisions do occur, they are likely to be cleared very quickly. It would be useful if the client could request how long to wait for locks to clear instead of immediately rejecting an edit request due to an 'in-use' error. Edit operations are implied by content. NETCONF uses a default operation and explicit operation attribute within an arbitrarily complete XML subtree to represent a configuration datastore. There are several corner-cases that are not standardized, and very implementation-dependent: - interpretation of implied operations vs. explicit operations - order the edits are processed - handling of nested operation attributes - handling of duplicate subtrees - error handling (code points, number of errors, etc.) - move operations are not explicit and can interpreted as a request to remove and re-add an entry, not just move user-ordered data Edit operations are not protected against multi-client alterations. It is a simple and common practice to retrieve a configuration data resource, changing 1 or more fields, and then update the resource on the server. Since retrieval and edit operations are separate there is always a chance that another client has altered the resource after the operation, but before the operation, by the first client. Each client could be protected if there was an entity tag associated with each data resource, and an edit request could be rejected if the client attempted to edit a different version Bierman Expires April 24, 2015 [Page 7] Internet-Draft NETCONF-EX October 2014 of the data resource than expected. There is no bulk-edit support. If the same edit is needed in multiple instances of a particular data resource, then the data must be repeated for each instance in the or request. The request message size could be minimized if there was a way to apply a set of edits to multiple target nodes at once. There is no confirmed commit support for the running datastore. The ability to backup the running datastore, change it, and revert it unless the client confirms the changes has nothing to do with the candidate datastore. A NETCONF server with limited memory is not likely to support the candidate datastore. This feature is useful for any type of network-wide configuration change, regardless of device size. 1.2.3. Data Retrieval NETCONF data retrieval via the and operations can be very inefficient. Some vendors do not even support because it can be such a resource-intensive operation and return an enormous amount of data, especially if all server data is requested at once. A client cannot retrieve just the non-configuration data. The NETCONF operation allows a client to retrieve data from the server but it returns all data, including configuration datastore nodes. The operation already returns all configuration datastore nodes. It was originally thought that should return all nodes so the client would not have to correlate configuration and non- configuration data nodes, since they would be mixed together in the reply. Operational experience has shown that the operation without reasonable filters to reduce the returned data can significantly degrade device performance and return enormous XML instance documents in the . There is no "last-modified" indication or time filtering. The NETCONF protocol has no standard mechanisms to indicate to a client when a datastore was last modified, or to allow a client to retrieve data only if it has been modified since a specified time. This makes polling applications very inefficient because they will regularly burden the server and the network and themselves with retrieval and processing requests for data that has not changed. There is no simple list instance discovery mechanism. Sometimes the client application wants to discover what data exists on the server, particularly list entries. There is a need for a simple mechanism to Bierman Expires April 24, 2015 [Page 8] Internet-Draft NETCONF-EX October 2014 retrieve just the key leaf nodes within a subtree. The NETCONF subtree filtering mechanism does provide a very complex way for the client to request just key leafs for specific list entries. A simpler mechanism is needed which will allow the client to discover the list instances present. There is no subtree depth control. NETCONF filters allow the client to select specific sub-trees within the conceptual datastore on the server. However, sometimes the client does not really need the entire subtree, which may contain many nested list entries, and be very large. There is sometimes a need to limit the depth of the sub- trees retrieved from the server. A consistent and simple algorithm for determining what data nodes start a new level is needed. The content filter specification is not extensible. The NETCONF and operations use a hard-coded content filtering mechanism. They use a "type" XML attribute to indicate which of two filter specification types they support, and a "select" XML attribute if the :xpath capability is supported and an XPath [XPATH] expression filter specification is provided. This design does not allow additional content filter specification types to be supported by an implementation. It does not allow the standard to be easily extended in a modular fashion. In addition, this design does not allow YANG statements to be used to properly describe the protocol operation. The special "get-filter-element-attributes" YANG extension in the ietf-netconf module is not extensible, and it does not really count as proper YANG, since this extension is outside the YANG language definition. There is no standard metadata or standard way to retrieve metadata. The parameter allows 1 specific type of metadata to be returned (i.e., 'report-all-tagged' mode). This ad-hoc approach does not scale well and is not extensible. It would be useful if standard and vendor-specific metadata could be identified and retrieved with standard operations. 1.3. Solution This document defines some NETCONF protocol operations and new capabilities to reduce network usage and increase functionality at the same time. All NETCONF efficiency extensions are completely backward-compatible with the current definitions in [RFC6241]. An old client will ignore any new URIs sent by the server, and will not use the new operations. No existing operations are affected by the new operations, so the extensions will be transparent to an existing Bierman Expires April 24, 2015 [Page 9] Internet-Draft NETCONF-EX October 2014 NETCONF client. 1.3.1. Configuration ID Advertisement A new capability called "config-id" is defined to identify the current running datastore configuration contents with an opaque string. A client can cache this value for each server that supports this capability, along with a copy of its running configuration. When a new session is started, the client can examine the "config-id" URI sent by the server. If it is the same as the cached value then the client can use the cached running datastore copy instead of sending an initial operation to the server. The :config-id capability is ignored in the calculation of the :capability-id capability. Refer to Section 2.1 for details on configuration ID advertisement. 1.3.2. Operation A new NETCONF protocol operation called is defined to address the deficiencies described in Section 1.2.2. This operation allows the entire NETCONF edit procedure to be accomplished with 1 request message. The editing procedures are aligned with the resource model defined in [RESTCONF]. Refer to Section 2.2 for details on operation. The "confirmed-commit" procedure has been integrated into the operation, and can be supported by any server without requiring support for the candidate datastore. It is optional to implement, based on the "confirmed-edit" capability defined in Section 2.6. Refer to Section 2.3 for details on the operation and Section 2.4 for details on the operation. 1.3.3. Operation A new NETCONF protocol operation called is defined to address the deficiencies described in Section 1.2.3. This operation allows several filter types to be combined to control the data that is returned in the message, and an extensible framework for retrieving metadata associated with datastore or data resources. Refer to Section 2.5 for details on operation. Bierman Expires April 24, 2015 [Page 10] Internet-Draft NETCONF-EX October 2014 2. Definitions This section defines the NETCONF efficiency extensions: - :config-id Capability - Operation - Operation - Operation - Operation 2.1. "config-id" Capability 2.1.1. Overview The :config-id capability indicates that the server maintains a config ID for the running configuration datastore. This identifier value is selected by the server and treated as an opaque string by the client. 1) Client keeps a cache of server configurations. 2) Server always sends its current config-id value in the "config-id" URI. Client Server X message +---------------+ +------------------+ | | | config-id=1234 | | Server Config | <------- | | | Cache | | ... | +---------------+ +------------------+ 3) Client checks cache for server X, config-id=1234. If found, then OK to use the cached configuration copy. If not found, then send a for the running configuration to create or update the cached copy. The server SHOULD save the config ID for the running datastore in non-volatile storage. When the server boots or restarts, the initial configuration ID SHOULD be the same as the last instantiation, if the server does not support the :startup capability (so the non-volatile stored version mirrors the running datastore). If the server does support the :startup capability, then the initial configuration ID SHOULD be the same as the version last saved to non-volatile storage. 2.1.1.1. :config-id Capability Example The :config-id capability is sent in every server message. The "id" parameter for the :config-id capability is set to the Bierman Expires April 24, 2015 [Page 11] Internet-Draft NETCONF-EX October 2014 current config ID for the running datastore on the server: # Server starts session 3 with an abbreviated urn:ietf:params:netconf:capability:config-id?id=4284 // ... rest of elements 3 2.1.2. Dependencies The :config-id capability is not dependent on any other capabilities. 2.1.3. Capability Identifier The :config-id capability is identified by the following capability string: urn:ietf:params:netconf:capability:config-id:1.0 This capability MUST be advertised in every server message. The :config-id capability URI MUST contain an "id" argument assigned an opaque string value indicating the current config ID value for the running datastore. For example: urn:ietf:params:netconf:capability:config-id:1.0?id=6882391 The current config ID value MUST be updated any time a "netconf-config-change" event would be generated by the server. If [RFC6470] is supported, then the "config-id" leaf defined in Section 2.6 MUST be included in event notifications. If the "with-metadata" parameter in the operation specifies the "config-id" identity, then the server MUST return the current config ID for the running datastore, if the "source" parameter identifies the running datastore. The server MAY maintain config IDs for other datastores as well. 2.1.4. New Operations The :config-id capability does not introduce any new protocol operations. Bierman Expires April 24, 2015 [Page 12] Internet-Draft NETCONF-EX October 2014 2.1.5. Modifications to Existing Operations The :config-id capability does not modify any existing protocol operations. 2.1.6. Interactions with Other Capabilities The :config-id capability does not interact with any other capabilities. 2.2. Protocol Operation The operation is specified with a YANG "rpc" statement, defined in Section 2.6. This operation allows the entire NETCONF transaction procedure to be performed in a single operation or multiple operations, depending on the input parameters used. There are no XML attributes used (e.g., "operation" from RFC 6241, "insert", "value" from RFC 6020). Instead, configuration edits are specified with an edit list, using the YANG Patch mechanism defined in [RESTCONF]. This is used instead of a complete XML instance document, e.g. element, to represent an unordered patch list inferred from the diffs. (Although YANG Patch can be used in this mode if client wants to merge or replace the entire configuration datastore). 2.2.1. Input o target: name of the configuration datastore being edited o target-resource: XPath node-set expression representing 1 or more target resources within the datastore to edit. o yang-patch: container of ordered edits to apply to the target resource(s). o test-only: flag to request that the edit request be validated but no edits should actually be applied o if-match: if the entity tag for the target resource(s) does not exactly match the supplied value then the edit request is rejected. o with-locking: if present then the server will provide exclusive write access to this operation and possible confirmed- commit procedure. Bierman Expires April 24, 2015 [Page 13] Internet-Draft NETCONF-EX October 2014 o max-lock-wait: amount of time the client is willing to wait for locks to clear, if "with-locking" parameter is present. o activate-now: if present and the target is the candidate datastore, then an implicit operation will be performed if the edit operation is successfully applied. o nvstore-now: if present and the server supports the startup datastore, and the edits have been activated in the running datastore, then an implicit operation (from the running to the startup datastore) will be attempted by the server. o confirmed: request that a confirmed commit be started or extended. o confirm-timeout: the amount of time for the server to wait for an request that extends, a request to finish, or a request to cancel a confirmed commit procedure in progress. o persist: identifier string to use in the "persist-id" parameter to extend, complete, or cancel a confirmed commit procedure. o persist-id: identifier string to extend a confirmed commit procedure in progress. 2.2.2. Output Positive Response: This operation returns data containing a "yang-patch-status" report (defined in [RESTCONF]) instead of an "ok" element. This report contains an "ok" element that is present if the entire operation succeeded. Error Response: The element can be returned, e.g., if the message contains invalid parameter syntax. The server MUST report editing errors in the "edit" list within the "yang-patch-status" container. 2.2.3. YANG Tree Diagram Key: DRI = data-resource-identifier +---x edit2 +--ro input | +--ro target Bierman Expires April 24, 2015 [Page 14] Internet-Draft NETCONF-EX October 2014 | | +--ro (datastore-target) | | +--:(candidate) | | | +--ro candidate? empty | | +--:(running) | | +--ro running? empty | +--ro target-resource? yang:xpath1.0 | +--ro yang-patch | | +--ro patch-id? string | | +--ro comment? string | | +--ro edit [edit-id] | | +--ro edit-id string | | +--ro operation enumeration | | +--ro target data-resource-identifier | | +--ro point? data-resource-identifier | | +--ro where? enumeration | | +--ro value | +--ro test-only? empty | +--ro if-match? yang-entity-tag | +--ro with-locking? empty | +--ro max-lock-wait? uint32 | +--ro activate-now? empty | +--ro nvstore-now? empty | +--ro confirmed? empty | +--ro confirm-timeout? uint32 | +--ro persist? string | +--ro persist-id? string +--ro output +--ro yang-patch-status +--ro patch-id? string +--ro (global-status)? | +--:(global-errors) | | +--ro errors | | +--ro error | | +--ro error-type enumeration | | +--ro error-tag string | | +--ro error-app-tag? string | | +--ro error-path? DRI | | +--ro error-message? string | | +--ro error-info | | | +--:(ok) | +--ro ok? empty +--ro edit-status +--ro edit [edit-id] +--ro edit-id string +--ro (edit-status-choice)? +--:(ok) | +--ro ok? empty Bierman Expires April 24, 2015 [Page 15] Internet-Draft NETCONF-EX October 2014 +--:(errors) +--ro errors +--ro error +--ro error-type enumeration +--ro error-tag string +--ro error-app-tag? string +--ro error-path? DRI +--ro error-message? string +--ro error-info 2.2.4. Example In this example, an "all-in-one" YANG Patch edit is shown. the following conditions apply: - The server supports the :candidate and :startup capabilities - The "example-ex" YANG module is supported by the server The starting state of the "/forests" data structure is described in Appendix B.2. The client is adding an "oak" tree and changing the location of the "birch" tree in the "north" forest. Bierman Expires April 24, 2015 [Page 16] Internet-Draft NETCONF-EX October 2014 /ex:forests/ex:forest[ex:name='north'] north-forest-patch Add an oak tree and change location of the birch tree oak create /ex:trees oak hillside birch merge /ex:trees/ex:tree/birch west valley The edit succeeds, and the "yang-patch-status" container is returned to the client with the status for both tree edits: Bierman Expires April 24, 2015 [Page 17] Internet-Draft NETCONF-EX October 2014 north-forest patch oak birch Refer to Appendix B.3 for additional protocol operation examples. 2.3. Operation A new NETCONF protocol operation called is defined to complete a confirmed commit procedure. 2.3.1. Input There is one optional parameter for this protocol operation: o persist-id: an identifier string that MUST match the "persist" value, if it was used in the confirmed-commit procedure. 2.3.2. Output Positive Response: The there is a confirmed-commit procedure in progress and it is successfully completed, then an element is returned. Negative Response: An response is sent if the request cannot be completed for any reason. Bierman Expires April 24, 2015 [Page 18] Internet-Draft NETCONF-EX October 2014 2.3.3. YANG Tree Diagram +---x complete-commit +--ro input +--ro persist-id? string 2.3.4. Example In this example, the client has previously started a confirmed commit procedure using the "persist" parameter set to the value "abcdef". abcdef 2.4. Operation A new NETCONF protocol operation called is defined to cancel a confirmed commit procedure and revert the running datastore. The operation in [RFC6241] cannot be used because it requires the implementation of the candidate capability. 2.4.1. Input There is one optional parameter for this protocol operation: o persist-id: an identifier string that MUST match the "persist" value, if it was used in the confirmed-commit procedure. 2.4.2. Output Positive Response: If there is a confirmed-commit procedure in progress and it is successfully cancelled, and the running datastore successfully reverted, then an element is returned. Negative Response: An response is sent if the request Bierman Expires April 24, 2015 [Page 19] Internet-Draft NETCONF-EX October 2014 cannot be completed for any reason. 2.4.3. YANG Tree Diagram +---x revert-commit +--ro input +--ro persist-id? string 2.4.4. Example In this example, the client has previously started a confirmed commit procedure using the "persist" parameter set to the value "abcdef". abcdef 2.5. Protocol Operation The operation is specified with a YANG "rpc" statement, defined in Section 2.6. A specific datastore is selected for the source of the retrieval operation. Several different types of filters are provided. Filters are combined in a conceptual "logical-AND" operation, and are optional to use by the client. Not all filtering mechanisms are mandatory-to-implement for the server. 2.5.1. Depth Filters A depth filter indicates how many subtree levels should be returned in the . This filter is specified with the "depth" input parameter for the protocol operation. The default "0" indicates that all levels from the requested subtrees should be returned. A new level is started for each YANG data node within the requested subtree. All top level data nodes are considered to be child nodes (level 1) of a conceptual root. Bierman Expires April 24, 2015 [Page 20] Internet-Draft NETCONF-EX October 2014 If no content filters are provided, then level 1 is considered to include all top-level data nodes within the source datastore. Otherwise only the levels in selected subtrees will be considered, and not any additional top-level data nodes. If the depth requested is equal to "1", then only the requested data nodes (or top-level data nodes) will be returned. This mechanism can be used to detect the existence of containers and list entries within a particular subtree, without returning any of the descendant nodes. Higher depth values indicates the number of descendant nodes to include in the response. For example, if the depth requested is equal to "2", then only the requested data nodes (or top-level data nodes) and their immediate child data nodes will be returned. 2.5.2. Time Filters A time filter specifies that data should only be returned if the last-modified timestamp for the target datastore is more recent than the timestamp specified in the "if-modified-since" parameter. If this feature is supported, then the server will maintain a "last-modified" timestamp for the running datastore. The server MAY support additional nested timestamps for data nodes within the datastore. The server MAY support timestamps for other datastores. When a request containing the "if-modified-since" parameter is received, the server will compare that timestamp to the "last-modified" timestamp for the source datastore. If it is greater than the specified value then data may be returned (depending on other filters). If the datastore timestamp value is less than or equal to the specified value, then an empty element will be returned in the . If the "full-delta" parameter is present, and the server maintains "last-modified" timestamps for any data nodes within the source datastore, then the same type of comparison will be done for the data node to determine if it should be included in the response. If no "last-modified" timestamp is maintained for a data node, then the server will use the "last-modified" timestamp for its nearest ancestor, or for the datastore itself if there are none. 2.5.3. Input o source: A container indicating the conceptual datastore for the retrieval request. Bierman Expires April 24, 2015 [Page 21] Internet-Draft NETCONF-EX October 2014 o filter-spec: A choice indicating the content filter specification for the retrieval request. o keys-only: A leaf indicating that only the key leafs, combined with other filtering criteria, should be returned. o if-modified-since: A leaf indicating the time filter specification for the retrieval request, according to the procedures in Section 2.5.2. o full-delta: If present and the "if-modified-since" parameter is also present, then the entire datastore will be filtered by last modification time, not just the entire datastore. o depth: A leaf indicating the subtree depth level for the retrieval request, according to the procedures in Section 2.5.1. o with-defaults: A leaf indicating the type of defaults handling requested, according to procedures in [RFC6243]. o with-metadata: A leaf-list indicating the specific metadata that the server should add to the response, such as "last-modified" or "etag", encoded in XML according to the schema in Section 2.7. o with-locking: if present then the server will provide exclusive write access to this operation so the target datastore is not modified during the entire retrieval operation. o max-lock-wait: amount of time the client is willing to wait for locks to clear, if "with-locking" parameter is present. 2.5.4. Output Positive Response: A element is returned which contains the data corresponding to the input parameters specified in the request. The child nodes of the container correspond to top-level YANG data nodes. If the server supports the "timestamps" YANG feature, and the target is the running datastore, then a "last-modified" attribute SHOULD be included in the element. Negative Response: An response is sent if the request cannot be completed for any reason. Bierman Expires April 24, 2015 [Page 22] Internet-Draft NETCONF-EX October 2014 2.5.5. YANG Tree Diagram +---x get2 +--ro input | +--ro source | | +--ro (datastore-source)? | | +--:(candidate) | | | +--ro candidate? empty | | +--:(running) | | | +--ro running? empty | | +--:(startup) | | | +--ro startup? empty | | +--:(url) | | | +--ro url? inet:uri | | +--:(operational) | | +--ro operational? empty | +--ro (filter-spec)? | | +--:(subtree-filter) | | | +--ro subtree-filter | | +--:(xpath-filter) | | +--ro xpath-filter? yang:xpath1.0 | +--ro keys-only? empty | +--ro if-modified-since? yang:date-and-time | +--ro full-delta? empty | +--ro depth? uint32 | +--ro with-defaults? with-defaults-mode | +--ro with-metadata* identityref | +--ro with-locking? empty | +--ro max-lock-wait? uint32 +--ro output +--ro data 2.5.6. Example In this example, the retrieval the "forests" resource is shown. the following conditions apply: - The server supports the :candidate and :startup capabilities - The "example-ex" YANG module is supported by the server The starting state of the "/forests" data structure is described in Appendix B.2. The client is retrieving just the "forests" node, along with the "last-modified" and "etag" metadata for that node. The "config-id" for the datastore is also requested. Locking is requested (with a maximum lock wait time of 5 seconds), just to make sure the metadata does not change during the request. Bierman Expires April 24, 2015 [Page 23] Internet-Draft NETCONF-EX October 2014 1 ncex:timestamps ncex:etags ncex:config-id 5 The server has a "forests" node so this node is returned along with the requested metadata for the node. Note that the XML namespace for the "ncex" metadata is the XSD target namespace defined in Section 2.7, not the YANG namespace URI defined in Section 2.6. Refer to Appendix B.4 for additional protocol operation examples. 2.6. NETCONF-EX YANG Module This module imports the "with-defaults-parameters" grouping from [RFC6243]. Several YANG features are imported from [RFC6241]. These correspond to the NETCONF capabilities (e.g., candidate, url, startup, xpath) but defined as YANG features instead of URIs. Some data types are imported from [RFC6991]: Bierman Expires April 24, 2015 [Page 24] Internet-Draft NETCONF-EX October 2014 - date-and-time - uri - xpath1.0 Two YANG groupings are imported from [YANG-Patch]: - yang-patch - yang-patch-status One notification is augmented from [RFC6470]. - netconf-configuration-change RFC Ed.: update the date below with the date of RFC publication and remove this note. file "ietf-netconf-ex@2014-10-21.yang" module ietf-netconf-ex { namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-ex"; prefix ncex; import ietf-inet-types { prefix inet; } import ietf-netconf { prefix nc; } import ietf-netconf-notifications { prefix ncn; } import ietf-netconf-with-defaults { prefix ncwd; } import ietf-yang-patch { prefix yp; } import ietf-yang-types { prefix yang; } organization Bierman Expires April 24, 2015 [Page 25] Internet-Draft NETCONF-EX October 2014 "IETF NETCONF (Network Configuration Protocol) Working Group"; contact "WG Web: WG List: WG Chair: Mehmet Ersue WG Chair: Bert Wijnen Editor: Andy Bierman "; description "This module contains a collection of YANG definitions for the efficient operation of a NETCONF server. Protocol operations are defined to reduce network usage and transaction complexity. Copyright (c) 2014 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; // RFC Ed.: replace XXXX with actual RFC number and remove this // note. // RFC Ed.: remove this note // Note: extracted from // draft-bierman-netconf-efficiency-extensions-02.txt // RFC Ed.: update the date below with the date of RFC publication // and remove this note. revision "2014-10-21" { description "Initial revision. operation originally published in draft-bierman-netconf-get2-03.txt"; reference "RFC XXXX: NETCONF Efficiency Extensions"; Bierman Expires April 24, 2015 [Page 26] Internet-Draft NETCONF-EX October 2014 } /* Features */ feature timestamps { description "This feature indicates that the server implements the operations parameters which require last modification timestamps to be maintained by the server. If this feature is advertised then one global 'last-modified' timestamp for the entire running configuration datastore MUST be supported. The server MAY support additional timestamps for additional datastores and data nodes within a datastore. The 'with-metadata' parameter can be used to identify which data nodes support a 'last-modified' timestamp."; } feature with-defaults { description "This feature indicates that the server supports the 'with-defaults' parameter for the operation. A NETCONF server SHOULD support this feature."; reference "RFC 6243: With-defaults Capability for NETCONF"; } feature confirmed-edit { description "This feature indicates that the server supports the confirmed commit procedure for the protocol operation."; } /* Identities */ identity metadata { description "Base for all metadata identifiers used by the 'with-metadata' parameter in the operation."; } Bierman Expires April 24, 2015 [Page 27] Internet-Draft NETCONF-EX October 2014 identity timestamps { base metadata; description "Describes metadata identifying the last modification time of the associated datastore or data resource."; } identity etags { base metadata; description "Describes metadata identifying the entity tag value of the associated datastore or data resource."; } identity config-id { base metadata; description "Describes metadata identifying the config ID of the associated datastore or data resource."; } /* Typedefs */ typedef yang-entity-tag { type string; description "Contains an opaque string representing a specific instance of a datastore or data resource. A client can use this string for equality comparisons between yang-entity-tag values. If any configuration data node values changes, or the relative order of any user-ordered data changes, then the server MUST change the entity tag value for the running datastore to a different value. If the server maintains entity-tag values for configuration data nodes, then the server MUST change the yang-entity-tag value for any affected data node. Only yang-entity-tag values for the same target resource instance can be compared. Only the 'strong entity tag' form is required. A server MAY support the 'weak entity tag' form. If so, then 2 YANG data node resource instances are considered to be equivalent if they contain the same value subtrees and all user-ordered data nodes share the same relative order."; reference Bierman Expires April 24, 2015 [Page 28] Internet-Draft NETCONF-EX October 2014 "RFC 2616, section 3.11."; } /* Groupings */ grouping lock-parms { description "Common parameters to control datastore locking."; leaf with-locking { type empty; description "If this parameter is present then the request MUST be performed with exclusive write access to all datastores involved in the operation. An 'operation-not-supported' error-tag value is returned if the target datastore for the operation does not support locking (e.g., 'url' or 'operational'). If the server cannot provide exclusive write access for the entire requested operation then an 'in-use' error-tag value is returned. If the 'max-lock-wait' parameter is also present then the server MAY choose to wait up to that amount of time attempting to obtain exclusive write access, before returning an error."; } leaf max-lock-wait { when "../with-locking" { description "Only relevant if locking is requested."; } type uint32 { range "1 .. 600"; } units seconds; description "If this parameter is present and the 'with-locking' parameter is also present, then the server MAY wait up to the specified number of seconds attempting to obtain exclusive write access for the requested operation."; } } Bierman Expires April 24, 2015 [Page 29] Internet-Draft NETCONF-EX October 2014 /* Protocol Operations */ rpc get2 { description "Retrieve NETCONF datastore information"; input { container source { description "The datastore (or non-configuration data) to use for the source for the retrieval operation."; choice datastore-source { default running; description "The configuration source for the retrieval operation. The running configuration is the default choice if this parameter is not present."; leaf candidate { if-feature nc:candidate; type empty; description "The candidate configuration datastore is the retrieval source."; } leaf running { type empty; description "The running configuration datastore is the retrieval source."; } leaf startup { if-feature nc:startup; type empty; description "The startup configuration datastore is the retrieval source."; } leaf url { if-feature nc:url; type inet:uri; description "The URL-based configuration is the retrieval source."; } leaf operational { type empty; description "The retrieval source is the collection of all Bierman Expires April 24, 2015 [Page 30] Internet-Draft NETCONF-EX October 2014 operational (non-configuration) data nodes supported by the server. Any ancestor container and/or list and list key nodes are also returned. No other leafs or leaf-lists will be included in the reply. The server MAY return ancestor container, and/or list and list key nodes that do not contain any non-configuration nodes. This can occur for several reasons, e.g., the implementation streams replies and cannot defer instrumentation or access control filtering of descendant data nodes."; } } } choice filter-spec { description "The content filter specification for this request"; anyxml subtree-filter { description "This parameter identifies the portions of the target datastore to retrieve."; reference "RFC 6241, Section 6."; } leaf xpath-filter { if-feature nc:xpath; type yang:xpath1.0; description "This parameter contains an XPath expression identifying the portions of the target datastore to retrieve."; } } leaf keys-only { type empty; description "This parameter selects only data nodes which are key leaf nodes. Parent container and list nodes are also returned, but no other leafs, or any leaf-lists will be included in the reply."; } leaf if-modified-since { if-feature timestamps; Bierman Expires April 24, 2015 [Page 31] Internet-Draft NETCONF-EX October 2014 type yang:date-and-time; description "This parameter selects the target datastore only if the last-modified timestamp for the datastore is more recent than the specified time. If not, then an empty element is returned. If the target datastore does not maintain a last-modified timestamp, then this parameter is ignored."; } leaf full-delta { if-feature timestamps; type empty; description "This parameter selects only data nodes which have been modified since the specified time. It is ignored unless the 'if-modified-since' parameter is also provided and the target datastore supports a last-modified timestamp."; } leaf depth { type uint32; default 0; description "This parameter selects how many conceptual sub-tree levels should be returned in the . If this parameter is equal to '0', then entire subtrees will be returned. If this parameter is greater than '0', then only the specified number of subtree levels will be returned."; } uses ncwd:with-defaults-parameters { if-feature with-defaults; description "This parameter controls the retrieval of default values."; reference "RFC 6243: With-defaults Capability for NETCONF"; } Bierman Expires April 24, 2015 [Page 32] Internet-Draft NETCONF-EX October 2014 leaf-list with-metadata { type identityref { base metadata; } description "This parameter will cause the server to return metadata in the (e.g. as XML attributes in XML encoding) associated with the specified metadata identity. If the server does not support any specified metadata identifier, then the operation fails with an 'invalid-value' error."; } uses lock-parms { description "Exclusive write access can be requested to ensure that no other sessions modify the configuration data during the retrieval operation"; } } output { anyxml data { description "Copy of the requested datastore subset which matched the filter criteria (if any). An empty data container indicates that the request did not produce any results."; } } } rpc edit2 { description "Edit NETCONF datastore contents. All operations requested in the yang-patch edit list are applied, or the target datastore is left unchanged."; input { container target { description "The datastore to use as the target for this edit operation."; choice datastore-target { mandatory true; Bierman Expires April 24, 2015 [Page 33] Internet-Draft NETCONF-EX October 2014 description "The configuration target for the edit operation."; leaf candidate { if-feature nc:candidate; type empty; description "The candidate configuration datastore is the edit target."; } leaf running { if-feature nc:writable-running; type empty; description "The running configuration datastore is the edit target."; } } } leaf target-resource { if-feature nc:xpath; type yang:xpath1.0; description "This parameter identifies 1 or more data node instances for which the yang-patch edits will be applied. The target-resource expression MUST evaluate to a node-set result. Each operation in the yang-patch edit list will be applied to each target-resource instance, as if it were the document root for the operation. If multiple instances are represented by the target-resource value, then the server will apply all edits to all instances. If any errors occur, then all edits from this request will be undone from the target datastore. The user MUST have appropriate write permissions for all data accessed by every operation within the edit list. If this parameter is not present or not supported then the target resource is the root node of the datastore identified by the 'target' parameter."; } Bierman Expires April 24, 2015 [Page 34] Internet-Draft NETCONF-EX October 2014 uses yp:yang-patch { description "The yang-patch parameter contains the ordered list of edits to perform on the target resource(s). The conceptual document root for the 'target' parameter is defined to be the value of a data node represented by the 'target-resource' parameter or the target datastore conceptual root node if that parameter is not present."; } leaf test-only { type empty; description "If this parameter is present the server will not actually perform the requested edits. Instead the edit request will be validated as if it were going to be applied. Any parameter errors or datastore validation errors SHOULD be reported in the response. No attempt to apply, activate the edits or save them in non-volatile storage will be made if this parameter is present."; } leaf if-match { type yang-entity-tag; description "If this parameter is set, then the entire edit request will be rejected unless the entity tag for the target resource matches this value. An rpc-error with an 'operation-failed' error-tag value MUST returned, and the edit operation MUST NOT be attempted. The 'error-app-tag' field SHOULD be set to 'precondition-failed'. If the target datastore does not maintain a last-modified timestamp, then this parameter is ignored."; } uses lock-parms { description "Exclusive write access can be requested to ensure that no other sessions modify the configuration data during the edit operation and possibly the entire confirmed commit procedure. Bierman Expires April 24, 2015 [Page 35] Internet-Draft NETCONF-EX October 2014 If the 'with-locking' parameter is used to start or extend a confirmed commit procedure, then the exclusive write access will be maintained until the confirmed commit procedure terminates somehow. If the 'with-locking' parameter is used for a plain edit operation, then exclusive write access will be maintained until this operation has completed."; } leaf activate-now { type empty; description "If present and the edit operation succeeds, then the server will activate the configuration changes right away. The server will conceptually perform a operation after the edit operation. The user MUST have execute permission for the operation or the operation fails with an 'access-denied' error. This parameter has no affect unless the 'datasource-target' choice is the 'candidate' leaf."; } leaf nvstore-now { type empty; description "If present and the edit operation succeeds, and the configuration changes are activated in the running datastore, then the server will persist the configuration changes right away in non-volatile store. The server will conceptually perform a operation from the running to the startup datastore. The user MUST have execute permission for the operation or the operation fails with an 'access-denied' error. This parameter has no affect unless the 'startup' capability is supported by the server."; } leaf confirmed { if-feature confirmed-edit; type empty; description "If the requested edit operation succeeds and the configuration changes are applied to the running Bierman Expires April 24, 2015 [Page 36] Internet-Draft NETCONF-EX October 2014 datastore, then a confirmed commit procedure is requested by the client. A confirmed commit procedure is an operation that contains this parameter. The operation is used to complete the confirmed commit procedure. The operation is used to cancel the confirmed commit procedure and revert the running datastore back to the contents before the first confirmed commit operation. If no or operation is invoked within the timeout interval then the server will revert the running datastore back to the contents before the first confirmed edit operation. This is the same as the confirmed commit procedure in RFC 6241 except the candidate capability is not required. The server will save the running datastore contents before the edit operation is activated, if there is no confirmed edit already in progress. If the 'with-locking' parameter is present then the server will maintain exclusive write access for the specified session until the confirmed edit procedure is completed somehow."; reference "RFC 6241, Section 8.3.4.1"; } leaf confirm-timeout { when "../confirmed" { description "Only relevant if the parameter is present"; } if-feature confirmed-edit; type uint32 { range "1..max"; } units "seconds"; default "600"; // 10 minutes description "The timeout interval for a confirmed edit procedure. If exclusive write access was granted for this confirmed commit procedure, then it is removed if the timeout Bierman Expires April 24, 2015 [Page 37] Internet-Draft NETCONF-EX October 2014 occurs and the confirmed commit procedure is terminated."; reference "RFC 6241, Section 8.3.4.1"; } leaf persist { if-feature confirmed-edit; type string; description "This parameter is used to make a confirmed commit procedure persistent. A persistent confirmed commit is not aborted if the NETCONF session terminates. The only way to abort a persistent confirmed commit is to let the timer expire, or to use the operation. The value of this parameter is a token that MUST be given in the 'persist-id' parameter of the , , or operations in order to extend, confirm, or cancel the persistent confirmed commit procedure. The token SHOULD be a random string."; reference "RFC 6241, Section 8.3.4.1"; } leaf persist-id { if-feature confirmed-edit; type string; description "This parameter is given in order to extend a persistent confirmed edit. The value must be equal to the value given in the 'persist' parameter to the operation. If it does not match, the operation fails with an 'invalid-value' error."; reference "RFC 6241, Section 8.3.4.1"; } } output { uses yp:yang-patch-status; } } rpc complete-commit { if-feature confirmed-edit; description Bierman Expires April 24, 2015 [Page 38] Internet-Draft NETCONF-EX October 2014 "This operation is used to complete an ongoing confirmed commit procedure. If exclusive write access was granted for this confirmed commit procedure, then it is removed if this operation is successfully completed. If the confirmed commit is persistent, the parameter 'persist-id' MUST be given, and it MUST match the value of the 'persist' parameter given in the operation. If not confirmed commit procedure is in progress then the operation fails with an 'operation-failed' error."; reference "RFC 6241, Section 8.4.5.1"; input { leaf persist-id { type string; description "This parameter is given in order to complete a persistent confirmed commit procedure. The value MUST be equal to the value given in the 'persist' parameter to the operation. If it does not match, the operation fails with an 'invalid-value' error."; } } } rpc revert-commit { if-feature confirmed-edit; description "This operation is used to cancel an ongoing confirmed commit. If exclusive write access was granted for this confirmed commit procedure, then it is removed if this operation is successfully completed. If the confirmed commit is persistent, the parameter 'persist-id' MUST be given, and it MUST match the value of the 'persist' parameter. If not confirmed commit procedure is in progress then the operation fails with an 'operation-failed' error."; reference "RFC 6241, Section 8.4.4.1"; input { leaf persist-id { type string; description "This parameter is given in order to cancel a persistent confirmed commit and revert the running configuration Bierman Expires April 24, 2015 [Page 39] Internet-Draft NETCONF-EX October 2014 datastore to its state before the confirmed commit procedure started. The value MUST be equal to the value given in the 'persist' parameter to the operation. If it does not match, the operation fails with an 'invalid-value' error."; } } } /* Notifications */ augment /ncn:netconf-config-change { description "Add the updated config-id capability value to a configuration change event."; leaf config-id { type string; description "Contains the new configuration ID for the running datastore on the server, representing the datastore after the configuration changes."; } } } 2.7. XSD for NETCONF-EX Metadata The following XML Schema document [XSD] defines the "last-modified" and "etag" attributes, described within this document. The "last-modified" attribute is only relevant if the server supports the "timestamps" YANG feature within the "ietf-netconf-ex" YANG module. The "last-modified" attribute uses the XSD data type "dateTime", in accordance with Section 3.2.7.1 of XML Schema Part 2: Datatypes. This is equivalent to the YANG data type "date-and-time". The "etag" attribute uses the XSD data type "string", in accordance with the "yang-entity-tag" YANG typedef defined in Section 2.6. Bierman Expires April 24, 2015 [Page 40] Internet-Draft NETCONF-EX October 2014 The "config-id" attribute uses the XSD data type "string". file "netconf-ex.xsd" This schema defines the syntax for the "last-modified" and "etag" attributes described within this document. This attribute indicates the current config ID for the running configuration datastore, corresponding to the XML element containing this attribute. This attribute indicates the date and time when a modification was last detected by the server for the datastore or data node corresponding to the XML element containing this attribute. This attribute indicates the entity tag for the datastore or data node corresponding to the XML element containing this attribute. Bierman Expires April 24, 2015 [Page 42] Internet-Draft NETCONF-EX October 2014 3. IANA Considerations 3.1. NETCONF-EX XML Namespace This document registers a URI in the IETF XML registry [RFC3688]. Following the format in RFC 3688, the following registration is requested: URI: urn:ietf:params:xml:ns:netconf:netconf-ex:1.0 Registrant Contact: The NETCONF WG of the IETF. XML: N/A, the requested URI is an XML namespace. 3.2. NETCONF-EX XML Schema This document registers a URI for the NETCONF XML schema in the IETF XML registry [RFC3688]. // RFC Ed. remove this line and uncomment next line when published //IANA has updated the following URI to reference this document. URI: urn:ietf:params:xml:schema:netconf-ex 3.3. NETCONF-EX YANG Module This document registers 1 YANG module in the YANG Module Names registry [RFC6020]. name: ietf-netconf-ex namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-ex prefix: ncex // RFC Ed. remove this line and replace XXXX in next line reference: RFC XXXX Bierman Expires April 24, 2015 [Page 43] Internet-Draft NETCONF-EX October 2014 4. Security Considerations This document does not introduce any new security concerns in addition to those specified in [RFC6241], section 9. Bierman Expires April 24, 2015 [Page 44] Internet-Draft NETCONF-EX October 2014 5. Change Log -- RFC Ed.: remove this section before publication. 5.1. 01 to 02 5.1.1. Removed :encoding Capability The :encoding URI exchange was removed because the developers who want to use JSON are using RESTCONF instead of NETCONF. The NETCONF protocol should support a binary format that can be streamed by servers. This should be done as a separate standards effort. 5.2. 00 to 01 5.2.1. Removed :capability-id Capability The :capability-id URI exchange was removed because the NETCONF protocol does not allow the server to delay its message so the client cannot choose the full or abbreviated . This makes the :capability-id URI exchange unworkable for several reasons: o Since the client cannot select the server hello format based on its own notion of the cached capability set, the server must be configured to always use the full or always use the abbreviated message. o All clients must support the new capability exchange or the server cannot practically be configured to use the abbreviated message. o Since the client will not know the capability-id value for a server the first time the particular value is seen, the "schema" list in the "ietf-netconf-monitoring" YANG module would have to be mandatory-to-implement by both client and server, and mandatory- to-use by the client. o Forcing the client to perform a request and wait for an before using the NETCONF session introduces 1 round- trip of extra latency into the protocol. o Forcing the client to perform a request and wait for an before using the NETCONF session introduces extra complexity into the protocol. Bierman Expires April 24, 2015 [Page 45] Internet-Draft NETCONF-EX October 2014 5.2.2. RESTCONF Alignment The YANG module was updated to align with new RESTCONF and YANG Patch drafts. The "location" leaf has been removed from the "yang-patch-status" grouping. Bierman Expires April 24, 2015 [Page 46] Internet-Draft NETCONF-EX October 2014 6. Normative References [RESTCONF] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", draft-ietf-netconf-restconf-02 (work in progress), October 2014. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010. [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011. [RFC6243] Bierman, A. and B. Lengyel, "With-defaults Capability for NETCONF", RFC 6243, June 2011. [RFC6470] Bierman, A., "Network Configuration Protocol (NETCONF) Base Notifications", RFC 6470, February 2012. [RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991, July 2013. [XPATH] Clark, J. and S. DeRose, "XML Path Language (XPath) Version 1.0", World Wide Web Consortium Recommendation REC-xpath-19991116, November 1999, . [XSD] Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes Second Edition", World Wide Web Consortium Recommendation REC-xmlschema-2-20041028, October 2004, . [YANG-Patch] Bierman, A., Bjorklund, M., Watsen, K., and R. Fernando, "YANG Patch Media Type", draft-ietf-netconf-yang-patch-01 (work in progress), July 2014. Bierman Expires April 24, 2015 [Page 47] Internet-Draft NETCONF-EX October 2014 Appendix A. Open Issues A.1. resource-identifier-type The resource-identifier-type typedef from yang-patch is a RESTCONF path expression, not an XPath path expression. The error-path parameter also uses RESTCONF path strings. Should either or both of these be XPath instead? A.2. no YANG for top-level message nodes The YANG module of the node is needed for JSON encoding, but there is no YANG schema definition for the , , or elements. The namespace for and is "ietf-netconf", but no module name at all exists for the element. A.3. config-id attribute Should the "config-id" (etag for the running datastore root) be returned in every response or only if requested? (Currently only if requested.) A.4. nodeset retrieval Should there be a retrieval mode for where only the nodes in an XPath node-set are returned? NETCONF returns all ancestor nodes and all ancestor or sibling key leafs as well. Sometime the XPath designer knows the context of the result node-set (e.g. path expression for 1 instance of a nested list). The XML scaffolding can add a lot of extra bytes to the . Bierman Expires April 24, 2015 [Page 48] Internet-Draft NETCONF-EX October 2014 Appendix B. Additional Examples B.1. YANG Module Used in Examples The "example-ex" YANG module models a collection of forests. Each forest has a collection of trees. For simplicity, only 1 tree of each type is allowed in a forest. +--rw forests +--rw forest [name] +--rw name string +--ro tree-count? uint32 +--rw trees +--rw tree [name] +--rw name string +--rw location? string +--ro height? decimal64 module example-ex { namespace "http://example.com/ns/example-ex"; prefix ex; organization "Example, Inc."; contact "support@example.com"; description "Module used in NETCONF-EX examples."; revision 2013-10-19 { description "Initial version"; reference "Example Spec 12.44"; } container forests { description "A collection of forests"; list forest { key name; description "A single forest"; leaf name { type string; description "The forest name"; } leaf tree-count { type uint32; config false; description "The number of trees in this forest"; Bierman Expires April 24, 2015 [Page 49] Internet-Draft NETCONF-EX October 2014 } container trees { description "A collection of trees"; list tree { key name; description "A single tree"; leaf name { type string; description "The tree name"; } leaf location { type string; description "The tree location"; } leaf height { type decimal64 { fraction-digits 3; } units meters; config false; description "The tree height"; } } // list tree } // container trees } // list forest } // container forests } B.2. YANG Data Used in Examples The follow instances are assumed in the following examples. list forest: "north": list tree: "birch", "ash", "maple" list forest: "south": list tree: "banyan", "palm" leaf "location": "hillside", "west valley", "southwest pasture", "east meadow", "greenhouse" The forests and trees are configured, which represent trees the company has planted and growing over time. Bierman Expires April 24, 2015 [Page 50] Internet-Draft NETCONF-EX October 2014 The operational data (tree height) represents the data that the company monitors for each tree over time. B.3. Examples B.3.1. Confirmed Commit on the "running" Datastore In this example, the server supports the :writable-running and :startup capabilities: /ex:forests/ex:forest[ex:name='north'] oak-tree-patch Create an oak tree oak create /ex:trees oak hillside 10 60 24ef8829a4 The edit succeeds, and the "yang-patch-status" container is returned to the client with the path expression of the new oak tree resource. The candidate and running datastores remain locked after this operation because a confirmed commit procedure is in progress. The startup datastore was not locked during this operation because the "nvstore-now" parameter was not provided. Bierman Expires April 24, 2015 [Page 51] Internet-Draft NETCONF-EX October 2014 oak-tree-patch oak After configuration verification (e.g., 20 seconds), the client decides to keep these configuration changes and sends a request. 24ef8829a4 The server completes the confirmed commit procedure and returns an "ok" element to indicate success: After the operation succeeds, the server releases all locks that were being held to allow exclusive write access for the entire confirmed commit procedure. The client can now save the activated configuration changes to the startup configuration using the protocol operation, as described in RFC 6241, section 8.7.5.1. B.3.2. Conditional Editing with "if-match" Parameter In this example the client is going to change the location of the "palm" tree is the "south" forest. The entity tag for the tree Bierman Expires April 24, 2015 [Page 52] Internet-Draft NETCONF-EX October 2014 resource is retrieved with the resource: /ex:forests/ex:forest[ex:name='south']/ex:trees/ ex:tree[ex:name='palm'] 1 ncex:etags The server returns a subtree containing data nodes representing the "palm" tree. The "etag" attribute is returned for this resource and its ancestors. Only the "tree" node itself, as requested with the "depth parameter. south The client then edits the list entry (e.g, reassigns tree location) but submits an "if-match" parameter with the "etag" value it received for the tree resource being edited: Bierman Expires April 24, 2015 [Page 53] Internet-Draft NETCONF-EX October 2014 /ex:forests/ex:forest[ex:name='south']/ex:trees /ex:tree[ex:name='palm'] move-palm-tree Move the palm tree palm merge / greenhouse 3477cc82 10 In this example the tree resource has been edited by another client since the reply for this client, so the edit request is not even attempted. Instead an "operation-failed" is returned: Bierman Expires April 24, 2015 [Page 54] Internet-Draft NETCONF-EX October 2014 move-palm-tree protocol operation-failed precondition-failed /ex:forests/ex:forest[ex:name='south']/ex:trees/ ex:tree[ex:name='palm'] if-match precondition failed B.3.3. Bulk Editing with "target-resource" Parameter In this example, the server supports the :candidate and :startup capabilities, so all 3 datastores (including running) are locked for the operation. There is a new pine tree for each forest that is being created and sent to the greenhouse. Bierman Expires April 24, 2015 [Page 55] Internet-Draft NETCONF-EX October 2014 /ex:forests/ex:forest pine-tree-patch Add 2 new pine trees to greenhouse pine create /ex:trees pine greenhouse 10 The edit succeeds, and the "yang-patch-status" container is returned to the client with the status information. pine-tree-patch pine Bierman Expires April 24, 2015 [Page 56] Internet-Draft NETCONF-EX October 2014 B.3.4. Edit Validation with "test-only" Parameter In this example, the client is checking if it can change the location field in the "palm" tree list entry by using the "test-only" parameter: /ex:forests/ex:forest[ex:name='south']/ex:trees palm-tree-move Move the palm tree to riverside palm merge /ex:tree/palm riverside Since "riverside" is not a supported location, an "invalid-value" error is returned for the requested edit operation: Bierman Expires April 24, 2015 [Page 57] Internet-Draft NETCONF-EX October 2014 palm-tree-move palm protocol invalid-value /ex:forests/ex:forest[ex:name='south']/ex:trees/ ex:tree[ex:name='palm'] value is invalid B.4. Examples B.4.1. If-Modified-Since Non-Empty Filter Retrieval In this example, the running datastore was last modified at "2012-09-09T01:43:27Z" because the forest named "north" was modified at this time. o The forest named "north" was last modified after the specified "if-modified-since" timestamp. o The forest named "south" was last modified before the specified "if-modified-since" timestamp. o The server maintains a last-modified timestamp for the running datastore and the "forest" list entries. o The client is requesting only the changed entries after 2012-09- 09T01:43:27Z, so the "full-delta" parameter is set. Bierman Expires April 24, 2015 [Page 58] Internet-Draft NETCONF-EX October 2014 o The client is also requesting that timestamps be returned within the data nodes. If any part of the "forest" subtree is modified then this timestamp will be updated. 2012-09-09T01:43:27Z ncex:timestamps north birch hillside ash southwest pasture maple east meadow Bierman Expires April 24, 2015 [Page 59] Internet-Draft NETCONF-EX October 2014 B.4.2. If-Modified-Since Empty Filter Retrieval In this example the client has changed the "if-modified-since" timestamp to a time in the future. o No "forest" list entry has been modified since this time so an empty data node is returned. o Note that the "last-modified" timestamp is returned for the node representing the datastore, even though no data nodes have been modified since the specified time. This allows the client to easily retrieve the last-modified timestamp for the entire datastore. 2012-09-09T03:43:27Z ncex:timestamps B.4.3. Keys Only Filter Retrieval This example retrieves only the names from the "forests" subtree in the running datastore. o The default source (running) is used. o The default depth="0" is used to retrieve all subtree levels. o The "keys-only" leaf is set o The "forests" subtree is selected. The xpath-filter is used instead of the subtree-filter. Bierman Expires April 24, 2015 [Page 60] Internet-Draft NETCONF-EX October 2014 o Whitespace added to xpath-filter element for display purposes only. /ex:forests north birch ash maple south banyan palm Bierman Expires April 24, 2015 [Page 61] Internet-Draft NETCONF-EX October 2014 B.4.4. Test for Node Existence with Depth=1 This example retrieves the "trees" node to determine which forests have any trees. o Only 1 subtree level is requested, instead of the default of all levels. o The default source (running) is used. o The "trees" subtree is selected. o The depth parameter is set to "1" to only retrieve the requested layer "trees" and its ancestor nodes and the configuration leaf nodes from each "forest" entry. 1 north south Bierman Expires April 24, 2015 [Page 62] Internet-Draft NETCONF-EX October 2014 B.4.5. Retrieve Only Non-Configuration Data Nodes This example retrieves only the name leafs from the "forest" list within the "forests" subtree, in the running datastore. o The "source" leaf is set to the "operational" data source o The "forests" subtree is selected Bierman Expires April 24, 2015 [Page 63] Internet-Draft NETCONF-EX October 2014 north birch 41.013 ash 16.523 maple 51.204 south banyan 91.433 palm 83.439 Bierman Expires April 24, 2015 [Page 64] Internet-Draft NETCONF-EX October 2014 Author's Address Andy Bierman YumaWorks, Inc. Email: andy@yumaworks.com Bierman Expires April 24, 2015 [Page 65]