Network Working Group R. Enns, Ed. Internet-Draft Juniper Networks Expires: August 19, 2005 February 18, 2005 NETCONF Configuration Protocol draft-ietf-netconf-prot-05 Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668. 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 August 19, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract The NETCONF configuration protocol defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML) based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized on top of a simple Remote Procedure Call (RPC) layer. Please send comments to netconf@ops.ietf.org. To subscribe, use Enns Expires August 19, 2005 [Page 1] Internet-Draft NETCONF Protocol February 2005 netconf-request@ops.ietf.org. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1 Protocol Overview . . . . . . . . . . . . . . . . . . . . 6 1.2 Capabilities . . . . . . . . . . . . . . . . . . . . . . . 7 1.3 Separation of Configuration and State Data . . . . . . . . 7 2. Application Protocol Requirements . . . . . . . . . . . . . . 8 2.1 Connection-oriented operation . . . . . . . . . . . . . . 9 2.2 Authentication, Integrity, and Privacy . . . . . . . . . . 9 2.3 Authentication . . . . . . . . . . . . . . . . . . . . . . 9 3. XML Considerations . . . . . . . . . . . . . . . . . . . . . . 10 3.1 Namespace . . . . . . . . . . . . . . . . . . . . . . . . 10 3.2 No DTDs . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. RPC Model . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.1 Element . . . . . . . . . . . . . . . . . . . . . . 10 4.2 Element . . . . . . . . . . . . . . . . . . . 11 4.3 Element . . . . . . . . . . . . . . . . . . . 12 4.4 Element . . . . . . . . . . . . . . . . . . . . . . . 14 4.5 Pipelining . . . . . . . . . . . . . . . . . . . . . . . . 14 5. Configuration Model . . . . . . . . . . . . . . . . . . . . . 14 5.1 Configuration Datastores . . . . . . . . . . . . . . . . . 15 6. Subtree Filtering . . . . . . . . . . . . . . . . . . . . . . 15 6.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . 15 6.2 Subtree filter components . . . . . . . . . . . . . . . . 16 6.3 Attribute Match Expressions . . . . . . . . . . . . . . . 16 6.4 Containment Nodes . . . . . . . . . . . . . . . . . . . . 17 6.5 Content Match Nodes . . . . . . . . . . . . . . . . . . . 17 6.6 Selection Nodes . . . . . . . . . . . . . . . . . . . . . 18 6.7 Subtree Filter Processing . . . . . . . . . . . . . . . . 18 6.8 Subtree Filtering Examples . . . . . . . . . . . . . . . . 18 6.8.1 No filter . . . . . . . . . . . . . . . . . . . . . . 19 6.8.2 Empty filter . . . . . . . . . . . . . . . . . . . . . 19 6.8.3 Select the entire subtree . . . . . . . . . . 19 6.8.4 Select all elements within the subtree . . . . . . . . . . . . . . . . . . . . . . . 21 6.8.5 One specific entry . . . . . . . . . . . . . . 22 6.8.6 Specific elements from a specific entry . . . . 23 6.8.7 Multiple Subtrees . . . . . . . . . . . . . . . . . . 24 6.8.8 Elements with attribute naming . . . . . . . . . . . . 26 7. Protocol Operations . . . . . . . . . . . . . . . . . . . . . 27 7.1 . . . . . . . . . . . . . . . . . . . . . . . 28 7.2 . . . . . . . . . . . . . . . . . . . . . . 30 7.3 . . . . . . . . . . . . . . . . . . . . . . 36 7.4 . . . . . . . . . . . . . . . . . . . . . 38 7.5 . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7.6 . . . . . . . . . . . . . . . . . . . . . . . . . 41 Enns Expires August 19, 2005 [Page 2] Internet-Draft NETCONF Protocol February 2005 7.7 . . . . . . . . . . . . . . . . . . . . . . . . . . 42 7.8 . . . . . . . . . . . . . . . . . . . . . 44 7.9 . . . . . . . . . . . . . . . . . . . . . . 45 8. Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . 46 8.1 Capabilities Exchange . . . . . . . . . . . . . . . . . . 46 8.2 Writable-Running Capability . . . . . . . . . . . . . . . 47 8.2.1 Description . . . . . . . . . . . . . . . . . . . . . 47 8.2.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 47 8.2.3 Capability and Namespace . . . . . . . . . . . . . . . 47 8.2.4 New Operations . . . . . . . . . . . . . . . . . . . . 48 8.2.5 Modifications to Existing Operations . . . . . . . . . 48 8.3 Candidate Configuration Capability . . . . . . . . . . . . 48 8.3.1 Description . . . . . . . . . . . . . . . . . . . . . 48 8.3.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 49 8.3.3 Capability and Namespace . . . . . . . . . . . . . . . 49 8.3.4 New Operations . . . . . . . . . . . . . . . . . . . . 49 8.3.5 Modifications to Existing Operations . . . . . . . . . 50 8.4 Confirmed Commit Capability . . . . . . . . . . . . . . . 51 8.4.1 Description . . . . . . . . . . . . . . . . . . . . . 51 8.4.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 51 8.4.3 Capability and Namespace . . . . . . . . . . . . . . . 52 8.4.4 New Operations . . . . . . . . . . . . . . . . . . . . 52 8.4.5 Modifications to Existing Operations . . . . . . . . . 52 8.5 Rollback on Error Capability . . . . . . . . . . . . . . . 53 8.5.1 Description . . . . . . . . . . . . . . . . . . . . . 53 8.5.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 53 8.5.3 Capability and Namespace . . . . . . . . . . . . . . . 53 8.5.4 New Operations . . . . . . . . . . . . . . . . . . . . 53 8.5.5 Modifications to Existing Operations . . . . . . . . . 53 8.6 Validate Capability . . . . . . . . . . . . . . . . . . . 54 8.6.1 Description . . . . . . . . . . . . . . . . . . . . . 54 8.6.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 54 8.6.3 Capability and Namespace . . . . . . . . . . . . . . . 54 8.6.4 New Operations . . . . . . . . . . . . . . . . . . . . 55 8.7 Distinct Startup Capability . . . . . . . . . . . . . . . 56 8.7.1 Description . . . . . . . . . . . . . . . . . . . . . 56 8.7.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 56 8.7.3 Capability and Namespace . . . . . . . . . . . . . . . 56 8.7.4 New Operations . . . . . . . . . . . . . . . . . . . . 56 8.7.5 Modifications to Existing Operations . . . . . . . . . 56 8.8 URL Capability . . . . . . . . . . . . . . . . . . . . . . 57 8.8.1 Description . . . . . . . . . . . . . . . . . . . . . 57 8.8.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 57 8.8.3 Capability and Namespace . . . . . . . . . . . . . . . 57 8.8.4 New Operations . . . . . . . . . . . . . . . . . . . . 58 8.8.5 Modifications to Existing Operations . . . . . . . . . 58 8.9 XPath Capability . . . . . . . . . . . . . . . . . . . . . 58 8.9.1 Description . . . . . . . . . . . . . . . . . . . . . 58 Enns Expires August 19, 2005 [Page 3] Internet-Draft NETCONF Protocol February 2005 8.9.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 58 8.9.3 Capability and Namespace . . . . . . . . . . . . . . . 58 8.9.4 New Operations . . . . . . . . . . . . . . . . . . . . 59 8.9.5 Modifications to Existing Operations . . . . . . . . . 59 9. Security Considerations . . . . . . . . . . . . . . . . . . . 59 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . 61 11. Authors and Acknowledgements . . . . . . . . . . . . . . . . 61 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 62 12.1 Normative References . . . . . . . . . . . . . . . . . . . . 62 12.2 Informative References . . . . . . . . . . . . . . . . . . . 62 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 63 A. NETCONF Error List . . . . . . . . . . . . . . . . . . . . . . 63 B. XML Schema for NETCONF RPC and Protocol Operations . . . . . . 66 C. Capability Template . . . . . . . . . . . . . . . . . . . . . 75 C.1 capability-name (template) . . . . . . . . . . . . . . . . 75 C.1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . 75 C.1.2 Dependencies . . . . . . . . . . . . . . . . . . . . . 75 C.1.3 Capability and Namespace . . . . . . . . . . . . . . . 75 C.1.4 New Operations . . . . . . . . . . . . . . . . . . . . 75 C.1.5 Modifications to Existing Operations . . . . . . . . . 75 C.1.6 Interactions with Other Capabilities . . . . . . . . . 75 D. Configuring Multiple Devices with NETCONF . . . . . . . . . . 76 D.1 Operations on Individual Devices . . . . . . . . . . . . . 76 D.1.1 Acquiring the Configuration Lock . . . . . . . . . . . 76 D.1.2 Loading the Update . . . . . . . . . . . . . . . . . . 77 D.1.3 Validating the Incoming Configuration . . . . . . . . 77 D.1.4 Checkpointing the Running Configuration . . . . . . . 78 D.1.5 Changing the Running Configuration . . . . . . . . . . 79 D.1.6 Testing the New Configuration . . . . . . . . . . . . 79 D.1.7 Making the Change Permanent . . . . . . . . . . . . . 80 D.1.8 Releasing the Configuration Lock . . . . . . . . . . . 80 D.2 Operations on Multiple Devices . . . . . . . . . . . . . . 81 E. Deferred Features . . . . . . . . . . . . . . . . . . . . . . 82 F. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 82 F.1 draft-ietf-netconf-prot-05 . . . . . . . . . . . . . . . . 82 F.2 draft-ietf-netconf-prot-04 . . . . . . . . . . . . . . . . 83 F.3 draft-ietf-netconf-prot-03 . . . . . . . . . . . . . . . . 84 F.4 draft-ietf-netconf-prot-02 . . . . . . . . . . . . . . . . 85 Intellectual Property and Copyright Statements . . . . . . . . 87 Enns Expires August 19, 2005 [Page 4] Internet-Draft NETCONF Protocol February 2005 1. Introduction The NETCONF protocol defines a simple mechanism through which a network device can be managed, configuration data information can be retrieved, and new configuration data can be uploaded and manipulated. The protocol allows the device to expose a full, formal, application programming interface (API). Applications can use this straight-forward API to send and receive full and partial configuration data sets. NETCONF uses a remote procedure call (RPC) paradigm to define a formal API for the network device. A client encodes an RPC in XML [1] and sends it to a server using a secure, connection-oriented session. The server responds with a reply encoded in XML. The contents of both the request and the response are fully described in XML DTDs or XML schemas, or both, allowing both parties to recognize the syntax constraints imposed on the exchange. A key aspect of NETCONF is that it allows the functionality of the API to closely mirror the native functionality of the device. This reduces implementation costs and allows timely access to new features. In addition, applications can access both the syntactic and semantic content of the device's native user interface. NETCONF allows a client to discover the set of protocol extensions supported by a server. These "capabilities" permit the client to adjust its behavior to take advantage of the features exposed by the device. The capability definitions can be easily extended in a noncentralized manner. Standard and non-standard capabilities can be defined with semantic and syntactic rigor. Capabilities are discussed in Section 8. The NETCONF protocol is a building block in a system of automated configuration. XML is the lingua franca of interchange, providing a flexible but fully specified encoding mechanism for hierarchical content. NETCONF can be used in concert with XML-based transformation technologies such as XSLT [9] to provide a system for automated generation of full and partial configurations. The system can query one or more databases for data about networking topologies, links, policies, customers, and services. This data can be transformed using one or more XSLT scripts from a task-oriented, vendor-independent data schema into a form that is specific to the vendor, product, operating system, and software release. The resulting data can be passed to the device using the NETCONF protocol. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this Enns Expires August 19, 2005 [Page 5] Internet-Draft NETCONF Protocol February 2005 document are to be interpreted as described in RFC 2119 [3]. 1.1 Protocol Overview NETCONF uses a simple RPC-based mechanism to facilitate communication between a client and a server. The client can be a script or application typically running as part of a network manager. The server is typically a network device. The terms "device" and "server" are used interchangeably in this document, as are "client" and "application". A NETCONF session is the logical connection between a network administrator or network configuration application and a network device. A device MUST support at least one NETCONF session, and SHOULD support multiple sessions. Global configuration attributes can be changed during any authorized session, and the affects are visible in all sessions. Session-specific attributes affect only the session in which they are changed. NETCONF can be conceptually partitioned into four layers: Layer Example +-------------+ +-----------------------------+ (4) | Content | | Configuration data | +-------------+ +-----------------------------+ | | +-------------+ +-----------------------------+ (3) | Operations | | , | +-------------+ +-----------------------------+ | | +-------------+ +-----------------------------+ (2) | RPC | | , | +-------------+ +-----------------------------+ | | +-------------+ +-----------------------------+ (1) | Application | | BEEP, SSH, SSL, console | | Protocol | | | +-------------+ +-----------------------------+ 1. The application protocol layer provides a communication path between the client and server. NETCONF can be layered over any application protocol that provides a set of basic requirements. Section 2 discusses these requirements. 2. The RPC layer provides a simple, transport-independent framing mechanism for encoding RPCs. Section 4 documents this protocol. 3. The operations layer defines a set of base operations invoked as Enns Expires August 19, 2005 [Page 6] Internet-Draft NETCONF Protocol February 2005 RPC methods with XML-encoded parameters. Section 7 details the list of base operations. 4. The content layer is outside the scope of this document. Given the current proprietary nature of the configuration data being manipulated, the specification of this content depends on the NETCONF implementation. It is expected that a separate effort to specify a standard data definition language and standard content will be undertaken. 1.2 Capabilities A NETCONF capability is a set of functionality that supplements the base NETCONF specification. The capability is identified by a uniform resource identifier (URI). These URIs should follow the guidelines as described in Section 8. Capabilities augment the base operations of the device, describing both additional operations and the content allowed inside operations. The client can discover the server's capabilities and use any additional operations, parameters, and content defined by those capabilities. The capability definition may name one or more dependent capabilities. To support a capability, the server MUST support any capabilities upon which it depends. Section 8 defines the capabilities exchange that allows the client to discover the server's capabilities. Section 8 also lists the set of capabilities defined in this document. Additional capabilities can be defined at any time in external documents, allowing the set of capabilities to expand over time. Standards bodies may define standardized capabilities and implementations may define proprietary ones. A capability URI MUST sufficiently distinguish the naming authority to avoid naming collisions. 1.3 Separation of Configuration and State Data The information that can be retrieved from a running system is separated into two classes, configuration data and state data. Configuration data is the set of writable data that is required to transform a system from its initial default state into its current state. State data is the additional data on a system that is not configuration data such as read-only status information and collected statistics. When a device is performing configuration operations a Enns Expires August 19, 2005 [Page 7] Internet-Draft NETCONF Protocol February 2005 number of problems would arise if state data were included: o Comparisons of configuration data sets would be dominated by irrelevant entries such as different statistics. o Incoming data could contain nonsensical requests, such as attempts to write read-only data. o The data sets would be large. o Archived data could contain values for read-only data items, complicating the processing required to restore archived data. To account for these issues, the NETCONF protocol recognizes the difference between configuration data and state data and provides operations for each. The operation retrieves configuration data only while the operation retrieves configuration and state data. Note that the NETCONF protocol is focused on the information required to get the device into its desired running state. The inclusion of other important, persistent data is implementation specific. For example, user files and databases are not treated as configuration data by the NETCONF protocol. If a local database of user authentication data is stored on the device, whether it is included in configuration data is an implementation dependent matter. 2. Application Protocol Requirements NETCONF uses an RPC-based communication paradigm. A client sends a series of one or more RPC request operations, which cause the server to respond with a corresponding series of RPC replies. The NETCONF protocol can be layered on any application protocol that provides the required set of functionality. It is not bound to any particular application protocol, but allows a mapping to define how it can be implemented over any specific protocol. The application protocol MUST provide a mechanism to indicate the session type (client or server) to the NETCONF protocol layer. This section details the characteristics that NETCONF requires from the underlying application protocol. Enns Expires August 19, 2005 [Page 8] Internet-Draft NETCONF Protocol February 2005 2.1 Connection-oriented operation NETCONF is connection-oriented, requiring a persistent connection between peers. This connection must provide reliable, sequenced data delivery. NETCONF connections are long-lived, persisting between protocol operations. This allows the client to make changes to the state of the connection that will persist for the lifetime of the connection. For example, authentication information specified for a connection remains in effect until the connection is closed. In addition, resources requested from the server for a particular connection MUST be automatically released when the connection closes, making failure recovery simpler and more robust. For example, when a lock is acquired by a client, the lock persists until either explicitly released or the server determines that the connection has been terminated. If a connection is terminated while the client holds a lock, the server can perform any appropriate recovery. The lock operation is further discussed in Section 7.5. 2.2 Authentication, Integrity, and Privacy NETCONF connections must provide authentication, data integrity, and privacy. NETCONF depends on the application protocol for this capability. A NETCONF peer assumes that an appropriate level of security and privacy are provided independent of this document. For example, connections may be encrypted in TLS [4] or SSH [10], depending on the underlying protocol. 2.3 Authentication NETCONF connections must be authenticated. The application protocol is responsible for authentication. The peer assumes that the connection's authentication information has been validated by the underlying protocol using sufficiently trustworthy mechanisms and that the peer's identity has been sufficiently proven. One goal of NETCONF is to provide a programmatic interface to the device that closely follows the functionality of the device's native interface. Therefore, it is expected that the underlying protocol uses existing authentication mechanisms defined by the device. For example, a device that supports RADIUS [7] should allow the use of RADIUS to authenticate NETCONF sessions. The authentication process should result in an identity whose permissions are known to the device. These permissions MUST be enforced during the remainder of the NETCONF session. Enns Expires August 19, 2005 [Page 9] Internet-Draft NETCONF Protocol February 2005 3. XML Considerations XML serves as the encoding format for NETCONF, allowing complex hierarchical data to be expressed in a text format that can be read, saved, and manipulated with both traditional text tools and tools specific to XML. This section discusses a small number of XML-related considerations pertaining to NETCONF. 3.1 Namespace All NETCONF protocol elements are defined in the following namespace: urn:ietf:params:xml:ns:netconf:base:1.0 Capability names may be either URIs [5] or URNs [6]. 3.2 No DTDs Document type declarations (DTDs) are not permitted to appear in NETCONF content. 4. RPC Model The NETCONF protocol uses an RPC-based communication model. NETCONF peers use and elements to provide application protocol-independent framing of NETCONF requests and responses. 4.1 Element The element is used to enclose a NETCONF request sent from the client to the server. The element has a mandatory attribute "message-id", which is an arbitrary string chosen by the sender of the RPC that will commonly encode a monotonically increasing integer. The receiver of the RPC does not decode or interpret this string but simply saves it to use as a "message-id" attribute in any resulting message. For example: ... Enns Expires August 19, 2005 [Page 10] Internet-Draft NETCONF Protocol February 2005 If additional attributes are present in an element, a NETCONF peer must return them unmodified in the element. The name and parameters of an RPC are encoded as the contents of the element. The name of the RPC is an element directly inside the element, and any parameters are encoded inside this element. The following example invokes a method called "my-own-method" which has two parameters, "my-first-parameter", with a value of "14", and "another-parameter", with a value of "fred": 14 fred The following example invokes a "rock-the-house" method with a "zip-code" parameter of "27606-0100": 27606-0100 The following example invokes the "rock-the-world" method with no parameters: 4.2 Element The message is sent in response to a operation. The element has a mandatory attribute "message-id", which is equal to the "message-id" attribute of the for which this is a response. A NETCONF peer must also return any additional attributes included in the element unmodified in the element. Enns Expires August 19, 2005 [Page 11] Internet-Draft NETCONF Protocol February 2005 The response name and response data are encoded as the contents of the element. The name of the reply is an element directly inside the element, and any data is encoded inside this element. For example: 4.3 Element The element is sent in messages if an error occurs during the processing of an request. The element includes the following information: error-type: Defines the conceptual layer that the error occurred. Enumeration. One of: * transport * rpc * protocol * application error-tag: Contains a string identifying the error condition. See Appendix A for allowed values. error-severity: Contains a string identifying the error severity, as determined by the device. One of: * error * warning error-app-tag: Contains a string identifying the data model specific or implementation specific error condition, if one exists. This element will not be present if no appropriate application error tag can be associated with a particular error condition. Enns Expires August 19, 2005 [Page 12] Internet-Draft NETCONF Protocol February 2005 error-path: Contains the absolute XPath [2] expression identifying the element path to the node which is associated with the error being reported in a particular rpc-error element. This element will not be present if no appropriate payload element can be associated with a particular error condition, or if the 'bad-element' QString returned in the 'error-info' container is sufficient to identify the node associated with the error. error-message: Contains a string suitable for human display which describes the error condition. This element will not be present if no appropriate message is provided for a particular error condition. error-info: Contains protocol or data model specific error content. This element will not be present if no such error content is provided for a particular error condition. The list in Appendix A defines any mandatory error-info content for each error. After any protocol-mandated content, a data model definition may mandate certain application layer error information be included in the error-info container. An implementation may include additional elements to provide extended and/or implementation-specific debugging information. Appendix A enumerates the standard NETCONF errors. Example: An error is returned if an element is received without a message-id attribute. Note that only in this case is it acceptable for the NETCONF peer to omit the message-id attribute in the element. Enns Expires August 19, 2005 [Page 13] Internet-Draft NETCONF Protocol February 2005 rpc MISSING_ATTRIBUTE error message-id rpc 4.4 Element The element is sent in messages if no error occurred during the processing of an request. For example: 4.5 Pipelining NETCONF requests MUST be processed serially by the managed device. Additional requests MAY be sent before previous ones have been completed. The managed device MUST send responses only in the order the requests were received. 5. Configuration Model NETCONF provides an initial set of operations and a number of capabilities that can be used to extend the base. NETCONF peers exchange device capabilities when the session is initiated as described in Section 8.1. Enns Expires August 19, 2005 [Page 14] Internet-Draft NETCONF Protocol February 2005 5.1 Configuration Datastores NETCONF defines the existence of one or more configuration datastores and allows configuration operations on them. A configuration datastore is defined as the complete set of configuration data that is required to get a device from its initial default state into a desired operational state. The configuration datastore does not include state data or executive commands. Only the configuration datastore is present in the base model. Additional configuration datastores may be defined by capabilities. Such configuration datastores are available only on devices that advertise the capabilities. o Running: The complete configuration currently active on the network device. Only one configuration datastore of this type exists on the device, and it is always present. NETCONF protocol operations refer to this datastore using the element. The capabilities in Section 8.3 and Section 8.7 define the and configuration datastores, respectively. 6. Subtree Filtering 6.1 Overview XML subtree filtering is a mechanism that allows an application to select particular XML subtrees to include in the for a or operation. A small set of filters for inclusion, simple content exact-match, and selection is provided, which allows some useful, but also very limited selection mechanisms. The server does not need to utilize any data-model specific semantics during processing, allowing for simple and centralized implementation strategies. A subtree filter is comprised of well-formed XML. No special tags, content, or structure are imposed in any way. It is possible that a subtree filter expression may contain an empty leaf node, even if the schema for the particular data model indicates some content is required (i.e., maxOccurs > 0). For this reason, it may not be possible to completely validate all filter expressions against a schema which represents the fully populated data model. Conceptually, a subtree filter is comprised of zero or more element subtrees, which represent the filter selection criteria. At each containment level within a subtree, the set of sibling nodes is logically processed by the server to determine if its subtree (and path to the root) are included in the filter output. Enns Expires August 19, 2005 [Page 15] Internet-Draft NETCONF Protocol February 2005 Element nodes have different purposes, depending on their position in the subtree. Most nodes in the subtree identify containment, in which the specified node name must exactly match a corresponding node in the server's data model. A leaf node in the filter with simple content is used to select matching data (some or all of the set of sibling nodes which includes this leaf node). XML attributes can be present in any node in the filter. Each attribute acts as an additional term for the "AND" expression for that particular node. In addition to matching the name and position of the element, only instances matching all specified attribute values will be included in the response. XML namespaces may be specified (via 'xmlns' declarations) within the filter data model. If so, the declared namespace must first exactly match a namespace supported by the server. Only data associated with a specified namespace will be considered in the filter operation. Response messages contain only the subtrees selected by the filter. Any selection criteria that were present in the request, within a particular selected subtree, is also included in the response. Specific data instances are not duplicated in the response in the event the request contains multiple filter subtree expressions which select the same data. 6.2 Subtree filter components A subtree filter is comprised of XML elements and their XML attributes. An attribute which appears in a subtree filter is called an "attribute match expression". All elements present in a particular subtree within a filter must match associated nodes present in the server's conceptual data model. Nodes which contain only child elements are called "containment nodes". Leaf nodes which contain simple content are called "content match nodes". Empty leaf nodes are called "selection nodes". 6.3 Attribute Match Expressions Any number of (unqualified or qualified) XML attributes may be present in any type of filter node. In addition to the selection criteria normally applicable to that node, the selected data must have matching values for every attribute specified in the node. If an element is not defined to include a specified attribute, then it is not selected in the filter output. Enns Expires August 19, 2005 [Page 16] Internet-Draft NETCONF Protocol February 2005 6.4 Containment Nodes Each node specified in a subtree filter represents an inclusive filter. Only associated nodes in the specified configuration datastore on the server are selected by the filter. A node must exactly match the namespace and absolute path name of the filter data, except the filter absolute path name is adjusted to start from the layer below . A containment node must have one or more child nodes. 6.5 Content Match Nodes A leaf node with simple content represents an exact-match filter on the simple content, which is combined (as an "AND" expression") with the criteria for a containment node, to select data model instances. All sibling content match nodes combine to represent a logical "AND" expression. If all specified sibling content match nodes in a subtree filter expression are 'true', then the server determines the nodes to be selected in the following manner: o If the set of all sibling nodes (at a given processing level) includes content match nodes, then all sibling subtrees (including the content match nodes) are selected by the filter. o If the set of all sibling nodes (at a given processing level) includes any containment or selection nodes, then the content match nodes, plus any sibling subtrees selected by further processing, are selected by the filter. o If a containment node is present in the sibling set, then it is potentially selected. If further recursive processing of its child nodes produces any selected filter output, then the containment nodes of the element hierarchy related to the particular subtree are included in the filter results. o If a selection node is present in the sibling set, then its subtree is selected in the filter output. If any of the sibling content match node tests are 'false', then no further filter processing is performed on that sibling set, and none of the sibling subtrees are selected by the filter, including the content match node(s). Note that explicit selection of empty content by specifying an empty content match node is not supported. Enns Expires August 19, 2005 [Page 17] Internet-Draft NETCONF Protocol February 2005 6.6 Selection Nodes An empty leaf node represents an "explicit selection" filter. Presence of any selection nodes (within a set of sibling nodes) will cause the filter to select the specified subtree(s). If a particular sibling set contains content match nodes and selection or containment nodes, then automatic selection of the entire sibling subtree is suppressed, and only the specified selection and/or containment nodes are selected by the filter. Unless further restricted by the application of attribute match expressions or content match nodes in the entire element hierarchy containing a particular node, the presence of a selection node will cause all instances of that node (and each node's subtree) to be selected by the filter output. 6.7 Subtree Filter Processing The filter output (the set of selected nodes) is initially empty. Each subtree filter can contain one or more data model fragments, which represent portions of the data model which should be selected (with all child nodes) in the filter output. Each subtree data fragment is compared by the server to the internal data models supported by the server. If the entire subtree data-fragment filter (starting from the root to the innermost element specified in the filter) exactly matches a corresponding portion of the supported data model, then that node and all its children are included in the result data. The server processes all nodes with the same parent node (sibling set) together, starting from the root to the leaf nodes. The root elements in the filter are considered to be in the same sibling set (assuming they are in the same namespace), even though they do not have a common parent. For each sibling set, the server determines which nodes are included (or potentially included) in the filter output, and which sibling subtrees are excluded (pruned) from the filter output. The server first determines which types of nodes are present in the sibling set, and processes the nodes according to the rules for their type. If any nodes in the sibling set are selected, then the process is recursively applied to the sibling sets of each selected node. The algorithm continues until all sibling sets in all subtrees specified in the filter have been processed. 6.8 Subtree Filtering Examples Enns Expires August 19, 2005 [Page 18] Internet-Draft NETCONF Protocol February 2005 6.8.1 No filter Leaving out the filter on the get operation returns the entire data model. 6.8.2 Empty filter An empty filter will select nothing because no content match or selection nodes are present. This is not an error. The filter type attribute used in these examples is discussed further in Section 7.1. 6.8.3 Select the entire subtree This filter in this example contains one selection node (), so just that subtree is selected by the filter. This example represents the fully-populated data model in most of the filter examples that follow. In a real data model, the 'company-info' would not likely be returned with the list of users for a particular host or network. Enns Expires August 19, 2005 [Page 19] Internet-Draft NETCONF Protocol February 2005 NOTE: The filtering and configuration examples used in this document appear in the namespace "http://example.com/schema/1.2/config". The root element of this namespace is . The element and it's descendents represent an example configuration data model only. root superuser Charlie Root 1 1 fred admin Fred Flintstone 2 2 barney admin Barney Rubble 2 Enns Expires August 19, 2005 [Page 20] Internet-Draft NETCONF Protocol February 2005 3 The following filter request would have produced the same result, but only because the container defines one child element () 6.8.4 Select all elements within the subtree This filter contains two containment nodes (, ), and one selector node (). All instances of the element in the same sibling set are selected in the filter output. The manager may need to know that is used as an instance identifier in this particular data structure, but the server does not need to know that meta-data in order to process the request. Enns Expires August 19, 2005 [Page 21] Internet-Draft NETCONF Protocol February 2005 root fred barney 6.8.5 One specific entry This filter contains two containment nodes (, ) and one content match node (). All instances of the sibling set containing , for which the value of equals "fred", are selected in the filter output. Enns Expires August 19, 2005 [Page 22] Internet-Draft NETCONF Protocol February 2005 fred fred admin Fred Flintstone 2 2 6.8.6 Specific elements from a specific entry This filter contains two containment nodes (, ), one content match node (), and two selector nodes (, ). All instances of the and elements in the same sibling set containing , for which the value of equals "fred", are selected in the filter output. The element is not included because the sibling set contains selection nodes. Enns Expires August 19, 2005 [Page 23] Internet-Draft NETCONF Protocol February 2005 fred fred admin Fred Flintstone 6.8.7 Multiple Subtrees This filter contains three subtrees (name=root, fred, barney) The "root" subtree filter contains two containment nodes (, ), one content match node (), and one selector node (). The subtree selection criteria is met, and just the company-info subtree for "root" is selected in the filter output. The "fred" subtree filter contains three containment nodes (, , ), one content match node (), and one Enns Expires August 19, 2005 [Page 24] Internet-Draft NETCONF Protocol February 2005 selector node (). The subtree selection criteria is met, and just the element within the company-info subtree for "fred" is selected in the filter output. The "barney" subtree filter contains three containment nodes (, , ), two content match nodes (, ), and one selector node (). The subtree selection criteria is not met because user "barney" is not a "superuser", and the entire subtree for "barney" (including its parent entry) is excluded from the filter output. root fred barney superuser Enns Expires August 19, 2005 [Page 25] Internet-Draft NETCONF Protocol February 2005 root 1 1 fred 2 6.8.8 Elements with attribute naming In this example, the filter contains one containment node (), one attribute match expression (ifName), and one selector node (). All instances of the subtree which have an ifName attribute equal to "eth0" are selected in the filter output. The filter data elements and attributes must be qualified because the ifName attribute will not be considered part of the 'schema/1.2' namespace if it is unqualified. Enns Expires August 19, 2005 [Page 26] Internet-Draft NETCONF Protocol February 2005 45621 774344 If ifName were a child node instead of an attribute, then the following request would produce similar results. eth0 7. Protocol Operations The NETCONF protocol provides a small set of low-level operations to manage device configurations and retrieve device state information. The base protocol provides operations to retrieve, configure, copy, and delete configuration datastores. Additional operations are Enns Expires August 19, 2005 [Page 27] Internet-Draft NETCONF Protocol February 2005 provided, based on the capabilities advertised by the device. The base protocol includes the following protocol operations: o get o get-config o edit-config o copy-config o delete-config o lock o unlock o close-session o kill-session A protocol operation may fail for various reasons, including "operation not supported". An initiator should not assume that any operation will always succeed. The return values in any RPC reply should be checked for error responses. The syntax and XML encoding of the protocol operations are formally defined in the XML schema in Appendix B. The following sections describe the semantics of each protocol operation. 7.1 Description: Retrieve all or part of a specified configuration. Parameters: source: Name of the configuration datastore being queried, such as . If this element is unspecified, the configuration is used. filter: Enns Expires August 19, 2005 [Page 28] Internet-Draft NETCONF Protocol February 2005 The filter element identifies the portions of the device configuration to retrieve. If this element is unspecified, the entire configuration is returned. The filter element may optionally contain a "type" attribute. This attribute indicates the type of filtering syntax used within the filter element. The default filtering mechanism in NETCONF is referred to as subtree filtering and is described in Section 6. The value "subtree" explicitly identifies this type of filtering. If the NETCONF peer supports the #xpath capability (Section 8.9), the value "xpath" may be used to indicate that the filter element contains an XPath expression. Positive Response: If the device can satisfy the request, the server sends an element containing a element with the results of the query. Negative Response: An element is included in the if the request cannot be completed for any reason. Example: To retrieve the entire subtree: Enns Expires August 19, 2005 [Page 29] Internet-Draft NETCONF Protocol February 2005 root superuser Charlie Root 1 1 Section 6 contains additional examples of subtree filtering. 7.2 Description: The operation loads all or part of a specified configuration to the specified target configuration. This operation allows the new configuration to be expressed in several ways, such as using a local file, a remote file, or inline. If the target configuration does not exist, it will be created. Enns Expires August 19, 2005 [Page 30] Internet-Draft NETCONF Protocol February 2005 The device analyzes the source and target configurations and performs the requested changes. The target configuration is not necessarily replaced, as with the message. Instead the target configuration is changed in accordance with the source's data and requested operations. Attributes: operation: Elements in the subtree may contain an "operation" attribute. The attribute identifies the point in the configuration to perform the operation, and MAY appear on multiple elements throughout the subtree. If the operation attribute is not specified, the configuration is merged into the configuration datastore. The operation attribute has one of the following values: merge: The configuration data identified by the element containing this attribute is merged with the configuration at the corresponding level in the configuration datastore identified by the target parameter. This is the default behavior. replace: The configuration data identified by the element containing this attribute replaces any related configuration in the configuration datastore identified by the target parameter. Unlike a operation, which replaces the entire target configuration, only the configuration actually present in the config parameter is affected. create: The configuration data identified by the element containing this attribute is added to the configuration if and only if the configuration data does not already exist on the device. If the configuration data exists, an element is returned with an value of DATA_EXISTS. delete: The configuration data identified by the element containing this attribute is deleted in the configuration datastore identified by the target parameter. Parameters: Enns Expires August 19, 2005 [Page 31] Internet-Draft NETCONF Protocol February 2005 target: Configuration datastore being edited, such as or . default-operation: Selects the default operation (as described in the "operation" attribute) for this request. The default value for the default-operation parameter is "merge". The default-operation parameter is optional, but if provided, must have one of the following values: merge: The configuration data in the parameter is merged with the configuration at the corresponding level in the target datastore. This is the default behavior. replace: The configuration data in the parameter completely replaces the configuration in the target datastore. This is useful for loading previously saved configuration data. none: The target datastore is unaffected by the configuration in the parameter, unless and until the incoming configuration data uses the "operation" attribute to request a different operation. If the configuration in the parameter contains data for which there is not a corresponding level in the target datastore, an is returned with an value of DATA_MISSING. Using "none" allows operations like "delete" to avoid unintentionally creating the parent hierarchy of the element to be deleted. test-option: The test-option element may be specified only if the device advertises the #validate capability (Section 8.6). The test-option element has one of the following values: test-then-set: Perform a validation test before attempting to set. If validation errors occur, do not perform the operation. This is the default test-option. set: Perform a set without a validation test first. Enns Expires August 19, 2005 [Page 32] Internet-Draft NETCONF Protocol February 2005 error-option: The error-option element has one of the following values: stop-on-error: Abort the edit-config operation on first error. This is the default error-option. ignore-error: Continue to process configuration data on error; error is recorded and negative response is generated if any errors occur. rollback-on-error: If an error condition occurs such that an error severity element is generated, the server will stop processing the edit-config operation and restore the specified configuration to its complete state at the start of this edit-config operation. This option requires the server to support the #rollback-on-error capability described in Section 8.5. config: Portion of the configuration subtree to edit. The namespace of this configuration should be specified as an attribute of this parameter. Positive Response: If the device was able to satisfy the request, an is sent containing an element. Negative Response: An response is sent if the request cannot be completed for any reason. Example: Set the MTU to 1500 on an interface named "Ethernet0/0" in the running configuration: Enns Expires August 19, 2005 [Page 33] Internet-Draft NETCONF Protocol February 2005 Ethernet0/0 1500 Add an interface named "Ethernet0/0" to the running configuration, replacing any previous interface with that name: Ethernet0/0 1500
1.2.3.4 24
Enns Expires August 19, 2005 [Page 34] Internet-Draft NETCONF Protocol February 2005 Delete the configuration for an interface named "Ethernet0/0" from the running configuration: none Ethernet0/0 Delete interface 192.168.0.1 from an OSPF area (other interfaces configured in the same area are unaffected): Enns Expires August 19, 2005 [Page 35] Internet-Draft NETCONF Protocol February 2005 none 0.0.0.0 192.168.0.1 7.3 Description: Create or replace an entire configuration datastore with the contents of another complete configuration datastore. If the target datastore exists, it is overwritten. Otherwise, a new one is created, if allowed. If a NETCONF peer supports the #url capability (Section 8.8), the element can appear as the or parameter. A device may choose not to support the configuration datastore as the parameter of a operation. A device may choose not to support remote to remote copy operations, where both the and parameters use Enns Expires August 19, 2005 [Page 36] Internet-Draft NETCONF Protocol February 2005 the element. If the source and target parameters identify the same URL or configuration datastore, an error MUST be returned with an error-tag containing INVALID_VALUE. Parameters: source: The configuration datastore to use as the source of the copy operation or the element containing the configuration subtree to copy. target: The configuration datastore to use as the destination of the copy operation. Positive Response: If the device was able to satisfy the request, an is sent that includes an element. Negative Response: An element is included within the if the request cannot be completed for any reason. Example: ftp://example.com/configs/testbed-dec10.txt Enns Expires August 19, 2005 [Page 37] Internet-Draft NETCONF Protocol February 2005 7.4 Description: Delete a configuration datastore. The configuration datastore cannot be deleted. If a NETCONF peer supports the #url capability (Section 8.8), the element can appear as the parameter. Parameters: target: Name of the configuration datastore to delete. Positive Response: If the device was able to satisfy the request, an is sent that includes an element. Negative Response: An element is included within the if the request cannot be completed for any reason. Example: 7.5 Enns Expires August 19, 2005 [Page 38] Internet-Draft NETCONF Protocol February 2005 Description: The lock operation allows the client to lock the configuration system of a device. Such locks are intended to be short-lived and allow a client to make a change without fear of interaction with other NETCONF clients, non-NETCONF clients (SNMP and CLI scripts) and human users. An attempt to lock the configuration MUST fail if an existing session or other entity holds a lock on any portion of the lock target. When the lock is acquired, the server MUST prevent any changes to the locked resource other than those requested by this session. SNMP and CLI requests to modify the resource MUST fail with an appropriate error. The duration of the lock is defined as beginning when the lock is acquired and lasting until either the lock is released or the NETCONF session closes. The session closure may be explicitly performed by the client, or implicitly performed by the server based on criteria such as failure of the underlying transport, or simple inactivity timeout. This criteria is dependent on the implementation and the underlying transport. The lock operation takes a mandatory parameter, target. The target parameter names the configuration that will be locked. When a lock is active, using the operation on the locked configuration and using the locked configuration as a target of the operation will be disallowed by any other NETCONF session. Additionally, the system will ensure that these locked configuration resources will not be modified by other non-NETCONF management operations such as SNMP and CLI. The message (at the RPC layer) can be used to force the release of a lock owned by another NETCONF session. It is beyond the scope of this document to define how to break locks held by other entities. A lock MUST not be granted if any of the following conditions are true: * a lock is already held by another NETCONF session or another entity * the target configuration has already been modified and these changes have not been committed or rolled back Enns Expires August 19, 2005 [Page 39] Internet-Draft NETCONF Protocol February 2005 The server MUST respond with either an element or an . A lock will be released by the system if the session holding the lock is terminated for any reason. Parameters: target: Name of the configuration datastore to lock. Positive Response: If the device was able to satisfy the request, an is sent that contains an element. Negative Response: An element is included in the if the request cannot be completed for any reason. If the lock is already held, the element will be IN_USE and the element will include the of the lock owner. If the lock is held by a non-NETCONF entity, a session-id of 0 (zero) is included. Note that any other entity performing a lock on even a partial piece of a target will prevent a NETCONF lock (which is global) from being obtained on that target. Example: The following example shows a successful acquisition of a lock. Enns Expires August 19, 2005 [Page 40] Internet-Draft NETCONF Protocol February 2005 Example: The following example shows a failed attempt to acquire of a lock when the lock is already in use. protocol IN_USE error Lock failed, lock is already held 454 7.6 Description: The unlock operation is used to release a configuration lock, previously obtained with the operation. An unlock operation will not succeed if any of the following conditions are true: * the specified lock is not currently active * the session issuing the operation is not the same session that obtained the lock Enns Expires August 19, 2005 [Page 41] Internet-Draft NETCONF Protocol February 2005 The server MUST respond with either an element or an . Parameters: target: Name of the configuration datastore to unlock. A NETCONF client is not permitted to unlock a configuration datastore that it did not lock. Positive Response: If the device was able to satisfy the request, an is sent that contains an element. Negative Response: An element is included in the if the request cannot be completed for any reason. Example: 7.7 Description: Retrieve running configuration and device state information. Parameters: Enns Expires August 19, 2005 [Page 42] Internet-Draft NETCONF Protocol February 2005 filter: This parameter specifies the portion of the system configuration and state data to retrieve. If this parameter is empty, all the device configuration and state information is returned. The filter element may optionally contain a "type" attribute. This attribute indicates the type of filtering syntax used within the filter element. The default filtering mechanism in NETCONF is referred to as subtree filtering and is described in Section 6. The value "subtree" explicitly identifies this type of filtering. If the NETCONF peer supports the #xpath capability (Section 8.9), the value "xpath" may be used to indicate that the filter element contains an XPath expression. Positive Response: If the device was able to satisfy the request, an is sent. The section contains the appropriate subset. Negative Response: An element is included in the if the request cannot be completed for any reason. Example: Enns Expires August 19, 2005 [Page 43] Internet-Draft NETCONF Protocol February 2005 eth0 eth0 45621 774344 7.8 Description: Request graceful termination of a NETCONF session. When a NETCONF server receives a request, it will gracefully close the session. The server will release any locks and resources associated with the session and gracefully close any associated connections. Any NETCONF requests received after a request will be ignored. Positive Response: If the device was able to satisfy the request, an is sent that includes an element. Enns Expires August 19, 2005 [Page 44] Internet-Draft NETCONF Protocol February 2005 Negative Response: An element is included in the if the request cannot be completed for any reason. Example: 7.9 Description: Force the termination of a NETCONF session. When a NETCONF entity receives a request for an open session, it will abort any operations currently in process, release any locks and resources associated with the session and close any associated connections. Parameters: session-id: Session identifier of the NETCONF session to be terminated. If this value is equal to the current session ID, an 'INVALID_VALUE' error is returned. Positive Response: If the device was able to satisfy the request, an is sent that includes an element. Negative Response: An element is included in the if the request cannot be completed for any reason. Enns Expires August 19, 2005 [Page 45] Internet-Draft NETCONF Protocol February 2005 Example: 4 8. Capabilities This section defines a set of capabilities that a client or a server MAY implement. Each peer advertises its capabilities by sending them during an initial capabilities exchange. Each peer needs to understand only those capabilities that it might use and must be able to process and ignore any capability received from the other peer that it does not require or does not understand. Additional capabilities can be defined using the template in Appendix C. Future capability definitions may be published as standards by standards bodies or published as proprietary extensions. A NETCONF capability is identified with a URI. The base capabilities are defined using URNs following the method described in RFC 3553 [8]. Capabilities defined in this document have the following format: urn:ietf:params:xml:ns:netconf:base:1.0#{name} where {name} is the name of the capability. Capabilities are often referenced in discussions and email using the shorthand #{name}. For example, the foo capability would have the formal name "urn:ietf:params:xml:ns:netconf:base:1.0#foo" and be called "#foo". The shorthand form MUST NOT be used inside the protocol. 8.1 Capabilities Exchange A NETCONF capability is a set of additional functionality implemented on top of the base NETCONF specification. The capability is distinguished by a URI. Capabilities are advertised in messages sent by each peer during Enns Expires August 19, 2005 [Page 46] Internet-Draft NETCONF Protocol February 2005 session establishment. When the NETCONF session is opened, each peer MUST send a element containing a list of that peer's capabilities. Each peer MUST send at least the base NETCONF capability, "urn:ietf:params:xml:ns:netconf:base:1.0". A server sending the element MUST include a element containing the session ID for this NETCONF session. In the following example, the peer advertises the base NETCONF capability, one NETCONF capability defined in the base NETCONF document, and one implementation-specific capability. urn:ietf:params:xml:ns:netconf:base:1.0 urn:ietf:params:xml:ns:netconf:base:1.0#startup http:/example.net/router/2.3/core#myfeature 4 Each peer sends its element simultaneously as soon as the connection is open. A peer MUST NOT wait to receive the capability set from the other side before sending its own set. 8.2 Writable-Running Capability 8.2.1 Description The #writable-running capability indicates that the device supports writes directly to the configuration datastore. In other words, the device supports edit-config and copy-config operations where the configuration is the target. 8.2.2 Dependencies None. 8.2.3 Capability and Namespace The #writable-running capability is identified by the following capability string: Enns Expires August 19, 2005 [Page 47] Internet-Draft NETCONF Protocol February 2005 urn:ietf:params:xml:ns:netconf:base:1.0#writable-running The #writable-running capability uses the base NETCONF namespace URN. 8.2.4 New Operations None. 8.2.5 Modifications to Existing Operations 8.2.5.1 The #writable-running capability modifies the operation to accept the element as a . 8.2.5.2 The #writable-running capability modifies the operation to accept the element as a . 8.3 Candidate Configuration Capability 8.3.1 Description The candidate configuration capability, #candidate, indicates that the device supports a candidate configuration datastore, which is used to hold configuration data that can manipulated without impacting the device's current configuration. The candidate configuration is a full configuration data set that serves as a work place for creating and manipulating configuration data. Additions, deletions, and changes may be made to this data to construct the desired configuration data. A operation may be performed at any time that causes the device's running configuration to be set to the value of the candidate configuration. The candidate configuration can be used as a source or target of any operation with a or parameter. The element is used to indicate the candidate configuration: Enns Expires August 19, 2005 [Page 48] Internet-Draft NETCONF Protocol February 2005 The candidate configuration may be shared among multiple sessions. Unless a client has specific information that the candidate configuration is not shared (for example, through another capability, e.g. #lock), it must assume that other sessions may be able to modify the candidate configuration at the same time. It is therefore prudent for a client to lock the candidate configuration before modifying it. The client can discard any changes since the last operation by executing the operation. The candidate configuration's content then reverts to the current committed configuration. 8.3.2 Dependencies None. 8.3.3 Capability and Namespace The #candidate capability is identified by the following capability string: urn:ietf:params:xml:ns:netconf:base:1.0#candidate The #candidate capability uses the base NETCONF namespace URN. 8.3.4 New Operations 8.3.4.1 Description: When a candidate configuration's content is complete, the configuration data can be committed, publishing the data set to the rest of the device and requesting the device to conform to the behavior described in the new configuration. To commit the candidate configuration as the device's new current configuration, use the operation. The operation instructs the device to implement the configuration data contained in the candidate configuration. If the device is unable to commit all of the changes in the candidate configuration datastore, then the running configuration MUST remain unchanged. If the device does succeed in committing, the running configuration MUST be updated with the contents of the candidate configuration. Enns Expires August 19, 2005 [Page 49] Internet-Draft NETCONF Protocol February 2005 If the system does not have the #candidate capability, the operation is not available. Positive Response: If the device was able to satisfy the request, an is sent that contains an element. Negative Response: An element is included in the if the request cannot be completed for any reason. Example: 8.3.4.2 If the client decides that the candidate configuration should not be committed, the operation can be used to revert the candidate configuration to the current committed configuration. This operation discards any uncommitted changes by reseting the candidate configuration with the content of the running configuration. 8.3.5 Modifications to Existing Operations 8.3.5.1 and The candidate configuration can be locked using the operation with the element as the parameter: Enns Expires August 19, 2005 [Page 50] Internet-Draft NETCONF Protocol February 2005 Similarly, the candidate configuration is unlocked using the element as the parameter: When a client fails with outstanding changes to the candidate configuration, recovery can be difficult. To facilitate easy recovery, any outstanding changes are discarded when the lock is released, whether explicitly with the operation or implicitly from session failure. 8.4 Confirmed Commit Capability 8.4.1 Description The #confirmed-commit capability indicates that the server will support the and parameters for the protocol operation. See section Section 8.3 for further details on the operation. For shared configurations, this feature can cause other configuration changes (for example, via other NETCONF sessions) to be inadvertently altered or removed, unless the configuration locking feature is used (in other words, lock obtained before the edit-config operation is started). Therefore, it is strongly suggested that in order to use this feature with shared configuration databases, configuration locking must also be available and used properly. 8.4.2 Dependencies The #confirmed-commit capability is only relevant if the #candidate capability is also supported. Enns Expires August 19, 2005 [Page 51] Internet-Draft NETCONF Protocol February 2005 8.4.3 Capability and Namespace The #confirmed-commit capability is identified by the following capability string: urn:ietf:params:xml:ns:netconf:base:1.0#confirmed-commit The #confirmed-commit capability uses the base NETCONF namespace URN. 8.4.4 New Operations None. 8.4.5 Modifications to Existing Operations 8.4.5.1 The #confirmed-commit capability allows 2 additional parameters to the operation confirmed: The element indicates that the operation MUST be reverted if a follow-up commit (called the "confirming commit") is not issued within ten (10) minutes. The timeout period can be adjusted with the element. confirm-timeout: Timeout period for confirmed commit, in minutes. 20 Enns Expires August 19, 2005 [Page 52] Internet-Draft NETCONF Protocol February 2005 8.5 Rollback on Error Capability 8.5.1 Description This capability indicates that the server will support the rollback-on-error value in the parameter to the operation. For shared configurations, this feature can cause other configuration changes (for example, via other NETCONF sessions) to be inadvertently altered or removed, unless the configuration locking feature is used (in other words, lock obtained before the edit-config operation is started). Therefore, it is strongly suggested that in order to use this feature with shared configuration databases, configuration locking must also be used. 8.5.2 Dependencies None 8.5.3 Capability and Namespace The #rollback-on-error capability is identified by the following capability string: urn:ietf:params:xml:ns:netconf:base:1.0#rollback-on-error The #rollback-on-error capability uses the base NETCONF namespace URN. 8.5.4 New Operations None. 8.5.5 Modifications to Existing Operations 8.5.5.1 The #rollback-on-error capability allows the rollback-on-error value to the parameter on the operation. Enns Expires August 19, 2005 [Page 53] Internet-Draft NETCONF Protocol February 2005 rollback-on-error Ethernet0/0 100000 8.6 Validate Capability 8.6.1 Description Validation consists of checking a candidate configuration for syntactical and semantic errors before applying the configuration to the device. If this capability is advertised, the device supports the protocol operation and checks at least for syntax errors. In addition, this capability supports the test-option parameter to the operation and, when it is provided, checks at least for syntax errors. 8.6.2 Dependencies None. 8.6.3 Capability and Namespace The #validate capability is identified by the following capability string: urn:ietf:params:xml:ns:netconf:base:1.0#validate Enns Expires August 19, 2005 [Page 54] Internet-Draft NETCONF Protocol February 2005 The #validate capability uses the base NETCONF namespace URN. 8.6.4 New Operations 8.6.4.1 Description: This protocol operation validates the contents of the specified configuration. Parameters: source: Name of the configuration datastore being validated, such as . Positive Response: If the device was able to satisfy the request, an is sent that contains an element. Negative Response: An element is included in the if the request cannot be completed for any reason. A validate operation can fail for any of the following reasons: + Syntax errors + Missing parameters + References to undefined configuration data Example: Enns Expires August 19, 2005 [Page 55] Internet-Draft NETCONF Protocol February 2005 8.7 Distinct Startup Capability 8.7.1 Description The device supports separate running and startup configuration datastores. Operations which affect the running configuration will not be automatically copied to the startup configuration. An explicit operation from the to the must be invoked to update the startup configuration to the current contents of the running configuration. NETCONF protocol operations refer to the startup datastore using the element. 8.7.2 Dependencies None. 8.7.3 Capability and Namespace The #startup capability is identified by the following capability string: urn:ietf:params:xml:ns:netconf:base:1.0#startup The #startup capability uses the base NETCONF namespace URN. 8.7.4 New Operations None. 8.7.5 Modifications to Existing Operations Enns Expires August 19, 2005 [Page 56] Internet-Draft NETCONF Protocol February 2005 8.7.5.1 To save the startup configuration, use the copy-config operation to copy the configuration datastore to the configuration datastore. 8.8 URL Capability 8.8.1 Description The NETCONF peer has the ability to accept the element in and parameters. The capability is further identified by URL arguments indicating the protocols supported. 8.8.2 Dependencies None. 8.8.3 Capability and Namespace The #url capability is identified by the following capability string: urn:ietf:params:xml:ns:netconf:base:1.0#url?protocol={name,...} The #url capability uses the base NETCONF namespace URN. The #url capability URI MUST contain a "protocol" argument assigned a comma-separated list of protocol names indicating which protocols the NETCONF peer supports. For example: urn:ietf:params:xml:ns:netconf:base:1.0#url?protocol=http,ftp,file The #url capability uses the base NETCONF namespace URN. Enns Expires August 19, 2005 [Page 57] Internet-Draft NETCONF Protocol February 2005 8.8.4 New Operations None. 8.8.5 Modifications to Existing Operations 8.8.5.1 The #url capability modifies the operation to accept the element as the parameter. 8.8.5.2 The #url capability modifies the operation to accept the element as the value of the the and the parameters. 8.8.5.3 The #url capability modifies the operation to accept the element as the value of the the parameters. If this parameter contains a URL, then it should identify a local configuration file. 8.8.5.4 The #url capability modifies the operation to accept the element as the value of the the parameter. 8.9 XPath Capability 8.9.1 Description The XPath capability indicates that the NETCONF peer supports the use of XPath expressions in the element. XPath is described in [2]. 8.9.2 Dependencies None. 8.9.3 Capability and Namespace The #xpath capability is identified by the following capability string: urn:ietf:params:xml:ns:netconf:base:1.0#xpath Enns Expires August 19, 2005 [Page 58] Internet-Draft NETCONF Protocol February 2005 The #xpath capability uses the base NETCONF namespace URN. 8.9.4 New Operations None. 8.9.5 Modifications to Existing Operations 8.9.5.1 and The #xpath capability modifies the and operations to accept the value "xpath" in the type attribute of the filter element. When the type attribute is set to "xpath", the contents of the filter element will be treated as an xpath expression and used to filter the returned data. For example: top/users/user[name="fred"] 9. Security Considerations This document does not specify an authorization scheme, as such a scheme should be tied to a meta-data model or a data model. Implementators SHOULD provide a well thought out authorization scheme with NETCONF. Authorization of individual users via the NETCONF server may or may not map 1:1 to other interfaces. First, the data models may be incompatible. Second, it may be desirable to authorize based on mechanisms available in the application protocol layer (TELNET, SSH, etc). In addition, operations on configurations may have unintended consequences if those operations are also not guarded by the global lock on the files or objects being operated upon. For instance, a partially complete access list could be committed from a candidate Enns Expires August 19, 2005 [Page 59] Internet-Draft NETCONF Protocol February 2005 configuration unbeknownst to the owner of the lock of the candidate configuration, leading to either an insecure or inaccessible device if the lock on the candidate configuration does not also apply to the operation when applied to it. Configuration information is by its very nature sensitive. Its transmission in the clear and without integrity checking leaves devices open to classic eavesdropping attacks. Configuration information often times contains passwords, user names, service descriptions, and topological information, all of which are sensitive. Because of this, this protocol should be implemented carefully with adequate attention to all manner of attack one might expect to experience with other management interfaces. The protocol, therefore, must minimally support options for both privacy and authentication. It is anticipated that the underlying protocol (SSH, BEEP, etc) will provide for both privacy and authentication, as is required. It is further expected that the identity of each end of a NETCONF session will be available to the other in order to determine authorization for any given request. One could also easily envision additional information such as transport and encryption methods being made available for purposes of authorization. NETCONF itself provide no means to reauthenticate, much less authenticate. All such actions occur at lower layers. Different environments may well allow different rights prior to and then after authentication. Thus, an authorization model is not specified in this document. When an operation is not properly authorized then a simple "permission denied" is sufficient. Note that authorization information may be exchanged in the form of configuration information, which is all the more reason to ensure the security of the connection. That having been said, it is important to recognize that some operations are clearly more sensitive by nature than others. For instance, to the startup or running configurations is clearly not a normal provisioning operation, where-as is. Such global operations MUST disallow the changing of information that an individual does not have authorization to perform. For example, if a user A is not allowed to configure an IP address on an interface but user B has configured an IP address on an interface in the configuration, user A must not be allowed to commit the configuration. Similarly, just because someone says go write a configuration through the URL capability at a particular place does not mean that an element should do it without proper authorization. Enns Expires August 19, 2005 [Page 60] Internet-Draft NETCONF Protocol February 2005 The operation will demonstrate that use of NETCONF is intended for use by systems that have at least some trust of the administrator. As specified in this document, it is possible to lock portions of a configuration that a principle might not otherwise have access to. After all, the entire configuration is locked. To mitigate this problem there are two approaches. It is possible to kill another NETCONF session programmatically from within NETCONF if one knows the session identifier of the offending session. The other possible way to break a lock is to provide an function within the device's native user interface. These two mechanisms suffer from a race condition that may be ameliorated by removing the offending user from an AAA server. However, such a solution is not useful in all deployment scenarios, such as those where SSH public/private key pairs are used. 10. IANA Considerations TBD. 11. Authors and Acknowledgements This document was written by: Andy Bierman, Cisco Systems Ken Crozier, Cisco Systems Rob Enns, Juniper Networks Ted Goddard, IceSoft Eliot Lear, Cisco Systems Phil Shafer, Juniper Networks Steve Waldbusser Margaret Wasserman, ThingMagic The authors would like to acknowledge the members of the NETCONF working group. In particular, we would like to thank Wes Hardaker for his persistance and patience in assisting us with security considerations. We would also like to thank Randy Presuhn, Sharon Chisolm, Juergen Schoenwalder, Glenn Waters, David Perkins, Weijing Chen, Simon Leinen, Keith Allen and Dave Harrington for all of their valuable advice. Enns Expires August 19, 2005 [Page 61] Internet-Draft NETCONF Protocol February 2005 12. References 12.1 Normative References [1] Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler, "Extensible Markup Language (XML) 1.0 (Second Edition)", W3C REC REC-xml-20001006, October 2000. [2] Clark, J. and S. DeRose, "XML Path Language (XPath) Version 1.0", W3C REC REC-xpath-19991116, November 1999. [3] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [4] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, January 1999. [5] Berners-Lee, T., "Universal Resource Identifiers in WWW: A Unifying Syntax for the Expression of Names and Addresses of Objects on the Network as used in the World-Wide Web", RFC 1630, June 1994. [6] Moats, R., "URN Syntax", RFC 2141, May 1997. [7] Rigney, C., Willens, S., Rubens, A. and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. [8] Mealling, M., Masinter, L., Hardie, T. and G. Klyne, "An IETF URN Sub-namespace for Registered Protocol Parameters", BCP 73, RFC 3553, June 2003. 12.2 Informative References [9] Clark, J., "XSL Transformations (XSLT) Version 1.0", W3C REC REC-xslt-19991116, November 1999. [10] Ylonen, T., Kivinen, T., Saarinen, M., Rinne, T. and S. Lehtinen, "SSH Protocol Architecture", draft-ietf-secsh-architecture-15 (work in progress), October 2003. Enns Expires August 19, 2005 [Page 62] Internet-Draft NETCONF Protocol February 2005 Author's Address Rob Enns (editor) Juniper Networks 1194 North Mathilda Ave Sunnyvale, CA 94089 US EMail: rpe@juniper.net Appendix A. NETCONF Error List Tag: IN_USE Error-type: protocol, application Severity: error Error-info: none Description: The request requires a resource that already in use. Tag: INVALID_VALUE Error-type: protocol, application Severity: error Error-info: none Description: The request specifies an unacceptable value for one or more parameters. Tag: TOO_BIG Error-type: transport, rpc, protocol, application Severity: error Error-info: none Description: The request or response (that would be generated) is too large for the implementation to handle. Tag: MISSING_ATTRIBUTE Error-type: rpc, protocol, application Severity: error Error-info: : name of the missing attribute : name of the element that should contain the missing attribute Description: An expected attribute is missing Tag: BAD_ATTRIBUTE Error-type: rpc, protocol, application Severity: error Error-info: : name of the attribute w/ bad value : name of the element that contains the attribute with the bad value Description: An attribute value is not correct; e.g., wrong type, out of range, pattern mismatch Enns Expires August 19, 2005 [Page 63] Internet-Draft NETCONF Protocol February 2005 Tag: UNKNOWN_ATTRIBUTE Error-type: rpc, protocol, application Severity: error Error-info: : name of the unexpected attribute : name of the element that contains the unexpected attribute Description: An unexpected attribute is present Tag: MISSING_ELEMENT Error-type: rpc, protocol, application Severity: error Error-info: : name of the missing element Description: An expected element is missing Tag: BAD_ELEMENT Error-type: rpc, protocol, application Severity: error Error-info: : name of the element w/ bad value Description: An element value is not correct; e.g., wrong type, out of range, pattern mismatch Tag: UNKNOWN_ELEMENT Error-type: rpc, protocol, application Severity: error Error-info: : name of the unexpected element Description: An unexpected element is present Tag: ACCESS_DENIED Error-type: rpc, protocol, application Severity: error Error-info: none Description: Access to the requested RPC, protocol operation, or application data model is denied because authorization failed Tag: LOCK_DENIED Error-type: protocol Severity: error Error-info: : session ID of session holding the requested lock, or zero to indicate a non-NETCONF entity holds the lock Description: Access to the requested lock is denied because the lock is currently held by another entity Tag: RESOURCE_DENIED Error-type: transport, rpc, protocol, application Severity: error Error-info: none Enns Expires August 19, 2005 [Page 64] Internet-Draft NETCONF Protocol February 2005 Description: Request could not be completed because of insufficient resources Tag: ROLLBACK_FAILED Error-type: protocol, application Severity: error Error-info: none Description: Request to rollback some configuration change (via rollback-on-error or discard-changes operations) was not completed for some reason. Tag: DATA_EXISTS Error-type: application Severity: error Error-info: none Description: Request could not be completed because the relevant data model content already exists. For example, a 'create' operation was attempted on data which already exists. Tag: DATA_MISSING Error-type: application Severity: error Error-info: none Description: Request could not be completed because the relevant data model content does not exist. For example, a 'modify' or 'delete' operation was attempted on data which does not exist. Tag: OPERATION_NOT_SUPPORTED Error-type: rpc, protocol, application Severity: error Error-info: none Description: Request could not be completed because the requested operation is not supported by this implementation. Tag: OPERATION_FAILED Error-type: rpc, protocol, application Severity: error Error-info: none Description: Request could not be completed because the requested operation failed for some reason not covered by any other error condition. Tag: PARTIAL_OPERATION Error-type: application Severity: error Enns Expires August 19, 2005 [Page 65] Internet-Draft NETCONF Protocol February 2005 Error-info: : identifies an element in the data model for which the requested operation has been completed for that node and all its child nodes. This element can appear zero or more times in the container. : identifies an element in the data model for which the requested operation has failed for that node and all its child nodes. This element can appear zero or more times in the container. : identifies an element in the data model for which the requested operation was not attempted for that node and all its child nodes. This element can appear zero or more times in the container. Description: Some part of the requested operation failed or was not attempted for some reason. Full cleanup has not been performed (e.g., rollback not supported) by the server. The error-info container is used to identify which portions of the application data model content for which the requested operation has succeeded (), failed (), or not attempted (). Appendix B. XML Schema for NETCONF RPC and Protocol Operations Enns Expires August 19, 2005 [Page 66] Internet-Draft NETCONF Protocol February 2005 Enns Expires August 19, 2005 [Page 67] Internet-Draft NETCONF Protocol February 2005 Enns Expires August 19, 2005 [Page 68] Internet-Draft NETCONF Protocol February 2005 Enns Expires August 19, 2005 [Page 70] Internet-Draft NETCONF Protocol February 2005 Enns Expires August 19, 2005 [Page 72] Internet-Draft NETCONF Protocol February 2005 Enns Expires August 19, 2005 [Page 73] Internet-Draft NETCONF Protocol February 2005 Enns Expires August 19, 2005 [Page 74] Internet-Draft NETCONF Protocol February 2005 Appendix C. Capability Template C.1 capability-name (template) C.1.1 Overview C.1.2 Dependencies C.1.3 Capability and Namespace The {name} is identified by following capability string: urn:ietf:params:xml:ns:netconf:base:1.0#{name} The {name} capability uses the base NETCONF namespace URN. C.1.4 New Operations C.1.4.1 C.1.5 Modifications to Existing Operations C.1.5.1 If existing operations are not modified by this capability, this section may be omitted. C.1.6 Interactions with Other Capabilities If this capability does not interact with other capabilities, this section may be omitted. Enns Expires August 19, 2005 [Page 75] Internet-Draft NETCONF Protocol February 2005 Appendix D. Configuring Multiple Devices with NETCONF D.1 Operations on Individual Devices Consider the work involved in performing a configuration update against a single individual device. In making a change to the configuration, the application needs to build trust that its change has been made correctly and that it has not impacted the operation of the device. The application (and the application user) should feel confident that their change has not damaged the network. Protecting each individual device consists of a number of steps: o Acquiring the configuration lock. o Loading the update. o Validating the incoming configuration. o Checkpointing the running configuration. o Changing the running configuration. o Testing the new configuration. o Making the change permanent (if desired). o Releasing the configuration lock. Let's look at the details of each step. D.1.1 Acquiring the Configuration Lock A lock should be acquired to prevent simultaneous updates from multiple sources. If multiple sources are affecting the device, the application is hampered in both testing of its change to the configuration and in recovery should the update fail. Acquiring a short-lived lock is a simple defense to prevent other parties from introducing unrelated changes. The lock can be acquired using the operation. Enns Expires August 19, 2005 [Page 76] Internet-Draft NETCONF Protocol February 2005 D.1.2 Loading the Update The configuration can be loaded onto the device without impacting the running system. If the #url capability is supported, incoming changes can be placed in a local file. file://incoming.conf If the #candidate capability is supported, the candidate configuration can be used. If the update fails, the user file can be deleted using the operation or the candidate configuration reverted using the operation. D.1.3 Validating the Incoming Configuration Before applying the incoming configuration, it is often useful to validate it. Validation allows the application to gain confidence that the change will succeed and simplifies recovery if it does not. Enns Expires August 19, 2005 [Page 77] Internet-Draft NETCONF Protocol February 2005 If the device supports the #url capability, use the operation with the parameter set to the proper user file: file://incoming.conf If the device supports the #candidate capability, some validation will be performed as part of loading the incoming configuration into the candidate. For full validation, either pass the parameter during the step given above, or use the operation with the parameter set to . D.1.4 Checkpointing the Running Configuration The running configuration can be saved into a local file as a checkpoint before loading the new configuration. If the update fails, the configuration can be restored by reloading the checkpoint file. The checkpoint file can be created using the operation. file://checkpoint.conf Enns Expires August 19, 2005 [Page 78] Internet-Draft NETCONF Protocol February 2005 To restore the checkpoint file, reverse the source and target parameters. D.1.5 Changing the Running Configuration When the incoming configuration has been safely loaded onto the device and validated, it is ready to impact the running system. If the device supports the #url capability, use the operation to merge the incoming configuration into the running configuration. file://incoming.conf If the device supports the #candidate capability, use the operation to set the running configuration to the candidate configuration. Use the parameter to allow automatic reverting to the original configuration if connectivity to the device fails. 15 D.1.6 Testing the New Configuration Now that the incoming configuration has been integrated into the running configuration, the application needs to gain trust that the change has affected the device in the way intended without affecting it negatively. To gain this confidence, the application can run tests of the operational state of the device. The nature of the test is dependent Enns Expires August 19, 2005 [Page 79] Internet-Draft NETCONF Protocol February 2005 on the nature of the change and is outside the scope of this document. Such tests may include reachability from the system running the application (using ping), changes in reachability to the rest of the network (by comparing the device's routing table), or inspection of the particular change (looking for operational evidence of the BGP peer that was just added). D.1.7 Making the Change Permanent When the configuration change is in place and the application has sufficient faith in the proper function of this change, the application should make the change permanent. If the device supports the #startup capability, the current configuration can be saved to the startup configuration by using the startup configuration as the target of the operation. If the device supports the #candidate capability and a confirmed commit was requested, the confirming commit must be sent before the timeout expires. D.1.8 Releasing the Configuration Lock When the configuration update is complete, the lock must be released, allowing other applications access to the configuration. Use the operation to release the configuration lock. Enns Expires August 19, 2005 [Page 80] Internet-Draft NETCONF Protocol February 2005 D.2 Operations on Multiple Devices When a configuration change requires updates across a number of devices, care should be taken to provide the required transaction semantics. The NETCONF protocol contains sufficient primitives upon which transaction-oriented operations can be built. Providing complete transactional semantics across multiple devices is prohibitively expensive, but the size and number of windows for failure scenarios can be reduced. There are two classes of multidevice operations. The first class allows the operation to fail on individual devices without requiring all devices to revert to their original state. The operation can be retried at a later time, or its failure simply reported to the user. A example of this class might be adding an NTP server. For this class of operations, failure avoidance and recovery are focused on the individual device. This means recovery of the device, reporting the failure, and perhaps scheduling another attempt. The second class is more interesting, requiring that the operation should complete on all devices or be fully reversed. The network should either be transformed into a new state or be reset to its original state. For example, a change to a VPN may require updates to a number of devices. Another example of this might be adding a class-of-service definition. Leaving the network in a state where only a portion of the devices have been updated with the new definition will lead to future failures when the definition is referenced. To give transactional semantics, the same steps used in single device operations listed above are used, but are performed in parallel across all devices. Configuration locks should be acquired on all target devices and kept until all devices are updated and the changes made permanent. Configuration changes should be uploaded and validation performed across all devices. Checkpoints should be made on each device. Then the running configuration can be changed, tested, and made permanent. If any of these steps fail, the previous configurations can be restored on any devices upon which it was Enns Expires August 19, 2005 [Page 81] Internet-Draft NETCONF Protocol February 2005 changed. After the changes have been completely implemented or completely discarded, the locks on each device can be released. Appendix E. Deferred Features The following features have been deferred until a future revision of this document. o Granular locking of configuration objects. o Named configuration files/datastores. o Support for multiple NETCONF channels. o Asynchronous notifications. Appendix F. Change Log RFC Editor: Please remove this section before RFC publication. F.1 draft-ietf-netconf-prot-05 o Change XPATH to XPath. o Fix I-D nits (mostly long lines). o Remove "--" from XSD comments. o Add attribute where it was missing in examples. o Clarified Section 8.1 by indicating that each peer MUST send a element at session startup. o Typo propriety -> proprietary in Section 8. o Fix some bugs in examples. o Section 7.1: typo: change to in the positive response section. o Section 7.1: If is unspecified, the entire configuration is returned. If it is empty, nothing is returned. o Be explicit about being atomic. o s/MAY/SHOULD/ wrt supporting more than one NETCONF session. Enns Expires August 19, 2005 [Page 82] Internet-Draft NETCONF Protocol February 2005 o Strengthen language to say that NETCONF requests MUST be processed serially. o Fix misspelling of "unbeknownst." o Change "Expect scripts" to "CLI scripts" in Section 7.5. o Change "system software" to "device" in Section 1.3. o The element must also include the session ID (issue I002). o Address all accepted clarifications from working group last call. See the NETCONF mailing list for details. o Address all closed issues from working group last call. See the NETCONF mailing list for details. F.2 draft-ietf-netconf-prot-04 Refer to the NETCONF issue list for futher detail on the issue numbers below. The issue list is found at http://www.nextbeacon.com/netconf/. o Update security considerations (action from IETF 60). o Add type attribute on filter element (issue 14.1). o Add #xpath capability (issue 14.1). o for returns element, not element (issue 14.1). o Add detailed description of subtree filtering (issue 14.1.2). o Typo: change confirmed-timeout -> confirm-timeout in XSD. o Typo: correct misnaming of test-option parameter in text for the validate capability. o is now a mandatory parameter for and . There is no default target (action from IETF 60). o Remove XML schema for NETCONF state data (action from IETF 60). o Correct namespace handling a number of examples. The fix is to put the device's configuration under a top level tag called which is in the device's namespace. Enns Expires August 19, 2005 [Page 83] Internet-Draft NETCONF Protocol February 2005 o Use message-id 101 everywhere. o Add default-operation parameter to (action from IETF 60). o Fix examples in Appendix D. o Update and reformat protocol XSD. o Remove XML usage guidelines. Add a section on XML considerations covering the NETCONF namespace and no DTD restriction (action from IETF 60). F.3 draft-ietf-netconf-prot-03 Refer to the NETCONF issue list for futher detail on the issue numbers below. The issue list is found at http://www.nextbeacon.com/netconf/. o Consistent naming of element. o Add #confirmed-commit capability (issue 10.3.2) o Use a URN for the NETCONF namespace (issue 11.1.2) and capabilities o Remove #manager capability (issue 11.2.1) o Remove #agent capability (issue 11.2.2) o Add "create" as a value for the operation attribute in (issue 13.3.1) o Add #rollback-on-error capability (issue 13.3.2) o Rename operation to . o Remove format parameter from two and one examples missed in the -02 draft (issue 13.3.3). o Add text indicating that the session-id is returned if the lock is already held (issue 13.12.3). Add example of this. o Remove parameter on the operation (issue 13.16.1), all outstanding changes are to be discarded when the candidate configuration is unlocked. Enns Expires August 19, 2005 [Page 84] Internet-Draft NETCONF Protocol February 2005 o Remove section 8.7, guidelines on namespace construction. o Add clarifying text regarding locks held by other entities. o Update the abstract. o Remove mention of the format parameter from the and operations and the XSD. o Updated security considerations section. o Removed terminology section, moved session description to protocol overview section. o New text describing . o Updated NETCONF protocol schema (to reflect new details, among other things). o Add parameter to and . Rename response the operation to . o Better description of the operation. o Add operation. o Removed format parameter to . o Removed restriction that a changed configuration datastore can't be locked. o Add note in section 2 that the application protocol must provide an indication of session type (manager or agent) to the NETCONF layer. F.4 draft-ietf-netconf-prot-02 Refer to the NETCONF issue list for futher detail on the issue numbers below. The issue list is found at http://www.nextbeacon.com/netconf/. o Remove , , and (issues 12.1, 12.2, 12.3). o Remove channels (issues 3.*). o Remove notifications (issues 2.*, 4.2, 13.9, 13.10, 13.11). Enns Expires August 19, 2005 [Page 85] Internet-Draft NETCONF Protocol February 2005 o Move version number to last component of the capability URI (issue 11.1.1). o Remove format parameter from (issue 13.3.3). o Remove mention of #lock capability from Appendix D. Locking is a mandatory NETCONF operation. o Added text indicating that attributes received in should be echoed on (issue 16.1). o Reworded Section 7.3 to encourage always prefixing attributes with namespaces. Enns Expires August 19, 2005 [Page 86] Internet-Draft NETCONF Protocol February 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. 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Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Enns Expires August 19, 2005 [Page 87]