Network Working Group G. Zheng Internet Draft X. Ji Intended status: Standard Track Huawei Technologies Expires: January 3, 2015 July 2, 2014 Integrating Operations in YANG Models draft-zheng-netmod-integrate-operations-00.txt Abstract This document introduces an extension to YANG. The extension allows operation methods to be directly integrated in YANG models. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 3, 2015. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Zheng & Ji Expires January 3, 2015 [Page 1] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 Table of Contents 1. Introduction .................................................. 3 2. Requirements Language and Terminology ......................... 3 3. Scenarios and Requirements of Operation Extension in Data Models3 3.1. Scenarios of Complex Operations .......................... 3 3.2. Scenario of Operation Authorization ...................... 6 3.3. The Requirements for Operation Extension in Data Models .. 6 4. Solution for Operation Extension in Data Models ............... 6 4.1. General Idea ............................................. 6 4.2. Usage Example ............................................ 7 5. Security Considerations ....................................... 9 6. IANA Considerations ........................................... 9 7. References .................................................... 9 7.1. Normative References ..................................... 9 7.2. Informative References .................................. 10 8. Acknowledgments .............................................. 10 Authors' Addresses .............................................. 11 Zheng & Ji Expires January 3, 2015 [Page 2] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 1. Introduction YANG is a data modeling language used to model data manipulated by the NETCONF Protocol. YANG provides the capability to describe configuration/state data in a tree structure; and it has been proven that YANG is an efficient language to model data for network configuration. However, along with management requirements of modern NMS becoming more and more sophisticate, the capability of only describing the data structure in the model seems to be insufficient in some scenarios. In a nutshell, these scenarios require some operations to be integrated in the model as well. This document firstly describes the scenarios and then introduces a YANG model extension which allows operation method to be directly integrated in YANG models. 2. Requirements Language and Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119] when they appear in ALL CAPS. When these words are not in ALL CAPS (such as "should" or "Should"), they have their usual English meanings, and are not to be interpreted as [RFC2119] key words. Terminology: 3. Scenarios and Requirements of Operation Extension in Data Models In some datastore operation scenarios, the operations triggered from the NETCONF client might be a set of combined operations or a complex single operation within the NETCONF agent, which may change the datastores. And sometimes the datastore change might not be from client but from the agent itself. These operations need to manipulate the data in running datastore or candidate datastore, and thus they need the capability a well as a unified authorization system to control the influence to the data stores caused by them. 3.1. Scenarios of Complex Operations The complex operations on data model such as batch creating or converting dynamic data to configuration data, are targeting the Zheng & Ji Expires January 3, 2015 [Page 3] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 running datastore or candidate datastore. Thus, the target datastore, error-option, confirmed-commit, validation and other attributes of operation need to be specified. The following are some examples. o Scenario 1: converting the device's dynamic ARP to static ARP The ARP data model contains static configuration attributes and dynamic non-configuration attributes; both of them are needed by ARP service. The difference between these two groups of attributes is that the static ARP is configured by the client while the dynamic ARP is learn from network peers. To accelerate the speed of dynamic ARP learning after rebooting device, or to simplify the configuration of the static ARP, the dynamic ARP entries need to be converted to static ARP entries when the network is stable. Current solution 1: The client gets the dynamic ARP data then uses these data as static ARP configuration and add them to the NETCONF agent by using operation. Problems of solution 1: - There are too many data communications between client and server, thus the performance is low. - The configured ARP by dynamic ARP from client is duplicated with the dynamic ARP in the device, thus the device has to process the duplication. Current solution 2: According to [RFC6020]/[RFC6241] RPC definition, define a new non-standard RPC to convert dynamic ARP to static ARP directly. Problems of solution 2: The new RPC cannot use the existing attributes of operation, such as target datastore, error-option, confirmed commit and validate. The NETCONF agent has to implement these operation attributes itself, which makes the agent more complex. o Scenario 2: batch operations on data model Zheng & Ji Expires January 3, 2015 [Page 4] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 In some situations, batch merge operations on the list of one module might be needed to reduce the communication data size. Current solutions: 1) Use with filter to get the data from the device, and then add all merge operations to and send it to the device. 2) According to [RFC6020]/[RFC6241] RPC definition, define a non- standard RPC to do the batch merge operation. Problems of current solutions 1) Solution 1 impacts the operation efficiency between host and device significantly. 2) Solution 2 has the same issues with Use Case 1's solution 2. o Scenario 3: maintaining operations on data models The data model of one module is usually hierarchical. Sometimes it needs maintaining operations on the sub nodes, such as resting the running services. Current solution: According to [RFC6020]/[RFC6241] RPC definition, define a non- standard RPC to do maintaining operations. Problems of current solution: 1) When defining the RPC operation, all the key attributes of parents path should appear in the input parameter of the RPC, otherwise the instance of the sub node could not be located. The additional key parameters make the input parameter definition redundant. 2) The scope of sub nodes that the new defined RPC would impact is not clear, thus users have to refer other documents to do authorization rather than just referring the RPC definition itself. Zheng & Ji Expires January 3, 2015 [Page 5] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 3.2. Scenario of Operation Authorization The user-defined non-standard RPC operations might impact the datastores, which need additional authorization. Current solution: When the user-defined RPC operation impact the datastores (either directly manipulate the datastores or impact the datastores as a side effect of the protocol operation), then the server MUST intercept the access operation and make sure the user is authorized to perform the requested access operation on the targeted data as defined in [RFC6536] Section 3.4.5. Problems of Current Solution: 1) Because the scope of datastores that the RPC operation would impact is not defined exactly, there is a risk that invocation of non-standard protocol operations might have undocumented side effects ([RFC6536] Section 3.7.2). 2) An administrator needs to set access control rules to make the configuration datastore protected from user-defined non-standard protocol operation's side effects. But, the rules definition has to depend on the relevant documents not directly on model definition, thus it is not the same as the data node access control rule definition, which makes the authorization management more complex. 3.3. The Requirements for Operation Extension in Data Models The user-defined non-standard operation should overload the standard operations of , , and so on, so that the new operation could inherit the capabilities of the base standard operations. The user-defined non-standard operations should be able to clearly define the scope of the datastores that the operations are allowed to impact in terms of build-in RPC semantics rather than outside documents. 4. Solution for Operation Extension in Data Models 4.1. General Idea 1) The operations to data nodes should be defined on the data model hierarchy tree as a part of the data model attributes; the data Zheng & Ji Expires January 3, 2015 [Page 6] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 node's sub-statement of the operations should also be defined as well.. 2) The operations that will effect or side effect datastores should be specified which base standard RPC operations are inherited. 3) When the data model operations are delivered by NETONCF, they MUST be in the format of the base protocol RPC operations; and the operations definition should be presented as a "Method" attribute of data node; the base protocol RPC operation capabilities should be inherited. 4) The operation access control rules should depend on the impact to data models by the operations defined in the model. 4.2. Usage Example This example is based on the ARP conversion scenario described in Section 3.1. Operation is defined as a "method" substatement in the YANG model: module arp { namespace "http://example.com/network"; prefix "arp"; container arp-records { list arpList { leaf ipAddr { type string } leaf macAddr { type string } leaf styleType { type string; Zheng & Ji Expires January 3, 2015 [Page 7] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 } method convert-arp { base edit-config description "A method to convert dynamic arp to static arp"; input { leaf source-arptype { type string; } leaf dest-arptype { type string; } } } } } Corresponding NETCONF operation is as the following: Zheng & Ji Expires January 3, 2015 [Page 8] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 dynamic dynamic 5. Security Considerations TBD 6. IANA Considerations This document requires no IANA registration. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010. [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011. [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, July 2013. Zheng & Ji Expires January 3, 2015 [Page 9] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 7.2. Informative References [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, March 2012. 8. Acknowledgments Many valuable comments were received from Gang Yan to improve the draft. Bing Liu also participated in forming this draft. This document was prepared using 2-Word-v2.0.template.dot. Zheng & Ji Expires January 3, 2015 [Page 10] Internet-Draft draft-zheng-netmod-integrate-operations-00 May 2014 Authors' Addresses Guangying Zheng Huawei Nanjing R&D Center Huawei Technologies Co., Ltd 101 Software Avenue, Yuhua District, Nanjing, Jiangsu P.R.China. 210012 Email: zhengguangying@huawei.com Xiaofeng Ji Q14-4-B Building Huawei Technologies Co., Ltd Zhong-Guan-Cun Environmental Protection Park, No.156 Beiqing Rd. Hai-Dian District, Beijing P.R. China. 100095 Email: jixiaofeng@huawei.com Zheng & Ji Expires January 3, 2015 [Page 11]