Network Working Group T. Iijima Internet-Draft Y. Atarashi Intended status: Informational H. Kimura Expires: April 21, 2008 Alaxala Networks Corp. K. Toumura H. Okita Central Research Laboratory, Hitachi, Ltd. October 19, 2007 Experience of implementing NETCONF over SOAP draft-iijima-netconf-soap-implementation-03 Status of this Memo 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 becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 21, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Iijima, et al. Expires April 21, 2008 [Page 1] Internet-Draft SOAP implementation October 2007 Abstract NETCONF protocol is standardized to be exchanged over SSH, SOAP, or BEEP. We developed a network management system based on NETCONF protocol. For several reasons, we chose the SOAP protocol as a transport protocol of NETCONF. This document describes why we chose SOAP as a transport protocol and the insight gained from actual development. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. NETCONF over SOAP . . . . . . . . . . . . . . . . . . . . 3 1.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3 1.3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Framework of Web service . . . . . . . . . . . . . . . . . . . 4 2.1. SOAP as a messaging technology . . . . . . . . . . . . . . 4 2.2. WSDL as an Interface Description Language . . . . . . . . 5 3. Insight from our Implementation . . . . . . . . . . . . . . . 6 3.1. SOAP implementation of the NMS . . . . . . . . . . . . . . 7 3.1.1. Session maintenance in NMS . . . . . . . . . . . . . . 7 3.2. SOAP implementation of network equipment . . . . . . . . . 7 3.2.1. SOAP Engine . . . . . . . . . . . . . . . . . . . . . 8 3.2.2. Session maintenance in network equipment . . . . . . . 8 4. A procedure of development of NETCONF manager and agent . . . 9 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 7.1. Normative References . . . . . . . . . . . . . . . . . . . 12 7.2. Informative References . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . . . 15 Iijima, et al. Expires April 21, 2008 [Page 2] Internet-Draft SOAP implementation October 2007 1. Introduction 1.1. NETCONF over SOAP In order to enable network equipment configuration automatically from network systems, NETCONF is designed to use XML as its description language since XML is easy for systems to understand. XML is a suitable technology to cope with flexible specification changes and frequent functional extensions, and it enables automatic operation. SOAP is also designed to use XML and is expected to become an indispensable technology of Web service. For this reason, SOAP is a prospective technology and well suited to the NETCONF protocol. 1.2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119 [3]. 1.3. Motivation This document describes why SOAP is practical as a transport protocol of NETCONF in developing a network management system. This document also describes the experience of implementing NETCONF over SOAP. Iijima, et al. Expires April 21, 2008 [Page 3] Internet-Draft SOAP implementation October 2007 2. Framework of Web service SOAP is considered to be an indispensable technology of Web service. So if we use SOAP as a transport protocol of NETCONF, network configuration by NETCONF is achieved on a framework of Web service. In this section, we describe the overall architecture of the Web service. +---+ +-----------+ +----------------+ +--------------+ +--------+ | | | Security | |Reliable Message| | Transaction | | Search | |XML| | | | | | | | | | | |WS-Security| | WS-Reliability | |WS-Transaction| | UDDI | | | | | | | | | +--------+ | | | | | | | | +--------+ +---------+ | | | | | | | | |language| | API | | | | | | | | | | | | | | | | | | | | | | WSDL | | JAXM | | | +-----------+ +----------------+ +--------------+ +--------+ | JAX-RPC | | | +----------------------------------------------------------+ | .NET | | | | Fundamental Messaging | | | | | | | | | | | | SOAP | | | +---+ +----------------------------------------------------------+ +---------+ +----------------------------------------------------------+ | Transport | | | | HTTP, HTTPS... | +----------------------------------------------------------+ Figure 1: Overall architecture of Web service As depicted in figure 1, peripheral technologies around SOAP/HTTP are well developed, including security technology. For instance, WS- Security and WS-Transaction technology are installed on SOAP only by inserting particular messages in the SOAP Header. If we do not choose SOAP/HTTP as a transport layer of the NETCONF protocol, we have to develop each surrounding technology from scratch. Hence, when introducing additional technologies around SOAP, the development of a NETCONF-based network management system is relatively easy when we choose SOAP as a transport protocol of NETCONF. 2.1. SOAP as a messaging technology SOAP is basically designed to use distributed objects scattered around the Internet regardless of platform. Therefore, SOAP is developed as a messaging technology that uses standardized internet Iijima, et al. Expires April 21, 2008 [Page 4] Internet-Draft SOAP implementation October 2007 technology such as HTTP and XML. In addition, SOAP is so flexible that it is easy to incorporate other technologies. For instance, the notion of session can be easily incorporated in SOAP by inserting a message ID into a SOAP Header. 2.2. WSDL as an Interface Description Language WSDL is designed so as to bind easily with SOAP. WSDL is an innovative technology for Web service since the development tool automatically generates interfaces to Web service by simply importing WSDL into the development tool. Developers only need to customize the programs by putting the generated interfaces together. Regarding development tools that understand WSDL, useful technologies are available with SOAP. For instance, Apache Axis is an interface generator from WSDL as well as a widely used SOAP implementation. If we choose SOAP as a transport protocol, we do not need to develop interfaces to Web service by ourselves owing to the development tool. Iijima, et al. Expires April 21, 2008 [Page 5] Internet-Draft SOAP implementation October 2007 3. Insight from our Implementation In this section, we describe the architecture of NETCONF implementation using SOAP as its transport protocol. Figure 2 is the architecture of the NETCONF implementation using SOAP. SOAP implementation is implemented on both a network management system and network equipment. And each SOAP implementation exchanges SOAP messages based on the WSDL which is provided by [2]. If Java library which is generated from the WSDL are provided on the network management system, engineers can develop NETCONF application, which can configure network equipment via the NETCONF protocol. NETCONF application works as a NETCONF manager and network equipment works as a NETCONF agent. +-------------------------------------------------------+ | Network Management System | | | | +--------------------------------------------+ | | | NETCONF application | | | +--------------------------------------------+ | | +--------------------------------------------+ | | | Java library | | | +--------------------------------------------+ | | +--------------------------------------------+ | | | SOAP Implementation | | | | | | | | Apache Axis | | | +--------------------------------------------+ | +---------------------|----------^----------------------+ | | rpc-request | | rpc-reply / SOAP | | / SOAP / HTTP(S) | | / HTTP(S) | | +---------------------v----------|----------------------+ | +--------------------------------------------+ | | | SOAP Implementation | | | +--------------------------------------------+ | | | | Network Equipment | +-------------------------------------------------------+ Figure 2: Architecture of NETCONF implementation using SOAP In the following section, we explain the SOAP implementation in Iijima, et al. Expires April 21, 2008 [Page 6] Internet-Draft SOAP implementation October 2007 detail in both a network management system and network equipment. 3.1. SOAP implementation of the NMS Several SOAP implementations capable of being installed on NMS (network management system) are available today. For instance, Apache Axis is a practical free software implementation of SOAP when we choose SOAP as a transport protocol. Rapid parsing in the NMS is achieved by Axis since it uses SAX as its parser. Also, Axis is not only a SOAP implementation but a useful tool to develop a NMS. For instance, WSDL2Java, one of Axis's tools, can generate Java's class file from WSDL file which is provided from another vendor. Another tool called Java2WSDL does the opposite. We can generate WSDL file from Java's class file. After we develop a Java library that can configure network equipment, the interface to network equipment can be opened to the public in a form of WSDL. Conclusively, various kinds of benefits can be acquired if we introduce Axis as a SOAP implementation. In order to develop NETCONF-capable applications, Java library, which is generated by Apache Axis tool and run over SOAP implementation, has to incorporate such functions as management of sessions, validation of XML messages, and releasing of log messages. By utilizing these Java library, engineers can easily develop NETCONF applications. 3.1.1. Session maintenance in NMS In order to enable session maintenance between NMS and network equipment, we used cookie field in a HTTP header as a session identifier. After NMS sends a hello message to network equipment, NMS receives a newly allocated session identifier which is written in the cookie field of a replying hello message. For the following SOAP messages exchange, NMS preserves the cookie paired with the network equipment's MAC address and uses the it as a session identifier after that. The store cookie is erased when the NMS sends a close session message and received a response message from network equipment. 3.2. SOAP implementation of network equipment SOAP must also be implemented in the network equipment in order to accept SOAP messages sent from the NMS. Like the case of NMS, some free SOAP implementations to be installed on network equipment are available today. However, in the case of network equipment, memory capacity might be limited. Therefore a memory saving method might be required when we implement SOAP in the network equipment. Iijima, et al. Expires April 21, 2008 [Page 7] Internet-Draft SOAP implementation October 2007 3.2.1. SOAP Engine The SOAP message consists of protocol header such as HTTP header and a SOAP Envelope. The SOAP Envelope is necessary in every SOAP message. But in regard to the SOAP encodingStyle attribute inside the Envelope elements, it is not required to be there even though it is encouraged. So if there's a memory constraint, we can omit a module of parsing encodingStyle. In that case, default encodingStyle of "http://schema.xmlsoap.org/soap/encoding" is applied. Inside of the SOAP Envelope, there are SOAP Header and SOAP Body. However, the SOAP Header is defined as optional. So, when memory capacity in network equipment is insufficient, the module that processes SOAP Header can be omitted. After all, a SOAP engine in network equipment is allowed to have only a SOAP Envelope and Body parser. 3.2.2. Session maintenance in network equipment In order to maintain sessions with the NMS, SOAP implementation in network equipment must provide session identifier to the NMS. SOAP implementation in network equipment sets session identifier paired with network equipment's MAC address in a cookie field of the HTTP header and sends it as a response message to initial hello message sent from the NMS. The session identifier is used when locking the configuration of the network equipment. When network equipment receives a close message from the NMS, the network equipment erases the cookie identifier. Iijima, et al. Expires April 21, 2008 [Page 8] Internet-Draft SOAP implementation October 2007 4. A procedure of development of NETCONF manager and agent TBD Iijima, et al. Expires April 21, 2008 [Page 9] Internet-Draft SOAP implementation October 2007 5. Security Considerations Security should be considered from two angles. One is transport- level security, and the other is message-level security. Transport- level security, such as encryption of entire messages, is a matter of SSL/TLS. However, message-level security, such as partial encryption of messages or signatures, should be done by using other technologies. To fulfill that need, WS-security has been defined. WS-Security is a Web service technology and is dependent on SOAP technology. WS-Security technology can be incorporated by inserting XML encryption and XML signatures into the SOAP Header. Also, WS-Reliability achieves confirmation of sent messages and resending of messages. WS-Reliability is also achieved by inserting particular messages into the SOAP Header. Iijima, et al. Expires April 21, 2008 [Page 10] Internet-Draft SOAP implementation October 2007 6. IANA Considerations This document has no actions for IANA. Iijima, et al. Expires April 21, 2008 [Page 11] Internet-Draft SOAP implementation October 2007 7. References 7.1. Normative References [1] Enns, R., "NETCONF Configuration Protocol", RFC 4741, December 2006. [2] Goddard, T., "Using NETCONF over the Simple Object Access Protocol (SOAP)", RFC 4743, December 2006. 7.2. Informative References [3] Bradner, S. , "Key words for use in RFCs to Indicate Requirement Levels" , BCP 14 , RFC 2119 , March 1997 . [4] Sperberg-McQueen, C. , Bray, T. , and J. Paoli , "XML 1.0 Recommendation" , World Wide Web Consortium FirstEdition REC- xml-19980210 , February 1998 , . [5] "Web Services - Axis" . [6] "Web Service Description Language (WSDL) 1.1". Iijima, et al. Expires April 21, 2008 [Page 12] Internet-Draft SOAP implementation October 2007 Authors' Addresses Iijima Tomoyuki Alaxala Networks Corp. Shin-Kawasaki Mitsui Bldg. 890 Saiwai-ku Kashimada Kawasaki, Kanagawa 212-0058 Japan Phone: +81-44-549-1200 Fax: +81-44-549-1272 Email: atarashi@alaxala.net Yoshifumi Atarashi Alaxala Networks Corp. Shin-Kawasaki Mitsui Bldg. 890 Saiwai-ku Kashimada Kawasaki, Kanagawa 212-0058 Japan Phone: +81-44-549-1200 Fax: +81-44-549-1272 Email: atarashi@alaxala.net Hiroyasu Kimura Alaxala Networks Corp. Shin-Kawasaki Mitsui Bldg. 890 Saiwai-ku Kashimada Kawasaki, Kanagawa 212-0058 Japan Phone: +81-44-549-1200 Fax: +81-44-549-1272 Email: h-kimura@alaxala.net Toumura Kunihiko Central Research Laboratory, Hitachi, Ltd. 1-280 Higashi-Koigakubo Kokubunji, Tokyo 185-8601 Japan Phone: +81-42-323-1111 Fax: +81-42-327-7868 Email: kunihiko.toumura.yv@hitachi.com Iijima, et al. Expires April 21, 2008 [Page 13] Internet-Draft SOAP implementation October 2007 Hideki Okita Central Research Laboratory, Hitachi, Ltd. 1-280 Higashi-Koigakubo Kokubunji, Tokyo 185-8601 Japan Phone: +81-42-323-1111 Fax: +81-42-327-7868 Email: hideki.okita.pf@hitachi.com Iijima, et al. Expires April 21, 2008 [Page 14] Internet-Draft SOAP implementation October 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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