Network Working Group T. Iijima Internet-Draft K. Toumura Intended status: Informational H. Okita Expires: October 21, 2007 Central Research Laboratory, Hitachi, Ltd. Y. Atarashi H. Kimura Alaxala Networks Corp. April 19, 2007 Experience of implementing NETCONF over SOAP draft-iijima-netconf-soap-implementation-02 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 October 21, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Iijima, et al. Expires October 21, 2007 [Page 1] Internet-Draft SOAP implementation April 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 . . . . . . . . . . . . . . 6 3.1.1. Session maintainance . . . . . . . . . . . . . . . . . 7 3.2. SOAP implementation of network equipment . . . . . . . . . 7 3.2.1. SOAP Envelope . . . . . . . . . . . . . . . . . . . . 7 3.2.2. SOAP Header . . . . . . . . . . . . . . . . . . . . . 7 3.2.3. SOAP Fault . . . . . . . . . . . . . . . . . . . . . . 8 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1. Normative References . . . . . . . . . . . . . . . . . . . 11 6.2. Informative References . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Intellectual Property and Copyright Statements . . . . . . . . . . 14 Iijima, et al. Expires October 21, 2007 [Page 2] Internet-Draft SOAP implementation April 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 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 October 21, 2007 [Page 3] Internet-Draft SOAP implementation April 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 October 21, 2007 [Page 4] Internet-Draft SOAP implementation April 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 by ourselves owing to the development tool. Iijima, et al. Expires October 21, 2007 [Page 5] Internet-Draft SOAP implementation April 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. In the following section, we explain the SOAP implementation in both a network management system and network equipment. +-------------------------------------------------------+ | Network Management System | | | | +--------------------------------------------+ | | | NETCONF application | | | +--------------------------------------------+ | | +--------------------------------------------+ | | | Java library | | | +--------------------------------------------+ | | +--------------------------------------------+ | | | SOAP Implementation | | | | | | | | Apache Axis | | | +--------------------------------------------+ | +---------------------|----------^----------------------+ | | rpc-request | | / SOAP | | rpc-reply | | / SOAP | | +---------------------v----------|----------------------+ | +--------------------------------------------+ | | | SOAP Implementation | | | +--------------------------------------------+ | | | | Network Equipment | +-------------------------------------------------------+ Figure 2: Architecture of NETCONF implementation using SOAP 3.1. SOAP implementation of the NMS Several SOAP implementations capable of being installed on NMS 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 since Axis uses SAX as its parser. Iijima, et al. Expires October 21, 2007 [Page 6] Internet-Draft SOAP implementation April 2007 Also, Axis is not only a SOAP implementation but a useful tool to develop a network management system. For instance, Java2WSDL, one of Axis's tools, can generate WSDL 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. Another tool called WSDL2Java does the opposite. We can generate a Java library from a WSDL file provided from another vendor. Conclusively, various kinds of benefits can be acquired if we introduce Axis as a SOAP implementation. 3.1.1. Session maintainance In order to enable session maintainance between NMS and network equipment, we used cookie as a session identifier. After NMS sends a hello message to network equipment, NMS receives a newly allocated cookie within a hello message sent back from the network equipment. For the following SOAP messages exchange, NMS preserves the cookie paired with the network equipment's MAC address and uses the cookie as a session identifier. The preserved cookie information is erased after the session is closed. 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 network management system. Like the NMS, some free SOAP implementations are available. 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. 3.2.1. SOAP Envelope The SOAP Envelope is a necessary in every SOAP message. The SOAP encodingStyle attribute is encouraged to be inside the Envelope element to indicate the serialization rules used in a SOAP message, but not required. 3.2.2. SOAP Header The SOAP Header is defined as optional. Therefore, when memory capacity in network equipment is insufficient, the module that processes SOAP Header can be omitted. The SOAPAction field is defined within the SOAP Header. The SOAPAction field is designed to make developers know the intention of the SOAP request message. The value is defined to be URI style. And when empty string("") is put into the SOAPAction field, the intention of the SOAP request message is provided by the HTTP Request-URI. Iijima, et al. Expires October 21, 2007 [Page 7] Internet-Draft SOAP implementation April 2007 However, if a receiver doesn't take any action by looking at SOAPAction field, a sender doesn't need to put any particular value into the SOAPAction field. 3.2.3. SOAP Fault The SOAP Fault is designed to return errors to clients when a malfunction occurrs in servers. However, the SOAP Fault is also optional, and error messages can be written in the SOAP Body as well. So when there are memory constraints, it is not always necessary to implement a SOAP Fault processor. After all, a SOAP engine in network equipment is allowed to have only a SOAP Body parser. Iijima, et al. Expires October 21, 2007 [Page 8] Internet-Draft SOAP implementation April 2007 4. 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 October 21, 2007 [Page 9] Internet-Draft SOAP implementation April 2007 5. IANA Considerations This document has no actions for IANA. Iijima, et al. Expires October 21, 2007 [Page 10] Internet-Draft SOAP implementation April 2007 6. References 6.1. 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. 6.2. Informative References [3] Bradner, S. , "Key words for use in RFCs to Indicate Requirement Levels" , BCP 14 , RFC 2119 , March 1997 . [4] Bray, T. , Paoli, J. , and C. Sperberg-McQueen , "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 October 21, 2007 [Page 11] Internet-Draft SOAP implementation April 2007 Authors' Addresses Iijima Tomoyuki 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: tomoyuki.iijima.fg@hitachi.com 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 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 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 Iijima, et al. Expires October 21, 2007 [Page 12] Internet-Draft SOAP implementation April 2007 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 Iijima, et al. Expires October 21, 2007 [Page 13] Internet-Draft SOAP implementation April 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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