Network Working Group T. Iijima
Internet-Draft K. Toumura
Intended status: Informational H. Okita
Expires: April 19, 2007 Central Research Laboratory,
Hitachi, Ltd.
Y. Atarashi
H. Kimura
Alaxala Networks Corp.
October 16, 2006
Experience of implementing NETCONF over SOAP
draft-iijima-netconf-soap-implementation-01
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Copyright (C) The Internet Society (2006).
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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 a Interface Description Language . . . . . . . . . 5
3. Insight from our Implementation . . . . . . . . . . . . . . . 6
3.1. SOAP implementation of the NMS . . . . . . . . . . . . . . 6
3.2. SOAP implementation of network equipment . . . . . . . . . 7
3.2.1. SOAP Header . . . . . . . . . . . . . . . . . . . . . 7
3.2.2. SOAP Fault . . . . . . . . . . . . . . . . . . . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Normative References . . . . . . . . . . . . . . . . . . . 10
6.2. Informative References . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
Intellectual Property and Copyright Statements . . . . . . . . . . 13
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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.
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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
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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 a 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.
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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.
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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.
3.2. 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 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.
3.2.2. 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.
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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.
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5. IANA Considerations
This document has no actions for IANA.
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6. References
6.1. Normative References
[1] Enns, R., "NETCONF Configuration Protocol",
draft-ietf-netconf-prot-12 (work in progress), March 2006.
[2] Goddard, T., "Using the Network Configuration Protocol (NETCONF)
Over the Simple Object Access Protocol (SOAP)",
draft-ietf-netconf-soap-08 (work in progress), March 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. , Sperberg-McQueen, C. , and J. Paoli , "XML 1.0
Recommendation" , World Wide Web Consortium FirstEdition REC-
xml-19980210 , February 1998 ,
<http://www.w3.org/TR/1998/REC-xml-19980210> .
[5] "Web Services - Axis" .
<http://ws.apache.org/axis/>
[6] "Web Service Description Language (WSDL) 1.1".
<http://www.w3.org/TR/wsdl/>
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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
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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
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