Network Working Group E. Lear Internet-Draft K. Crozier Expires:
AprilDecember 6, 2004 Cisco Systems OctoberJune 7, 20032004 BEEP Application Protocol Mapping for NETCONF draft-ietf-netconf-beep-00draft-ietf-netconf-beep-01 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 AprilDecember 6, 2004. Copyright Notice Copyright (C) The Internet Society (2003).(2004). All Rights Reserved. Abstract This document specifies an application protocol mapping for the NETCONF protocol over the Blocks Extensible Exchange Protocol (BEEP). Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Why BEEP? . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. BEEP Transport Mapping . . . . . . . . . . . . . . . . . . . 4 2.1 NETCONF Session Initiation . . . . . . . . . . . . . . . . . 4 2.2 NETCONF RPC Execution . . . . . . . . . . . . . . . . . . . 4 2.3 NETCONF <rpc-abort> and <rpc-progress> . . . . . . . . . . . 5 2.4 NETCONFSession Teardown . . . . . . . . . . . . . . . . . . 5 2.52.4 BEEP ProfilesProfile for NETCONF Channels .. . . . . . . . . . . . 5 2.5.1 Management Channel Profile . . . . . . . . . . .. . . . . . 5 126.96.36.199.1 Operations Channel Profile . . . . . . . . . . . . . . . . . 7 2.5.35 2.4.2 Notification Channel Profile . . . . . . . . . . . . . . . . 97 3. Security Considerations . . . . . . . . . . . . . . . . . . 108 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . 119 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 1210 Normative References . . . . . . . . . . . . . . . . . . . . 1311 Informative References . . . . . . . . . . . . . . . . . . . 1412 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 1412 A. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . 1514 1. Introduction The NETCONF protocol  defines a simple mechanism through which a network device can be managed. NETCONF is designed to be usable over a variety of application protocols. This document specifies an application protocol mapping for NETCONF over the Blocks Extensible Exchange Protocol (BEEP)  . 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 RFC 2119 . 1.1 Why BEEP? Use of BEEP is natural as an application protocol for transport of XML. As a peer to peer protocol, BEEP provides an easy way to implement NETCONF, no matter which side of the connection was the initiator. This "bidirectionality" allows for either side to play the role of the manager with no protocol changes. Either side can open a channel. Either side could initiate an RPC. This is particularly important to support operational models that involve small devices connecting to a manager, and those devices that must reverse the management connection in the face of firewalls and NATs. The SASL profile used by BEEP allows for a simple and direct mapping to the existing security model for CLI.CLI, while TLS provides a strong well tested encryption mechanism with either server or server and client-side authentication. 2. BEEP Transport Mapping All NETCONF over BEEP implementations MUST implement the profile and functional mapping between NETCONF and BEEP as described below. 2.1 NETCONF Session Initiation Managers may be either BEEP listeners or initiators. Similarly, agents may be either listeners or initiators. Thus the initial exchange takes place without regard to whether a manager or the agent is the initiator. After the transport connection is established, as greetings are exchanged, they should each announce their support for TLS  and optionally SASL  (see below), as well as for the SYSLOG profile . Once greetings are exchanged, if TLS is to be used and available by both parties, the listener STARTs a channel with the TLS profile. Once TLS has been started, a new greeting is sent by both initiator and listener, as required by the BEEP RFC. At this point, if SASL is desired, the initiator starts BEEP channel 1 to perform a SASL exchange to authenticate itself. When SASL is completed, the channel MUST be closed. Once authentication has occurred, there is no need to distinguish between initiator and listener. We now distinguish between manager and agent. The manager now establishes an NETCONF managementa new &dquot;operational&dquot; channel for the purpose of exchanging capabilities, monitoring progress,capabilitiesexchange and requests and aborting remote procedure calls.responses. As initiators assign odd channels and listeners assign even channels, the managementthis next channel is BEEP channel 1 or 2, depending on whether the manager is the initiator or the listener. The manager next establishes theCertain NETCONF operational channel for the purpose of issuing RPC requests. This channel is BEEP channel 3 or 4. Finally, if either manager or agent wishes to send or receive notifications, itcapabilities may issuerequire additional BEEP channels. When such capabilities are defined, a start on the next available channel if the other side has sent the send or receive NETCONF capability.BEEP mapping must be defined as well. At this point, the NETCONF session is established. 2.2 NETCONF RPC Execution To issue an RPC, the manager transmits on the operational channel a BEEP MSG containing the RPC and its arguments. In accordance with the BEEP standard, RPC requests may be split across multiple BEEP frames. Once received and processed, the agent responds with BEEP RPYs on the same channel with the response to the RPC. In accordance with the BEEP standard, responses may be split across multiple BEEP frames. 2.3 NETCONF <rpc-abort> and <rpc-progress> <rpc-abort> and <rpc-progress> requests are issued by the manager on the NETCONF management channel, and the agent responds with BEEP RPYs on that same channel. 2.4 NETCONFSession Teardown Either side may initiate the termination of an NETCONF session. In This is done by issuing a BEEP close on the operationalchannel 0 after the current RPC has completed. The same is done with any notification channels by the end that transmits notifications. Finally, BEEP channel 0 is closed. 2.5Having sent or received a BEEP Profiles for NETCONF Channels There are two profiles, the management channel profileclose, a manager MUST NOT send further requests, and the operations channel profile. Thesean agent MUST NOT send additional responses. If there are notadditional activities due to expanded capabilities, these MUST cease in an orderly manner, and should be confused withproperly described in the capability mapping. 2.4 BEEP control channel.Profile for NETCONF The operations channel will have two commands, <rpc> and <rpc-reply>. The management channel will have one additional operation with <rpc-progress>. 2.5.1 Management Channel Profile <!-- DTD for netconf management over BEEP Refer to this DTD as: <!ENTITY % NETCONF PUBLIC "netconf/management/1.0" ""> %NETCONF; --> <!-- Contents Overview Includes Profile Summaries Entity Definitions Operations rpc rpc-reply rpc-progress --> <!-- Overview NETCONF Management channel --> <!-- Includes --> <!ENTITY % BEEP PUBLIC "-//Blocks//DTD BEEP//EN" ""> %BEEP; <!-- Profile summaries BEEP profile NETCONF-MANAGEMENT role MSG RPY ERR ==== === === === I or L rpc ok error I or L rpc-reply ok error I or L rpc-progress ok error --> <!-- Entity Definitions entity syntax/reference example ====== ================ ======= a PRC RPC-DATA Alpha a RPC reply number RPC-REPLY 1*3DIGIT a RPC progress number RPC-PROGRESS 1*3DIGIT --> <!ENTITY % RPC-REPLY "CDATA"> <!ENTITY % RPC-DATA "CDATA"> <!ENTITY % RPC-PROGRESS "CDATA"> --> <!-- RPC command --> <!ELEMENT rpc (#PCDATA)> <!ATTLIST rpc rpc-data %RPC_DATA; #REQUIRED> <!-- Result of RPC. --> <!ELEMENT rpc-reply (#PCDATA)> <!ATTLIST rpc-reply rpc-reply %RPC-REPLY; #REQUIRED rpc-data %rpc-data #REQUIRED> <!-- Progress of RPC operation. --> <!ELEMENT rpc-progress (#PCDATA)> <!ATTLIST rpc-progress rpc-progress %RPC-PROGRESS; #REQUIRED> <!-- End of DTD --> 188.8.131.52.1 Operations Channel Profile <!-- DTD for netconf operations over BEEP Refer to this DTD as: <!ENTITY % NETCONF PUBLIC "netconf/Operation/1.0" ""> %NETCONF; --> <!-- Contents Overview Includes Profile Summaries Entity Definitions Operations rpc rpc-reply --> <!-- Overview NETCONF operation channel --> <!-- Includes --> <!ENTITY % BEEP PUBLIC "-//Blocks//DTD BEEP//EN" ""> %BEEP; <!-- Profile summaries BEEP profile NETCONF-MANAGEMENT role MSG RPY ERR ==== === === === I or L rpc ok error I or L rpc-reply ok error --> <!-- Entity Definitions entity syntax/reference example ====== ================ ======= a PRC RPC-DATA Alpha a RPC reply number RPC-REPLY 1*3DIGIT --> <!ENTITY % RPC-REPLY "CDATA"> <!ENTITY % RPC-DATA "CDATA"> --> <!-- RPC command --> <!ELEMENT RPC (#PCDATA)> <!ATTLIST RPC RPC-DATA %RPC_DATA; #REQUIRED> <!-- Result of RPC. --> <!ELEMENT RPC-REPLY (#PCDATA)> <!ATTLIST RPC-REPLY RPC-REPLY %RPC-REPLY; #REQUIRED RPC-DATA %RPC-DATA #REQUIRED> <!-- End of DTD --> 184.108.40.206.2 Notification Channel Profile The NETCONF notification channel profile is defined in RFC 3195 . 3. Security Considerations Configuration information is by its very nature sensitive. Its transmission in the clear and without integrity checking leaves devices open to classic so-called "person in the middle" attacks. Configuration information often times contains passwords, user names, service descriptions, and topological information, all of which are sensitive. A NETCONF application protocol, therefore, must minimally support options for both confidentiality and authentication. BEEP makes use of both transport layer security and SASL. We require that TLS be used in BEEP as described by the BEEP standard. Client-side certificates are strongly desirable, but an SASL authentication is the bare minimum. SASL allows for the use of protocols such as RADIUS , so that authentication can occur off the box. SASL authentication will occur on the first channel creation, and prior to issuance of any protocol operations. No further authentication may occur during the same session. This avoids a situation where rights are different between different channels. If an implementation wishes to support multiple accesses by different individuals with different rights, then multiple sessions are required. 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. 4. IANA Considerations The IANA will assign a TCP port for NETCONF. 5. Acknowledgments This work is the product of the NETCONF IETF working group, and many people have contributed to the NETCONF discussion. Most notably, Rob Ens, Phil Schafer, Andy Bierman, Wes Hardiger, Ted Goddard, and Margaret Wasserman all contributed in some fashion to this work, which was originally to be found in the NETCONF base protocol specification. Thanks also to Weijing Chen, Keith Allen, Juergen Schoenwaelder, and Eamon O'Tuathail for their very constructive participation. Normative References  Enns, R., "NETCONF Configuration Protocol", draft-ietf-netconf-prot-00draft-ietf-netconf-prot-01 (work in progress), AugustOctober 2003.  Rose, M., "The Blocks Extensible Exchange Protocol Core", RFC 3080, March 2001.  Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.  Myers, J., "Simple Authentication and Security Layer (SASL)", RFC 2222, October 1997.  Dierks, T., Allen, C., Treese, W., Karlton, P., Freier, A. and P. Kocher, "The TLS Protocol Version 1.0", RFC 2246, January 1999.  New, D. and M. Rose, "Reliable Delivery for syslog", RFC 3195, November 2001. Informative References  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.  Hollenbeck, S., Rose, M. and L. Masinter, "Guidelines for the Use of Extensible Markup Language (XML) within IETF Protocols", BCP 70, RFC 3470, January 2003.  Rigney, C., Willens, S., Rubens, A. and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. Authors' Addresses Eliot Lear Cisco Systems 170 W. Tasman Dr. San Jose, CA 95134-1706 US EMail: email@example.com Ken Crozier Cisco Systems 170 W. Tasman Dr. San Jose, CA 95134-1706 US EMail: firstname.lastname@example.org Appendix A. Change Log Removed management channel, rpc-status, rpc-abort, and associated profile changes. 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