Network Working Group                                            E. Lear
Internet-Draft                                                K. Crozier
Expires: April December 6, 2004                                  Cisco Systems
                                                             June 7, 2003 2004

              BEEP Application Protocol Mapping for NETCONF

Status of this Memo

    This document is an Internet-Draft and is in full conformance with
    all provisions of Section 10 of RFC2026.

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Copyright Notice

    Copyright (C) The Internet Society (2003). (2004). All Rights Reserved.


    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   NETCONF Session Teardown . . . . . . . . . . . . . . . . . .  5
    2.4   BEEP Profiles Profile for NETCONF Channels . . . . . . . . . . . . .  5
   2.5.1 Management Channel Profile . . . . . . . . . . . . . . . . .  5
    2.4.1 Operations Channel Profile . . . . . . . . . . . . . . . . .  7
   2.5.3  5
    2.4.2 Notification Channel Profile . . . . . . . . . . . . . . . .  9  7
    3.    Security Considerations  . . . . . . . . . . . . . . . . . . 10  8
    4.    IANA Considerations  . . . . . . . . . . . . . . . . . . . . 11  9
    5.    Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . 12 10
          Normative References . . . . . . . . . . . . . . . . . . . . 13 11
          Informative References . . . . . . . . . . . . . . . . . . . 14 12
          Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 14 12
    A.    Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 13
          Intellectual Property and Copyright Statements . . . . . . . 15 14

1. Introduction

    The NETCONF protocol [1] 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) [2] .

    The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
    document are to be interpreted as described in RFC 2119 [3].

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 [5] and optionally SASL [4] (see below), as well as for the
    SYSLOG profile [6]. 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 management a 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 management this next channel is BEEP channel 1
    or 2, depending on whether the manager is the initiator or the

   The manager next establishes the

    Certain NETCONF operational channel for the
   purpose of issuing RPC requests.  This channel is BEEP channel 3 or

   Finally, if either manager or agent wishes to send or receive
   notifications, it capabilities may issue require 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

    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

    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 NETCONF Session Teardown

    Either side may initiate the termination of an NETCONF session.  In
    This is done by issuing a BEEP close on the operational channel 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.

2.5  Having sent or received a BEEP Profiles for NETCONF Channels

   There are two profiles, the management channel profile close, a manager
    MUST NOT send further requests, and the
   operations channel profile. These an agent MUST NOT send additional
    responses.  If there are not additional activities due to expanded
    capabilities, these MUST cease in an orderly manner, and should be confused with
    properly 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

2.5.1 Management Channel Profile

      <!-- DTD for netconf management over BEEP

        Refer to this DTD as:

          <!ENTITY % NETCONF PUBLIC "netconf/management/1.0" "">

      <!--   Contents


          Profile Summaries
          Entity Definitions


      <!--  Overview   NETCONF Management channel  -->

      <!-- Includes -->

             <!ENTITY % BEEP PUBLIC "-//Blocks//DTD BEEP//EN"

      <!--  Profile summaries


          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">
        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 -->


2.4.1 Operations Channel Profile

       <!-- DTD for netconf operations over BEEP

         Refer to this DTD as:

           <!ENTITY % NETCONF PUBLIC "netconf/Operation/1.0" "">

       <!--   Contents


           Profile Summaries
           Entity Definitions


       <!--  Overview   NETCONF operation channel  -->

       <!-- Includes -->

              <!ENTITY % BEEP PUBLIC "-//Blocks//DTD BEEP//EN"
       <!--  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.

                 RPC-REPLY       %RPC-REPLY;                #REQUIRED
                 RPC-DATA    %RPC-DATA              #REQUIRED>
       <!-- End of DTD -->


2.4.2 Notification Channel Profile

    The NETCONF notification channel profile is defined in RFC 3195 [6].

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 [9], 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

    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

Normative References

    [1]  Enns, R., "NETCONF Configuration Protocol",
         draft-ietf-netconf-prot-01 (work in progress), August October 2003.

    [2]  Rose, M., "The Blocks Extensible Exchange Protocol Core", RFC
         3080, March 2001.

    [3]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

    [4]  Myers, J., "Simple Authentication and Security Layer (SASL)",
         RFC 2222, October 1997.

    [5]  Dierks, T., Allen, C., Treese, W., Karlton, P., Freier, A. and
         P. Kocher, "The TLS Protocol Version 1.0", RFC 2246, January

    [6]  New, D. and M. Rose, "Reliable Delivery for syslog", RFC 3195,
         November 2001.

Informative References

    [7]  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.

    [8]  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.

    [9]  Rigney, C., Willens, S., Rubens, A. and W. Simpson, "Remote
         Authentication Dial In User Service (RADIUS)", RFC 2865, June

Authors' Addresses

    Eliot Lear
    Cisco Systems
    170 W. Tasman Dr.
    San Jose, CA  95134-1706


    Ken Crozier
    Cisco Systems
    170 W. Tasman Dr.
    San Jose, CA  95134-1706


Appendix A. Change Log

    Removed management channel, rpc-status, rpc-abort, and associated
    profile changes.

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