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Description Option for the Port Control Protocol (PCP)

The information below is for an old version of the document that is already published as an RFC.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 7220.
Authors Mohamed Boucadair , Reinaldo Penno , Dan Wing
Last updated 2015-10-14 (Latest revision 2014-02-21)
Replaces draft-boucadair-pcp-description-option
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
Additional resources Mailing list discussion
Stream WG state Submitted to IESG for Publication
Document shepherd Dave Thaler
Shepherd write-up Show Last changed 2013-11-04
IESG IESG state Became RFC 7220 (Proposed Standard)
Action Holders
Consensus boilerplate Yes
Telechat date (None)
Responsible AD Ted Lemon
Send notices to (None)
IANA IANA review state IANA OK - Actions Needed
IANA action state RFC-Ed-Ack
PCP Working Group                                           M. Boucadair
Internet-Draft                                            France Telecom
Intended status: Standards Track                                R. Penno
Expires: August 25, 2014                                         D. Wing
                                                       February 21, 2014

                         PCP Description Option


   This document extends Port Control Protocol (PCP) with the ability to
   associate a description with a PCP-instantiated mapping.  It does so
   by defining a new DESCRIPTION option.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at

   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."

   This Internet-Draft will expire on August 25, 2014.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   ( in effect on the date of

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   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Format  . . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Behavior  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   This document extends the base PCP [RFC6887] with the ability to
   associate a human-readable description with a PCP-instantiated
   mapping.  It does so by defining a new DESCRIPTION option.

   This PCP option can be used in both simple scenarios with a PCP
   client and PCP server, as well as in more complex scenarios where an
   interworking function is used to proxy between a UPnP IGD Control
   Point and a PCP server [RFC6970].

   Querying the PCP server to get the description text of an existing
   mapping is out of scope.

2.  Format

   The format of the DESCRIPTION option is shown in Figure 1.

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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      |Option Code=TBA|  Reserved     |           Length              |
      |                           Description                         |
      :                                                               :

        This Option:

         Option Name: DESCRIPTION
         Number: <TBA>
         Purpose: Used to associate a text description with a mapping
         Valid for Opcodes: MAP, PEER
         Length: Variable,  maximum 1016 octets.
         May appear in: request. May appear in response only if it
                        appeared in the associated request.
         Maximum occurrences: 1

                       Figure 1: Description Option

   The 'Reserved' field is initialized as specified in section 7.3 of

   The Description field MUST carry UTF-8 encoded [RFC3629] description
   text.  The description text MUST NOT be null terminated.  The length
   of the description text is indicated by the Length field.  In
   particular, the description text is not null terminated and when a
   client or server receives a DESCRIPTION option, it MUST NOT rely on
   the presence of a NUL character in the wire format data to identify
   the end of the text.

   This option can be used by a user (or an application) to indicate a
   description associated with a given mapping such as "FTP server", "My
   remote access to my CP router", "Camera", "Network attached storage
   serve", etc.

   How the content of the DESCRIPTION option is used is deployment-
   specific.  For example, the description text can be used by the
   entity managing the PCP server for many purposes such as the

   o  The description text can be used as a hint when cleaning a mapping
      table by an administrator.

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   o  In some deployments making use of a portal to instruct PCP
      mappings (e.g., Section 5.2 of
      [I-D.boucadair-pcp-deployment-cases]), the description text can be
      used to store a subscriber identifier .

3.  Behavior

   The DESCRIPTION option is optional to be supported by PCP servers and
   PCP clients.  This option (Code TBA, Figure 1) MAY be included in a
   PCP MAP/PEER request to associate a description with the requested

   A PCP server MAY ignore the DESCRIPTION option sent to it by a PCP
   client (e.g., if it does not support the option, or it is configured
   to ignore it).  To signal that it has not accepted the option, a PCP
   server simply does not include the DESCRIPTION option in the
   response.  If the PCP client does not receive a DESCRIPTION option in
   a response to a request enclosing a DESCRIPTION option, this means
   the PCP server does not support that option or it is configured to
   ignore it.

   If the DESCRIPTION option is not included in the PCP client request,
   the PCP server MUST NOT include the DESCRIPTION option in the
   associated response.

   Because of the UDP payload limit of 1100 octets [RFC6887], the
   configured maximum length MUST NOT exceed 1016 octets.  The suggested
   maximum length is 128 octets.  If a PCP client includes a DESCRIPTION
   option with a length exceeding the maximum length supported by the
   PCP server, only the portion of the Description field fitting that
   maximum length is stored by the PCP server and returned to the PCP
   client in the response.

   If the PCP server receives a DESCRIPTION option having a length which
   does not exceed the maximum value configured, the PCP server MUST
   record the complete sequence of the description text and MUST send
   back to the PCP client the same DESCRIPTION option as the one
   included in the request.

   If the PCP client request contains invalid DESCRIPTION options (e.g.,
   the content is not a legal UTF-8 string), the PCP server MUST ignore
   the request (i.e., MUST NOT return a DESCRIPTION option in the

   To update the description text of a mapping maintained by a PCP
   server, the PCP client generates a PCP MAP/PEER renewal request which
   includes a DESCRIPTION option carrying the new description text.
   Upon receipt of the PCP request, the PCP server proceeds to the same

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   operations to validate a MAP/PEER request refreshing an existing
   mapping.  If validation checks are successfully passed, the PCP
   server replaces the old description text with the new one included in
   the DESCRIPTION option, and the PCP server returns the updated
   description text in the response, truncated (if necessary) as
   described above.

   The PCP client uses empty DESCRIPTION option (i.e., Length set to 0)
   to erase the description text associated with a mapping.  To indicate
   that the PCP server has successfully cleared the description text
   associated with a mapping, the PCP server returns back the empty
   DESCRIPTION option in the response.

4.  Security Considerations

   PCP-related security considerations are discussed in [RFC6887].  In
   addition, administrators of PCP servers SHOULD configure a maximum
   description length which does not lead to exhausting storage
   resources in the PCP server.

   If the PCP client and the PCP server are not under the same
   administrative entity, the DESCRIPTION option has the potential to
   leak privacy-related information.  PCP clients should not use
   DESCRIPTION option for such leakage.  For example, the option should
   not be used to include user identifiers, locations, or names.  Refer
   to Section 3.2 of [RFC6462] for a discussion on information leakage.

5.  IANA Considerations

   The following PCP Option Codes are to be allocated in the optional-
   to-process range (the registry is maintained in

      DESCRIPTION set to TBA (see Section 2)

6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, November 2003.

   [RFC6887]  Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
              Selkirk, "Port Control Protocol (PCP)", RFC 6887, April

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6.2.  Informative References

              Boucadair, M., "PCP Deployment Models", draft-boucadair-
              pcp-deployment-cases-01 (work in progress), December 2013.

   [RFC6462]  Cooper, A., "Report from the Internet Privacy Workshop",
              RFC 6462, January 2012.

   [RFC6970]  Boucadair, M., Penno, R., and D. Wing, "Universal Plug and
              Play (UPnP) Internet Gateway Device - Port Control
              Protocol Interworking Function (IGD-PCP IWF)", RFC 6970,
              July 2013.

Authors' Addresses

   Mohamed Boucadair
   France Telecom
   Rennes  35000


   Reinaldo Penno


   Dan Wing
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, California  95134


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