Internet DRAFT - draft-ietf-pcp-description-option
draft-ietf-pcp-description-option
PCP Working Group M. Boucadair
Internet-Draft France Telecom
Intended status: Standards Track R. Penno
Expires: August 25, 2014 D. Wing
Cisco
February 21, 2014
PCP Description Option
draft-ietf-pcp-description-option-05
Abstract
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",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
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
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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
(http://trustee.ietf.org/license-info) in effect on the date of
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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
[RFC6887].
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
following:
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
mapping.
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
response).
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 http://www.iana.org/
assignments/pcp-parameters):
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
2013.
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6.2. Informative References
[I-D.boucadair-pcp-deployment-cases]
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
France
Email: mohamed.boucadair@orange.com
Reinaldo Penno
Cisco
USA
Email: repenno@cisco.com
Dan Wing
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134
USA
Email: dwing@cisco.com
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