PCP Working Group                                           M. Boucadair
Internet-Draft                                            France Telecom
Intended status: Standards Track                                R. Penno
Expires: February 08, 2014                                       D. Wing
                                                                   Cisco
                                                         August 07, 2013


            DHCP Options for the Port Control Protocol (PCP)
                         draft-ietf-pcp-dhcp-08

Abstract

   This document specifies DHCP (IPv4 and IPv6) options to configure
   hosts with Port Control Protocol (PCP) Server IP addresses.  The use
   of DHCPv4 or DHCPv6 depends on the PCP deployment scenario.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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 February 08, 2014.

Copyright Notice

   Copyright (c) 2013 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



Boucadair, et al.       Expires February 08, 2014               [Page 1]


Internet-Draft              PCP DHCP Options                 August 2013


   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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  DHCPv6 PCP Server Option  . . . . . . . . . . . . . . . . . .   3
     3.1.  Format  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Client Behavior . . . . . . . . . . . . . . . . . . . . .   4
   4.  DHCPv4 PCP Option . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Format  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  Client Behavior . . . . . . . . . . . . . . . . . . . . .   5
   5.  Configuration Guidelines (Server Side)  . . . . . . . . . . .   5
   6.  Dual-Stack Hosts  . . . . . . . . . . . . . . . . . . . . . .   6
   7.  Hosts with Multiple Interfaces  . . . . . . . . . . . . . . .   6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     9.1.  DHCPv6 Option . . . . . . . . . . . . . . . . . . . . . .   6
     9.2.  DHCPv4 Option . . . . . . . . . . . . . . . . . . . . . .   7
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     11.2.  Informative References . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   This document defines DHCPv4 [RFC2131] and DHCPv6 [RFC3315] options
   that can be used to provision PCP server [RFC6887] IP addresses.

   This specification assumes a PCP server is reachable with one or
   multiple IP addresses.  As such, a list of IP addresses can be
   returned in the PCP server DHCP option.

   This specification allows to return one or multiple instances of the
   PCP server DHCP option.  This is used as a hint to guide the PCP
   client whether it needs to send PCP requests to one or multiple PCP
   servers.

   When multiple instances of the PCP server DHCP option or multiple IP
   addresses are received from the DHCP server, the PCP client follows
   the behavior specified in [I-D.ietf-pcp-server-selection].




Boucadair, et al.       Expires February 08, 2014               [Page 2]


Internet-Draft              PCP DHCP Options                 August 2013


   The use of DHCPv4 or DHCPv6 depends on the PCP deployment scenarios.

2.  Terminology

   This document makes use of the following terms:

   o  PCP server denotes a functional element that receives and
      processes PCP requests from a PCP client.  A PCP server can be co-
      located with or be separated from the function (e.g., NAT,
      Firewall) it controls.  Refer to [RFC6887].
   o  PCP client denotes a PCP software instance responsible for issuing
      PCP requests to a PCP server.  Refer to [RFC6887].
   o  DHCP refers to both DHCPv4 [RFC2131] and DHCPv6 [RFC3315].
   o  DHCP client (or client) denotes a node that initiates requests to
      obtain configuration parameters from one or more DHCP servers.
   o  DHCP server (or server) refers to a node that responds to requests
      from DHCP clients.

3.  DHCPv6 PCP Server Option

3.1.  Format

   The format of the DHCPv6 PCP server option is shown in Figure 1.

       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_PCP_SERVER        |         Option-length         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |                         ipv6-address                          |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |                         ipv6-address                          |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                              ...                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                    Figure 1: PCP Server DHCPv6 Option

   The fields of the option shown in Figure 1 are as follows:

   o  Option-code: OPTION_PCP_SERVER (TBA, see Section 9.1)




Boucadair, et al.       Expires February 08, 2014               [Page 3]


Internet-Draft              PCP DHCP Options                 August 2013


   o  Option-length: Length of the 'PCP server IP Address(es)' field in
      octets.  MUST be a multiple of 16.
   o  PCP server IPv6 Address(es): Includes one or more IPv6 addresses
      [RFC4291] of the PCP server(s) to be used by the PCP client.
      Note, IPv4-mapped IPv6 addresses (Section 2.5.5.2 of [RFC4291])
      are allowed to be included in this option.

3.2.  Client Behavior

   To discover a PCP server [RFC6887], the DHCPv6 client MUST include an
   Option Request Option (ORO) requesting the DHCPv6 PCP server option
   as described in Section 22.7 of [RFC3315] (i.e., include
   OPTION_PCP_SERVER on its OPTION_ORO).

   The client MUST be prepared to receive multiple instances of the
   DHCPv6 PCP server option; each instance is treated as a separate PCP
   server.

   The client MUST be prepared to receive one or multiple IPv6 addresses
   in the same PCP server option.

   If an IPv4-mapped IPv6 address is received in an OPTION_PCP_SERVER
   option, the PCP client issues IPv4 PCP messages to that PCP server.
   This behavior is compliant with the behavior of Windows and Mac OS as
   reported in Section 4.2 of [RFC6052].

   When multiple instances of the PCP server DHCPv6 option or multiple
   IPv6 addresses are received from the DHCPv6 server, the PCP client
   follows the behavior specified in [I-D.ietf-pcp-server-selection].

4.  DHCPv4 PCP Option

4.1.  Format

   The PCP server DHCPv4 option can be used to configure a list of IPv4
   addresses to be used by the PCP client to contact the PCP server.
   The format of this option is illustrated in Figure 2.

       Code   Len   PCP server IPv4 Address  PCP server IPv4 Address
      +-----+-----+-----+-----+-----+-----+-----+-----+--
      | TBA |  n  |  a1 |  a2 |  a3 |  a4 |  a1 |  a2 | ...
      +-----+-----+-----+-----+-----+-----+-----+-----+--


   This format assumes that an IPv4 address is encoded as a1.a2.a3.a4.

                    Figure 2: PCP Server DHCPv4 Option




Boucadair, et al.       Expires February 08, 2014               [Page 4]


Internet-Draft              PCP DHCP Options                 August 2013


   The description of the fields is as follows:

   o  Code: OPTION_PCP_SERVER (TBA, see Section 9.2);
   o  Length: Includes the length of included IP address(es) in octets;
      MUST be a multiple of 4.
   o  PCP server IPv4 Address(s): Contains one or more IPv4 addresses of
      the PCP server to be used by the PCP client.

4.2.  Client Behavior

   The DHCPv4 client expresses the intent to get OPTION_PCP_SERVER by
   specifying it in Parameter Request List Option [RFC2132].

   The client MUST be prepared to receive multiple instances of the
   DHCPv4 PCP server option; each instance is treated as a separate PCP
   server.

   The client MUST be prepared to receive one or multiple IPv4 addresses
   in the same PCP server option.

   When multiple instances of the PCP server DHCPv4 option or multiple
   IPv4 addresses are received from the DHCPv4 server, the PCP client
   follows the behavior specified in [I-D.ietf-pcp-server-selection].

5.  Configuration Guidelines (Server Side)

   DHCP servers supporting the DHCP PCP server option can be configured
   with a list of IP addresses of the PCP server(s).  If multiple IP
   addresses are configured, the DHCP server should be explicitly
   configured whether all or some of these addresses refer to:

   1.  the same PCP server: the DHCP server returns multiple addresses
       in the same instance of the DHCP PCP server option.

   2.  distinct PCP servers: the DHCP server returns multiple instances
       of the DHCP PCP server option to the requesting client; each
       instance is referring to a distinct PCP server.  For example,
       multiple OPTION_PCP_SERVER instances may be configured to a PCP
       client in some deployment contexts such as multi-homing.  It is
       out of scope of this document to enumerate all deployment
       scenarios that require multiple OPTION_PCP_SERVER instances to be
       returned.

   The DHCP server may be configured with one or multiple FQDNs of the
   PCP server(s).  In such case, the DHCP server must resolve these
   FQDNs into one or a list of IP addresses from pre-configured DNS
   server(s).  If multiple FQDNs are configured to the DHCP server, the
   DHCP server must include multiple OPTION_PCP_SERVER instances; each



Boucadair, et al.       Expires February 08, 2014               [Page 5]


Internet-Draft              PCP DHCP Options                 August 2013


   of them carries one or a list of IP addresses that resulted from the
   FQDN resolution.  DHCPv4 servers supporting PCP server option must
   resolve any configured FQDN into an IPv4 address while DHCPv6 servers
   may resolve any configured FQDN into an IPv6 and/or IPv4 address.  If
   an IPv4 address is retrieved by the DHCPv6 server, the corresponding
   IPv4-mapped IPv6 address is included in the OPTION_PCP_SERVER DHPCv6
   option.  If both IPv4 and IPv6 addresses are retrieved by the DHCPv6
   server, these addresses are included in the same OPTION_PCP_SERVER
   DHPCv6 option (IPv4 addresses are represented as IPv4-mapped IPv6
   addresses).

      Discussion: The motivation for this design is to accommodate
      deployment cases where an IPv4 connectivity service is provided
      while only DHPCv6 is in use (e.g., an IPv4-only PCP server in a
      DS-Lite context [RFC6333]).

   For guidelines on providing context-specific configuration
   information (e.g., returning a regional-based configuration), and
   information on how a server might be configured with FQDNs that get
   resolved on demand, see [I-D.lemon-dhc-topo-conf].

6.  Dual-Stack Hosts

   A Dual-Stack host may receive an OPTION_PCP_SERVER via both DHCPv4
   and DHCPv6.  The content of these OPTION_PCP_SERVER options may refer
   to the same or distinct PCP Servers.  This is deployment-specific and
   as such it is out of scope of this document.

7.  Hosts with Multiple Interfaces

   A host may have multiple network interfaces (e.g, 3G, IEEE 802.11,
   etc.); each configured differently.  Each PCP server learned MUST be
   associated with the interface via which it was learned.  Refer to
   [I-D.ietf-pcp-server-selection] and Section 8.4 of [RFC6887] for more
   discussion on multi-interface considerations.

8.  Security Considerations

   The security considerations in [RFC2131] and [RFC3315] are to be
   considered.  PCP-related security considerations are discussed in
   [RFC6887].

9.  IANA Considerations

9.1.  DHCPv6 Option






Boucadair, et al.       Expires February 08, 2014               [Page 6]


Internet-Draft              PCP DHCP Options                 August 2013


   IANA is requested to assign the following new DHCPv6 Option Code in
   the registry maintained in http://www.iana.org/assignments/
   dhcpv6-parameters:

                                Option Name Value
                          ----------------- -----
                          OPTION_PCP_SERVER TBA


9.2.  DHCPv4 Option

   IANA is requested to assign the following new DHCPv4 Option Code in
   the registry maintained in http://www.iana.org/assignments/bootp-
   dhcp-parameters/:

                                Option Name Value
                          ----------------- -----
                          OPTION_PCP_SERVER TBA


10.  Acknowledgements

   Many thanks to B. Volz, C. Jacquenet, R. Maglione, D. Thaler, T.
   Mrugalski, T. Reddy, S. Cheshire and M. Wasserman for their review
   and comments.

   Special thanks to T. Lemon for the review and his continuous effort
   to enhance this specification.

11.  References

11.1.  Normative References

   [I-D.ietf-pcp-server-selection]
              Boucadair, M., Penno, R., Wing, D., Patil, P., and T.
              Reddy, "PCP Server Selection", draft-ietf-pcp-server-
              selection-01 (work in progress), May 2013.

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

   [RFC2131]  Droms, R., "Dynamic Host Configuration Protocol", RFC
              2131, March 1997.

   [RFC2132]  Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
              Extensions", RFC 2132, March 1997.





Boucadair, et al.       Expires February 08, 2014               [Page 7]


Internet-Draft              PCP DHCP Options                 August 2013


   [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 3315, July 2003.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

   [RFC6887]  Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
              Selkirk, "Port Control Protocol (PCP)", RFC 6887, April
              2013.

11.2.  Informative References

   [I-D.lemon-dhc-topo-conf]
              Lemon, T., "Customizing DHCP Configuration on the Basis of
              Network Topology", draft-lemon-dhc-topo-conf-01 (work in
              progress), April 2013.

   [RFC6052]  Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
              Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
              October 2010.

   [RFC6333]  Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
              Stack Lite Broadband Deployments Following IPv4
              Exhaustion", RFC 6333, August 2011.

Authors' Addresses

   Mohamed Boucadair
   France Telecom
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com


   Reinaldo Penno
   Cisco
   USA

   Email: repenno@cisco.com










Boucadair, et al.       Expires February 08, 2014               [Page 8]


Internet-Draft              PCP DHCP Options                 August 2013


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

   Email: dwing@cisco.com












































Boucadair, et al.       Expires February 08, 2014               [Page 9]