One document matched: draft-ietf-pcp-dhcp-10.xml
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<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
<?rfc toc="yes"?>
<?rfc tocompact="yes"?>
<?rfc tocdepth="5"?>
<?rfc tocindent="yes"?>
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<?rfc comments="yes"?>
<?rfc inline="yes"?>
<?rfc compact="yes"?>
<?rfc subcompact="no"?>
<rfc category="std" docName="draft-ietf-pcp-dhcp-10" ipr="trust200902">
<front>
<title abbrev="PCP DHCP Options">DHCP Options for the Port Control
Protocol (PCP)</title>
<author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
<organization>France Telecom</organization>
<address>
<postal>
<street></street>
<city>Rennes</city>
<region></region>
<code>35000</code>
<country>France</country>
</postal>
<email>mohamed.boucadair@orange.com</email>
</address>
</author>
<author fullname="Reinaldo Penno" initials="R." surname="Penno">
<organization>Cisco</organization>
<address>
<postal>
<street></street>
<code></code>
<country>USA</country>
</postal>
<email>repenno@cisco.com</email>
</address>
</author>
<author fullname="Dan Wing" initials="D." surname="Wing">
<organization abbrev="Cisco">Cisco Systems, Inc.</organization>
<address>
<postal>
<street>170 West Tasman Drive</street>
<city>San Jose</city>
<region>California</region>
<code>95134</code>
<country>USA</country>
</postal>
<email>dwing@cisco.com</email>
</address>
</author>
<date day="01" month="April" year="2014" />
<workgroup>PCP Working Group</workgroup>
<keyword>PCP Server discovery, Port Mapping, Shared Address</keyword>
<abstract>
<t>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 scenarios. The set of
deployment scenarios to which use of DHCPv4 or DHCPv6 apply are outside
the scope of this document.</t>
</abstract>
<note title="Requirements Language">
<t>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 <xref
target="RFC2119">RFC 2119</xref>.</t>
</note>
</front>
<middle>
<section title="Introduction">
<t>This document defines DHCPv4 <xref target="RFC2131"></xref> and
DHCPv6 <xref target="RFC3315"></xref> options that can be used to
provision PCP server <xref target="RFC6887"></xref> IP addresses.</t>
<t>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 DHCP PCP server option.</t>
<t>This specification allows returning one or multiple lists of PCP
server IP addresses. This is used as a hint to guide the PCP client when
determining whether to send PCP requests to one or multiple PCP servers.
For guidelines on how a PCP client can use multiple IP addresses and
multiple PCP servers, see <xref
target="I-D.ietf-pcp-server-selection"></xref>.</t>
<t>The use of DHCPv4 or DHCPv6 depends on the PCP deployment scenarios.
The set of deployment scenarios to which use of DHCPv4 or DHCPv6 apply
are out of scope.</t>
</section>
<section title="Terminology">
<t>This document makes use of the following terms:<?rfc subcompact="yes" ?></t>
<t><list style="symbols">
<t>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 <xref target="RFC6887"></xref>.</t>
<t>PCP client denotes a PCP software instance responsible for
issuing PCP requests to a PCP server. Refer to <xref
target="RFC6887"></xref>.</t>
<t>DHCP refers to both DHCPv4 <xref target="RFC2131"></xref> and
DHCPv6 <xref target="RFC3315"></xref>.</t>
<t>DHCP client denotes a node that initiates requests to obtain
configuration parameters from one or more DHCP servers.</t>
<t>DHCP server refers to a node that responds to requests from DHCP
clients.</t>
</list><?rfc subcompact="no" ?></t>
</section>
<section title="DHCPv6 PCP Server Option">
<t></t>
<section title="Format">
<t>The DHCPv6 PCP server option can be used to configure a list of
IPv6 addresses of a PCP server.</t>
<t>The format of this option is shown in <xref
target="dhcpv6_name_option"></xref>.</t>
<t><figure anchor="dhcpv6_name_option"
title="DHCPv6 PCP server option">
<preamble></preamble>
<artwork><![CDATA[ 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_V6_PCP_SERVER | Option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| ipv6-address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| ipv6-address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>The fields of the option shown in <xref
target="dhcpv6_name_option"></xref> are as follows:<?rfc subcompact="yes" ?></t>
<t><list style="symbols">
<t>Option-code: OPTION_V6_PCP_SERVER (TBA, see <xref
target="iana6"></xref>)</t>
<t>Option-length: Length of the 'PCP server IP Address(es)' field
in octets. MUST be a multiple of 16.</t>
<t>PCP server IPv6 Addresses: Includes one or more IPv6 addresses
<xref target="RFC4291"></xref> of the PCP server to be used by the
PCP client. Note, IPv4-mapped IPv6 addresses (Section 2.5.5.2 of
<xref target="RFC4291"></xref>) are allowed to be included in this
option.</t>
</list></t>
<t><?rfc subcompact="no" ?></t>
</section>
<section title="DHCPv6 Client Behavior">
<t>To discover one or more PCP servers, the DHCPv6 client requests PCP
server IP addresses by including OPTION_V6_PCP_SERVER in an Option
Request Option (ORO), as described in Section 22.7 of <xref
target="RFC3315"></xref>.</t>
<t>The DHCPv6 client MUST be prepared to receive multiple instances of
OPTION_V6_PCP_SERVER; each instance is to be treated as a separate PCP
server.</t>
<t>If an IPv4-mapped IPv6 address is received in OPTION_V6_PCP_SERVER,
it indicates that the PCP server has the corresponding IPv4
address.</t>
</section>
</section>
<section title="DHCPv4 PCP Option">
<t></t>
<section title="Format">
<t>The DHCPv4 PCP server option can be used to configure a list of
IPv4 addresses of a PCP server. The format of this option is
illustrated in <xref target="dhcppcp"></xref>.</t>
<t><figure anchor="dhcppcp" title="DHCPv4 PCP server option">
<preamble></preamble>
<artwork><![CDATA[ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| List-Length | List of |
+-+-+-+-+-+-+-+-+ PCP server |
/ IPv4 Addresses /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ---
| List-Length | List of | |
+-+-+-+-+-+-+-+-+ PCP server | |
/ IPv4 Addresses / |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
. ... . optional
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| List-Length | List of | |
+-+-+-+-+-+-+-+-+ PCP server | |
/ IPv4 Addresses / |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ---
]]></artwork>
<postamble></postamble>
</figure></t>
<t>The description of the fields is as follows:<?rfc subcompact="yes" ?><list
style="symbols">
<t>Code: OPTION_V4_PCP_SERVER (TBA, see <xref
target="iana4"></xref>);</t>
<t>Length: Length of all included data in octets. The minimum
length is 5.</t>
<t>List-Length: Length of the "List of PCP server IPv4 Addresses"
field in octets; MUST be a multiple of 4.</t>
<t>List of PCP server IPv4 Addresses: Contains one or more IPv4
addresses of the PCP server to be used by the PCP client. The
format of this field is shown in <xref target="list"></xref>.</t>
<t>OPTION_V4_PCP_SERVER can include multiple lists of PCP server
IPv4 addresses; each list is treated as a separate PCP server.
When several lists of PCP server IPv4 addresses are to be
included, "List-Length" and "PCP server IPv4 Addresses" fields are
repeated.</t>
</list><figure anchor="list"
title="Format of the List of PCP server IPv4 Addresses">
<artwork><![CDATA[ 0 8 16 24 32 40 48
+-----+-----+-----+-----+-----+-----+--
| a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+--
IPv4 Address 1 IPv4 Address 2 ...]]></artwork>
<postamble>This format assumes that an IPv4 address is encoded as
a1.a2.a3.a4.</postamble>
</figure></t>
<t><?rfc subcompact="no" ?>OPTION_V4_PCP_SERVER is a
concatenation-requiring option. As such, the mechanism specified in
<xref target="RFC3396"></xref> MUST be used if OPTION_V4_PCP_SERVER
exceeds the maximum DHCPv4 option size of 255 octets.</t>
</section>
<section title="DHCPv4 Client Behavior">
<t>To discover one or more PCP servers, the DHCPv4 client requests PCP
server IP addresses by including OPTION_V4_PCP_SERVER in a Parameter
Request List Option <xref target="RFC2132"></xref>.</t>
<t>The DHCPv4 client MUST be prepared to receive multiple lists of PCP
server IPv4 addresses in the same DHCPv4 PCP server option; each list
is to be treated as a separate PCP server.</t>
</section>
</section>
<section title="DHCP Server Configuration Guidelines">
<t>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 MUST be explicitly configured
whether all or some of these addresses refer to:</t>
<t><list style="numbers">
<t>the same PCP server: the DHCP server returns multiple addresses
in the same instance of the DHCP PCP server option.</t>
<t>distinct PCP servers: the DHCP server returns multiple lists of
PCP server IP addresses to the requesting DHCP client (encoded as
multiple OPTION_V6_PCP_SERVER or in the same OPTION_V4_PCP_SERVER);
each list is referring to a distinct PCP server. For example,
multiple PCP servers 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
PCP servers to be returned.</t>
</list></t>
<t>The DHCP server MAY be configurable with one or multiple Fully
Qualified Domain Names (FQDNs) of the PCP server(s). In such case, the
DHCP server MUST resolve these FQDNs into one or a list of IP addresses.
If multiple FQDNs are configured to the DHCP server, the DHCP server
MUST include multiple lists of PCP server IP addresses in the PCP server
option (encoded as multiple OPTION_V6_PCP_SERVER or in the same
OPTION_V4_PCP_SERVER); each 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 FQDNs into IPv4
addresses while DHCPv6 servers may resolve any configured FQDNs into
IPv6 and/or IPv4 addresses. If an IPv4 address is retrieved by the
DHCPv6 server, the corresponding IPv4-mapped IPv6 address is included in
OPTION_V6_PCP_SERVER. If both IPv4 and IPv6 addresses are retrieved by
the DHCPv6 server, these addresses are included in the same
OPTION_V6_PCP_SERVER (IPv4 addresses are represented as IPv4-mapped IPv6
addresses).<list style="empty">
<t>Discussion: The motivation for this design is to accommodate
deployment cases where an IPv4 connectivity service is provided
while only DHCPv6 is in use (e.g., an IPv4-only PCP server in a
DS-Lite context <xref target="RFC6333"></xref>).</t>
</list></t>
<t>For guidelines on providing context-specific configuration
information (e.g., returning a regional-based configuration), and
information on how a DHCP server might be configured with FQDNs that get
resolved on demand, see <xref
target="I-D.ietf-dhc-topo-conf"></xref>.</t>
</section>
<section title="Dual-Stack Hosts">
<t>A Dual-Stack host might receive PCP server option via both DHCPv4 and
DHCPv6. For guidance on how a DHCP client can handle PCP server IP lists
for the same network but obtained via different mechanisms, see <xref
target="I-D.ietf-pcp-server-selection"></xref>.</t>
</section>
<section anchor="mif" title="Hosts with Multiple Interfaces">
<t>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 <xref
target="I-D.ietf-pcp-server-selection"></xref> and Section 8.4 of <xref
target="RFC6887"></xref> for more discussion on multi-interface
considerations.</t>
</section>
<section anchor="Security" title="Security Considerations">
<t>The security considerations in <xref target="RFC2131"></xref> and
<xref target="RFC3315"></xref> are to be considered. PCP-related
security considerations are discussed in <xref
target="RFC6887"></xref>.</t>
</section>
<section anchor="IANA" title="IANA Considerations">
<t></t>
<section anchor="iana6" title="DHCPv6 Option">
<t>IANA is requested to assign the following new DHCPv6 Option Code in
the registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters:</t>
<texttable style="headers">
<ttcol align="right">Option Name</ttcol>
<ttcol>Value</ttcol>
<c>OPTION_V6_PCP_SERVER</c>
<c>TBA</c>
</texttable>
</section>
<section anchor="iana4" title="DHCPv4 Option">
<t>IANA is requested to assign the following new DHCPv4 Option Code in
the registry maintained in
http://www.iana.org/assignments/bootp-dhcp-parameters/:</t>
<texttable style="headers">
<ttcol align="right">Option Name</ttcol>
<ttcol>Value</ttcol>
<ttcol>Data length</ttcol>
<ttcol>Meaning</ttcol>
<c>OPTION_V4_PCP_SERVER</c>
<c>TBA</c>
<c>Variable; the minimum length is 5.</c>
<c>Includes one or multiple lists of PCP server IP addresses; each
list is treated as a separate PCP server. </c>
</texttable>
<t></t>
</section>
</section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>Many thanks to C. Jacquenet, R. Maglione, D. Thaler, T. Mrugalski, T.
Reddy, S. Cheshire, M. Wasserman, and C. Holmberg for their review and
comments.</t>
<t>Special thanks to T. Lemon and B. Volz for the review and their
effort to enhance this specification.</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include="reference.RFC.2119"?>
<?rfc include='reference.RFC.3315'?>
<?rfc include='reference.RFC.2131'?>
<?rfc include='reference.RFC.4291'?>
<?rfc include='reference.RFC.2132'?>
<?rfc include='reference.RFC.6887'?>
<?rfc include='reference.RFC.3396'?>
</references>
<references title="Informative References">
<?rfc include='reference.I-D.ietf-dhc-topo-conf'?>
<?rfc include='reference.I-D.ietf-pcp-server-selection'?>
<?rfc include='reference.RFC.6333'?>
</references>
</back>
</rfc>
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