DHCP Options for the Port Control Protocol (PCP)
draft-ietf-pcp-dhcp-08
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 7291.
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|
|---|---|---|---|
| Authors | Mohamed Boucadair , Reinaldo Penno , Dan Wing | ||
| Last updated | 2013-08-06 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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draft-ietf-pcp-dhcp-08
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
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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. 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].
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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)
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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
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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
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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
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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.
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[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
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Dan Wing
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134
USA
Email: dwing@cisco.com
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