PCP Working Group M. Boucadair Internet-Draft France Telecom Intended status: Standards Track R. Penno Expires: May 09, 2014 D. Wing Cisco November 05, 2013 DHCP Options for the Port Control Protocol (PCP) draft-ietf-pcp-dhcp-09 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 May 09, 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 May 09, 2014 [Page 1] Internet-Draft PCP DHCP Options November 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. DHCP Server Configuration Guidelines . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . 6 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 11.1. Normative References . . . . . . . . . . . . . . . . . . 7 11.2. Informative References . . . . . . . . . . . . . . . . . 7 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 returning one or multiple instances of the PCP server DHCP option. 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 [I-D.ietf-pcp-server-selection]. The use of DHCPv4 or DHCPv6 depends on the PCP deployment scenarios. Boucadair, et al. Expires May 09, 2014 [Page 2] Internet-Draft PCP DHCP Options November 2013 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 PCP server DHCPv6 option can be used to configure a list of IPv6 addresses of a PCP server. The format of this 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 May 09, 2014 [Page 3] Internet-Draft PCP DHCP Options November 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 Addresses: Includes one or more IPv6 addresses [RFC4291] of the PCP server 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, the DHCPv6 client requests PCP server IP addresses by including OPTION _PCP_SERVER in an Option Request Option (ORO), as described in Section 22.7 of [RFC3315]. The client MUST be prepared to receive multiple instances of the DHCPv6 PCP server option; each instance is to be treated as a separate PCP server. If an IPv4-mapped IPv6 address is received in an OPTION_PCP_SERVER option, it indicates that the PCP server has the corresponding IPv4 address. 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 of a 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 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. Boucadair, et al. Expires May 09, 2014 [Page 4] Internet-Draft PCP DHCP Options November 2013 o PCP server IPv4 Addresses: Contains one or more IPv4 addresses of the PCP server to be used by the PCP client. 4.2. Client Behavior To discover a PCP server, the DHCPv4 client requests PCP server IP addresses by including OPTION_PCP_SERVER in a Parameter Request List Option [RFC2132]. The client MUST be prepared to receive multiple instances of the DHCPv4 PCP server option; each instance is to be treated as a separate PCP server. 5. DHCP Server Configuration Guidelines 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: 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 configurable 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. If multiple FQDNs are configured to the DHCP server, the DHCP server MUST include multiple OPTION_PCP_SERVER instances; 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 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). Boucadair, et al. Expires May 09, 2014 [Page 5] Internet-Draft PCP DHCP Options November 2013 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.ietf-dhc-topo-conf]. 6. Dual-Stack Hosts A Dual-Stack host might receive OPTION_PCP_SERVER via both DHCPv4 and DHCPv6. For guidance on how a client can handle PCP server IP lists for the same network but obtained via different mechanisms, see [I-D.ietf-pcp-server-selection]. 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 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 Boucadair, et al. Expires May 09, 2014 [Page 6] Internet-Draft PCP DHCP Options November 2013 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 [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. [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.ietf-dhc-topo-conf] Lemon, T. and T. Mrugalski, "Customizing DHCP Configuration on the Basis of Network Topology", draft- ietf-dhc-topo-conf-00 (work in progress), October 2013. Boucadair, et al. Expires May 09, 2014 [Page 7] Internet-Draft PCP DHCP Options November 2013 [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. [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 Dan Wing Cisco Systems, Inc. 170 West Tasman Drive San Jose, California 95134 USA Email: dwing@cisco.com Boucadair, et al. Expires May 09, 2014 [Page 8]