PCP Working Group M. Boucadair Internet-Draft France Telecom Intended status: Informational April 15, 2014 Expires: October 17, 2014 Port Control Protocol (PCP) Deployment Models draft-boucadair-pcp-deployment-cases-02 Abstract This document lists a set of Port Control Protocol (PCP) deployment models. 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 October 17, 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 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 Boucadair Expires October 17, 2014 [Page 1] Internet-Draft PCP Deployment Cases April 2014 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 . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Single Homed CPE Model: Local PCP Server . . . . . . . . . . 3 4. Single Homed CPE Model: Multiple PCP Servers . . . . . . . . 3 5. Hide PCP Servers Model . . . . . . . . . . . . . . . . . . . 4 5.1. PCP Proxy Model . . . . . . . . . . . . . . . . . . . . . 4 5.2. HTTP-Triggered PCP Client Model . . . . . . . . . . . . . 5 6. Separated PCP Server & PCP-controlled Device Model . . . . . 6 7. Cascaded PCP-controlled Nodes Model . . . . . . . . . . . . . 7 7.1. Single Homed CPE Model: PCP Proxy Model . . . . . . . . . 9 7.2. UPnP IGD-PCP Interworking Model . . . . . . . . . . . . . 9 8. Multi-Homed CPE Model: One Single PCP Server . . . . . . . . 10 9. Multi-Homed CPE Model: Multiple PCP Servers . . . . . . . . . 11 10. Security Considerations . . . . . . . . . . . . . . . . . . . 12 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 12.1. Normative References . . . . . . . . . . . . . . . . . . 13 12.2. Informative References . . . . . . . . . . . . . . . . . 13 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction This document lists a set of PCP [RFC6887] deployment models. 2. Terminology This document makes use of the following terms: o PCP client denotes a functional element responsible for issuing PCP requests to a PCP server. Refer to [RFC6887]. 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 proxy refers to a functional elements that is responsible for relaying PCP requests received from PCP client to upstream PCP servers. Boucadair Expires October 17, 2014 [Page 2] Internet-Draft PCP Deployment Cases April 2014 3. Single Homed CPE Model: Local PCP Server This model assumes PCP is enabled in the LAN side to control functions located in the CPE. The PCP server is reachable with the IP address of the private-faced interface of the CPE. Typical functions that can be controlled by PCP in this model are NAT and firewall. +-------------+ | PCP | | Client |----+ ,-----------. +-------------+ | +------------+ ,' `--. +---| CPE | / : | PCP server |_______; ISP | +---| NAT+FW+.. | : | +-------------+ | +------------+ \ | | PCP |----+ -------------------. | Client | +-------------+ PCP client can be configured with their PCP server using DHCP for instance [I-D.ietf-pcp-dhcp]. If no PCP server is configured, PCP clients assume their default gateway is the PCP server. This model applies for both residential or corporate markets. 4. Single Homed CPE Model: Multiple PCP Servers This model assumes a customer site is connected to the same ISP's network. One or multiple PCP servers are deployed in the ISP's domain; each of them manage distinct set of functions. In the example shown in the following figure: o NAT64 device [RFC6146] are used to interwork with IPv4-only devices. o NPTv6 function [RFC6296] is used for engineering motivation internal to the ISP. Boucadair Expires October 17, 2014 [Page 3] Internet-Draft PCP Deployment Cases April 2014 +-------------+ | PCP | | Client |----+ ,-----------. +-------------+ | +------------+ ,' ISP `--. +---| CPE | / : | |________; NAT64 | +---| | : | +-------------+ | +------------+ \ NPTv6 | | PCP |----+ ----------------. | Client | +-------------+ The use of NAT64 and NPTv6 functions is for illustration purposes; other functions can be enabled in the ISP's network side. PCP clients located behind the CPE, must discover both the external IPv4 address and port numbers assigned by the NAT64 and the external IPv6 address assigned by the NPTv6. These external addresses are used for example in referrals to indicate to remote peers both the IPv4 address and IPv6 address to reach an internal server deployed in an IPv6-only domain. The use of a PCP anycast address ([I-D.ietf-pcp-anycast]) is not recommended for this deployment case because two state entries must be created in both NAT64 and NPTv6. Explicit means such as [I-D.ietf-pcp-dhcp] must be used instead to provision IP addresses of available PCP servers. [I-D.ietf-pcp-dhcp] may be used to provision the IP addresses of these PCP servers, or the CPE must embed a PCP proxy function that must follow [I-D.ietf-pcp-server-selection] to contact all PCP servers. 5. Hide PCP Servers Model 5.1. PCP Proxy Model In order to hide PCP servers deployed within an administrative domain, an administrative entity may decide to deploy one or more PCP proxies [I-D.ietf-pcp-proxy] in front of PCP clients. A PCP proxy is responsible for relaying PCP requests to the appropriate PCP server(s): o In order to prevent single failure scenarios, multiple PCP proxies can be hosted within an administrative domain. o A PCP proxy can be configured with one or multiple PCP servers. Boucadair Expires October 17, 2014 [Page 4] Internet-Draft PCP Deployment Cases April 2014 o A PCP proxy can be configured with the logic indicating how it should proceed to contact upstream PCP servers. The PCP proxy will then follow the procedure defined in [I-D.ietf-pcp-server-selection] to contact those PCP servers. o Internal PCP clients may be configured with the IP address(es) of the appropriate PCP proxy (e.g., [I-D.ietf-pcp-dhcp]). * If all PCP proxies interact with the same PCP server(s), the same IP address can be provisioned to PCP clients. * If PCP proxies do not interact with the same set of PCP server(s), appropriate IP address(es) are to be returned to each requesting PCP client. +------------------------------------+ | Administrative Domain | +----------+ | +-------------------+ | |PCP client|---|----| PCP proxy | | +----------+ | +-------------------+ | | | | | | | | | | +------+------+ +-+------------+ | | | PCP server | | PCP server | | | +-------------+ +--------------+ | +------------------------------------+ The PCP proxy should not use the PCP anycast address ([I-D.ietf-pcp-anycast]) if available PCP servers do not manage the same PCP-controlled device. Deterministic means should be used instead. PCP client should not use the PCP anycast address to reach a PCP proxy if deployed PCP proxies do not interact with the same PCP servers. Explicit provisioning means should be preferred. If the PCP proxy is reachable using the PCP anycast address, available PCP servers must not be reachable using the same PCP anycast address. 5.2. HTTP-Triggered PCP Client Model Another deployment model to hide the identity of back-end PCP servers is to rely on HTTP to invoke the PCP service. This model can be used by operators to accommodate cases where a PCP client implementation is not available at the customer side (e.g., unmanaged CPE model). The deployment model relies on the following: Boucadair Expires October 17, 2014 [Page 5] Internet-Draft PCP Deployment Cases April 2014 o An HTTP administration based interface (e.g. GUI) is provided to the user to manage its flow-based forwarding rules. o The HTTP user interface can be part of a CPE management interface or be provided as part of the customer care portal. o The HTTP server embeds also a PCP client. o HTTP requests are translated into appropriate PCP requests in order to install the requested state. o The PCP client uses THIRD_PARTY option. o The PCP client should be configured with the PCP server that controls the on-path PCP-controlled device for that user. o One or multiple PCP servers can be deployed. The logic of contacting these PCP servers may be explicitly configured to the PCP client. If not, the procedure defined in [I-D.ietf-pcp-server-selection] is used to contact those PCP servers. o The use of a well-known address ([I-D.ietf-pcp-anycast]) to reach internal PCP servers might not be convenient if all PCP servers do not manage the same set of mapping entries (e.g., NAT64, NPTv6, IPv6 firewall, etc.). +------------------------------------+ | Administrative Domain | +----------+ | +----------------------+ | | Host |---|----|HTTP Server+PCP client| | +----------+ | +----------------------+ | | | | | | | | | | +------+------+ +-+------------+ | | | PCP server | | PCP server | | | +-------------+ +--------------+ | +------------------------------------+ 6. Separated PCP Server & PCP-controlled Device Model This model assumes the PCP server is not co-located with the PCP- controlled device. Moreover: o In order to prevent single failure scenarios, multiple PCP servers can be hosted within an administrative domain. o A PCP server can control one or many PCP-controlled devices. Boucadair Expires October 17, 2014 [Page 6] Internet-Draft PCP Deployment Cases April 2014 o Multiple PCP servers can be enabled; each of them manages a set of PCP-controlled devices. o Internal PCP clients are configured with the IP address(es) of the appropriate PCP server. * If all PCP servers interact with the same PCP-controlled devices, the same PCP server's IP address can be provisioned to PCP clients. * If PCP servers do not interact with the same set of PCP- controlled devices, PCP server IP address(es) are to be returned to each requesting PCP client. Note, PCP is not used between the PCP server and the PCP-controlled device. Other protocols (e.g., H.248) can be used for that purpose. 7. Cascaded PCP-controlled Nodes Model This model assumes cascaded PCP-controlled devices are deployed. A typical example is provided below. Boucadair Expires October 17, 2014 [Page 7] Internet-Draft PCP Deployment Cases April 2014 ,-----------. PCP server ,' `--. +-------+ +------+ +----------+ / : |PCP |____|Home |______|ISP CPE |________; Public | |Client | |Router| |NAT Router| : Internet | +-------+ +------+ +----------+ \ | \ ; `------. ,-' `-----' ,-----------. PCP server ,' `--. +-------+ +------+ +-------+ / : |PCP |____|CPE |______|CGN/FW |___________; Public | |Client | | | | | : Internet | +-------+ +------+ +-------+ \ | \ ; `------. ,-' `-----' ,-----------. PCP proxy PCP server ,' `--. +-------+ +------+ +-------+ / : |PCP |____|CPE |_______________|CGN/FW |__; Public | |Client | | | | | : Internet | +-------+ +------+ +-------+ \ | \ ; `------. ,-' `-----' ,-----------. PCP server PCP server ,' `--. +-------+ +------+ +-------+ / : |PCP |____|CPE |_______________|CGN/FW |__; Public | |Client | | | | | : Internet | +-------+ +------+ +-------+ \ | \ ; `------. ,-' `-----' This model requires a PCP proxy function [I-D.ietf-pcp-proxy] be deployed in intermediate PCP-controlled devices: o The PCP client is not aware of the presence of more than one level of PCP servers. o Each intermediate PCP proxy must contact the appropriate next hop PCP server(s). o The use of PCP anaycast address may not be appropriate when the PCP server is co-located with the PCP-controlled device. Boucadair Expires October 17, 2014 [Page 8] Internet-Draft PCP Deployment Cases April 2014 7.1. Single Homed CPE Model: PCP Proxy Model This model assumes no PCP-controlled function is located in the CPE (e.g., DS-Lite case). The upstream PCP server is located in the ISP's network. The PCP server can be deduced from other provisioning parameters (e.g., use the IP address of the AFTR as PCP server); otherwise the IP address (s) must be discovered by other means. The use of an anycast-based model may not be convenient in some cases (e.g., multiple PCP-controlled devices are deployed; each of them manage a subset of services and state). +-------------+ | Host | | |----+ ,-----------. +-------------+ | +------------+ ,' `--. +---| CPE | / ISP : | PCP proxy |_____; PCP server 1 | +---| PCP client | : PCP server i | +-------------+ | +------------+ \ | | PCP |----+ -------------------. | Client | +-------------+ 7.2. UPnP IGD-PCP Interworking Model This model is specified in [RFC6970]. The interworking function must be provisioned with the IP address(es) of remote PCP server(s). Boucadair Expires October 17, 2014 [Page 9] Internet-Draft PCP Deployment Cases April 2014 (a) +-------------+ | IGD Control | | Point |----+ +-------------+ | +-----+ +--------+ +------+ +---| IGD-| |Provider| |Remote| | PCP |--| NAT |-----| Host | +---| IWF | | | | | +-------------+ | +-----+ +--------+ +------+ | Local Host |----+ +-------------+ LAN Side External Side <======UPnP IGD==============><=====PCP=====> (b) +-------------+ | IGD Control | | Point |----+ +-------------+ | +-----+ +--------+ +------+ +---| IGD-| |Provider| |Remote| | PCP |--| NAT |-----| Host | +---| IWF | | | | | +-------------+ | +-----+ +--------+ +------+ | Local Host |----+ NAT1 NAT2 +-------------+ 8. Multi-Homed CPE Model: One Single PCP Server A typical example of this model is shown in the following figure: Boucadair Expires October 17, 2014 [Page 10] Internet-Draft PCP Deployment Cases April 2014 ==================== | Internet | ===================== | | | | +----+--------+ +-+------------+ | ISP1 | | ISP2 | | | | | +----+--------+ +-+------------+ | | | | .............................................................. | | | Port1 | Port2 Subscriber Network | | +----------------------+ | NAT & PCP servers | | GW Router | +----+-----------------+ | | | -----+-------------- | +-+-----+ | Hosts | (private address space) +-------+ Internal PCP clients can interact with one single PCP server. 9. Multi-Homed CPE Model: Multiple PCP Servers A typical example of this model is shown in the following figure: Boucadair Expires October 17, 2014 [Page 11] Internet-Draft PCP Deployment Cases April 2014 ================== | Internet | ================== | | | | +----+-+ +-+----+ | ISP1 | | ISP2 | +----+-+ +-+----+ | | ......................................................... | | | | Subscriber Network +-------+---+ +----+------+ | rtr1 with | | rtr2 with | | FW1 | | FW2 | +-------+---+ +----+------+ | | | | | | -------+----------+------ | +-+-----+ | Hosts | +-------+ The PCP client must interact with all PCP servers; otherwise complications arise to communicate with remote peers. The procedure defined in [I-D.ietf-pcp-server-selection] is used to contact those servers. The use of anycast-based model ([I-D.ietf-pcp-anycast]) might induce failures when communicating with external peers (e.g., incoming packets will be dropped by one of the firewalls). 10. Security Considerations PCP-related security considerations are discussed in [RFC6887]. 11. IANA Considerations This document does not require any action from IANA. 12. References Boucadair Expires October 17, 2014 [Page 12] Internet-Draft PCP Deployment Cases April 2014 12.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6887] Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P. Selkirk, "Port Control Protocol (PCP)", RFC 6887, April 2013. 12.2. Informative References [I-D.ietf-pcp-anycast] Kiesel, S., Penno, R., and S. Cheshire, "PCP Anycast Address", draft-ietf-pcp-anycast-01 (work in progress), February 2014. [I-D.ietf-pcp-dhcp] Boucadair, M., Penno, R., and D. Wing, "DHCP Options for the Port Control Protocol (PCP)", draft-ietf-pcp-dhcp-13 (work in progress), April 2014. [I-D.ietf-pcp-proxy] Perreault, S., Boucadair, M., Penno, R., Wing, D., and S. Cheshire, "Port Control Protocol (PCP) Proxy Function", draft-ietf-pcp-proxy-05 (work in progress), February 2014. [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-02 (work in progress), January 2014. [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", RFC 6146, April 2011. [RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix Translation", RFC 6296, June 2011. [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. Author's Address Boucadair Expires October 17, 2014 [Page 13] Internet-Draft PCP Deployment Cases April 2014 Mohamed Boucadair France Telecom Rennes 35000 France Email: mohamed.boucadair@orange.com Boucadair Expires October 17, 2014 [Page 14]