Internet DRAFT - draft-boucadair-pcp-deployment-cases
draft-boucadair-pcp-deployment-cases
PCP Working Group M. Boucadair
Internet-Draft France Telecom
Intended status: Informational July 03, 2014
Expires: January 4, 2015
Port Control Protocol (PCP) Deployment Models
draft-boucadair-pcp-deployment-cases-03
Abstract
This document lists a set of Port Control Protocol (PCP) deployment
models.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. CPE Models . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.1. Single Homed CPE Model: Local PCP Server . . . . . . . . 3
3.2. Single Homed CPE Model: Multiple PCP Servers . . . . . . 3
3.3. Multi-Homed CPE Model: One Single PCP Server . . . . . . 4
3.4. Multi-Homed CPE Model: Multiple PCP Servers . . . . . . . 5
3.5. PCP Proxy Model . . . . . . . . . . . . . . . . . . . . . 6
3.6. UPnP IGD-PCP Interworking Model . . . . . . . . . . . . . 7
3.7. HTTP-based User Interface . . . . . . . . . . . . . . . . 8
3.8. Cascaded PCP-controlled Nodes Model . . . . . . . . . . . 8
4. Hide PCP Servers Model . . . . . . . . . . . . . . . . . . . 10
4.1. PCP Proxy Model . . . . . . . . . . . . . . . . . . . . . 10
4.2. HTTP-Triggered PCP Client Model . . . . . . . . . . . . . 11
5. Separated PCP Server & PCP-controlled Device Model . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
8.1. Normative References . . . . . . . . . . . . . . . . . . 13
8.2. Informative References . . . . . . . . . . . . . . . . . 13
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 14
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.
3. CPE Models
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3.1. 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.
3.2. 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.
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+-------------+
| 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.
3.3. Multi-Homed CPE Model: One Single PCP Server
A typical example of this model is shown in the following figure:
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====================
| 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.
3.4. Multi-Homed CPE Model: Multiple PCP Servers
A typical example of this model is shown in the following figure:
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==================
| 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).
3.5. 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).
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+-------------+
| Host |
| |----+ ,-----------.
+-------------+ | +------------+ ,' `--.
+---| CPE | / ISP :
| PCP proxy |_____; PCP server 1 |
+---| PCP client | : PCP server i |
+-------------+ | +------------+ \ |
| PCP |----+ -------------------.
| Client |
+-------------+
3.6. 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).
(a)
+-------------+
| IGD Control |
| Point |----+
+-------------+ | +-----+ +--------+ +------+
+---| IGD-| |Provider| |Remote|
| PCP |--| NAT |--<Internet>---| Host |
+---| IWF | | | | |
+-------------+ | +-----+ +--------+ +------+
| Local Host |----+
+-------------+
LAN Side External Side
<======UPnP IGD==============><=====PCP=====>
(b)
+-------------+
| IGD Control |
| Point |----+
+-------------+ | +-----+ +--------+ +------+
+---| IGD-| |Provider| |Remote|
| PCP |--| NAT |--<Internet>---| Host |
+---| IWF | | | | |
+-------------+ | +-----+ +--------+ +------+
| Local Host |----+ NAT1 NAT2
+-------------+
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3.7. HTTP-based User Interface
This deployment model relies on the following:
o An HTTP administration based interface (e.g. GUI) is provided to
the user to manage its flow-based forwarding rules. This
interface is part of the CPE management interface.
o The CPE embeds 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.).
+-------------+
| Host 1 |----+ ,-----------.
+-------------+ | +------------+ ,' `--.
+---| CPE | / ISP :
| HTTP Server|_____; |
+---| PCP client | : PCP server i |
+-------------+ | +------------+ \ |
| Host 2 |----+ -------------------.
+-------------+
This model can co-exist with the models discussed in Section 3.5 and
Section 3.6.
3.8. Cascaded PCP-controlled Nodes Model
This model assumes cascaded PCP-controlled devices are deployed. A
typical example is provided below.
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,-----------.
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.
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4. Hide PCP Servers Model
4.1. 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.
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.
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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.
4.2. 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:
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.).
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+------------------------------------+
| Administrative Domain |
+----------+ | +----------------------+ |
| Host |---|----|HTTP Server+PCP client| |
+----------+ | +----------------------+ |
| | | |
| | | |
| +------+------+ +-+------------+ |
| | PCP server | | PCP server | |
| +-------------+ +--------------+ |
+------------------------------------+
5. 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.
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.
6. Security Considerations
PCP-related security considerations are discussed in [RFC6887].
7. IANA Considerations
This document does not require any action from IANA.
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8. References
8.1. 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.
8.2. 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-03 (work in progress), April 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.
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Author's Address
Mohamed Boucadair
France Telecom
Rennes 35000
France
Email: mohamed.boucadair@orange.com
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