Internet DRAFT - draft-boucadair-pcp-capability
draft-boucadair-pcp-capability
PCP Working Group M. Boucadair
Internet-Draft France Telecom
Intended status: Standards Track T. Reddy
Expires: May 29, 2014 Cisco
November 25, 2013
Retrieving the Capabilities of a PCP-controlled Device
draft-boucadair-pcp-capability-03
Abstract
This document extends Port Control Protocol (PCP) with the ability to
retrieve the capabilities of PCP-controlled device: CAPABILITY
Option.
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.
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This Internet-Draft will expire on May 29, 2014.
Copyright Notice
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carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. CAPABILITY . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. PCP Client/Server Behavior . . . . . . . . . . . . . . . . . 3
4. Option Usage . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
This document extends the base PCP [RFC6887] with a new feature to
discover the capabilities of a PCP-controlled device. Retrieving the
capabilities of a PCP-controlled device would allow to avoid error,
provide a hint why some applications fails, help select the OpCode to
issue, etc.
This option can be elected to be defined as a new OpCode.
2. CAPABILITY
The CAPABILITY option (Code: TBA, Figure 1) is used by a PCP Server
to indicate to a requesting PCP Client the capabilities it supports
with regards to port forwarding operations.
One single Capability option is conveyed in the same PCP response
message even if several functions are co-located in the same PCP-
controlled device (e.g., NAT44 and NAT64, NAT44 and ports set
assignment capability, etc.).
This option, when received from a PCP Server, is used by a PCP Client
to constraint the content of its requests and therefore avoid errors.
0 1 2 3
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CAPABILITY | Reserved | Length=16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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|A| Capability |
+-+ |
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This Option:
Option Name: PCP Capabilities Option (CAPABILITY)
Number: TBA (IANA)
Purpose: Retrieve the capabilities of a PCP-controlled device
Valid for Opcodes: ANNOUNCE, MAP, PEER
Length: 16
May appear in: both request and response
Maximum occurrences: None
Figure 1: Capability option
A-bit when set (i.e., 1) indicates the PCP Server supports
authentication. If this bit is set to 0, is indicates plain PCP is
supported.
The Capability Field is encoded in 127 bits. Each bit in the
Capability bit mask is used to represent the PCP-controlled device
capability. Several bits can be set if several functions are co-
located in the same device. The following values for the Capability
field are:
Bit #: Description
1: NAT44
2: Stateless NAT64 [RFC6145].
4: Stateful NAT64 [RFC6146].
8: A+P Port Range Router [RFC6346]
9: Supports PORT_SET option [I-D.ietf-pcp-port-set].
16: IPv4 firewall.
32: IPv6 Firewall [RFC6092].
64: NPTv6 [RFC6296].
125: DSCP re-marking function.
126: FLOWDATA-aware function ([I-D.wing-pcp-flowdata]).
127: ILNP Translator [RFC6740].
3. PCP Client/Server Behavior
This section specifies the behavior of the PCP Client and the PCP
Server to handle the CAPABILITY Option.
The PCP Server MAY be configured to return the CAPABILITY Option even
if it is not included in the request.
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Once the PCP Client is configured with its PCP Server(s), it MAY
issue an ANNOUNCE OpCode which enclose a CAPABILITY Option. Sending
the ANNOUNCE OpCode and the CAPABILITY Option allows the PCP Client
to determine whether the PCP Server is alive and also to retrieve its
capabilities. Based on the received capabilities, the PCP Client may
decide to tune its requests (e.g., Section 4) and decide whether all
PCP Servers need to be contacted in parallel or only a subset of them
should be contacted.
Upon receipt of a PCP request from a PCP Client requiring the PCP
Server to enforce an operation beyond its capabilities, the PCP
Server MAY return an error code together with the CAPABILITY option.
When a new PCP Server joins the network then it MAY send an ANNOUNCE
OpCode with its capabilities (i.e., CAPABILITY Option).
4. Option Usage
Below are provided examples of the CAPABILITY Option usage:
o In an IPv6 network with NPTv6 [RFC6296], Firewalls implementing
the PCP Server are on different devices: the PCP Client learns of
the available PCP Servers by using DHCP [I-D.ietf-pcp-dhcp] or any
other PCP Server discovery technique defined in future
specifications. PCP Client learns the PCP Server capabilities
using CAPABILITY Option. The PCP Client sends MAP PCP request to
PCP-controlled NPTv6 device with Internal Port=0 and Protocol=0
(which means 'all ports for all protocols') to find the external
IP address. This PCP request has to be sent only once since NPTv6
is stateless and provides a 1:1 relationship between addresses in
the "inside" and "outside" prefixes. The PCP Client will send PCP
re-request to NTPv6 only before the Assigned Lifetime of the MAP
response expires or when the host embedding the PCP Client
acquires a new IPv6 address using "inside" prefix. However PCP
Client will send MAP/PEER requests to Firewall to create/delete
dynamic outbound mapping or use PCP instead of its default
application keep-alives to maintain the Firewall state alive.
PCP
Client __________
+-----------+ +------+ +------+ / \ +-----------+
|Application|___| NPTv6|___| FW |____| Internet |___|Application|
| Client | | | | | | | | Server |
+-----------+ +------+ +------+ \__________/ +-----------+
Figure 2: NPTv6 and FW not collocated with PCP server Capability
o In a network with NAT64 [RFC6146], Firewall implementing PCP
servers are on different devices: IPv6-only PCP Client can send
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PREFIX64 PCP Option [I-D.ietf-pcp-nat64-prefix64] only to the PCP-
controlled NAT64 device to learn the Prefix64(s) used to build
IPv4-embedded IPv6 addresses.
o Multiple PCP-controlled devices: See Figure 3 the example of a
network deploying several techniques to ensure interconnection
with IPv4, provide IPv6-only connectivity, etc. Of course, one
can argue this configuration is no realistic.
+-----+
______|NPTv6|___________
/ +-----+ \
| |
| +-----+
+-----------+ +------+ | | PRR |
|Application|___| IPv6 |______| SP Network +-----+
|PCP Client| | FW | | |
+-----------+ +------+ | +------+
| | NAT64|
+-----------+ +-------+ | | + |
|PCP Client |___|A+P NAT|_____| | FW |
+-----------+ +-------+ | +-----+ +------+
\______|NPTv6|___________/
+-----+
Figure 3: Multiple PCP-controlled devoce
o In a IPv6 network with ILNP translator [RFC6740], Firewall
implementing PCP servers are on different devices. PCP client
needs to send PCP request only to the PCP-controlled ILNP
translator to find Global Locators associated with Internal
Locators.
o When the PCP-controlled device is a PRR, the PCP Client should use
PORT_SET [I-D.ietf-pcp-port-set] option.
5. Security Considerations
Security considerations discussed in [RFC6887] must be considered.
6. IANA Considerations
The following PCP Option Code is to be allocated in the optional-to-
process range (the registry is maintained in http://www.iana.org/
assignments/pcp-parameters/pcp-parameters.xml#options):
CAPABILITY
A sub-registry is required to track the set of capabilities of PCP-
controlled devices.
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7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011.
[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.
[RFC6887] Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
Selkirk, "Port Control Protocol (PCP)", RFC 6887, April
2013.
7.2. Informative References
[I-D.ietf-opsawg-firewalls]
Baker, F. and P. Hoffman, "On Firewalls in Internet
Security", draft-ietf-opsawg-firewalls-01 (work in
progress), October 2012.
[I-D.ietf-pcp-dhcp]
Boucadair, M., Penno, R., and D. Wing, "DHCP Options for
the Port Control Protocol (PCP)", draft-ietf-pcp-dhcp-09
(work in progress), November 2013.
[I-D.ietf-pcp-nat64-prefix64]
Boucadair, M., "Learning NAT64 PREFIX64s using PCP",
draft-ietf-pcp-nat64-prefix64-04 (work in progress), July
2013.
[I-D.ietf-pcp-port-set]
Qiong, Q., Boucadair, M., Sivakumar, S., Zhou, C., Tsou,
T., and S. Perreault, "Port Control Protocol (PCP)
Extension for Port Set Allocation", draft-ietf-pcp-port-
set-04 (work in progress), November 2013.
[I-D.wing-pcp-flowdata]
Wing, D., Penno, R., and T. Reddy, "PCP Flowdata Option",
draft-wing-pcp-flowdata-00 (work in progress), July 2013.
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[RFC6092] Woodyatt, J., "Recommended Simple Security Capabilities in
Customer Premises Equipment (CPE) for Providing
Residential IPv6 Internet Service", RFC 6092, January
2011.
[RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix
Translation", RFC 6296, June 2011.
[RFC6346] Bush, R., "The Address plus Port (A+P) Approach to the
IPv4 Address Shortage", RFC 6346, August 2011.
[RFC6740] Atkinson,, RJ., "Identifier-Locator Network Protocol
(ILNP) Architectural Description", RFC 6740, November
2012.
Authors' Addresses
Mohamed Boucadair
France Telecom
Rennes 35000
France
Email: mohamed.boucadair@orange.com
Tirumaleswar Reddy
Cisco Systems, Inc.
Cessna Business Park, Varthur Hobli
Sarjapur Marathalli Outer Ring Road
Bangalore, Karnataka 560103
India
Email: tireddy@cisco.com
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