Internet DRAFT - draft-boucadair-pcp-extensions
draft-boucadair-pcp-extensions
Network Working Group M. Boucadair
Internet-Draft France Telecom
Intended status: Standards Track R. Penno
Expires: October 27, 2012 D. Wing
Cisco
April 25, 2012
Some Extensions to Port Control Protocol (PCP)
draft-boucadair-pcp-extensions-03
Abstract
This document extends Port Control Protocol (PCP) with new
functionalities.
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
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 27, 2012.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Provisions Relating to IETF Documents
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carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. DSCP_POLICY . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. CAPABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. REPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. CLIENT_IDENTIFIER . . . . . . . . . . . . . . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
9. Normative References . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
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1. Introduction
This document extends the base PCP [I-D.ietf-pcp-base] with various
PCP Options.
Some of these options may be defined as new PCP OpCodes.
The main goal of this document is to kick-off discussions on the need
to define some useful PCP options which are not part of base PCP.
2. DESCRIPTION
This option (Code TBA, Figure 1) MAY be included in a PCP MAP request
to include a description associated with a requested mapping. This
option is optional to be supported by PCP Servers and PCP Clients.
The maximum length SHOULD be a configurable option in the PCP Server.
If a PCP Client includes a Description PCP option with a length
exceeding the maximum length supported by the PCP Server, only the
portion of the Description field fitting that maximum length is
stored by the PCP Server.
This option can be used by a user to indicate a description
associated with a given mapping such as "My mapping for my FTP
server" or "My remote access to my CP router", etc. In addition, in
the some deployment scenarios, this field can be used for
troubleshooting purposes and can be used to convey values as the ones
listed hereafter:
o "This is the mapping for my specific IPsec implementation"
o "This is the mapping for subscriber bob@example.com"
o "This is the mapping for special subscriber
adsl-line-1234@example.com"
o "This is the mapping that failed before due to XYZ"
Issues related to the usage of this field for troubleshooting or for
any further usage are out of scope of this document.
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This Option:
Option Name: Description Option (DESCRIPTION)
Number: TBA (IANA)
Purpose: Used to associate a text description with a mapping
Valid for Opcodes: MAP
Length: Variable
May appear in: both request and response
Maximum occurrences: 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DESCRIPTION | Reserved | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Description |
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Description Option
3. DSCP_POLICY
In some scenarios, the DSCP marking in the internal interface (i.e.,
customer-facing interface) and the external one (i.e., Internet-
facing interface) of the PCP-controlled device may be distinct. A
Service Provider MAY allow its customers to configure their DSCP
marking policies in an upstream device. Distinct DSCP marking
policies can be implemented in the internal and external sides of the
PCP-controlled device. A PCP Client MAY issue a PCP MAP request
indicating its internal DS code point and the external DSCP value.
Instructed forwarding policies are applied only for packets marked
with a given DSCP value.
A Service Provider may not support DSCP re-marking feature and adopt
a transparent scheme to QoS policy enforcement, that is, not
controllable by subscribers. Generic QoS enforcement policies can be
enforced for all customers: such as leave DSCP field values
unchanged.
This option is mandatory to process.
This option (Code TBA, Figure 2) allows to:
o Re-write any DSCP value to a specific value;
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o Re-write a specific DSCP value to another specific value.
This Option:
Option Name: PCP DSCP Marking Policy Option (DSCP_POLICY)
Number: TBA (IANA); mandatory to process
Purpose: Associated a DSCP re-marking policy with a mapping
Valid for Opcodes: MAP, PEER
Length: 0x04
May appear in: both request and response
Maximum occurrences: 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DSCP_POLICY | Reserved | 0x04 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|DIR| Int DSCP | Ext DSCP | 00...00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
DIR : Indicates the direction:
0 Inbound
1 Outbound
2 Both
Int DSCP: Indicates the DSCP value in the customer-faced interface.
0x3F is used to indicate ANY value.
Ext DSCP: Indicates the DSCP value in the Internet-faced interface.
0x3F is used to indicate ANY value.
Figure 2: DSCP Marking option
4. CAPABILITY
The CAPABILITY option (Code: TBA, Figure 3) is used by a PCP Server
to indicate to a requesting PCP Client the capabilities it supports
with regards to port forwarding operations. Several Capability
options MAY be conveyed in the same PCP response message 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.
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This Option:
Option Name: PCP Capabilities Option (CAPABILITY)
Number: TBA (IANA)
Purpose: Retrieve the capabilities of a PCP-controlled device
Valid for Opcodes: can be returned in a error message
Length: 0x01
May appear in: both request and response
Maximum occurrences: None
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 | 0x01 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|F T P A S C I O| 00...00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Capability option
Below is provided a description of the F, T, P, A, S, C, I and O
bits:
Name Description
---- ----------------------------------------------------------------
F This bit indicates the address family of the source address
issued by internal hosts
T This bit indicates the address family of the source address of
the packets forwarded in the external side of the PCP-controlled
device
P This bit indicates whether the source port number is translated
or not.
A This bit indicates whether the source IP address is translated
or not.
S This bit indicates whether the controlled device supports the
ability to assign a set or ports
C This bit indicates whether the PCP-controlled devices inspects
the received packets and if it can block them
I This bit indicates whether incoming packets are rejected unless
an explicit rule is enforced in the PCP-controlled device
O This bit indicates whether outbound packets are inspected or not
before being granted to leave the internal realm.
The value of the F, T, P, A, S, C, I and O bits are as follows:
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Position Name Meaning
-------- ------------------ ------------------------------
1 From (F) 0=from IPv4, 1=from IPv6
2 To (T) 0=to IPv4, 1=to IPv6
3 Port-Xlate (P) 1=translated, 0=not translated
4 Addr-Xlate (A) 1=translated, 0=not translated
5 Port-Set (S) 1=enabled, 0=not supported
6 Packet-Control (C) 1=enabled, 0=not supported
7 Direction-Out (I) 1=enabled, 0=disabled
8 Direction-In (O) 1=enabled, 0=disabled
A stateless NAT64 [RFC6145] would have the following values:
From=0 (IPv4)
To=1 (IPv6)
Port-Xlate=0 (No)
Addr-Xlate=1 (Yes)
Port-Set=0 (No)
Packet-control=0 (No)
Direction-out (0) (No)
Direction-In=0 (No)
A stateful NAT64 [RFC6146] would have the following values:
From=0 (IPv4)
To=1 (IPv6)
Port-Xlate=1 (Yes)
Addr-Xlate=1 (Yes)
Port-Set=0 (No)
Packet-control=0 (No)
Direction-out (0) (No)
Direction-In=0 (No)
A NAT44 would be characterized as follows:
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From=0 (IPv4)
To=0 (IPv4)
Port-Xlate=1 (Yes)
Addr-Xlate=1 (Yes)
Port-Set=0 (No)
Packet-control=0 (No)
Direction-out (0) (No)
Direction-In=0 (No)
5. REPORT
The Report PCP Option (Code TBA, Figure 4) is used by a PCP Client to
report a set of useful information to the PCP Server. Several Report
Options with distinct Report Sub-Code values MAY be conveyed in the
same PCP message. Only report data associated with the PCP Server to
which this option is sent MUST be included in a Report Option.
This option can be used for troubleshooting or diagnose purposes.
This Option:
Option Name: PCP Report Option (REPORT)
Number: TBA (IANA)
Purpose: Send a set of report data
Valid for Opcodes: MAP
Length: Variable
May appear in: both request and response
Maximum occurrences: Multiple
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCOPE | Reserved | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Report Sub-Code | 00...00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Report Data |
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Report Option
The following Report Sub-Code values are defined:
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Position Meaning
-------- ------------------------------------------------------------
0x00 Time since last reboot/boot
0x01 Count of transmitted PCP messages to the PCP Server since
last boot
0x02 Count of retransmitted PCP messages to the PCP Server since
last boot
0x03 Count of received PCP Error messages from the PCP Server
6. CLIENT_IDENTIFIER
PCP CLIENT_ID (Code TBA, Figure 5) is a token randomly [RFC4086]
generated by the PCP Client. Only one CLIENT_ID Option MUST be
present in a PCP message. The PCP Client and PCP Server MUST store
the value included in this Option in a PCP MAP request.
o The CLIENT_ID MUST be generated by the PCP Client and not the PCP
Server;
o Upon change of the IP address of the PCP Client (or a third party
on behalf of which a mapping has been created), the CLIENT_ID is
used to update related mappings (e.g., PCP MAP delete request and
PCP MAP create request);
o The same CLIENT_ID MUST be used for all requested mappings, unless
a new CLIENT_ID is generated by the PCP Client (e.g., reboot, OS
crash, etc.);
o The CLIENT_ID is stored by the PCP Server for all mappings
(persistent storage);
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This Option:
Option Name: PCP Client Identifier Option (CLIENT_ID)
Number: TBA (IANA); mandatory to process option
Purpose: Associate an identifier with the mappings
Valid for Opcodes: MAP
Length: Variable
May appear in: both request and response
Maximum occurrences: 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CLIENT_ID | Reserved | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Client Identifier |
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: CLIENT_ID PCP Option
The length of the CLIENT_ID is encoded in the Length field in bytes.
The length of the CLIENT_ID MUST be at least 4 bytes and MUST NOT
exceed 16 bytes.
The RECOMMENDED value is 16 bytes so as to have a robust random
CLIENT_ID. If a CLIENT_ID longer than 16 bytes or shorter than 4
bytes is received, the PCP Server MUST issue a PCP Error message with
an error cause equal to "Invalid Client-ID".
For sanity checks, a PCP Server maintains the same CLIENT_ID value
(which is used in the latest PCP request) for a given PCP Client for
all mappings associated with the same internal IP address belonging
to the same subscriber. Indeed, the PCP Server maintains an
additional identifier denoted as subscriber-Id. A subscriber-is can
be an IP address, IPv6 prefix or a subscriber identifier configured
locally.
7. Security Considerations
Security considerations discussed in [I-D.ietf-pcp-base] must be
considered. The use of CLIENT_ID option allows to soften issues
related to stale mappings.
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8. IANA Considerations
The following PCP Option Codes are to be allocated:
DESCRIPTION
DSCP_POLICY: The "O" bit MUST be set to 1.
CAPABILITY
REPORT
CLIENT_IDENTIFIER: The "O" bit MUST be set to 1.
9. Normative References
[I-D.ietf-pcp-base]
Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
Selkirk, "Port Control Protocol (PCP)",
draft-ietf-pcp-base-24 (work in progress), March 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4086] Eastlake, D., Schiller, J., and S. Crocker, "Randomness
Requirements for Security", BCP 106, RFC 4086, June 2005.
[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.
Authors' Addresses
Mohamed Boucadair
France Telecom
Rennes, 35000
France
Email: mohamed.boucadair@orange.com
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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
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