Network Working Group Dayong Guo
Internet Draft Sheng Jiang
Intended status: Standards Track Huawei Technologies Co., Ltd
Expires: January 07, 2011 July 05, 2010
RADIUS Attribute for Softwire Concentrator in IPv6 Transition
draft-guo-radext-softwire-concentrator-00.txt
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Abstract
6rd and DS-Lite are two most popular methods to provide both IPv4 and
IPv6 connectivity services simultaneously during the IPv4/IPv6 co-
existing period. Both mechanisms need to configure the softwire
concentrator information on the host. In many networks, the
information may be stored in AAA servers while user configuration is
mainly through DHC protocol. This document defines several RADIUS
attributes that carries softwire concentrator information.
Table of Contents
1. Introduction.................................................3
2. Terminology..................................................3
3. Softwire Concentrator Configuration with RADIUS..............3
4. Attributes...................................................4
4.1. DS-Lite-Add Attribute...................................4
4.2. DS-Lite-Name Attribute..................................5
4.3. 6rd Attribute...........................................6
4.4. Table of attributes.....................................6
5. Diameter Considerations......................................7
6. Security Considerations......................................7
7. IANA Considerations..........................................7
8. Acknowledgments..............................................7
9. References...................................................8
9.1. Normative References....................................8
9.2. Informative References..................................8
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1. Introduction
Recently providers start to deploy IPv6 and consider how to transit
to IPv6. 6rd [I-D.ietf-softwire-ipv6-6rd] and DS-Lite
[I-D.ietf-softwire-ds-lite] are two most popular methods to provide
both IPv4 and IPv6 connectivity services simultaneously during the
IPv4/IPv6 co-existing period. 6rd is used to provide IPv6
connectivity service through IPv4-only infrastructure while DS-Lite
is aiming to provide IPv4 connectivity service through IPv6-only
network.
Both 6rd and DS-Lite adopt DHCP as auto-configuring protocol. In DS-
lite, The DHCPv6 options are used to discover the IPv6 address or
name of the AFTR (i.e. softwire concentrator)
[I-D.ietf-softwire-ds-lite-tunnel-option]. Similarly the 6rd CPE
extends DHCP option to discover 6rd border relay (i.e. softwire
concentrator) and to configuring IPv6 address and prefix.
In many networks, user configuration information may be managed by
AAA servers, together with user Authentication, Authorization, and
Accounting (AAA). Current AAA servers communicate using the RADIUS
(Remote Authentication Dial In User Service, [RFC2865]) protocol.
[I-D.ietf-radext-ipv6-access] describes a fixed line broadband
network scenario in which the Broadband Network Gateways (BNGs) act
as the access gateway of users (hosts or CPEs). The BNGs are assumed
to embed a DHCPv6 server function that allows them to locally handle
any DHCPv6 requests issued by hosts.
Since the 6rd/DS-Lite softwire concentrator information is stored in
AAA servers and user configuration is mainly through DHC protocol
between BNGs and hosts. New RADIUS attributes are needed to propagate
these information from AAA servers to BNGs.
2. Terminology
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 RFC2119 [RFC2119].
3. Softwire Concentrator Configuration with RADIUS
The below Figure 1 illustrates how the RADIUS protocol and DHCPv6 are
cooperated to provide users/hosts with DS-Lite configuration. 6rd has
the same operation.
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User/host BNG AAA Server
| | |
|----------Solicit-------->| |
| |---Request (DS-Lite-Addr)--->|
| | |
| |<---Accept (DS-Lite-Addr)----|
|<--------Advertise--------| |
| | |
|----------Request-------->| |
| (DS-Lite tunnel Option) | |
|<----------Reply----------| |
| (DS-Lite tunnel option) | |
| | |
DHCPv6 RADIUS
Figure 1: the cooperation between DHCPv6 and RADIUS
BNGs act as a bridge between user and AAA server. First, a BNG
receives a user DHCPv6 solicit. It initiates the BNG to request
correspondent user authentication relevant from an AAA server using
RADIUS protocol. A DS-Lite-Addr request may be also sent in the same
message. If the user authentication is approved by the AAA server, an
Accept message is acknowledged with the DS-Lite-Addr attribute,
defined in the next Section. After the BNG responds to the user with
an Advertise message, the user requests for a DS-Lite tunnel Option.
Then, the BNG can reply the user using DHCPv6 protocol.
4. Attributes
This section defines three RADIUS attributes that carries softwire
concentrator information. DS-Lite-Addr Attribute and DS-Lite-Name
Attribute can be used in DS-Lite scenario independently. 6rd
Attribute should be used in the 6rd scenario.
4.1. DS-Lite-Add Attribute
The DS-Lite-Add Attribute is structured as follows:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| DS-Lite tunnel-endpoint-addr (IPv6 Address) |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD1
Length 18
DS-Lite tunnel-endpoint-addr The address of DS-Lite is used to
establish tunnel. In the DS-Lite scenarios the
Address Family Transition Router element (AFTR) is
an IPv6 address.
4.2. DS-Lite-Name Attribute
The DS-Lite-Name Attribute is structured as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Name of DS-Lite tunnel-endpoint (FQDN) |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD2
Length The length of the entire attribute, in bytes.
Name of DS-Lite tunnel-endpoint The Fully Qualified Domain
Name of softwire concentrator. In the DS-Lite
scenarios, it is the domain name of Address Family
Transition Router element (AFTR).
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4.3. 6rd Attribute
The 6rd Attribute is structured as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | IPv4MaskLen | 6rdPrefixLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| 6rdPrefix |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 6rdBRIPv4Address(es) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD3
Length the length of the DHCP option in octets (22 octets
with one BR IPv4 address).
IPv4MaskLen The number of high-order bits that are identical
across all CE IPv4 addresses within a given 6rd
domain. This may be any value between 0 and 32.
Any value greater than 32 is invalid.
6rdPrefixLen The IPv6 Prefix length of the Service Provider's
6rd IPv6 prefix in number of bits. The
6rdPrefixLen MUST be less than or equal to 128.
6rdPrefix The Service Provider's 6rd IPv6 prefix represented
as a 16 octet IPv6 address. The bits after the
6rdPrefixlen number of bits in the prefix SHOULD
be set to zero.
6rdBRIPv4Address One or more IPv4 addresses of the 6rd Border
Relay(s) for a given 6rd domain.
4.4. Table of attributes
The following table provides a guide to which attributes may be found
in which kinds of packets, and in what quantity.
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Request Accept Reject Challenge Accounting # Attribute
Request
0+ 0+ 0 0 0+ TBD1 DS-Lite-Addr
0+ 0+ 0 0 0+ TBD2 DS-Lite-Name
0+ 0+ 0 0 0+ TBD3 6rd
5. Diameter Considerations
This attribute is usable within either RADIUS or Diameter [RFC3588].
Since the Attributes defined in this document will be allocated from
the standard RADIUS type space, no special handling is required by
Diameter entities.
6. Security Considerations
In DS-Lite scenarios, the RADIUS protocol is run over IPv6. In 6rd
scenarios, the RADIUS protocol is run over IPv4. Known security
vulnerabilities of the RADIUS protocol are discussed in RFC 2607
[RFC2607], RFC 2865 [RFC2865], and RFC 2869 [RFC2869]. Use of IPsec
[RFC4301] for providing security when RADIUS is carried in IPv6 is
discussed in RFC 3162 [RFC3162].
Security considerations for the Diameter protocol are discussed in
RFC 3588 [RFC3588].
7. IANA Considerations
This document requires the assignment of two new RADIUS Attribute
Types in the "Radius Types" registry (currently located at
http://www.iana.org/assignments/radius-types for the following
attributes:
o DS-Lite-Add
o DS-Lite-Name
o 6rd
IANA should allocate these numbers from the standard RADIUS
Attributes space using the "IETF Review" policy [RFC5226].
8. Acknowledgments
The authors would like to thank Maglione Roberta, Telecom Italia, for
valuable comments.
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9. Change Log [RFC Editor please remove]
draft-guo-radext-softwire-concentrator-00, original version, 2010-07-
05.
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)", RFC
2865, June 2000.
[RFC3162] Aboba, B., Zorn, G., and D. Mitton, "RADIUS and IPv6", RFC
3162, August 2001.
[RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.,
Arkko, "Diameter Base Protocol", RFC 3588, September 2003.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, December 2005.
[RFC5226] T. Narten, H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", RFC 5226, May 2008.
10.2. Informative References
[RFC2607] Aboba, B. and J. Vollbrecht, "Proxy Chaining and Policy
Implementation in Roaming", RFC 2607, June 1999.
[RFC2869] Rigney, C., Willats, W., and P. Calhoun, "RADIUS
Extensions", RFC 2869, June 2000.
[I-D.ietf-radext-ipv6-access] Lourdelet, B., et al., "RADIUS
attributes for IPv6 Access Networks", draft-ietf-radext-
ipv6-access, work in progress, April 2010.
[I-D.ietf-softwire-ds-lite] Durand A., et al., "Dual-stack lite
broadband deployments post IPv4 exhaustion", draft-ietf-
softwire-dual-stack-lite, work in progress, March 2010.
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[I-D.ietf-softwire-ds-lite-tunnel-option] Hankins, D. and T.
Mrugalski, "Dynamic Host Configuration Protocol for IPv6
(DHCPv6) Options for Dual-Stack Lite", draft-ietf-softwire-
ds-lite-tunnel-option, work in progress, March 2010.
[I-D.ietf-softwire-ipv6-6rd] Townsley W., et al., "IPv6 via IPv4
Service Provider Networks (6rd)", draft-ietf-softwire-ipv6-
6rd, (work in progress), March 2010.
Author's Addresses
Dayong Guo
Huawei Technologies Co., Ltd
Huawei Building, No.3 Xinxi Rd.,
Shang-Di Information Industry Base, Hai-Dian District, Beijing 100085
P.R. China
Email: guoseu@huawei.com
Sheng Jiang
Huawei Technologies Co., Ltd
Huawei Building, No.3 Xinxi Rd.,
Shang-Di Information Industry Base, Hai-Dian District, Beijing 100085
P.R. China
Email: shengjiang@huawei.com
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