RADIUS Extensions for DS-Lite Multicast
draft-hu-softwire-multicast-radius-ext-01
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| Authors | Jie Hu , Wei Meng , Cui Wang | ||
| Last updated | 2012-07-13 | ||
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draft-hu-softwire-multicast-radius-ext-01
Softwire WG J. Hu
Internet-Draft China Telecom
Intended status: Standards Track W. Meng
Expires: January 14, 2013 C. Wang
ZTE Corporation
July 13, 2012
RADIUS Extensions for DS-Lite Multicast
draft-hu-softwire-multicast-radius-ext-01
Abstract
DS-Lite Multicast [I-D.ietf-softwire-dslite-multicast] is a solution
to offer multicast service on DS-lite circumstance. DS-Lite
Multicast requires pre-configuration of the IPv4-embedded IPv6
prefixes information on the multicast Basic Bridging BroadBand (mB4)
element and multicast Address Family Translation Router(mAFTR). This
document specifies a new Remote Authentication Dial-In User Service
(RADIUS) attribute to carry the DS-Lite multicast prefixes
information; the RADIUS attribute is defined based on the equivalent
DHCPv6 OPTION_PREFIX64 option.
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
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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 January 14, 2013.
Copyright Notice
Copyright (c) 2012 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
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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
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 . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Convention and Terminology . . . . . . . . . . . . . . . . . . 4
3. DS-Lite multicast prefixes Configuration with RADIUS and
DHCPv6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. RADIUS Attribute . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. DS-Lite Multicast Prefixes . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
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1. Introduction
DS-Lite Multicast [I-D.ietf-softwire-dslite-multicast] is a solution
to offer multicast service on DS-lite circumstance.This solution
relies upon a stateless translation to built part of the IPv6
multicast distribution tree and IPv4 multicast distribution tree,
also uses IPv4-in-IPv6 encapsulation scheme to deliver IPv4 multicast
traffic over an IPv6 multicast-enabled network to IPv4 receivers.
But how do the mB4 element and the mAFTR element pre-provision the
multicast source and multicast group IPv4-embedded IPv6 prefixes to
fulfill the stateless translation and encapsution?
To inform the mB4 element and the mAFTR element of the multicast
prefixes, [I-D.ietf-softwire-multicast-prefix-option] defines a
DHCPv6 option that is meant to be used by a mB4 element and a mAFTR
to convey the IPv6 prefixes to be used for constructing these IPv4-
embedded IPv6 address. In order to be able to populate such an
option, the DHCPv6 server must be pre-provisioned with the multicast
prefixes.
In broadband environments, a customer profile may be managed by
Authentication, Authorization, and Accounting (AAA) servers, together
with AAA for users. The Remote Authentication Dial-In User Service
(RADIUS) protocol [RFC2865] is usually used by AAA servers to
communicate with network elements. Since the DS-Lite multicast
prefixes information can be stored in AAA servers and the client
configuration is mainly provided through DHCP running between the NAS
and the requesting clients, a new RADIUS attribute is needed to send
DS-Lite multicast prefixes information from the AAA server to the
NAS.
This document defines a new RADIUS attribute to be used for carrying
the DS-Lite Multicast prefixes, based on the equivalent DHCPv6 option
already specified in [I-D.ietf-softwire-multicast-prefix-option]
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2. Convention and 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].
The terms DS-Lite multicast Basic Bridging BroadBand element (mB4)
and the DS-Lite multicast Address Family Transition Router element
(mAFTR) are defined in [I-D.ietf-softwire-dslite-multicast]
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3. DS-Lite multicast prefixes Configuration with RADIUS and DHCPv6
Figure 1 illustrates how the RADIUS protocol and DHCPv6 work together
to accomplish DS-Lite multicast prefixes configuration on the mB4
element and the mAFTR element for multicast service.
mB4 NAS AAA
| | Server
|------ DHCPv6 Solicit ---------> | |
| | |
| |----Access-Request ---->|
| | |
| |<---Access-Accept-------|
| | (DS-Lite-Multicast- |
| | Prefixes) |
|<-------DHCPv6 Advertisement------| |
| (DHCPv6 OPTION_PREFIX64 ) | |
| | |
|------- DHCPv6 Request -------->| |
| | |
| | |
|<----- DHCPv6 Reply ------------- | |
| (DHCPv6 OPTION_PREFIX64 ) | |
DHCPv6 RADIUS
Figure 1: RADIUS and DHCPv6 Multicast prefixes attribute Message Flow
The NAS operates as a client of RADIUS and as a DHCP Server of mB4.
When the mB4 initially sends a DHCPv6 Solicit message to NAS(DHCP
Server). The NAS initially sends a RADIUS Access-Request message to
the RADIUS server, requesting authentication. Once the RADIUS server
receives the request, it validates the sending client, and if the
request is approved, the AAA server replies with an Access-Accept
message including a list of attribute-value pairs that describe the
parameters to be used for this session. This list MAY also contain
the Multicast Prefixes attribute (asm-length,ASM_PREFIX64,ssm-length,
SSM_PREFIX64,unicast-length,U_PREFIX64).Then,when the NAS receives
the DHCPv6 Request message containing the OPTION_PREFIX64 option,the
NAS SHALL use the prefixes returned in the RADIUS DS-Lite Multicast
prefixes attribute to populate the DHCPv6 OPTION_PREFIX64 option in
the DHCPv6 reply message.
If the NAS does not receive the Multicast prefixes attribute in the
Access-Accept message, it MAY fall back to a pre-configured default
multicast prefixes, if any. If the NAS does not have any pre-
configured, the delivery of muticast traffic is not supported.
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Figure 2 describes another scenario, which mB4 may be initiated by
another user behavior rather than ethernet, for example,PPP dial-up.
The NAS also obtains the Multicast Options from the AAA server
through the RADIUS protocol. When an user is online and sends DHCPv6
Request , the NAS replies OPTION_PREFIX64 option in DHCPv6 Reply
message.
mB4 NAS AAA
| | Server
| |----Access-Request ---->|
| | |
| |<---Access-Accept-------|
| | (DS-Lite-Multicast- |
| | Prefixes) |
|------- DHCPv6 Request -------->| |
| | |
| | |
|<----- DHCPv6 Reply ------------- | |
| (DHCPv6 OPTION_PREFIX64 ) | |
Figure 2: RADIUS and DHCPv6 Multicast prefixes attribute Message Flow
According to [RFC3315], if the DHCPv6 server to which the DHCPv6
Renew message was sent at time T1 has not responded, the DHCPv6
client initiates a Rebind/Reply message exchange with any available
server. In this scenario, the NAS receiving the DHCPv6 Rebind
message MUST initiate a new Access-Request message towards the AAA
server. The NAS MAY include the Multicast prefixes attribute in its
Access-Request message.
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4. RADIUS Attribute
This section specifies the format of the new RADIUS attribute.
4.1. DS-Lite Multicast Prefixes
The DS-Lite Multicast Prefixes attribute conveys the IPv6 prefixes to
be used in [I-D.ietf-softwire-dslite-multicast] to synthesize IPv4-
embedded IPv6 addresses. The NAS SHALL use the IPv6 prefixes
returned in the RADIUS DS-Lite Multicast Prefixes attribute to
populate the DHCPv6 PREFIX64 Option
[I-D.ietf-softwire-multicast-prefix-option] .
A summary of the DS-Lite Multicast Prefixes RADIUS attribute format
is shown Figure 3. The fields are transmitted from left to right.
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| asm-length | |
+-+-+-+-+-+-+-+-+ :
: ASM_PREFIX64 (12 octets) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ssm-length | |
+-+-+-+-+-+-+-+-+ :
: SSM_PREFIX64 (12 octets) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unicast-length| |
+-+-+-+-+-+-+-+-+ :
: U_PREFIX64 (12 octets) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: RADIUS attribute format for multicast prefixes
Type:
145 for DS-Lite Multicast Prefix
Length:
This field indicates the total length in octets of this attribute
including the Type and Length fields, and the length in octets of the
PREFIX field. Equals to 41 octets.
asm-length:
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The length for the ASM IPv4-emebdded IPv6 prefix in bits. If the
field is set to 0, all bits of ASM_PREFIX64 field MUST be set to
zeros.
ASM_PREFIX64:
This field identifies the IPv6 multicast prefix to be used to
synthesize the IPv4-embedded IPv6 addresses of the multicast groups.
The conveyed multicast IPv6 prefix MUST belong to the ASM range
defined in [I-D.ietf-mboned-64-multicast-address-format] (i.e., ffxx:
8000/17).
ssm-length:
The length for the SSM IPv4-emebdded IPv6 prefix in bits. If the
field is set to 0, all bits of SSM_PREFIX64 field MUST be set to
zeros.
SSM_PREFIX64:
This field identifies the IPv6 multicast prefix to be used to
synthesize the IPv4-embedded IPv6 addresses of the multicast groups.
The conveyed multicast IPv6 prefix MUST belong to the SSM range
defined in [I-D.ietf-mboned-64-multicast-address-format] (i.e.,
ff3x:0: 8000/33).
unicast-length:
The length for the unicast IPv4-emebdded IPv6 prefix in bits. If the
field is set to 0, all bits of U_PREFIX64 field MUST be set to zeros.
U_PREFIX64:
This field identifies the IPv6 unicast prefix to be used in SSM mode
for constructing the IPv4-embedded IPv6 addresses of the multicast
sources. It may also used to extract the IPv4 address from the
received multicast data flows. The address mapping MUST follow the
guidelines documented in [RFC6052].
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5. Security Considerations
This document has no additional security considerations beyond those
already identified in [RFC2865] for the RADIUS protocol and in
[RFC5176] for CoA messages.
The security considerations documented in [RFC3315] and [RFC6052] are
to be considered.
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6. IANA Considerations
Per this document, IANA has allocated a new RADIUS attribute type
from the IANA registry "Radius Attribute Types" located at
http://www.iana.org/assignments/radius-types.
DS-Lite Multicast Prefix - 145
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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.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, June 2000.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC5176] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B.
Aboba, "Dynamic Authorization Extensions to Remote
Authentication Dial In User Service (RADIUS)", RFC 5176,
January 2008.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
October 2010.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, August 2011.
[RFC6334] Hankins, D. and T. Mrugalski, "Dynamic Host Configuration
Protocol for IPv6 (DHCPv6) Option for Dual-Stack Lite",
RFC 6334, August 2011.
[RFC6519] Maglione, R. and A. Durand, "RADIUS Extensions for Dual-
Stack Lite", RFC 6519, February 2012.
7.2. Informative References
[I-D.ietf-mboned-64-multicast-address-format]
Boucadair, M., Qin, J., Lee, Y., Venaas, S., Li, X., and
M. Xu, "IPv6 Multicast Address Format With Embedded IPv4
Multicast Address",
draft-ietf-mboned-64-multicast-address-format-02 (work in
progress), May 2012.
[I-D.ietf-softwire-dslite-multicast]
Qin, J., Boucadair, M., Jacquenet, C., Lee, Y., and Q.
Wang, "Multicast Extensions to DS-Lite Technique in
Broadband Deployments",
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draft-ietf-softwire-dslite-multicast-02 (work in
progress), May 2012.
[I-D.ietf-softwire-multicast-prefix-option]
Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6
Option for IPv4-Embedded Multicast and Unicast IPv6
Prefixes", draft-ietf-softwire-multicast-prefix-option-00
(work in progress), March 2012.
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Authors' Addresses
Jie Hu
China Telecom
No.118, Xizhimennei
Beijing 100035
China
Email: huj@ctbri.com.cn
Wei Meng
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Email: meng.wei2@zte.com.cn
Cui Wang
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Email: wang.cui1@zte.com.cn
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