RADIUS Extensions for IPv4-Embedded Multicast and Unicast IPv6 Prefixes
draft-hu-softwire-multicast-radius-ext-02
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|---|---|---|---|
| Authors | Qian Wang , Wei Meng , Cui Wang , Mohamed Boucadair | ||
| Last updated | 2012-09-03 | ||
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draft-hu-softwire-multicast-radius-ext-02
Softwire WG Q. Wang
Internet-Draft China Telecom
Intended status: Standards Track W. Meng
Expires: March 8, 2013 C. Wang
ZTE Corporation
M. Boucadair
France Telecom
September 4, 2012
RADIUS Extensions for IPv4-Embedded Multicast and Unicast IPv6 Prefixes
draft-hu-softwire-multicast-radius-ext-02
Abstract
This document specifies a new Remote Authentication Dial-In User
Service (RADIUS) attribute to carry the Multicast-Prefixes-64
information, aiming to delivery the Multicast and Unicast IPv6
Prefixes to be used to build multicast and unicast IPv4-Embedded IPv6
addresses. this 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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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 March 8, 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
publication of this document. Please review these documents
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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. Multicast-Prefixes-64 Configuration with RADIUS and DHCPv6 . . 5
4. RADIUS Attribute . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Multicast-Prefixes-64 . . . . . . . . . . . . . . . . . . 8
5. Table of Attributes . . . . . . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
8. Normative References . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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1. Introduction
The solution specified in [I-D.ietf-softwire-dslite-multicast] relies
on stateless functions to graft 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. DS-Lite
Multicast [I-D.ietf-softwire-dslite-multicast] is a solution in
particular to offer multicast service to DS-Lite serviced customers.
[I-D.ietf-softwire-multicast-prefix-option] defines a DHCPv6 option
that is meant to be used by a mB4 element to convey the IPv6 prefixes
to be used for constructing IPv4-embedded IPv6 addresses and
extracting the IPv4 address when needed. In order to be able to
populate such an option, the DHCPv6 server must be pre-provisioned
with the required 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 Multicast-Prefixes-64
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
Multicast-Prefixes-64 information from the AAA server to the NAS.
This document defines a new RADIUS attribute to be used for carrying
the Multicast-Prefixes-64, based on the equivalent DHCPv6 option
already specified in [I-D.ietf-softwire-multicast-prefix-option].
This document makes use of the same terminology defined in
[I-D.ietf-softwire-dslite-multicast] and
[I-D.ietf-mboned-64-multicast-address-format]
This attribute can be in particular used in the context of DS-Lite
Mulitcast, MAP-E Multicast and other IPv4-IPv6 Multicast techniques.
This attribute is however not limited to DS-Lite Multicast.
DS-Lite unicast RADIUS extentions are defined in [RFC6519] .
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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. Multicast-Prefixes-64 Configuration with RADIUS and DHCPv6
Figure 1 illustrates in DS-Lite scenario how the RADIUS protocol and
DHCPv6 work together to accomplish Multicast-Prefixes-64
configuration on the mB4 element for multicast service when an IP
session is used to provide connectivity to the user.
mB4 NAS AAA
| | Server
|------ DHCPv6 Solicit ---------> | |
| | |
| |----Access-Request ---->|
| | |
| |<---Access-Accept-------|
| |(Multicast-Prefixes-64) |
| | |
|<-------DHCPv6 Advertisement------| |
| (DHCPv6 OPTION_PREFIX64 ) | |
| | |
|------- DHCPv6 Request -------->| |
| (DHCPv6 OPTION_PREFIX64 ) | |
| | |
|<----- DHCPv6 Reply ------------- | |
| (DHCPv6 OPTION_PREFIX64 ) | |
DHCPv6 RADIUS
Figure 1: RADIUS and DHCPv6 Multicast-Prefixes-64 attribute Message
Flow for a IP Session
The NAS operates as a client of RADIUS and as a DHCP Server/Relay for
mB4. When the mB4 sends a DHCPv6 Solicit message to NAS(DHCP Server/
Relay). The NAS sends a RADIUS Access-Request message to the RADIUS
server, requesting authentication. Once the RADIUS server receives
the request, it validates it based on 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 contain the
Multicast-Prefixes-64 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
Multicast-Prefixes-64 attribute to populate the DHCPv6
OPTION_PREFIX64 option in the DHCPv6 reply message.
If the NAS does not receive the Multicast-Prefixes-64 attribute in
the Access-Accept message, it MAY fall back to a pre-configured
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default Multicast-Prefixes-64, if any. If the NAS does not have any
pre-configured, the delivery of multicast traffic is not supported.
NAS MAY be configured to return the configured Multicast-Prefixes-64
by the AAA Server to any requesting client without relaying each
received request to the AAA Server.
Figure 2 describes another scenario, which accomplish DS-Lite
Multicast-Prefixes-64 configuration on the mB4 element for multicast
service when a PPP session is used to provide connectivity to the
user. Once the NAS obtains the Multicast-Prefixes-64 attribute from
the AAA server through the RADIUS protocol, the NAS MUST store the
received Multicast-Prefixes-64 locally. When a user is online and
sends a DHCPv6 Request message , the NAS retrieves the previously
stored Multicast-Prefixes-64 and uses it as OPTION_PREFIX64 option in
DHCPv6 Reply message.
mB4 NAS AAA
| | Server
| | |
|----PPP LCP Config-Request------> | |
| | |
| |----Access-Request ---->|
| | |
| |<---- Access-Accept-----|
| | (Multicast-Prefixes-64)|
|<-----PPP LCP Config-ACK ------- | |
| | |
| | |
|--- PPP IPv6CP Config-Request --->| |
| | |
|<----- PPP IPv6CP Config-ACK -----| |
| | |
|------- DHCPv6 Solicit -------->| |
| | |
|<-------DHCPv6 Advertisement -----| |
| (DHCPv6 OPTION_PREFIX64 ) | |
| | |
|------- DHCPv6 Request -------->| |
| | |
| | |
|<-------- DHCPv6 Reply ---------- | |
| (DHCPv6 OPTION_PREFIX64) | |
DHCPv6 RADIUS
Figure 2: RADIUS and DHCPv6 Multicast-Prefixes-64 attribute Message
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Flow for a PPP Session
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-64 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. Multicast-Prefixes-64
The Multicast-Prefixes-64 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 Multicast-Prefixes-64 attribute to populate
the DHCPv6 PREFIX64 Option
[I-D.ietf-softwire-multicast-prefix-option] .
This attribute MAY be used in Access-Request packets as a hint to the
RADIUS server, for example, if the NAS is pre-configured with
Multicast-Prefixes-64, these prefixes MAY be inserted in the
attribute. The RADIUS server MAY ignore the hint sent by the NAS,
and it MAY assign a different Multicast-Prefixes-64 attribute.
If the NAS includes the Multicast-Prefixes-64 attribute, but the AAA
server does not recognize it, this attribute MUST be ignored by the
AAA server.
NAS MAY be configured with both ASM and SSM prefixes or only one of
them. Concretely, AAA server MAY return ASM or SSM prefix based on
the user profile and service policies. AAA MAY return both ASM and
SSM prefixes. When SSM prefix is returned by the AAA server, unicast
IPv4-Embedded IPv6 prefix MUST also be returned by the AAA server.
If the NAS does not receive the Multicast-Prefixes-64 attribute in
the Access-Accept message, it MAY fall back to a pre-configured
default Multicast-Prefixes-64, if any. If the NAS does not have any
pre-configured, the delivery of multicast traffic is not supported.
If the NAS is pre-provisioned with a default Multicast-Prefixes-64
and the Multicast-Prefixes-64 received in the Access-Accept message
are different from the configured default, then the Multicast-
Prefixes-64 attribute received in the Access-Accept message MUST be
used for the session.
A summary of the Multicast-Prefixes-64 RADIUS attribute format is
shown Figure 3. The fields are transmitted from left to right.
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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-64
Type:
145 for Multicast-Prefixes-64
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:
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
[I-D.ietf-mboned-64-multicast-address-format] of the multicast groups
for the ASM mode.
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.
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SSM_PREFIX64:
This field identifies the IPv6 multicast prefix to be used to
synthesize the IPv4-embedded IPv6 addresses
[I-D.ietf-mboned-64-multicast-address-format] of the multicast groups
for the SSM mode.
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 [RFC6052] 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.
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5. Table of Attributes
The following tables provide a guide to which attributes may be found
in which kinds of packets, and in what quantity.
The following table defines the meaning of the above table entries.
Access- Access- Access- Challenge Accounting- # Attribute
Request Accept Reject Request
0-1 0-1 0 0 0-1 145 Multicast-Prefixes-64
CoA- CoA- CoA- # Attribute
Request ACK NACK
0-1 0 0 145 Multicast-Prefixes-64
0 This attribute MUST NOT be present in the packet.
0+ Zero or more instances of this attribute MAY be present in the
packet.
0-1 Zero or one instances of this attribute MAY be present in the
packet.
1 Exactly one instances of this attribute MAY be present in the
packet.
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6. 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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7. 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.
Multicast-Prefixes-64 - 145
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8. Normative 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 With Embedded IPv4
Multicast Address",
draft-ietf-mboned-64-multicast-address-format-04 (work in
progress), August 2012.
[I-D.ietf-softwire-dslite-multicast]
Qin, J., Boucadair, M., Jacquenet, C., Lee, Y., and Q.
Wang, "Delivery of IPv4 Multicast Services to IPv4 Clients
over an IPv6 Multicast Network",
draft-ietf-softwire-dslite-multicast-03 (work in
progress), August 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-01
(work in progress), August 2012.
[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.
[RFC6519] Maglione, R. and A. Durand, "RADIUS Extensions for Dual-
Stack Lite", RFC 6519, February 2012.
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Authors' Addresses
Qian Wang
China Telecom
No.118, Xizhimennei
Beijing 100035
China
Email: wangqian@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
Mohamed Boucadair
France Telecom
Rennes, 35000
France
Email: mohamed.boucadair@orange.com
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