softwire R. Maglione
Internet-Draft Telecom Italia
Intended status: Standards Track A. Durand
Expires: April 15, 2011 Juniper Networks
October 12, 2010
RADIUS Extensions for Dual-Stack Lite
draft-ietf-softwire-dslite-radius-ext-00
Abstract
Dual-Stack Lite is a solution to offer both IPv4 and IPv6
connectivity to customers which are addressed only with an IPv6
prefix. DS-Lite requires to pre-configure the AFTR tunnel
information on the B4 element. In many networks, the customer
profile information may be stored in AAA servers while client
configurations are mainly provided through DHC protocol. This
document specifies two new RADIUS attributes to carry Dual-Stack Lite
Address Family Transition Router (AFTR) IPv6 address and name; the
RADIUS attributes are defined based on the equivalent DHCPv6 options
already specified in draft-ietf-softwire-ds-lite-tunnel-option.
These RADIUS attributes are meant to be used between the RADIUS
Server and the NAS, they are not intended to be used directly between
the B4 element and the RADIUS Server.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
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This Internet-Draft will expire on April 15, 2011.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. DS-Lite Configuration with RADIUS and DHCPv6 . . . . . . . . . 5
4. Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. DS-Lite-Tunnel-Addr . . . . . . . . . . . . . . . . . . . . 6
4.2. DS-Lite-Tunnel-Name . . . . . . . . . . . . . . . . . . . . 6
5. Table of attributes . . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
8. Normative References . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
Dual-Stack Lite [I-D.ietf-softwire-dual-stack-lite] is a solution to
offer both IPv4 and IPv6 connectivity to customers which are
addressed only with an IPv6 prefix (no IPv4 address is assigned to
the attachment device). One of its key components is an IPv4-over-
IPv6 tunnel, but a DS-Lite Basic Bridging BroadBand (B4) will not
know if the network it is attached to offers Dual-Stack Lite support,
and if it did, would not know the remote end of the tunnel to
establish a connection.
To inform the B4 of the AFTR's location, either an IPv6 address or
Fully Qualified Domain Name (FQDN) may be used. Once this
information is conveyed, the presence of the configuration indicating
the AFTR's location also informs a host to initiate Dual-Stack Lite
(DS-Lite) service and become a Softwire Initiator.
The draft draft-ietf-softwire-ds-lite-tunnel-option
[I-D.ietf-softwire-ds-lite-tunnel-option] specifies two DHCPv6
options which are meant to be used by a Dual-Stack Lite client (Basic
Bridging BroadBand element, B4) to discover its Address Family
Transition Router (AFTR) address. In order to be able to populate
such options the DHCPv6 Server must be pre-provisioned with the
Address Family Transition Router (AFTR) address or name.
In Broadband environments, customer profile may be managed by AAA
servers, together with user Authentication, Authorization, and
Accounting (AAA). RADIUS protocol [RFC2865] is usually used by AAA
Servers to communicate with network elements.
[I-D.ietf-radext-ipv6-access] describes a typical broadband network
scenario in which the Network Access Server (NAS) acts as the access
gateway for the users (hosts or CPEs) and the NAS embeds a DHCPv6
Server function that allows it to locally handle any DHCPv6 requests
issued by the clients.
Since the DS-Lite AFTR information can be stored in AAA servers and
the client configuration is mainly provided through DHC protocol
running between the NAS and the requesting clients, new RADIUS
attributes are needed to send AFTR information from AAA server to the
NAS.
This document aims at defining two new RADIUS attributes to be used
for carrying the DS-Lite Tunnel Name and DS-Lite Tunnel Address,
based on the equivalent DHCPv6 options already specified in
[I-D.ietf-softwire-ds-lite-tunnel-option]
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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].
The terms DS-Lite Basic Bridging BroadBand element (B4) and the DS-
Lite Address Family Transition Router element (AFTR) are defined in
[I-D.ietf-softwire-dual-stack-lite]
3. DS-Lite Configuration with RADIUS and DHCPv6
The Figure 1 illustrates how the RADIUS protocol and DHCPv6 work
together to accomplish DS-Lite configuration on the B4 element.
B4 NAS AAA
| | Server
| | |
| | |
| |-----Access Request -------->|
| | |
| |<----Access Accept(
| | DS-Lite-Tunnel-Add |
| | DS-Lite-Tunnel-Name) |
| | |
|------DHCPv6 Request----->| |
| (DS-Lite tunnel Option) | |
| | |
|<-----DHCPv6 Reply--------| |
| (DS-Lite tunnel option) | |
DHCPv6 RADIUS
Figure 1: RADIUS and DHCPv6 Message Flow
The Network Access Server (NAS) operates as a client of RADIUS and as
DHCP Server for DHC protocol. 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 AFTR Tunnel IPv6
Address and/or the AFTR Tunnel Name. When the NAS receives a DHCPv6
client request containing the DS-Lite tunnel Option, the NAS shall
use the address returned in the RADIUS DS-Lite-Tunnel-Addr attribute
to populate the DHCPv6 OPTION_DS_LITE_ADDR option in the DHCPv6 reply
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message.
4. Attributes
This section specifies the format of the two new RADIUS attributes.
4.1. DS-Lite-Tunnel-Addr
Description
The DS-Lite-Tunnel-Addr RADIUS attribute contains a 128 bit IPv6
address that identifies the location of the remote tunnel endpoint,
expected to be located at an AFTR. The NAS shall use the address
returned in the RADIUS DS-Lite-Tunnel-Addr attribute to populate the
DHCPv6 OPTION_DS_LITE_ADDR option
[I-D.ietf-softwire-ds-lite-tunnel-option].
This attribute MAY be used in Access-Accept packets and it MAY be
present in Accounting-Request records where the Acct-Status-Type is
set to Start, Stop or Interim-Update. The DS-Lite-Tunnel-Addr RADIUS
attribute and MUST NOT appear more than once in a message.
A summary of the DS-Lite-Tunnel-Addr RADIUS attribute format is shown
below. The fields are transmitted from left to right.
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-Addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DS-Lite-Tunnel-Addr (IPv6 Address)(cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
TBA1 for DS-Lite-Tunnel-Addr.
Length:
16 octets
DS-Lite-Tunnel-Addr:
A 128-bit IPv6 address of the DS-Lite AFTR.
4.2. DS-Lite-Tunnel-Name
Description
The DS-Lite-Tunnel-Name RADIUS attribute contains a Fully Qualified
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Domain Name that refers to the AFTR the client is requested to
establish a connection with. The NAS shall use the name returned in
the RADIUS DS-Lite-Tunnel-Name attribute to populate the DHCPv6
OPTION_DS_LITE_NAME option [I-D.ietf-softwire-ds-lite-tunnel-option]
This attribute MAY be used in Access-Accept packets and it MAY be
present in Accounting-Request records where the Acct-Status-Type is
set to Start, Stop or Interim-Update. The DS-Lite-Tunnel-Name RADIUS
attribute and MUST NOT appear more than once in a message.
A summary of the DS-Lite-Tunnel-Name RADIUS attribute format is shown
below. The fields are transmitted from left to right.
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-Name (FQDN) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DS-Lite-Tunnel-Name (FQDN) (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
TBA2 for DS-Lite-Tunnel-Name.
Length:
Length in octets of the DS-Lite-Tunnel-Name (FQDN)
DS-Lite-Tunnel-Name:
A single Fully Qualified Domain Name of the remote tunnel
endpoint, located at the DS-Lite AFTR.
5. Table of attributes
The following table provides a guide to which attributes may be found
in which kinds of packets, and in what quantity.
Request Accept Reject Challenge Accounting # Attribute
Request
0-1 0-1 0 0 0-1 TBA1 DS-Lite-Tunnel-Addr
0-1 0-1 0 0 0-1 TBA2 DS-Lite-Tunnel-Name
The following table defines the meaning of the above table entries.
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0 This attribute MUST NOT be present in packet.
0+ Zero or more instances of this attribute MAY be present in
packet.
0-1 Zero or one instance of this attribute MAY be present in packet.
6. Security Considerations
This document has no additional security considerations beyond those
already identified in [RFC2865]
[I-D.ietf-softwire-dual-stack-lite] discusses DS-Lite related
security issues.
7. IANA Considerations
This document requests the allocation of two new Radius attribute
types from the IANA registry "Radius Attribute Types" located at
http://www.iana.org/assignments/radius-types
DS-Lite-Tunnel-Addr - TBA1
DS-Lite-Tunnel-Name - TBA2
8. Normative References
[I-D.ietf-radext-ipv6-access]
Lourdelet, B., Dec, W., Sarikaya, B., Zorn, G., and D.
Miles, "RADIUS attributes for IPv6 Access Networks",
draft-ietf-radext-ipv6-access-02 (work in progress),
July 2010.
[I-D.ietf-softwire-ds-lite-tunnel-option]
Hankins, D. and T. Mrugalski, "Dynamic Host Configuration
Protocol for IPv6 (DHCPv6) Option for Dual- Stack Lite",
draft-ietf-softwire-ds-lite-tunnel-option-05 (work in
progress), September 2010.
[I-D.ietf-softwire-dual-stack-lite]
Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", draft-ietf-softwire-dual-stack-lite-06 (work
in progress), August 2010.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, June 2000.
Authors' Addresses
Roberta Maglione
Telecom Italia
Via Reiss Romoli 274
Torino 10148
Italy
Phone:
Email: roberta.maglione@telecomitalia.it
Alain Durand
Juniper Networks
1194 North Mathilda Avenue
Sunnyvale, CA 94089-1206
USA
Phone:
Fax:
Email: adurand@juniper.net
URI:
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