Network Working Group Sheng Jiang (Editor)
Internet Draft Yu Fu
Intended status: Standards Track Huawei Technologies Co., Ltd
Expires: July 14, 2012 Peter Deacon
IEA Software, Inc.
January 12, 2012
RADIUS Attribute for MAP
draft-jiang-softwire-map-radius-00.txt
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Abstract
Mapping of Address and Port (MAP) is a stateless mechanism for
running IPv4 over IPv6-only infrastructure. It provides both IPv4 and
IPv6 connectivity services simultaneously during the IPv4/IPv6 co-
existing period. The Dynamic Host Configuration Protocol for IPv6
(DHCPv6) MAP options has been defined to configure MAP Customer Edge
(CE). However, in many networks, the configuration information may be
stored in Authentication Authorization and Accounting (AAA) servers
while user configuration is mainly from Broadband Network Gateway
(BNG) through DHCPv6 protocol. This document defines a Remote
Authentication Dial In User Service (RADIUS) attribute that carries
MAP configuration information from AAA server to BNG. The MAP RADIUS
attribute are designed following the simplify principle. It provides
just enough information to form the correspondent DHCPv6 MAP option.
Table of Contents
1. Introduction ................................................. 3
2. Terminology .................................................. 3
3. MAP Configuration process with RADIUS ........................ 3
4. Attributes ................................................... 5
4.1. IPv6-MAP-Configuration Attribute ........................ 5
4.2. MAP Rule Option.......................................... 6
4.3. Necessary Sub Options ................................... 7
4.3.1. Rule-IPv6-Prefix Sub Option ........................ 7
4.3.2. Rule-IPv4-Prefix Sub Option ........................ 8
4.4. Optional Sub Options .................................... 8
4.4.1. Rule ID Sub Option ................................. 8
4.4.2. Encapsulation/Translation Flag Sub Option........... 9
4.4.3. Exclude Port Sub Option ............................ 9
4.4.4. Port Calculation Option ........................... 10
4.5. Table of attributes .................................... 11
5. Diameter Considerations ..................................... 11
6. Security Considerations ..................................... 11
7. IANA Considerations ......................................... 12
8. Acknowledgments ............................................. 12
9. References .................................................. 12
9.1. Normative References ................................... 12
9.2. Informative References ................................. 13
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1. Introduction
Recently providers start to deploy IPv6 and consider how to transit
to IPv6. Mapping of Address and Port (MAP)
[I-D.mdt-softwire-mapping-address-and-port] is a stateless mechanism
for running IPv4 over IPv6-only infrastructure. It provides both IPv4
and IPv6 connectivity services simultaneously during the IPv4/IPv6
co-existing period. MAP has adopted Dynamic Host Configuration
Protocol for IPv6 (DHCPv6) [RFC3315] as auto-configuring protocol.
The MAP Customer Edge (CE) uses the DHCPv6 extension options
[I-D.mdt-softwire-map-dhcp-option] to discover MAP Border Relay (in
tunnel model only) and to configure relevant MAP rules.
In many networks, user configuration information may be managed by
AAA (Authentication, Authorization, and Accounting) servers. Current
AAA servers communicate using the Remote Authentication Dial In User
Service (RADIUS) [RFC2865] protocol. In a fixed line broadband
network, the Broadband Network Gateways (BNGs) act as the access
gateway of users. The BNGs are assumed to embed a DHCPv6 server
function that allows them to locally handle any DHCPv6 requests
issued by hosts.
Since the MAP configuration information is stored in AAA servers and
user configuration is mainly through DHCPv6 protocol between BNGs and
hosts/CEs, new RADIUS attributes are needed to propagate the
information from AAA servers to BNGs. The MAP RADIUS attribute are
designed following the simplify principle, while providing enough
information to form the correspondent DHCPv6 MAP option.
[I-D.mdt-softwire-map-dhcp-option].
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].
The terms MAP CE and MAP Border Relay are defined in
[I-D.mdt-softwire-mapping-address-and-port].
3. MAP Configuration process with RADIUS
The below Figure 1 illustrates how the RADIUS protocol and DHCPv6
cooperate to provide MAP CE with MAP configuration information.
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MAP CE BNG AAA Server
| | |
|------DHCPv6 Solicit----->| |
| |--Access-Request(MAP Attr)-->|
| | |
| |<--Access-Accept(MAP Attr)---|
|<---DHCPv6 Advertisement--| |
| | |
|------DHCPv6 Request---->| |
| (MAP Option) | |
|<---- -DHCPv6 Reply-------| |
| (MAP option) | |
| | |
DHCPv6 RADIUS
Figure 1: the cooperation between DHCPv6 and RADIUS
BNGs act as a client of RADIUS and as a DHCPv6 server for DHCPv6
protocol. First, a BNG receives a DHCPv6 Solicit message from the MAP
CE. It initiates the BNG to request correspondent user authentication
relevant from an AAA server using RADIUS protocol. A MAP
configuration request may also be sent in the same message. If the
user authentication is approved by the AAA server, an Access-Accept
message is acknowledged with the IPv6-MAP-Configuration Attribute,
defined in the next Section. After the BNG responds to the user with
an Advertisement message, the user requests for a MAP Option. Then,
the BNG can reply the user using the DHCPv6 protocol.
In the abovementioned scenario, the Access-Request packet contains a
Service-Type attribute with the value Authorize Only (17), thus
according to [RFC5080] the Access-Request packet MUST contain a State
attribute.
Figure 2 describes another scenario, in which the authentication
operation is not coupled with DHCPv6. In the authentication stage,
which may be initiated by other user behavior, such as PPP dial-up,
the BNG obtains the MAP configuration information from the AAA server
through the RADIUS protocol. When the user requests the MAP Option,
the BNG replies with a MAP option in DHCPv6 Reply message.
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MAP CE BNG AAA Server
| | |
| |--Access-Request(MAP Attr)-->|
| | |
| |<--Access-Accept(MAP Attr)---|
| | |
|------DHCPv6 Request----->| |
| (Map Option) | |
|<---- -DHCPv6 Reply-------| |
| (MAP option) | |
| | |
DHCPv6 RADIUS
Figure 2: the cooperation between DHCPv6 and RADIUS
After receiving the IPv6-MAP-Configuration Attribute in the initial
Access-Accept, the BNG MUST store the received MAP configuration
parameters locally. When the MAP CE sends a DHCPv6 Request message to
request an extension of the lifetimes for the assigned address, the
BNG does not have to initiate a new Access-Request towards the AAA
server to request the MAP configuration parameters. The BNG retrieves
the previously stored MAP configuration parameters and use them in
its reply.
If the DHCPv6 server to which the DHCPv6 Request message was sent at
time T1 has not responded, the DHCPv6 client enters the Rebind state
and attempts to contact any server. In this scenario the BNG
receiving the DHCPv6 message MUST initiate a new Access-Request
towards the AAA server. The BNG MAY include the IPv6-MAP-
Configuration Attribute in its Access-Request. If the BNG does not
receive the IPv6-MAP-Configuration Attribute in the Access-Accept it
MAY fallback to a pre-configured default MAP configuration, if any.
4. Attributes
This section defines IPv6-MAP-Configuration Attribute which is used
in the MAP scenario. The attribute design follows [RFC6158].
The MAP RADIUS attribute are designed following the simplify
principle. The sub options are organized into two categories: the
necessary and the optional.
4.1. IPv6-MAP-Configuration Attribute
The IPv6-MAP-Configuration 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
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
+ Rule Option(s) +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
TBD
Length
2 + the length of the Rule option(s)
Sub Option
a variable field that may contains one or more Rule option(s),
defined in Section 4.2.
4.2. MAP Rule Option
Depending on deployment scenario, one or more MAP Rules may be
included in one IPv6-MAP-Configuration Attribute.
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 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
+ Sub Options +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
0
Length
2 + the length of the sub options
Sub Option
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a variable field that contains necessary sub options defined in
Section 4.3 and zero or several optional sub options, defined
in Section 4.4.
4.3. Necessary Sub Options
Rule-IPv6-Prefix Sub Option and Rule-IPv4-Prefix Sub Option are
necessary for every MAP Rule option. They should appear for once and
only once.
4.3.1. Rule-IPv6-Prefix Sub Option
The IPv6 Prefix sub option is follow the framed IPv6 prefix designed
in [RFC3162].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | Reserved | prefix6-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| rule-ipv6-prefix |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
0 (SubType number, for the Rule-IPv6-Prefix6 sub option)
SubLen
20 (the length of the Rule-IPv6-Prefix6 sub option)
Reserved
Reserved for future usage. It should be set to all zero.
prefix6-len
length of the IPv6 prefix, specified in the rule-ipv6-prefix
field, expressed in bits
rule-ipv6-prefix
a 128-bits field that specifies an IPv6 prefix that appears in
a MAP rule
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"For the encapsulation mode the Rule IPv6 prefix can be the full IPv6
address of the BR." [I-D.mdt-softwire-mapping-address-and-port]
4.3.2. Rule-IPv4-Prefix Sub Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | Reserved | prefix4-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rule-ipv4-prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
1 (SubType number, for the Rule-IPv4-Prefix6 sub option)
SubLen
8 (the length of the Rule-IPv4-Prefix6 sub option)
Reserved
Reserved for future usage. It should be set to all zero.
Prefix4-len
length of the IPv6 prefix, specified in the rule-ipv6-prefix
field, expressed in bits
rule-ipv4-prefix
a 32-bits field that specifies an IPv4 prefix that appears in
a MAP rule
4.4. Optional Sub Options
This section presents several optional sub options. They may appear
once in each Rule Option. Different from
[I-D.mdt-softwire-map-dhcp-option], EA-Len, Embedded-Address (EA)
length, is not present at all, because it can be calculated by the
combine of prefix4len, prefix6-len, excluded ports and off bits.
4.4.1. Rule ID Sub Option
0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | rule-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
2 (SubType number, for the rule-id sub option)
SubLen
3 (the length of the rule-id sub option)
rule-id
identifier that uniquely identifies this rule.
4.4.2. Encapsulation/Translation Flag Sub Option
0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | E/T Flag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
3 (SubType number, for the rule-id sub option)
SubLen
3 (the length of the rule-id sub option)
E/T Flag
indicate the MAP transport mode: encapsulation or translation.
all 0 for encapsulation, all 1 for translation.
If this sub option is not present, the following default values are
to be assumed: encapsulation mode.
4.4.3. Exclude Port Sub Option
0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | exclude-port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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SubType
4 (SubType number, for the exclude-port sub option)
SubLen
3 (the length of the exclude-port sub option)
excluded-ports: defines upper bound for range of excluded
ports. The lower range is 0. For example, for value 2047,
excluded range is 0-2047 ports. Value of 0 (range 0-0) means
that no ports are excluded.
If this sub option is not present, the following default values are
to be assumed: Excluded ports: 0-1023 (excluded-ports field value is
1023).
4.4.4. Port Calculation Option
Port Calculation Sub Option includes parameters that will be used to
calculate IPv4/IPv6 address and port mapping.
0 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | port-cal |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
5 (SubType number, for the port-cal sub option)
SubLen
3 (the length of the port-cal sub option)
Port-cal field
Port-cal field include 3 parts as below:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|A| rsv | off |
+-+-+-+-+-+-+-+-+
A: Specifies if the offset is for a (0) or m (1).
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svd: This 4-bits long field is currently not used and MUST be
set to 0 by server. Its value MUST be ignored by clients.
off: specifies offset bits. Currently defined values are 4 and
6.
If this sub option is not present, the following default values are
to be assumed:
a). A: offset is for a (A field value is 0)
b). Offset bits: 6 (off field value is 6)
If administrator wants to provision only one of those two parameters,
remaining fields SHOULD be set to their default value.
4.5. 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 TBD1 IPv6-MAP-
Configuration
The following table defines the meaning of the above table entries.
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.
1 Exactly one instance of this attribute MUST be present in
packet.
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
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].
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Security considerations for the Diameter protocol are discussed in
RFC 3588 [RFC3588].
7. IANA Considerations
This document requires the assignment of two new RADIUS Attributes
Types in the "Radius Types" registry (currently located at
http://www.iana.org/assignments/radius-types for the following
attributes:
o IPv6-MAP-Configuration TBD1
IANA should allocate the numbers from the standard RADIUS Attributes
space using the "IETF Review" policy [RFC5226].
8. Acknowledgments
The authors would like to thank for valuable comments.
9. References
9.1. 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.
[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.
[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.
[RFC5080] Nelson, D. and DeKok A., "Common Remote Authentication Dial
In User Service (RADIUS) Implementation Issues and
Suggested Fixes", RFC 5080, December 2007.
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[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226, May 2008.
[RFC6158] DeKok, A. and G. Weber, "RADIUS Design Guidelines", RFC
6158, March 2011.
[I-D.mdt-softwire-mapping-address-and-port]
O. Troan, "Mapping of Address and Port (MAP)", draft-mdt-
softwire-mapping-address-and-port, working in progress.
[I-D.mdt-softwire-map-dhcp-option]
T. Mrugalski, "DHCPv6 Options for Mapping of Address and
Port", draft-mdt-softwire-map-dhcp-option, working in
progress.
9.2. 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.
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Author's Addresses
Sheng Jiang (Editor)
Huawei Technologies Co., Ltd
Q14 Huawei Campus, 156 BeiQi Road,
ZhongGuan Cun, Hai-Dian District, Beijing 100085
P.R. China
EMail: jiangsheng@huawei.com
Yu Fu
Huawei Technologies Co., Ltd
Q14 Huawei Campus, 156 BeiQi Road,
ZhongGuan Cun, Hai-Dian District, Beijing 100085
P.R. China
EMail: eleven.fuyu@huawei.com
Peter Deacon
IEA Software, Inc.
P.O. Box 1170
Veradale, WA 99037
USA
EMail: peterd@iea-software.com
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