7 Network Working Group J. Salowey
8 Request for Comments: 4818 R. Droms
9 Category: Standards Track Cisco Systems, Inc.
13 RADIUS Delegated-IPv6-Prefix Attribute
17 This document specifies an Internet standards track protocol for the
18 Internet community, and requests discussion and suggestions for
19 improvements. Please refer to the current edition of the "Internet
20 Official Protocol Standards" (STD 1) for the standardization state
21 and status of this protocol. Distribution of this memo is unlimited.
25 Copyright (C) The IETF Trust (2007).
29 This document defines a RADIUS (Remote Authentication Dial In User
30 Service) attribute that carries an IPv6 prefix that is to be
31 delegated to the user. This attribute is usable within either RADIUS
58 Salowey & Droms Standards Track [Page 1]
60 RFC 4818 Delegated-IPv6-Prefix Attribute April 2007
65 This document defines the Delegated-IPv6-Prefix attribute as a RADIUS
66 [1] attribute that carries an IPv6 prefix to be delegated to the
67 user, for use in the user's network. For example, the prefix in a
68 Delegated-IPv6-Prefix attribute can be delegated to another node
69 through DHCP Prefix Delegation [2].
71 The Delegated-IPv6-Prefix attribute can be used in DHCP Prefix
72 Delegation between the delegating router and a RADIUS server, as
73 illustrated in the following message sequence.
76 Requesting Router Delegating Router RADIUS Server
78 |-Solicit------------>| |
79 | |-Request------------------------>|
80 | |<--Accept(Delegated-IPv6-Prefix)-|
81 |<--Advertise(Prefix)-| |
82 |-Request(Prefix)---->| |
83 |<--Reply(Prefix)-----| |
88 The Framed-IPv6-Prefix attribute [4] is not designed to support
89 delegation of IPv6 prefixes to be used in the user's network, and
90 therefore Framed-IPv6-Prefix and Delegated-IPv6-Prefix attributes may
91 be included in the same RADIUS packet.
95 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
96 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
97 document are to be interpreted as described in RFC 2119 [3].
114 Salowey & Droms Standards Track [Page 2]
116 RFC 4818 Delegated-IPv6-Prefix Attribute April 2007
121 The format of the Delegated-IPv6-Prefix is:
124 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
125 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
126 | Type | Length | Reserved | Prefix-Length |
127 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
133 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
135 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
139 123 for Delegated-IPv6-Prefix
143 The length of the entire attribute, in bytes. At least 4 (to
144 hold Type/Length/Reserved/Prefix-Length for a 0-bit prefix),
145 and no larger than 20 (to hold Type/Length/ Reserved/Prefix-
146 Length for a 128-bit prefix)
150 Always set to zero by sender; ignored by receiver
154 The length of the prefix being delegated, in bits. At least
155 0 and no larger than 128 bits (identifying a single IPv6
158 Note that the prefix field is only required to be long enough to hold
159 the prefix bits and can be shorter than 16 bytes. Any bits in the
160 prefix field that are not part of the prefix MUST be zero.
162 The Delegated-IPv6-Prefix MAY appear in an Access-Accept packet, and
163 can appear multiple times. It MAY appear in an Access-Request packet
164 as a hint by the NAS to the server that it would prefer these
165 prefix(es), but the server is not required to honor the hint.
170 Salowey & Droms Standards Track [Page 3]
172 RFC 4818 Delegated-IPv6-Prefix Attribute April 2007
175 The Delegated-IPv6-Prefix attribute MAY appear in an Accounting-
178 The Delegated-IPv6-Prefix MUST NOT appear in any other RADIUS
181 4. Table of Attributes
183 The following table provides a guide to which attributes may be found
184 in which kinds of packets, and in what quantity.
186 +-------------------------------------------------------------------+
187 | Request Accept Reject Challenge Accounting # Attribute |
189 | 0+ 0+ 0 0 0+ 123 Delegated-IPv6- |
191 +-------------------------------------------------------------------+
193 The meaning of the above table entries is as follows:
194 0 This attribute MUST NOT be present.
195 0+ Zero or more instances of this attribute MAY be present.
196 0-1 Zero or one instance of this attribute MAY be present.
197 1 Exactly one instance of this attribute MUST be present.
198 1+ One or more of these attributes MUST be present.
200 5. Diameter Considerations
202 When used in Diameter, the attribute defined in this specification
203 can be used as a Diameter AVP from the Code space 1-255, i.e., RADIUS
204 attribute compatibility space. No additional Diameter Code values
205 are therefore allocated. The data types of the attributes are as
208 Delegated-IPv6-Prefix OctetString
210 The attribute in this specification has no special translation
211 requirements for Diameter to RADIUS or RADIUS to Diameter gateways,
212 i.e., the attribute is copied as is, except for changes relating to
213 headers, alignment, and padding. See also RFC 3588 [5], Section 4.1,
214 and RFC 4005 [6], Section 9.
216 The text in this specification describing the applicability of the
217 Delegated-IPv6-Prefix attribute for RADIUS Access-Request applies in
218 Diameter to AA-Request [6] or Diameter-EAP-Request [7].
220 The text in this specification describing the applicability of the
221 Delegated-IPv6-Prefix attribute for RADIUS Access-Accept applies in
222 Diameter to AA-Answer or Diameter-EAP-Answer that indicates success.
226 Salowey & Droms Standards Track [Page 4]
228 RFC 4818 Delegated-IPv6-Prefix Attribute April 2007
231 The text in this specification describing the applicability of the
232 Delegated-IPv6-Prefix attribute for RADIUS Accounting-Request applies
233 to Diameter Accounting-Request [6] as well.
235 The AVP flag rules [5] for the Delegated-IPv6-Prefix attribute are:
237 +---------------------+
239 |----+-----+----+-----|----+
240 AVP | | |SHLD| MUST| |
241 Attribute Name Code Value Type |MUST| MAY | NOT| NOT|Encr|
242 ---------------------------------|----+-----+----+-----|----|
243 Delegated-IPv6- 123 OctetString| M | P | | V | Y |
245 ---------------------------------|----+-----+----+-----|----|
247 6. IANA Considerations
249 IANA assigned a Type value, 123, for this attribute from the RADIUS
250 Attribute Types registry.
252 7. Security Considerations
254 Known security vulnerabilities of the RADIUS protocol are discussed
255 in RFC 2607 [8], RFC 2865 [1], and RFC 2869 [9]. Use of IPsec [10]
256 for providing security when RADIUS is carried in IPv6 is discussed in
259 Security considerations for the Diameter protocol are discussed in
264 8.1. Normative References
266 [1] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote
267 Authentication Dial In User Service (RADIUS)", RFC 2865, June
270 [2] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host
271 Configuration Protocol (DHCP) version 6", RFC 3633, December
274 [3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
275 Levels", BCP 14, RFC 2119, March 1997.
282 Salowey & Droms Standards Track [Page 5]
284 RFC 4818 Delegated-IPv6-Prefix Attribute April 2007
287 9.2. Informative References
289 [4] Aboba, B., Zorn, G., and D. Mitton, "RADIUS and IPv6", RFC 3162,
292 [5] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko,
293 "Diameter Base Protocol", RFC 3588, September 2003.
295 [6] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter
296 Network Access Server Application", RFC 4005, August 2005.
298 [7] Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible
299 Authentication Protocol (EAP) Application", RFC 4072, August
302 [8] Aboba, B. and J. Vollbrecht, "Proxy Chaining and Policy
303 Implementation in Roaming", RFC 2607, June 1999.
305 [9] Rigney, C., Willats, W., and P. Calhoun, "RADIUS Extensions",
308 [10] Kent, S. and K. Seo, "Security Architecture for the Internet
309 Protocol", RFC 4301, December 2005.
319 Phone: +1 206.310.0596
320 EMail: jsalowey@cisco.com
325 1414 Massachusetts Avenue
329 Phone: +1 978.936.1674
330 EMail: rdroms@cisco.com
338 Salowey & Droms Standards Track [Page 6]
340 RFC 4818 Delegated-IPv6-Prefix Attribute April 2007
343 Full Copyright Statement
345 Copyright (C) The IETF Trust (2007).
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394 Salowey & Droms Standards Track [Page 7]