Network Working Group Sheng Jiang (Editor) Internet Draft Yu Fu Intended status: Standards Track Bing Liu Expires: January 14, 2013 Huawei Technologies Co., Ltd July 16, 2012 RADIUS Attribute for 4rd draft-jiang-softwire-4rd-radius-01.txt 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 time. It is inappropriate to use Internet-Drafts as reference 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 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. Jiang, et al. Expires January 14, 2012 [Page 1] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 Abstract IPv4 Residual Deployment via IPv6 (4rd) 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) 4rd options has been defined to configure 4rd 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 4rd configuration information from AAA server to BNG. The 4rd RADIUS attribute are designed following the simplify principle. It provides just enough information to form the correspondent DHCPv6 4rd option. Table of Contents 1. Introduction ................................................. 3 2. Terminology .................................................. 3 3. 4rd Configuration process with RADIUS ........................ 3 4. Attributes ................................................... 5 4.1. IPv6-4rd-Configuration Attribute ........................ 5 4.2. 4rd Non-mapping-rule Parameter option ................... 6 4.3. 4rd Rule Options ........................................ 7 4.4. 4rd Rule Sub Options .................................... 7 4.4.1. Rule-IPv6-Prefix Sub Option ........................ 8 4.4.2. Rule-IPv6-Suffix Sub Option ........................ 8 4.4.3. Rule-IPv4-Prefix Sub Option ........................ 9 4.4.4. Misc Sub Option ................................... 10 4.5. Table of attributes .................................... 10 5. Diameter Considerations ..................................... 11 6. Security Considerations ..................................... 11 7. IANA Considerations ......................................... 11 8. Acknowledgments ............................................. 11 9. References .................................................. 11 9.1. Normative References ................................... 11 9.2. Informative References ................................. 12 Jiang, et al. Expires January 14, 2013 [Page 2] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 1. Introduction Recently providers start to deploy IPv6 and consider how to transit to IPv6. IPv4 Residual Deployment via IPv6 (4rd) [I-D.ietf-softwire-4rd] 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. 4rd has adopted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) [RFC3315] as auto-configuring protocol. The 4rd Customer Edge (CE) uses the DHCPv6 extension options [I-D.ietf-softwire-4rd] to discover 4rd Border Relay and to configure relevant 4rd 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 4rd 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 4rd RADIUS attribute are designed following the simplify principle, while providing enough information to form the correspondent DHCPv6 4rd option. [I-D.ietf-softwire-4rd]. 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 4rd CE and 4rd Border Relay are defined in [I-D.ietf-softwire-4rd]. 3. 4rd Configuration process with RADIUS The below Figure 1 illustrates how the RADIUS protocol and DHCPv6 cooperate to provide 4rd CE with 4rd configuration information. Jiang, et al. Expires January 14, 2013 [Page 3] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 4rd CE BNG AAA Server | | | |------DHCPv6 Solicit----->| | | |--Access-Request(4rd Attr)-->| | | | | |<--Access-Accept(4rd Attr)---| |<---DHCPv6 Advertisement--| | | | | |------DHCPv6 Request---->| | | (4rd Option) | | |<---- -DHCPv6 Reply-------| | | (4rd 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 4rd CE. It initiates the BNG to request correspondent user authentication relevant from an AAA server using RADIUS protocol. A 4rd 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 IPv6-4rd-Configuration Attribute, defined in the next Section. After the BNG responds to the user with an Advertisement message, the user requests for a 4rd 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 4rd configuration information from the AAA server through the RADIUS protocol. When the user requests the 4rd Option, the BNG replies with a 4rd option in DHCPv6 Reply message. Jiang, et al. Expires January 14, 2013 [Page 4] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 4rd CE BNG AAA Server | | | | |--Access-Request(4rd Attr)-->| | | | | |<--Access-Accept(4rd Attr)---| | | | |------DHCPv6 Request----->| | | (4rd Option) | | |<---- -DHCPv6 Reply-------| | | (4rd option) | | | | | DHCPv6 RADIUS Figure 2: the cooperation between DHCPv6 and RADIUS After receiving the IPv6-4rd-Configuration Attribute in the initial Access-Accept, the BNG MUST store the received 4rd configuration parameters locally. When the 4rd 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 4rd configuration parameters. The BNG retrieves the previously stored 4rd 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 IPv6-4rd- Configuration Attribute in its Access-Request. If the BNG does not receive the IPv6-4rd-Configuration Attribute in the Access-Accept it MAY fallback to a pre-configured default 4rd configuration, if any. 4. Attributes This section defines IPv6-4rd-Configuration Attribute which is used in the 4rd scenario. The attribute design follows [RFC6158]. The 4rd RADIUS attribute are designed following the simplify principle. The sub options are organized into two categories: the necessary and the optional. 4.1. IPv6-4rd-Configuration Attribute The IPv6-4rd-Configuration Attribute is structured as follows: Jiang, et al. Expires January 14, 2013 [Page 5] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 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 | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + 4rd Option(s) + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type TBD Length 6 + the length of the Rule option(s) Sub Option a variable field that may contains a 4rd non-mapping-rule parameter option andone or more Rule option(s), defined in Section 4.2 and 4.3. 4.2. 4rd Non-mapping-rule Parameter 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | option-code = OPTION_4RD | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |H| 0 |T| traffic-class | domain-pmtu | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 1 Length 4 H bit Hub&spoke topology (= 1 if Yes) T bit Jiang, et al. Expires January 14, 2013 [Page 6] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 Traffic-class flag (= 1 if a Tunnel traffic class is provided) traffic-class Tunnel-traffic class domain-pmtu Domain PMTU (at least 1280) 4.3. 4rd Rule Options Depending on deployment scenario, at least one BR Mapping Rule one and one or more CE Mapping Rules MUST be included in one IPv6-4rd- 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 2 BR Mapping Rule 3 CE Mapping Rule Length 2 + the length of the sub options Sub Option 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. 4.4. 4rd Rule Sub Options Rule-IPv6-Prefix Sub Option and Rule-IPv4-Prefix Sub Option are necessary for every 4rd Rule option. They should appear for once and only once. Different from [I-D.ietf-softwire-4rd], EA-Len, Embedded- Jiang, et al. Expires January 14, 2013 [Page 7] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 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-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 4rd rule 4.4.2. Rule-IPv6-Suffix Sub Option Jiang, et al. Expires January 14, 2013 [Page 8] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 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 | suffix6-len | ipv6-suffix | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ SubType 1 (SubType number, for the Rule-IPv6-Suffix6 sub option) SubLen 4 (the length of the Rule-IPv6-Suffix6 sub option) prefix6-len length of the IPv6 suffix, specified in the rule-ipv6-suffix field, expressed in bits. In attendance, the value should be 1~4 only. rule-ipv6-suffix a 8-bits field that specifies an IPv6 suffix that appears in a 4rd rule 4.4.3. 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 2 (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. Jiang, et al. Expires January 14, 2013 [Page 9] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 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 4rd rule 4.4.4. Misc 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 |W| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ SubType 3 (SubType number, for the Rule-IPv4-Prefix6 sub option) SubLen 1 (the length of the Rule-IPv4-Prefix6 sub option) Reserved Reserved for future usage. It should be set to all zero. W bit WKP authorized, = 1 if set 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 IPv6-4rd- Configuration The following table defines the meaning of the above table entries. Jiang, et al. Expires January 14, 2013 [Page 10] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 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]. 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 IPv6-4rd-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. Jiang, et al. Expires January 14, 2013 [Page 11] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 [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. [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.ietf-softwire-4rd] R. Despres, et al., "IPv4 Residual Deployment via IPv6 - a unified Stateless Solution (4rd)", draft-ietf-softwire-4rd, 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. Jiang, et al. Expires January 14, 2013 [Page 12] Internet-Draft draft-jiang-softwire-4rd-radius-01 July 2012 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 Bing Liu Huawei Technologies Co., Ltd Q14 Huawei Campus, 156 BeiQi Road, ZhongGuan Cun, Hai-Dian District, Beijing 100085 P.R. China EMail: leo.liubing@huawei.com Jiang, et al. Expires January 14, 2013 [Page 13]