Softwire WG J. Hu Internet-Draft China Telecom Intended status: Standards Track W. Meng Expires: January 10, 2013 C. Wang L. Jin ZTE Corporation July 9, 2012 RADIUS Extensions for DS-Lite Multicast draft-hu-softwire-multicast-radius-ext-00 Abstract DS-Lite Multicast [I-D.ietf-softwire-dslite-multicast] is a solution to offer multicast service on DS-lite circumstance. DS-Lite Multicast requires pre-configuration of the IPv4-embedded IPv6 prefix(es) information on the multicast Basic Bridging BroadBand (mB4) element and multicast Address Family Translation Router(mAFTR). This document specifies a new Remote Authentication Dial-In User Service (RADIUS) attribute to carry the DS-Lite multicast prefixes information; the 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 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 10, 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 Hu, et al. Expires January 10, 2013 [Page 1] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 (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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Convention and Terminology . . . . . . . . . . . . . . . . . . 4 3. DS-Lite multicast prefixes Configuration with RADIUS and DHCPv6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. RADIUS Attribute . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. DS-Lite Multicast Prefixes . . . . . . . . . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7.1. Normative References . . . . . . . . . . . . . . . . . . . 11 7.2. Informative References . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Hu, et al. Expires January 10, 2013 [Page 2] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 1. Introduction DS-Lite Multicast [I-D.ietf-softwire-dslite-multicast] is a solution to offer multicast service on DS-lite circumstance.This solution relies upon a stateless translation to built 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. But how do the mB4 element and the multicast Address Family Translation Router(mAFTR) configure the unicast and multicast IPv4- embedded IPv6 prefixes to fulfill the stateless translation and encapsution? To inform the mB4 element and the mAFTR of the unicast and multicast prefixes, [I-D.ietf-softwire-multicast-prefix-option] defines a DHCPv6 option that is meant to be used by a mB4 element and a mAFTR to convey the IPv6 prefixes to be used for constructing these IPv4- embedded IPv6 address. In order to be able to populate such an option, the DHCPv6 server must be pre-provisioned with the 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 DS-Lite multicast prefixes 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 DS-Lite multicast prefixes information from the AAA server to the NAS. This document defines a new RADIUS attribute to be used for carrying the DS-Lite Multicast prefixes, based on the equivalent DHCPv6 option already specified in [I-D.ietf-softwire-multicast-prefix-option] Hu, et al. Expires January 10, 2013 [Page 3] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 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] Hu, et al. Expires January 10, 2013 [Page 4] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 3. DS-Lite multicast prefixes Configuration with RADIUS and DHCPv6 Figure 1 illustrates how the RADIUS protocol and DHCPv6 work together to accomplish DS-Lite multicast prefixes configuration on the mB4 element when an IP session is used to provide connectivity to the user. B4 NAS AAA | | Server |------ DHCPv6 Solicit ---------> | | | | | | |----Access-Request ---->| | | | | |<---Access-Accept-------| | |(DS-Lite-Multicast-option)| | | Information) | |<-------DHCPv6 Advertisement------| | | (DHCPv6 OPTION_PREFIX64 ) | | | | | |------- DHCPv6 Request -------->| | | | | | | | |<----- DHCPv6 Reply ------------- | | | (DHCPv6 OPTION_PREFIX64 ) | | DHCPv6 RADIUS Figure 1: RADIUS and DHCPv6 Multicast prefix Information Message Flow The NAS operates as a client of RADIUS and as a DHCP Server. 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 Multicast Information (asm-length,ASM_PREFIX64,ssm-length, SSM_PREFIX64,unicast-length,U_PREFIX64). 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 Information attribute in its Access-Request message. If the NAS does not receive the Multicast prefixes Information Hu, et al. Expires January 10, 2013 [Page 5] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 attribute in the Access-Accept message, it MAY fall back to a pre- configured default multicast prefixes, if any. If the NAS does not have any pre-configured, the delivery of muticast traffic is not supported. Hu, et al. Expires January 10, 2013 [Page 6] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 4. RADIUS Attribute This section specifies the format of the new RADIUS attribute. 4.1. DS-Lite Multicast Prefixes The DS-Lite Multicast Prefixes attribute conveys the IPv6 prefixes to be used [I-D.ietf-softwire-dslite-multicast] to synthesize IPv4- embedded IPv6 addresses. The NAS SHALL use the IPv6 prefixes returned in the RADIUS DS-Lite Multicast Prefixes attribute to populate the DHCPv6 PREFIX64 Option [I-D.ietf-softwire-multicast-prefix-option]. A summary of the DS-Lite Multicast Prefixes RADIUS attribute format is shown Figure 2. The fields are transmitted from left to right. 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 2: RADIUS attribute format for multicast prefixes Type: 145 for DS-Lite Multicast Prefix 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: Hu, et al. Expires January 10, 2013 [Page 7] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 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 of the multicast groups. The conveyed multicast IPv6 prefix MUST belong to the ASM range defined in [I-D.ietf-mboned-64-multicast-address-format] (i.e., ffxx: 8000/17). 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. SSM_PREFIX64: This field identifies the IPv6 multicast prefix to be used to synthesize the IPv4-embedded IPv6 addresses of the multicast groups. The conveyed multicast IPv6 prefix MUST belong to the SSM range defined in [I-D.ietf-mboned-64-multicast-address-format] (i.e., ff3x:0: 8000/33). 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 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. The address mapping MUST follow the guidelines documented in [RFC6052]. Hu, et al. Expires January 10, 2013 [Page 8] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 5. 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. Hu, et al. Expires January 10, 2013 [Page 9] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 6. 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. DS-Lite Multicast Prefix - 145 Hu, et al. Expires January 10, 2013 [Page 10] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 7. References 7.1. 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. [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. [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- Stack Lite Broadband Deployments Following IPv4 Exhaustion", RFC 6333, August 2011. [RFC6334] Hankins, D. and T. Mrugalski, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Option for Dual-Stack Lite", RFC 6334, August 2011. [RFC6519] Maglione, R. and A. Durand, "RADIUS Extensions for Dual- Stack Lite", RFC 6519, February 2012. 7.2. Informative 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 Format With Embedded IPv4 Multicast Address", draft-ietf-mboned-64-multicast-address-format-02 (work in progress), May 2012. [I-D.ietf-softwire-dslite-multicast] Qin, J., Boucadair, M., Jacquenet, C., Lee, Y., and Q. Wang, "Multicast Extensions to DS-Lite Technique in Broadband Deployments", Hu, et al. Expires January 10, 2013 [Page 11] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 draft-ietf-softwire-dslite-multicast-02 (work in progress), May 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-00 (work in progress), March 2012. Hu, et al. Expires January 10, 2013 [Page 12] Internet-Draft RADIUS Extensions for DS-Lite Multicast July 2012 Authors' Addresses Jie Hu China Telecom No.118, Xizhimennei Beijing 100035 China Email: huj@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 Lizhong Jin ZTE Corporation 889 Bibo Road Shanghai 201203 P.R.China Email: lizhong.jin@zte.com.cn Hu, et al. Expires January 10, 2013 [Page 13]