Netext WG X. Zhou Internet-Draft ZTE Corporation Intended status: Standards Track J. Korhonen Expires: September 13, 2012 Nokia Siemens Networks C. Williams Consultant S. Gundavelli Cisco CJ. Bernardos UC3M March 12, 2012 Prefix Delegation for Proxy Mobile IPv6 draft-ietf-netext-pd-pmip-02 Abstract Proxy Mobile IPv6 enables IP mobility for a host without requiring its participation in any mobility signaling, being the network responsible for managing IP mobility on behalf of the host. However, Proxy Mobile IPv6 does not support assigning a prefix to a router and managing its IP mobility. This document specifies an extension to Proxy Mobile IPv6 protocol for supporting network mobility using DHCPv6-based Prefix Delegation. 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 September 13, 2012. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. Zhou, et al. Expires September 13, 2012 [Page 1] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Convention and Terminology . . . . . . . . . . . . . . . . . . 4 3. DHCPv6 Prefix Delegation for Proxy Mobile IPv6 . . . . . . . . 5 3.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. Network Mobility Service . . . . . . . . . . . . . . . . . 5 3.3. Binding association with the delegated prefix . . . . . . 5 3.3.1. Mobile Router initiated prefix delegation in PMIPv6 . 6 3.3.2. Refreshing the Delegated Prefix in Proxy Mobile IPv6 . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3.3. Deletion of the Delegated Prefix in Proxy Mobile IPv6 . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.4. Mobile Access Gateway Operation . . . . . . . . . . . . . 8 3.4.1. Extension to Binding Update List Entry Data Structure . . . . . . . . . . . . . . . . . . . . . . 8 3.4.2. Forwarding . . . . . . . . . . . . . . . . . . . . . . 8 3.4.3. Handover . . . . . . . . . . . . . . . . . . . . . . . 8 3.5. Local Mobility Anchor Operation . . . . . . . . . . . . . 9 3.5.1. Extension to Binding Cache Entry Data Structure . . . 9 3.5.2. Forwarding . . . . . . . . . . . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 10 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 7.1. Normative References . . . . . . . . . . . . . . . . . . . 13 7.2. Informative References . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Zhou, et al. Expires September 13, 2012 [Page 2] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 1. Introduction Proxy Mobile IPv6 [RFC5213] enables an IPv6 host to move within a PMIPv6-Domain without requiring its participation in any IP mobility signaling. However, PMIPv6 does not support providing a network- based mobility service to a complete network which is roaming within a PMIPv6-Domain without requiring the mobile router of that network to run the Network Mobility Basic Support protocol [RFC3963]. In order to support network mobility in Proxy Mobile IPv6, the IPv6 prefix used by the mobile network should be topologically anchored by the local mobility anchor. DHCPv6 Prefix Delegation [RFC3633] (DHCPv6-PD) can be used to assign mobile network prefix(es) to a mobile router (MR) as specified in DHCPv6 Prefix Delegation for Network Mobility (NEMO) [RFC6276]. However, if the mobile router is provided with PMIPv6 Protocol as its mobility management when connecting the network and uses DHCPv6-PD [RFC3633] to obtain prefix(es) for the nodes in the mobile network behind the MR, currently PMIPv6 network entities (i.e., mobile access gateway and local mobility anchor) are not aware of the delegated prefix(es) and therefore any packets sourced from or destined to the delegated prefix would be discarded by the MAG or the LMA. This document describes extension to PMIPv6 for supporting prefix delegation. Zhou, et al. Expires September 13, 2012 [Page 3] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 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]. All the mobility related terms used in this document are to be interpreted as defined in Mobile IPv6 (MIPv6) [RFC6275], Proxy Mobile IPv6 specification [RFC5213], DHCPv6-PD for NEMO [RFC6276], DHCPv6-PD [RFC3633] and Mobility Related Terminology [RFC3753]. This document also provides the following context-specific explanation to the following term used in this document. Mobile Router (MR) Throughout this document, the term mobile router is used to refer to an IP router whose mobility is managed by the network. The mobile router is not required to participate in any IP mobility related signaling for achieving mobility for an IPv6 prefix that is obtained in that Proxy Mobile IPv6 domain. Zhou, et al. Expires September 13, 2012 [Page 4] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 3. DHCPv6 Prefix Delegation for Proxy Mobile IPv6 3.1. Assumptions This specification extends PMIPv6 to assign a mobile network prefix to a mobile router for supporting network mobility. The specification assumes that a MR is a regular IPv6 router without extension for mobility management. The MR sends the packets from its mobile network to the MAG and the MAG delivers the packets to the mobile network via the MR. In order to use DHCPv6-PD as mobile network prefix assignment mechanism in mobile networks, this specification has following assumptions. o The mobile router (MR) MUST be able to function as a requesting router (RR). o The delegating router (DR) is located at the LMA. o The MAG MUST have a DHCPv6 Relay Agent functionality (as described in [RFC5213] to be able to intercept the related DHCPv6 message sourced from the MR. o The MR MUST either obtain the Home Network Prefix (HNP) before initiating the DHCPv6-PD procedure or in case of stateful address configuration simultaneously while configuring the Mobile Node Home Address (MN-HoA). o The MR (as a RR) SHOULD support Prefix Exclude Option for DHCPv6-PD as described in [I-D.ietf-dhc-pd-exclude]. 3.2. Network Mobility Service The network mobility service of a MR is managed by the policy profile defined in [RFC5213]. During mobile router's initial attach procedure, the mobile access gateway (MAG) MUST identify the MR and acquire the policy profile to determine whether the network mobility service is offered to the MR. If the network mobility service needs to be offered to the mobile node, the mobile access gateway MUST set the Mobile Router Flag (R) when sending the Proxy Binding Update (PBU) message to the LMA. 3.3. Binding association with the delegated prefix Zhou, et al. Expires September 13, 2012 [Page 5] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 3.3.1. Mobile Router initiated prefix delegation in PMIPv6 +-------------+ +--------------+ +-------------------+ |Mobile Router| | MAG | | LMA | |(Req. Router)| |(DHCPv6 Relay)| |(Delegating Router)| +-------------+ +--------------+ +-------------------+ | | | | |o========================o| 1) | | PMIPv6 tunnel | | |o========================o| 2) |-- Solicit ------>| | | | | 3) | |----------PBU------------>| | | | 4) | |<---------PBA-------------| | | | 5) | |--- Solicit ------------->| - - - - <-+ 6) | |<-- Advertise ------------| | | | | | 7) |<- Advertise -----| | Opt | | | ion 8) |-- Request ------>| | al. | | | | 9) | |--- Request ------------->| | - - - - <-+ 10) | |<-- Reply-----------------| | | | 11) |<-- Reply --------| | | | | Figure 1: Prefix Delegation in PMIPv6 during the initial attachment to the PMIPv6 Domain The steps of the procedures required to complete the delegation of an IPv6 prefix to a mobile router that is provided with network-based network mobility service in Figure 1 are as following: 1. The PMIPv6 tunnel is set up between the MAG and LMA as described in [RFC5213]. The MAG has the function of DHCPv6 Relay Agent between the MR and the DHCPv6 server and intercept all the DHCPv6 related messages. 2. The MR, acting as a "Requesting Router" as described in [RFC3633], sends a DHCPv6 SOLICIT message including one or more IA_PD option(s) to the MAG to acquire the delegated prefix(es). Zhou, et al. Expires September 13, 2012 [Page 6] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 3. Upon receiving the DHCPv6 SOLICIT message, the MAG sends a PBU message including a Mobile Network Prefix (MNP) mobility option as defined in Section 4.3 of [RFC3963] to the LMA. All the considerations from Section 5.3.1 of [RFC5213] MUST be applied on the encapsulated Proxy Binding Update message. If the MAG does not know the delegated prefix, then mobile network prefix in the MNP option MUST be set to unspecified address "::" and prefix length to 0. The LMA either assigns the MR a new delegated prefix or returns an existing one. 4. On reception of the PBU the LMA returns the assigned prefix in the MNP option carried by a Proxy Binding Acknowledgment (PBA) to the MAG, unless the prefix was the IPv6 unspecified address "::". The assigned prefix is the same one that will be assigned via DHCPv6PD in step 6. This prefix MUST be added to the delegated prefix(es) in the LMA binding cache which is extended as in Section 3.5.1. 5. The DHCPv6 Relay Agent on the MAG as described in [RFC3315] relays the DHCPv6 SOLICIT message to the delegation router. The DR inserts one or more IA_PD option(s) including the delegated prefix(es) to the reply message. Note: steps 6 to 9 are not present if DHCPv6 Rapid Commit is used. 6. The DR sends delegated prefix(es) in one or more IA_PD(s) to the MAG (DHCPv6 Relay Agent) inside the DHCPv6 ADVERTISE message. 7. The MAG relays the DHCPv6 ADVERTISE message to the MR. 8. The MR sends DHCPv6 REQUEST message with the IA_PD option(s) received from previous message to the MAG (DHCPv6 Relay Agent). 9. The MAG relays the DHCPv6 REQUEST message to the DR. 10. The DR responses to the REQUEST from the MAG using DHCPv6 REPLY message. 11. The MR receives one or more IA_PD prefix(es) in the DHCPv6 REPLY message from the MAG. 3.3.2. Refreshing the Delegated Prefix in Proxy Mobile IPv6 When the MR sends DHCPv6 Renew messages to extend the lifetime of the delegated prefix, the messages are also intercepted by the MAG (acting as DHCPv6 Relay Agent) and relayed to the DR. Zhou, et al. Expires September 13, 2012 [Page 7] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 3.3.3. Deletion of the Delegated Prefix in Proxy Mobile IPv6 If the lifetime of the delegated prefix (included in the IA_PD Prefix Option carried by the DHCPv6 Reply message) is set to zero, the MAG MUST trigger a PBU to remove the binding for that home mobile network prefix. 3.4. Mobile Access Gateway Operation 3.4.1. Extension to Binding Update List Entry Data Structure In order to support this specification, the conceptual Binding Update List Entry (BULE) data structure needs to be extended with a new prefix information field as [RFC3963] does. This prefix information field is used to store the MNP information which is assigned to the MR in the PBA. 3.4.2. Forwarding Forwarding packets sent to the mobile router's MNP: o On receiving a packet from the bi-directional tunnel established with the MR's LMA, the MAG MUST first decapsulate the packet (removing the outer header) and then use the destination address of the (inner) packet to forward it on the interface through which the destination MNP is reachable. Forwarding packets sent by the mobile router: o On receiving packets from a MR connected to one access link, the MAG MUST ensure that there is an established binding for the MR and its LMA before tunneling the packet to the MR's LMA. Other considerations from Section 6.10.5 of [RFC5213] also apply here. 3.4.3. Handover When the MR moves from the previously attached MAG to the newly attached target MAG, the newly attached target MAG MAY know the mobile network prefix which was assigned during the previous attachment from some network element, e.g. from the previous MAG. It is out of scope of this specification how the newly attached MAG could obtain the previously assigned mobile network prefix. After handover to the new target MAG, a PBU message including the assigned mobile network prefix (if available) MUST be sent from the new target MAG to the LMA. The LMA MUST check the mobile network prefix in the PBU message and return the same assigned mobile network prefix in the Zhou, et al. Expires September 13, 2012 [Page 8] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 PBA message. If the previously assigned mobile network prefix is not available in the new target MAG, the new target MAG MUST contain the mobile network prefix set to unspecified address "::" and the prefix length to 0 in the PBU message. In this case, the LMA MUST return the same previously assigned mobile network prefix in PBA. 3.5. Local Mobility Anchor Operation 3.5.1. Extension to Binding Cache Entry Data Structure In order to support this specification, the conceptual Binding Cache Entry (BCE) data structure needs to be extended with a new prefix information field as [RFC3963] does. This prefix information field is used to store the mobile network prefix information which is assigned to the BCE in the PBA during the procedure of binding association with the delegated prefix in Section 3.2 3.5.2. Forwarding Intercepting packets sent to the MR's mobile network prefix: o When the LMA is serving to the MR, it MUST be able to receive packets destined to the MR's mobile network. In order to receive those packets, the LMA MUST be the topological anchor of the MR's MNP(s). Forwarding packets to the MR: o On receiving a packet from a correspondent node with the destination address matching the MR's MNP(s) the LMA MUST forward the packet through the bi-directional tunnel set up for the MR. Other considerations from Section 5.6.2 of [RFC5213] also apply here. Zhou, et al. Expires September 13, 2012 [Page 9] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 4. Security Considerations This document describes extensions to the Proxy Mobile IPv6 protocol for supporting network mobility using DHCPv6-based Prefix Delegation. The security considerations for DHCPv6 described in the "Security Considerations" section of the DHCPv6 base specification [RFC3315], the "Security Considerations" of the DHCPv6 Prefix Delegation specification [RFC3633], and the security considerations from the base Proxy Mobile IPv6 [RFC5213] apply when using the extensions defined in this document. Zhou, et al. Expires September 13, 2012 [Page 10] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 5. IANA Considerations This document reuses the mobile network prefix option defined in [RFC3963] in Proxy Mobile IPv6 to assign the mobile network prefix via DHCPv6 Prefix Delegation. It does not introduce any additional IANA considerations. Zhou, et al. Expires September 13, 2012 [Page 11] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 6. Acknowledgments The work of Carlos J. Bernardos has also been partially supported by the European Community's Seventh Framework Programme (FP7-ICT-2009-5) under grant agreement n. 258053 (MEDIEVAL project) and by the Ministry of Science and Innovation of Spain under the QUARTET project (TIN2009-13992-C02-01). Zhou, et al. Expires September 13, 2012 [Page 12] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 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. [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. [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host Configuration Protocol (DHCP) version 6", RFC 3633, December 2003. [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, "Network Mobility (NEMO) Basic Support Protocol", RFC 3963, January 2005. [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. [RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, July 2011. [RFC6276] Droms, R., Thubert, P., Dupont, F., Haddad, W., and C. Bernardos, "DHCPv6 Prefix Delegation for Network Mobility (NEMO)", RFC 6276, July 2011. 7.2. Informative References [I-D.ietf-dhc-pd-exclude] Korhonen, J., Savolainen, T., Krishnan, S., and O. Troan, "Prefix Exclude Option for DHCPv6-based Prefix Delegation", draft-ietf-dhc-pd-exclude-04 (work in progress), December 2011. [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC 3753, June 2004. Zhou, et al. Expires September 13, 2012 [Page 13] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 March 2012 Authors' Addresses Xingyue Zhou ZTE Corporation No.50 Software Avenue, Yuhuatai District Nanjing China Phone: +86-25-8801-4634 Email: zhou.xingyue@zte.com.cn Jouni Korhonen Nokia Siemens Networks Linnoitustie 6 Espoo FIN-02600 Finland Email: jouni.nospam@gmail.com Carl Williams Consultant San Jose, CA USA Email: carlw@mcsr-labs.org Sri Gundavelli Cisco 170 West Tasman Drive San Jose, CA 95134 USA Email: sgundave@cisco.com Carlos J. Bernardos Universidad Carlos III de Madrid Av. Universidad, 30 Leganes, Madrid 28911 Spain Phone: +34 91624 6236 Email: cjbc@it.uc3m.es URI: http://www.it.uc3m.es/cjbc/ Zhou, et al. Expires September 13, 2012 [Page 14]