netext X. Zhou Internet-Draft ZTE Corporation Intended status: Standards Track J. Korhonen Expires: January 12, 2012 Nokia Siemens Networks C. Williams Consultant July 11, 2011 Prefix Delegation for Proxy Mobile IPv6 draft-zhou-netext-pd-pmip-01.txt Abstract This document explains how network mobility and DHCPv6-based Prefix Delegation works with Proxy Mobile IPv6. 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 12, 2012. Copyright Notice Copyright (c) 2011 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. Zhou, et al. Expires January 12, 2012 [Page 1] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Convention & Terminology . . . . . . . . . . . . . . . . . . . 4 3. DHCPv6 Prefix Delegation for PMIPv6 . . . . . . . . . . . . . 5 3.1. Assumption . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. Network Mobility Service . . . . . . . . . . . . . . . . . 5 3.3. Binding association with the delegated prefix . . . . . . 6 3.3.1. Mobile Router initiated prefix delegation in PMIPv6 . 6 3.3.2. Mobile Router refresh prefix delegation in PMIPv6 . . 7 3.4. Mobile Access Gateway Operation . . . . . . . . . . . . . 7 3.4.1. Extension to Binding Update List Entry Data Structure . . . . . . . . . . . . . . . . . . . . . . 7 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. Normative References . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Zhou, et al. Expires January 12, 2012 [Page 2] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 1. Introduction DHCPv6 prefix delegation [RFC 3633] (DHCPv6PD) can be used to assign mobile network prefix(es) to a Mobile Router as specified in DHCPv6 Prefix Delegation for NEMO [draft-ietf-mext-nemo-pd-07]. However, there is a gap currently for this NEMO support in PMIPv6 architecture. If a mobile router (MR) is provided Proxy Mobile IPv6 Protocol as its mobility management when connecting the network and use DHCPv6PD to obtain prefix(es) for the nodes in the mobile network behind the MR, currently neither the Mobile Access Gateway (MAG) nor the Local Mobility Anchor (LMA) can be able to identify the packet including delegated prefix(es). When the MR (Requesting Router) uses DHCPv6 PD to obtain the delegated prefix(es), these prefix(es) SHOULD be associated with the PMIPv6 binding. Otherwise the packets addressed to the delegated prefix will be discarded by the MAG or the LMA. This document describes extension to PMIPv6 for supporting prefix delegation. Zhou, et al. Expires January 12, 2012 [Page 3] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 2. Convention & 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 [RFC 2119]. All the mobility related terms used in this document are to be interpreted as defined in Mobile IPv6 [RFC 3775], Network Mobility Basic Support protocol [RFC 3963], Proxy Mobile IPv6 specification [RFC 5213], DHCPv6 Prefix Delegation for NEMO [draft-ietf-mext-nemo-pd-07], DHCP Prefix Delegation [RFC3633] and Mobility Related Terminology [RFC 3753]. This document does not define any new terms. Zhou, et al. Expires January 12, 2012 [Page 4] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 3. DHCPv6 Prefix Delegation for PMIPv6 3.1. Assumption This specification extends PMIPv6 to assign not only the home network prefix but also the mobile network prefix for supporting network mobility. It assumes that a MR is a regular IPv6 router without extension for mobility managements. 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 DHCPv6PD as mobile network prefix assignment mechanism in mobile networks, this specification has following assumptions. o The Mobile Router MUST play the role of the Requesting Router. o The Delegating Router can be located either at LMA or some other device in the PMIPv6 domain. o The MAG MUST play the role of DHCPv6 Relay Agent to intercept the related DHCPv6 message from the Mobile Router. o The Mobile Router (Requesting Router) MUST obtain the home network prefix before initiating the DHCPv6 prefix delegation procedure. o All the mobile network prefixes managed in the Delegating Router MUST be reachable via local mobility anchor. o The Mobile Router (Requesting Router) SHOULD support Prefix Exclude Option for DHCPv6-based Prefix Delegation as described in [draft-ietf-dhc-pd-exclude]. 3.2. Network Mobility Service The network mobility service of a mobile router is managed by the mobile node's policy profile defined in [RFC 5213]. During mobile router initial attachment procedure, the mobile access gateway MUST identify the mobile router and acquire the mobile router!_s policy profile to determine whether the network mobility service is offered to the mobile router. 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 message to the local mobility anchor. Zhou, et al. Expires January 12, 2012 [Page 5] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 3.3. Binding association with the delegated prefix 3.3.1. Mobile Router initiated prefix delegation in PMIPv6 +-------------------+ +------------------+ +--------+ +------------+ | Mobile Router | | MAG | | LMA | | Delegating | |(Requesting Router)| |(DHCP Relay Agent)| +--------+ | Router | +-------------------+ +------------------+ | +------------+ | | | | | |---------------------| | | | 1.PMIPv6 tunnel | | | |---------------------| | |--2.DHCPv6 SOLICIT-->| | | | | | | | |--------3.PBU------->| | | | | | | |<-------4.PBA--------| | | | | | | |---------5.DHCPv6 SOLICIT---------->| | |<--------6.DHCPv6 ADVERTISE---------| | | | | |<-7.DHCPv6 ADVERTISE-| | | | | | | |--8.DHCPv6 REQUEST-->| | | | |--9.DHCPv6 REQUEST----------------->| | | | | | |<-----10.DHCPv6 REPLAY--------------| |<--11.DHCPv6 REPLY---| | | | | | | Figure 1: Prefix Delegation in PMIPv6 The steps of the procedure in Figure 1 are as following. 1. The PMIPv6 tunnel is set up between the MAG and LMA. The MAG plays function of DHCPv6 relay agent between the MN and the DHCPv6 server and intercept all the DHCP related messages. 2. The mobile router which acts as a "Requesting Router" as described in [RFC 3633] sends DHCPv6 SOLICIT massage including one or more IA_PD option(s) to the MAG to acquire the delegated prefix(es). 3. Upon receiving DHCPv6 SOLICIT the MAG sends a Proxy Binding Update message including a Mobile Network Prefix mobility option as defined in Section 4.3 of [RFC 3963] to the LMA. All the considerations from Section 5.3.1 of [RFC 5213] MUST be applied on the encapsulated Proxy Binding Update message. Zhou, et al. Expires January 12, 2012 [Page 6] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 4. On reception of the Proxy Binding Update the LMA returns the assigned prefix in the Mobile Network Prefix option carried by a Proxy Binding Acknowledgment to the MAG. The assigned prefix is the same one which will be assigned via DHCPv6PD in step 6 which MUST be added the delegated prefix(es) in its binding cache which is extended as in Section 3.5.1. 5. The DHCPv6 relay agent on the MAG as described in [RFC 3315] relays the DHCPv6 SOLICIT message to the delegation router. NOTE: Step 3 and Step 5 are processed in parallel. 6. The delegating router inserts one or more IA_PD option(s) including the delegated prefix(es) and send it to the MAG (DHCPv6 relay agent) via the DHCPv6 ADVERTISE message. 7. The MAG relays the DHCPv6 ADVERTISE message to the MN. 8. The MN 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 delegating router. 10. The delegating router responses the REQUEST to the MAG via DHCPv6 REPLY message. 11. The MN receives one or more IA_PD prefix(es) in the DHCPv6 REPLY message from the MAG. 3.3.2. Mobile Router refresh prefix delegation in PMIPv6 When the mobile router sends DHCPv6 Renew messages to extend the lifetime of the delegated prefix, the messages are also intercepted by the MAG and relayed to the delegating router. If the MAG finds that the lifetime of the delegated prefix which is stored in the IA_PD Prefix Option carried by the DHCPv6 reply message set to zero, the MAG SHOULD triggers a Proxy Binding Update to remove the binding for that 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 Cache entry data structure needs to be extended with a new prefix information field as [RFC 3963] does. This prefix information field is used to store the mobile network prefix information which is assigned to the mobile router in the Proxy Binding Acknowledgement Zhou, et al. Expires January 12, 2012 [Page 7] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 during the procedure of Binding association with the delegated prefix in section 3.2. 3.4.2. Forwarding Forwarding packets sent to the mobile router!_s mobile network prefix o On receiving a packet from the bi-directional tunnel established with the mobile router!_s local mobility anchor, the mobile access gateway MUST use the destination address of the inner packet to forward it on the interface where the destination mobile network prefix is hosted. Forwarding packets sent by the mobile router o On receiving a packet from a mobile router connected to its access link, the mobile access gateway MUST ensure that there is an established binding for that mobile router with its local mobility anchor before tunneling the packet to the mobile router!_s local mobility anchor. All other considerations from 6.10.5 MUST be applied here also. 3.4.3. Handover When the mobile router moves from the previously attached mobile access gateway to the newly attached mobile access gateway, the newly attached mobile access gateway MAY know the mobile network prefix which is assigned during the previous attachment from some network element, e.g. from the previous mobile access gateway. It is out of scope of this specification that how the newly attached mobile access gateway obtains the previously assigned mobile network prefix. After handover to the new mobile access gateway, a Proxy Binding Update message including the assigned mobile network prefix (if available) MUST be sent from the new mobile access gateway to the local mobility anchor. The local mobility anchor MUST check the mobile network prefix in the Proxy Binding Update message and return the same assigned mobile network prefix in the Proxy Binding Acknowledgement message. If the previously assigned mobile network prefix is not available in the new mobile access gateway, the new mobile access gateway MUST contain the mobile network prefix set with 0 in the Proxy Binding Update message. In this case, the local mobility anchor MUST return the same previously assigned mobile network prefix in Proxy Binding Acknowledgement. Zhou, et al. Expires January 12, 2012 [Page 8] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 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 data structure needs to be extended with a new prefix information field as [RFC 3963] does. This prefix information field is used to store the mobile network prefix information which is assigned to the mobile router in the Proxy Binding Acknowledgement during the procedure of Binding association with the delegated prefix in section 3.2. 3.5.2. Forwarding Intercepting packets sent to the mobile router!_s mobile network prefix o When the local mobility anchor is serving to the mobile router, it MUST be able to receive packets those are sent to the mobile router!_s mobile network. In order to receive those packets, the mobile access gateway MUST advertise a connected route into the Routing Infrastructure for the mobile router!_s mobile network prefix(es). Forwarding packets to the mobile router o On receiving a packet from a correspondent node with the destination address matching the mobile router!_s mobile network prefix(es) the local mobility anchor MUST forward the packet through the bi-directional tunnel set up for that mobile router. All other considerations from 5.6.2 MUST be applied here also. Zhou, et al. Expires January 12, 2012 [Page 9] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 4. Security Considerations All security considerations from the base Proxy Mobile IPv6 [RFC 5213], DHCPv6 Prefix Delegation specification [RFC 3633] apply when using the extensions defined in this document. Zhou, et al. Expires January 12, 2012 [Page 10] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 5. IANA Considerations This document reuses the mobile network prefix option defined in [RFC 3963] in Proxy Mobile IPv6 to assign the mobile network prefix via DHCPv6 for prefix delegation. It does not introduce any additional IANA considerations. Zhou, et al. Expires January 12, 2012 [Page 11] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 6. 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. Zhou, et al. Expires January 12, 2012 [Page 12] Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011 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 Zhou, et al. Expires January 12, 2012 [Page 13]