DMM Working Group Z. Yan Internet-Draft CNNIC Intended status: Standards Track J. Lee Expires: January 6, 2016 Sangmyung University X. Lee CNNIC July 5, 2015 Home Network Prefix Renumbering in PMIPv6 draft-yan-dmm-hnprenum-02.txt Abstract In the basic Proxy Mobile IPv6 (PMIPv6) specification, an Mobile Node (MN) is assigned with a 64-bit Home Network Prefix (HNP) during its initial attachment for the Home Address (HoA) configuration. During the movement of the MN, this prefix remains unchanged and in this way it is unnecessary for the MN to reconfigure its HoA and reconnect the ongoing communications. However, the current protocol [RFC5213] does not specify related operations to support the MN to timely receive and use a new HNP when the allocated HNP changes. In this draft, a possible solution to support the HNP renumbering is proposed, as an update of RFC5213. Requirements Language 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. 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 6, 2016. Yan, et al. Expires January 6, 2016 [Page 1] Internet-Draft PMIPv6 HNP Renumbering July 2015 Copyright Notice Copyright (c) 2015 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Usage scenarios . . . . . . . . . . . . . . . . . . . . . . . 2 3. PMIPv6 extensions . . . . . . . . . . . . . . . . . . . . . . 3 4. Session connectivity . . . . . . . . . . . . . . . . . . . . 5 5. Message format . . . . . . . . . . . . . . . . . . . . . . . 5 6. Other issues . . . . . . . . . . . . . . . . . . . . . . . . 6 7. Security considerations . . . . . . . . . . . . . . . . . . . 6 8. Normative References . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction Network managers currently prefer to Provider Independent (PI) addressing for IPv6 to attempt to minimize the need for future possible renumbering. However, widespread use of PI addresses may cause very serious Border Gateway Protocol (BGP) scaling problems. It is thus desirable to develop tools and practices that may make IPv6 renumbering a simpler process to reduce demand for IPv6 PI space [RFC6879]. In this draft, we aim to solve the HNP renumbering problem when the HNP in PMIPv6 [RFC5213] is not the type of PI. 2. Usage scenarios There are a number of reasons why the HNP renumbering support is useful and a few are identified below: o Scenario 1: the PMIPv6 service provider is assigned with the HNP set from the (uplink) Internet Service Provider (ISP), and then the HNP renumbering may happen if the PMIPv6 service provider switches to a different ISP. Yan, et al. Expires January 6, 2016 [Page 2] Internet-Draft PMIPv6 HNP Renumbering July 2015 o Scenario 2: multiple Local Mobility Anchors (LMAs) may be deployed by the same PMIPv6 service provider, and then each LMA may serve for a specific HNP set. In this case, the HNP of an MN may change if the current serving LMA switches to another LMA but without inheriting the assigned HNP set [RFC6463]. o Scenario 3: the PMIPv6 HNP renumbering may be caused by the re- building of the network architecture as the companies split, merge, grow, relocate or reorganize. For example, the PMIPv6 service provider may reorganize its network topology. In the scenario 1, we assume that only the HNP is renumbered while the serving LMA remains unchanged and this is the basic scenario of this document. In the scenario 2 and scenario 3, more complex results may be caused, for example, the HNP renumbering may happen due to the switchover of serving LMA. In the Mobile IPv6 (MIPv6), when the home network prefix changes (may be also caused by the above reasons), the Home Agent (HA) will actively notify the new prefix to the MN and then the renumbering of the HoA can be well supported [RFC6275]. While in the basic PMIPv6, the PMIPv6 binding is triggered by the Mobile Access Gateway (MAG), which detected the attachment of the MN. When the HNP renumbering happens, a scheme is also needed for the LMA to immediately initiate the PMIPv6 binding state refreshment. Although this issue is also discussed in the [RFC5213] (Section 6.12), the related solution has not been specified. 3. PMIPv6 extensions When the HNP renumbering happens in PMIPv6, the LMA has to notify the new HNP to the MAG and then the MAG has to announce the new HNP to the MN accordingly. Also, the LMA and the MAG must delete the created routing states for the renumbered prefix. To support this procedure, RFC7077 can be adopted which specifies asynchronously update from the LMA to the MAG about the updated session parameters. This document considers the following two cases: (1)HNP is renumbered in the same LMA In this case, the LMA remains unchanged as in the scenario 1 and scenario 3. The operation steps are shown in Figure 1. Yan, et al. Expires January 6, 2016 [Page 3] Internet-Draft PMIPv6 HNP Renumbering July 2015 +-----+ +-----+ +-----+ | MN | | MAG | | LMA | +-----+ +-----+ +-----+ | | | | | Allocate new HNP | | | | |<------------- UPN ---| | | | | Update routing state | | | | |<-----RA/DHCP --------| | | | | HoA Configuration | | | | | | |--- UNA ------------->| | | | | | Update routing state | | | Figure 1: Signaling call flow of HNP renumbering o When the PMIPv6 service provider renumbers the HNP set in the same LMA, the serving LMA will initiate the HNP renumbering operation. The LMA allocates a new HNP for the related MN. o The LMA sends the Update Notification (UPN) message to the MAG to update the HNP information. If the DHCP is used in PMIPv6 to allocate the HoA, the new HNP should be also notified to the DHCP infrastructure. o After the MAG receives this UPN message, it recognizes that the related MN has a new HNP. Then the MAG should notify the MN about the new HNP with a RA message or allocate a new address within the new HNP with a DHCP message. o When the MN obtains the new HNP information, it deletes the old HoA and configures a new HoA with the newly allocated HNP. o The MAG sends back the Update Notification Acknowledgement (UNA) to the LMA for the notification of successful update of the HNP, related binding state, and routing state. Then the LMA updates the routing information corresponding to the MN to replace the old HNP with the new one. (2) HNP renumbering caused by LMA switchover Because the HNP is assigned by the LMA, the HNP renumbering may be caused by the LMA switchover, as in the scenario 2 and scenario 3. Yan, et al. Expires January 6, 2016 [Page 4] Internet-Draft PMIPv6 HNP Renumbering July 2015 The information of LMA is the basic configuration information of MAG. When the LMA changes, the related profile should be updated by the service provider. In this way, the MAG will initiate the re- registration to the new LMA as specified in RFC5213. When the HNP renumbering is caused in this case, the new HNP information will be sent by the LMA during the new bingding procedure. Accordingly, the MAG will withdraw the old HNP information of the MN and advise the new HNP to the MN as Step (3) in Section 3.1. 4. Session connectivity HNP renumbering may cause the disconnection of the ongoing communications of the MN. Basiclly, there are two modes to manage the session connectivity during the HNP renumbering. (1)Soft-mode The LMA will temporarily maintain the state of the old HNP during the HNP renumbering (after the UNA reception) in order to redirect the packets to the MN before the MN reconnets the ongoing session and notifies its new HoA to the Corresponding Node (CN). This mode is aiming to reduce the packet loss during the HNP renumbering but the binding state and routing entry corresponding to the old HNP should be marked for example as transient binding [RFC6058]. This temporary binding should only be used for the downwards packet transmission and its lifetime should be set to lower than the normal lifetime of the PMIPv6 binding state. (2)Hard-mode If the HNP renumbering happens with the switchover of the LMA, the hard-mode is recommended to keep the protocol simple and efficient. The LMA will delete the state of the old HNP after it receives the UNA message from MAG. In this mode, the LMA will silently discard the packets destinated to the old HNP. 5. Message format (1)UPN message In the UPN message sent from the LMA to the MAG, the notification reason is set to 2 (UPDATE-SESSION-PARAMETERS). Besides, the HNP option containing the new HNP and the Mobile Node Identifier option carrying Identifier of MN are contained as Mobility Options of UPN. (2)RA Message Yan, et al. Expires January 6, 2016 [Page 5] Internet-Draft PMIPv6 HNP Renumbering July 2015 When the RA message is used by the MAG to advise the new HNP, two Prefix Information options are contained in the RA message [RFC2461]. In the first Prefix Information option, the old HNP is carried but both the related Valid Lifetime and Preferred Lifetime are set to 0. In the second Prefix Information option, the new HNP is carried with the Valid Lifetime and Preferred Lifetime set to larger than 0. (3)DHCP Message When the DHCP is used in PMIPv6 to configure the HoA for the MN, a new IPv6 HoA is generated based on the new HNP. Trigged by the UPN message, the MAG will request the new HoA from the DHCP server first and then the MAG updates the allocated HoA to the MN through the DHCP server-initiated configuration exchange [RFC3315]. 6. Other issues In order to maintain the reachability of the MN, the DNS resource record corresponding to this MN may need to be updated when the HNP of MN changes [RFC3007]. However, this is out the scope of this draft. 7. Security considerations This extension causes no further security problem. The security considerations in [RFC5213] and [RFC7077] are enough for the basic operation of this draft. Other security issues will be analyzed further. 8. Normative References [RFC2461] Narten, T., Nordmark, E., and W. Simpson, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998. [RFC3007] Wellington, B., "Secure Domain Name System (DNS) Dynamic Update", RFC 3007, November 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. [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. [RFC6058] Liebsch, M., Muhanna, A., and O. Blume, "Transient Binding for Proxy Mobile IPv6", RFC 6058, March 2011. Yan, et al. Expires January 6, 2016 [Page 6] Internet-Draft PMIPv6 HNP Renumbering July 2015 [RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, July 2011. [RFC6463] Korhonen, J., Gundavelli, S., Yokota, H., and X. Cui, "Runtime Local Mobility Anchor (LMA) Assignment Support for Proxy Mobile IPv6", RFC 6463, February 2012. [RFC6879] Jiang, S., Liu, B., and B. Carpenter, "IPv6 Enterprise Network Renumbering Scenarios, Considerations, and Methods", RFC 6879, February 2013. [RFC7077] Krishnan, S., Gundavelli, S., Liebsch, M., Yokota, H., and J. Korhonen, "Update Notifications for Proxy Mobile IPv6", RFC 7077, November 2013. Authors' Addresses Zhiwei Yan CNNIC No.4 South 4th Street, Zhongguancun Beijing 100190 China EMail: yanzhiwei@cnnic.cn Jong-Hyouk Lee Sangmyung University 31, Sangmyeongdae-gil, Dongnam-gu Cheonan Republic of Korea EMail: jonghyouk@smu.ac.kr Xiaodong Lee CNNIC No.4 South 4th Street, Zhongguancun Beijing 100190 China EMail: xl@cnnic.cn Yan, et al. Expires January 6, 2016 [Page 7]