NETEXT Working Group CJ. Bernardos Internet-Draft M. Calderon Intended status: Informational UC3M Expires: September 13, 2012 I. Soto UPM March 12, 2012 PMIPv6 and Network Mobility Problem Statement draft-bernardos-netext-pmipv6-nemo-ps-02 Abstract The NETLMM WG standardized Proxy Mobile IPv6 (PMIPv6). PMIPv6 enables mobile devices to connect to a PMIPv6 domain and roam across gateways without changing the IP address. Current PMIPv6 specification does only support the movement of hosts within the localized mobility domain. A mobile network (commonly referred to as a NEMO, NEtwork that MOves) can also benefit from the network-based localized mobility support provided by PMIPv6 [I-D.ietf-netext-pd-pmip], but with some limitations. This I-D describes what can be done with current standardized protocols, and describes the problem statement of fully supporting network mobility in 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 September 13, 2012. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. Bernardos, et al. Expires September 13, 2012 [Page 1] Internet-Draft PMIPv6 & NEMO PS 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 and Motivation . . . . . . . . . . . . . . . . . . 3 2. Conventions and Terminology . . . . . . . . . . . . . . . . . . 4 3. PMIPv6 and Network Mobility Problem Statement . . . . . . . . 4 3.1. Applicability of existing standards . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References . . . . . . . . . . . . . . . . . . . 7 7.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Bernardos, et al. Expires September 13, 2012 [Page 2] Internet-Draft PMIPv6 & NEMO PS March 2012 1. Introduction and Motivation Proxy Mobile IPv6 (PMIPv6), specified in [RFC5213], provides network- based mobility management to hosts connecting to a PMIPv6 domain. PMIPv6 introduces two new functional entities, the Local Mobility Anchor (LMA) and the Mobility Access Gateway (MAG). The MAG is the first layer three hop detecting Mobile Node (MN) attachment and providing IP connectivity. The LMA is the entity assigning one or more Home Network Prefixes (HNPs) to the MN and is the topological anchor for all traffic from/to the MN. The network-based localized mobility support provided by PMIPv6 was designed for hosts, so a mobile host can freely roam within the PMIPv6 domain, without changing its IP address. An interesting scenario -- which is not supported by current standards (as we will explain later in this document) -- is the following: let's consider a scenario in which users move around a large area (e.g., an airport, an exhibition site, a fairground or even a metropolitan area covered by different public transportation systems). In these areas, attachment points to the Internet might be available both in fixed locations (such as coffee shops, airport terminals or train stations) or in mobile platforms, such as vehicles (e.g., buses that move between pavilions at a fair or a train that moves from one terminal to another at an airport). Users demand the ability to keep their ongoing communications while changing their point of attachment to the network as they move around (e.g., when a user leaves a coffee shop and gets on a bus). While PMIPv6 [RFC5213] is the solution specified to provide network- based localized mobility support (which nicely fits the requirements related to providing Internet access in a large area, such as in the use cases described above), and the NEMO Basic Support Protocol [RFC3963] is the solution to provide transparent network mobility support to a set of nodes moving together (which nicely fits the requirements related to providing Internet access to users in mobile platforms, such in the use cases described above), these two solutions cannot fully cope -- neither working standalone nor in a combined fashion -- with the kind of use case introduced above. We need therefore a solution -- which may be for example based on extending NEMO mechanisms, extending PMIPv6 or both -- to address this scenario. We next explain with a bit more detail the problem statement of combining PMIPv6 with network mobility support and explain why current IETF standards are not able to fully tackle this problem. Bernardos, et al. Expires September 13, 2012 [Page 3] Internet-Draft PMIPv6 & NEMO PS March 2012 2. Conventions and Terminology Readers are expected to be familiar with all the terms defined in [RFC5213], [RFC3753] and [RFC4885]. In addition, the following terms are used in the context of this problem statement: MR/MAG We use this term to refer to the router providing connectivity to a set of nodes moving together. We do not use the term Mobile Router (MR) to avoid confusion with its well accepted meaning in the context of the NEMO Basic Support protocol (i.e. we do not assume nor prevent the MR/MAG to implement the MR functionality specified in [RFC3963]). Analogously, since the nodes attached to the MR/MAG are expected to obtain network-based localized mobility support, it might be tempting to refer to this entity as a MAG, but an RFC 5213-compliant MAG cannot move (i.e. change its point of attachment within the PMIPv6 domain). Network Mobility Within the scope of this document, we refer to network mobility as the capacity of a set of nodes -- attached to an MR/MAG -- to move together _within_ the PMIPv6 domain (similarly as done in [I-D.ietf-netext-pd-pmip]). We do not consider the case of mobile networks that may roam across PMIPv6 domains (i.e. global mobility). Although this scenario might be also interesting, current PMIPv6 does not support inter-domain mobility, thus we limit the scope of the problem statement to the same of PMIPv6. 3. PMIPv6 and Network Mobility Problem Statement Figure 1 shows an example of the use case scenario described in Section 1. Let's consider a very simple PMIPv6 domain composed of one LMA and two MAGs: MAG 1 and MAG 2. There are three MNs: MN 1, MN 2 and MN 3. Additionally, there is also an MR/MAG: MER/MAG 1. The goal is to enable any MN to freely roam within the PMIPv6 domain, without changing its IP address -- and without requiring any mobility support nor involvement from the MN -- even if the MN moves between the mobile network and the fixed access network (i.e. the MN changes its point of attachment from the MR/MAG 1 to the MAG 1 or MAG 2). Bernardos, et al. Expires September 13, 2012 [Page 4] Internet-Draft PMIPv6 & NEMO PS March 2012 +-----+ | LMA | +-----+ // \\ +---------//---\\-------------+ ( // \\ ) PMIPv6 domain ( // \\ ) +------//---------\\----------+ // \\ // \\ +-------+ +-------+ | MAG 1 | | MAG 2 | +-------+ +-------+ | | (( o )) (( o )) . .. . .. . .. . .. . .. . .. . : mobile network : . ( o ) . ( o ) : | : | . | ---------- . ------ | : --|MR/MAG 1|-- : |MN 1|-- . ---------- | . ------ : | : . << v >> . : : . Y Y . : ------ | | ------ : . |MN 2|-- --|MN 3| . : ------ ------ : . .. . .. . .. . .. . .. . .. . Figure 1: PMIPv6 and network mobility scenario 3.1. Applicability of existing standards This section briefly analyzes how the use of current standards fails to fully support the scenario described in this problem statement: 1. PMIPv6 only. By using PMIPv6 only, a single host (i.e. an MN) would be able to freely roam between fixed points of attachment (MAG 1 and MAG 2 in Figure 1). By enabling bridging on an MR/MAG attaching to a fixed MAG, some very limited kind of network mobility support could be achieved (if the Per-MN-Prefix model [RFC5213] is used). [I-D.ietf-netext-pd-pmip] specifies extensions to Proxy Mobile IPv6 to support network mobility. However, none of these approaches do support a mobile node leaving the mobile network and attaching to another MAG (or MR/ Bernardos, et al. Expires September 13, 2012 [Page 5] Internet-Draft PMIPv6 & NEMO PS March 2012 MAG) without changing IP address of the mobile node. 2. NEMO Basic Support (NEMO B.S.) only. In this case, MAG 1 and MAG 2 in the example of Figure 1 would only play the role of plain IPv6 Access Routers. If NEMO B.S is enabled on the MR/MAG (and a Home Agent is deployed in the network), a set of nodes would be able to freely roam within the domain . However, an MN would not be able to move between the mobile network and the fixed access network (because the addresses that nodes may use while connected to the MR/MAG would belong to the Mobile Network Prefix -- MNP -- of the network, which is different from the prefixes provided by the LMA within the PMIPv6 domain). Additionally, this scenario requires the deployment of a NEMO B.S. Home Agent (for example at the location where the LMA is placed in Figure 1) and involves the NEMO B.S. signaling every time the MR/MAG moves. 3. NEMO B.S. + PMIPv6: by enabling NEMO B.S. on the MR/MAG and deploying PMIPv6 in the domain, we would achieve the same level of functionality as the previous case, but saving the NEMO signaling required every time the MR/MAG moves, since its Care-of Address (CoA) would not change while it is roaming within the domain (the address the MR/MAG uses as CoA is anchored at the LMA and does not change despite of the MR/MAG movements, thanks to the PMIPv6 support). In this scenario, NEMO B.S. HA and the PMIPv6 LMA could be collocated. The previous compilation of potential approaches does not consider the use of Mobile IPv6 [RFC6275] on the MNs, since this would not meet the fundamental feature of network-based localized mobility solutions (such as PMIPv6): not to involve the MN on the signaling nor on the management of its own mobility. As shown, with existing standards, there is no way of achieving the level of functionality required in our scenario. It is therefore required to work on new solutions/extensions to existing protocols (either to the NEMO B.S., to PMIPv6 or to both when working in a combined way). 4. IANA Considerations This document makes no request of IANA. 5. Security Considerations Security considerations regarding the MR/MAG would be needed. It might be safe to assume that the MR/MAG has the same level of trust/ Bernardos, et al. Expires September 13, 2012 [Page 6] Internet-Draft PMIPv6 & NEMO PS March 2012 security that the MAGs of the network, but this may depend on the particular solution. 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). The research of Carlos J. Bernardos and Maria Calderon has also been partially supported by the Ministry of Science and Innovation of Spain under the QUARTET project (TIN2009-13992-C02-01). 7. References 7.1. Normative References [I-D.ietf-netext-pd-pmip] Zhou, X., Korhonen, J., Williams, C., Gundavelli, S., and C. Bernardos, "Prefix Delegation for Proxy Mobile IPv6", draft-ietf-netext-pd-pmip-02 (work in progress), March 2012. [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. 7.2. Informative References [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC 3753, June 2004. [RFC4885] Ernst, T. and H-Y. Lach, "Network Mobility Support Terminology", RFC 4885, July 2007. Bernardos, et al. Expires September 13, 2012 [Page 7] Internet-Draft PMIPv6 & NEMO PS March 2012 Authors' Addresses 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/ Maria Calderon Universidad Carlos III de Madrid Av. Universidad, 30 Leganes, Madrid 28911 Spain Phone: +34 91624 8780 Email: maria@it.uc3m.es Ignacio Soto Universidad Politecnica de Madrid Email: isoto@dit.upm.es Bernardos, et al. Expires September 13, 2012 [Page 8]