Network Working Group G. Wolfner Internet-Draft J. Korhonen, Ed. Intended status: Informational Nokia Siemens Networks Expires: April 7, 2010 October 4, 2009 Connection Identifier for Proxy Mobile IPv6 draft-wolfner-netext-pmip6-connid-01.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 7, 2010. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract This document describes a Connection Identifier mobility option for Proxy Mobile IPv6. The new mobility option can be used to uniquely identify multiple mobility sessions to the same selected service, for Wolfner & Korhonen Expires April 7, 2010 [Page 1] Internet-Draft Connection Identifier for PMIPv6 October 2009 example, in the Evolved Packet System scope. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Proxy Mobile IPv6 Domain Assumptions . . . . . . . . . . . . . 4 4. Connection Identifier Mobility Option . . . . . . . . . . . . . 4 5. Extensions to Conceptual Data Structures and Lookups . . . . . 5 5.1. Binding Cache . . . . . . . . . . . . . . . . . . . . . . . 5 5.2. Binding Update List . . . . . . . . . . . . . . . . . . . . 5 5.3. Lookup Keys . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Processing Considerations . . . . . . . . . . . . . . . . . . . 6 6.1. Capability Exchange . . . . . . . . . . . . . . . . . . . . 6 6.2. Mobile Access Gateway Considerations . . . . . . . . . . . 6 6.3. Local Mobility Anchor Considerations . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 10.1. Normative References . . . . . . . . . . . . . . . . . . . 7 10.2. Informative References . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Wolfner & Korhonen Expires April 7, 2010 [Page 2] Internet-Draft Connection Identifier for PMIPv6 October 2009 1. Introduction A Mobile Node (MN) may have several mobility sessions via a single interface with the same Local Mobility Anchor (LMA). An example where a MN may have several mobility sessions with the same LMA is the 3GPP environment using Enhanced Packet Core (EPC) [3GPP.23.401] [3GPP.23.402]. In the 3GPP environment these mobility sessions are called PDN connections (PDN stands for the Packet Data Network), and PDN connections to the same service defined by an Access Point Name (APN) use the same LMA instance. In 3GPP access networks these PDN connections of a single MN can be identified by a unique identifier called EPS bearer identifier (EPS stands for the Evolved Packet System). Moreover, 3GPP EPC system can be used with access networks that are not defined by the 3GPP such as CDMA or WLANs. These access networks are generally referred as non-3GPP accesses. Therefore, an unique identification of mobility sessions of a MN with the same LMA is also needed with those non-3GPP access networks. It has been identified that base Proxy Mobile IPv6 (PMIPv6) [RFC5213] parameters and existing IETF standardized mobility options are not enough in the EPC scope. Generally in PMIPv6 and especially in the EPC, different APNs are identified using the Service Selection mobility option [RFC5149]. However, in a case of multiple PDN connections to the same APN, and assuming that Home Network Prefixes (HNP) are not always available in a Mobile Access Gateway (MAG) after a handover and that the "APN name" in the Service Selection mobility option cannot be decorated (i.e. making each APN unique), there is a need for a new identifier to uniquely identify PDN connections to the same APN. Note that an optional GRE key option defined in [I-D.ietf-netlmm-grekey-option] as such does not help to differentiate the mobility sessions. The reason for this is that only the downlink GRE key is included in the Proxy Binding Update (PBU) messages, and the downlink GRE key option is local to MAG. Therefore, the preservation of the same downlink GRE key values during inter-MAG handovers cannot be guaranteed. This document describes a new Connection Identifier (CID) mobility option for PMIPv6. The Connection Identifier mobility option enables that a MN can have several mobility sessions via a single interface with the same LMA by carrying an unique connection identifier. This allows the MAG and the LMA to uniquely identify mobility sessions of a MN. The combination of MN-Identifier + Service Selection + Connection Identifier can uniquely identify mobility sessions even if the selected service on each mobility session for the same MN- Identifier are the same. Furthermore, if Service Selection [RFC5149] is not used or supported, the Connection Identifier functionality can still be used to manage multiple HNPs individually on a single interface. Effectively that means a combination of MN-Identifier + Wolfner & Korhonen Expires April 7, 2010 [Page 3] Internet-Draft Connection Identifier for PMIPv6 October 2009 Connection Identifier can uniquely identify mobility sessions of a MN. This allows a MN to configure additional HNPs to an interface that is already assigned with a HNP. How the Connection Identifier is created and learnt by the MAG, is out of the scope of this document. The identifier is required to be available in a MAG already when a PBU is to be sent and guaranteed to preserve its value when a MN handoffs from a MAG to another. The MAG may learn this identifier for example from "lower layers" or external control signaling during the PDN connection setup. The identifier could even be an uplink GRE key if that is readily available in a MAG when a PBU gets sent. After a successful creation of a mobility session, and an allocation of the Connection Identifier, both the MAG and LMA MUST include the Connection Identifier in all subsequent PMIPv6 signaling messages related to that mobility session. 2. Requirements 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]. 3. Proxy Mobile IPv6 Domain Assumptions The functionality described in this specification is supported only when multiple mobility sessions to the same selected service are anchored to a single LMA. Also the multiple mobility sessions to the same selected service that the MN is using go via the same MAG. 4. Connection Identifier Mobility Option At most one Connection Identifier mobility option MAY be included in any PBU message sent by the MAG. The LMA MUST echo the received Connection Identifier back in a Proxy Binding Acknowledgement (PBA) message, assuming the LMA understands the Connection Identifier mobility option in the first place. The echoed Connection Identifier mobility option MUST be an unchanged copy of the Connection Identifier mobility option received in the corresponding PBU message. The Connection Identifier mobility option has the alignment requirement of 4n+2 and the following format: Wolfner & Korhonen Expires April 7, 2010 [Page 4] Internet-Draft Connection Identifier for PMIPv6 October 2009 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Option Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Connection Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Connection Identifier Mobility Option Option Type 8-bit identifier set to TBD1. Option Length 8-bit unsigned integer, representing the length in octets of the mobility option, not including the Option Type and Option Length fields. Connection Identifier A 32-bit identifier value. The value is in network order. 5. Extensions to Conceptual Data Structures and Lookups 5.1. Binding Cache Each Binding Cache Entry (BCE) MUST be extended with a Connection Identifier parameter. This concerns only LMAs that implement the Connection Identifier mobility option and the associated functionality. 5.2. Binding Update List Each Binding Update List Entry (BULE) MUST be extended with a Connection Identifier parameter. This concerns only MAGs that implement the Connection Identifier mobility option and the associated functionality. 5.3. Lookup Keys Both BCE and BULE MAY be queried using the Connection Identifier mobility option value as one additional lookup key. The lookup key combination: Wolfner & Korhonen Expires April 7, 2010 [Page 5] Internet-Draft Connection Identifier for PMIPv6 October 2009 MN-Identifier + Service Selection + Connection Identifier MUST uniquely identify a single BCE or a BULE. In a case Service Selection [RFC5149] is not used at all or supported by a MAG-LMA pair, then the lookup key combination: MN-Identifier + Connection Identifier MUST uniquely identify a single BCE or a BULE. 6. Processing Considerations 6.1. Capability Exchange The Connection Identifier mobility option in the PBU is also an indication to a LMA that the MAG supports multiple mobility sessions to the same selected service (identified by the Service Selection mobility option). Similarly, the Connection Identifier mobility option in the PBA is an indication to the MAG that the LMA supports the multiple mobility sessions to the same selected service. Using this simple mechanism the MAG and the LMA can dynamically find out whether both support the multiple mobility sessions to the same selected service functionality. 6.2. Mobile Access Gateway Considerations If the multiple mobility session to the same selected service functionality is enabled and mutually supported by the MAG and the LMA, then the MAG MUST include the Connection Identifier mobility option in all PBUs. How the MAG maps connections originated from the MN to connection identifiers is out of scope of this specification. The mapping of mobility sessions and connection identifiers MUST remain the lifetime of the mobility session. How the MAG knows/learns the connection identifiers after a handover between MAGs is out of scope of this specification. However, mechanisms such as context transfer between MAGs may be used. 6.3. Local Mobility Anchor Considerations If the multiple mobility session to the same selected service functionality is enabled and mutually supported by the MAG and the LMA, then the LMA MUST echo the Connection Identifier mobility option in all PBAs that it received in the corresponding PBUs. In a case the LMA does not support the Connection Identifier mobility Wolfner & Korhonen Expires April 7, 2010 [Page 6] Internet-Draft Connection Identifier for PMIPv6 October 2009 option, the LMA MUST silently ignore the option and process the remaining of the PBU as defined in [RFC5213] and [RFC5149]. It is implementation specific which BCE for a given MN-Identifier is returned when e.g. the BC lookup using the MN-Identifier and the Service Selection option as the lookup key match multiple BCEs. 7. Security Considerations The protection for the Connection Identifier mobility option depends on the services that are being connected to. If the Connection Identifier information should not be revealed on the wire, Proxy Binding Updates and Proxy Binding Acknowledgements should use Encapsulating Security Payload (ESP) [RFC4303] in transport mode with a non-null encryption transform to provide message confidentiality. 8. IANA Considerations A new mobility option for the use with PMIPv6 is defined in the [RFC3775] "Mobility Options" registry. The mobility options are defined in Section 4: Connection Identifier mobility option is set to TBD1 9. Acknowledgements The authors thank Basavaraj Patil and Xiangsong Cui for their comments and discussion on this document. 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. Wolfner & Korhonen Expires April 7, 2010 [Page 7] Internet-Draft Connection Identifier for PMIPv6 October 2009 10.2. Informative References [3GPP.23.401] 3GPP, "General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access", 3GPP TS 23.401 8.6.0, June 2009. [3GPP.23.402] 3GPP, "Architecture enhancements for non-3GPP accesses", 3GPP TS 23.402 8.6.0, June 2009. [I-D.ietf-netlmm-grekey-option] Muhanna, A., Khalil, M., Gundavelli, S., and K. Leung, "GRE Key Option for Proxy Mobile IPv6", draft-ietf-netlmm-grekey-option-09 (work in progress), May 2009. [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", RFC 4303, December 2005. [RFC5149] Korhonen, J., Nilsson, U., and V. Devarapalli, "Service Selection for Mobile IPv6", RFC 5149, February 2008. Authors' Addresses Gyorgy Wolfner Nokia Siemens Networks Email: gyorgy.wolfner@nsn.com Jouni Korhonen (editor) Nokia Siemens Networks Linnoitustie 6 FIN-02600 Espoo FINLAND Email: jouni.nospam@gmail.com Wolfner & Korhonen Expires April 7, 2010 [Page 8]