Network Working Group J. Korhonen Internet-Draft Nokia Siemens Networks Intended status: Standards Track March 3, 2009 Expires: September 4, 2009 Redirect Option for Proxy Mobile IPv6 draft-korhonen-netext-redirect-00.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 September 4, 2009. 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 Redirect mobility option and redirect functionality for Proxy Mobile IPv6. The redirection takes place during a Proxy Binding Update and Acknowledgement messages exchange. Korhonen Expires September 4, 2009 [Page 1] Internet-Draft Redirect Option for Proxy Mobile IPv6 March 2009 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements and Terminology . . . . . . . . . . . . . . . . . 3 2.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Redirect Mobility Option . . . . . . . . . . . . . . . . . . . 4 4. Proxy Mobile IPv6 Domain Considerations . . . . . . . . . . . . 5 5. Processing Considerations . . . . . . . . . . . . . . . . . . . 5 5.1. Mobile Access Gateway Considerations . . . . . . . . . . . 6 5.2. Local Mobility Anchor Considerations . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 9. Normative References . . . . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 Korhonen Expires September 4, 2009 [Page 2] Internet-Draft Redirect Option for Proxy Mobile IPv6 March 2009 1. Introduction This document describes a Redirect mobility option and redirect functionality for Proxy Mobile IPv6 (PMIPv6). The redirection takes place during a Proxy Binding Update (PBU) and a Proxy Binding Acknowledgement (PBA) messages exchange between a Mobile Access Gateway (MAG) and a Local Mobility Anchor (LMA). The redirection functionality defined in this document may be used, for example, for load balancing purposes or for administrative and mobility services subscription provisioning reasons. The redirection functionality described in this document does not depend on information provisioned to external entities, such as the Domain Name System (DNS) or the Authentication, Authorization and Accounting (AAA) infrastructure. The redirection is only applicable between MAGs and LMAs that have an existing Security Association (SA) set up. The trust relationship and coordination management between LMAs within a PMIPv6 Domain is deployment specific and not described in this document. 2. Requirements and Terminology 2.1. 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]. 2.2. Terminology In addition to the terminology defined in RFC 5213 [RFC5213], the following terminology is also used: rfLMA The LMA which receives the PBU from a MAG and decides to redirect the IP mobility session, and forwards the PBU to the target LMA (r2LMA). r2LMA The LMA to which a MAG was redirected to. During the redirection, the PBA is already sent to the MAG from this LMA. Korhonen Expires September 4, 2009 [Page 3] Internet-Draft Redirect Option for Proxy Mobile IPv6 March 2009 3. Redirect Mobility Option The Redirect mobility option allows a LMA to inform a MAG of a redirection to a new LMA during any PBU/PBA exchange. The redirection functionality can be used, for example, for load balancing purposes or for administrative and mobility services subscription provisioning reasons. After the redirection, the MAG MUST send subsequent PBUs and user traffic to the redirected LMA address for the mobility session that the redirection concerned. A PBU message MAY contain the Redirect mobility option as an indication to a LMA that a MAG supports the redirection functionality. In the PBU, the LMA Address included in the Redirect mobility option MUST be set to an unspecified address (0::0 for IPv6 and 0.0.0.0 for IPv4). The LMA MAY include the Redirection mobility option in a PBA only if the MAG indicated support for the redirection functionality and the mobility session was redirected from the LMA to another. The Redirect mobility option in the PBA MUST contain the IPv6 address (unicast or anycast) of the rfLMA and MAY contain the IPv4 address of the rfLMA. The PBA containing the Redirect mobility option MUST be sent from the r2LMA. After receiving the PBA containing the Redirect mobility option from the r2LMA, the MAG MUST send subsequent PBUs and user traffic to the r2LMA that concern the redirected mobility session. The redirection functionality negotiation during the PBU/PBA exchange is stateless. The LMA MUST NOT include the Redirect mobility option in the PBA and perform the redirection, unless the MAG indicated the redirection functionality support in the corresponding PBU. The LMA MUST NOT include the Redirect mobility option unsolicited even if the MAG had earlier indicated support for the redirection functionality. The MAG MUST NOT conclude LMA's redirection functionality support based on the absence of the Redirect mobility option in the PBA. The Redirect mobility option has the alignment requirement of 4n+2. There can zero or one Redirect mobility option in the PBU or in the PBA. The format of the Redirect mobility option is shown below: Korhonen Expires September 4, 2009 [Page 4] Internet-Draft Redirect Option for Proxy Mobile IPv6 March 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IPv6 LMA Address | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optional IPv4 LMA Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Redirect Mobility Option o Option Type: 8-bit identifier set to TBD1. o Option Length: 8-bit unsigned integer, representing the length of the Redirect mobility option in octets, excluding the Option Type and Length fields. If the IPv4 LMA Address is included in the option, the Option Length MUST be set to 20. Otherwise, the Option Length MUST be set to 16. o IPv6 LMA Address: the IPv6 address of the rfLMA or an unspecified IPv6 address (i.e., 0::0). o Optional IPv4 LMA Address: the IPv4 address of the rfLMA or an unspecified IPv4 address (i.e., 0.0.0.0). 4. Proxy Mobile IPv6 Domain Considerations The redirection solution defined in this document is only possible between MAGs and LMAs that have an existing SA set up. It is the responsibility of the rfLMA that receives a PBU from a MAG to redirect the MAG to a such r2LMA whom the MAG already has a SA set up with. Furthermore, the rfLMA and the r2LMA MUST have a prior agreement and an established trust relationship to perform the redirection. How a LMA learns and knows of other LMAs where the mobility session can be redirected, is not covered by this document. Dynamic negotiation of the SA during the redirection process is not either covered by this document. 5. Processing Considerations Korhonen Expires September 4, 2009 [Page 5] Internet-Draft Redirect Option for Proxy Mobile IPv6 March 2009 5.1. Mobile Access Gateway Considerations If a MAG supports the redirection functionality defined in this document, then the MAG MAY include the Redirect mobility option in any PBU as an indication to a LMA that it supports the redirection functionality. The Redirect mobility option MAY be included in the initial PBU sent to the LMA or in any binding refreshing PBU. When the MAG includes the Redirect mobility option in the PBU, the IPv6 LMA Address in the option MUST be set to unspecified address (i.e., 0::0). If the MAG has IPv4 support enabled and the MAG supports switching from IPv6 transport to IPv4 transport, the MAG SHOULD also include an unspecified IPv4 address (i.e., 0.0.0.0) in the Redirect mobility option. If the MAG receives a PBA that contains the Redirect mobility option from a LMA without first including the Redirect mobility option in the corresponding PBU, the MAG MUST treat the PBA as if the binding update failed and log the event. If the MAG receives a PBA that contains the Redirect mobility option and the MAG had included the Redirect mobility option in the corresponding PBU, then the MAG MUST perform the following steps in addition to the normal RFC 5213 PBA processing: o Check if the Redirect mobility option contains the IP address of the LMA to whom the MAG originally sent the PBU (i.e. the rfLMA). If the check fails, then the MAG MUST treat the PBA as if the binding update failed and log the event. o Update the Binding Update List to correspond to the LMA Address where the newly received PBA came from. If the redirection was successful, the MAG MUST send subsequent PBUs and user traffic to the new r2LMA Address for the mobility session that the redirection concerned. The redirection concerns always one mobility session at time. If the MAG includes the Redirect mobility option in subsequent PBUs, the LMA MAY redirect the MAG again. 5.2. Local Mobility Anchor Considerations If a LMA does not support the redirection functionality and the Redirect mobility option defined in this document, then the LMA MUST ignore the option received in PBUs. If the LMA supports the redirection functionality and the received PBU contains the Redirect mobility option, then the LMA MAY redirect the MAG to a new LMA. In the case of redirection, the r2LMA MUST always include the IPv6 address (unicast or anycast) of the rfLMA in the Redirect mobility option in the PBA. If the rfLMA had IPv4 support enabled, then the Korhonen Expires September 4, 2009 [Page 6] Internet-Draft Redirect Option for Proxy Mobile IPv6 March 2009 r2LMA MUST include the IPv4 address of the rfLMA in the Redirect mobility option. If the redirection takes place during an established mobility session, then the rfLMA MUST clean up and remove the mobility session after redirecting the MAG to the new LMA. The LMA MUST NOT redirect the MAG to a new LMA that it knows the MAG does not have a SA with. The LMA MUST NOT redirect the MAG to a LMA that the LMA does not have a prior redirection agreement and an established trust relationship to perform the redirection. These SA related knowledge issues and trust relationships are deployment specific in a PMIPv6 Domain. If the redirection were to involve context transfer and other coordination management between LMAs, that is again deployment specific for LMAs and in a PMIPv6 Domain. The LMA MUST NOT redirect a MAG using IPv6 transport to a new LMA using IPv4 transport, if the MAG does not indicate support for IPv4 in the Redirect mobility option, as there is no guarantee that the MAG supports switching from IPv6 transport to IPv4 transport. 6. Security Considerations The security considerations of PMIPv6 signaling described in RFC 5213 [RFC5213] apply to this document. An incorrectly configured LMA may cause unwanted redirection attempts to non-existing LMAs or to other LMAs that do not have and will not have a SA with the redirected MAG. At the same time, a falsely redirected MAG will experience failed binding updates or creation of mobility sessions. An incorrectly configured LMA may also cause biased load distribution within a PMIPv6 Domain. This document also assumes that the LMAs that participate to redirection have adequate prior agreement and trust relationship between each other. 7. IANA Considerations A new mobility option for the use with PMIPv6 is defined in the RFC 3775 [RFC3775] "Mobility Options" registry. The mobility option is defined in Section 3: Redirect Mobility Option is set to TBD1 Korhonen Expires September 4, 2009 [Page 7] Internet-Draft Redirect Option for Proxy Mobile IPv6 March 2009 8. Acknowledgements The author would like to thank Basavaraj Patil and Domagoj Premec for their reviews and comments. 9. 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. Author's Address Jouni Korhonen Nokia Siemens Networks Linnoitustie 6 FI-02600 Espoo FINLAND Email: jouni.nospam@gmail.com Korhonen Expires September 4, 2009 [Page 8]