Network Working Group A. Muhanna Internet-Draft Nortel Intended status: Standards Track V. Devarapalli Expires: December 27, 2009 WiChorus S. Gundavelli Cisco Systems June 25, 2009 Mobility Session Suspend Support in PMIPv6 draft-muhanna-netext-mobility-session-suspend-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 December 27, 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. Muhanna, et al. Expires December 27, 2009 [Page 1] Internet-Draft Mobility Session Suspend in PMIPv6 June 2009 Abstract This specification defines a new extension to Proxy Mobile IPv6 for suspending a mobility session by using a new Mobility Session Suspend option. This option is used by the mobile access gateway in the Proxy Binding Update to request the local mobility anchor to suspend a specific mobile node mobility session. When the local mobility anchor successfully processes the Proxy Binding Update, the local mobility anchor suspends the delivery of the downlink traffic to the specified mobile node mobility session. The mobile access gateway sends another Proxy Binding Update with the mobility session suspend option and the suspend flag cleared to indicate to the local mobility anchor to resume sending the downlink traffic for the mobile node mobility session. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions & Terminology . . . . . . . . . . . . . . . . . . . 4 2.1. Conventions used in this document . . . . . . . . . . . . . 4 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Mobile Access Gateway Considerations . . . . . . . . . . . . . 4 3.1. Extensions to the Conceptual Data Structure . . . . . . . . 4 3.2. Operational Summary . . . . . . . . . . . . . . . . . . . . 4 4. Local Mobility Anchor Considerations . . . . . . . . . . . . . 5 4.1. Extensions to the Binding Cache Entry . . . . . . . . . . . 5 4.2. Operational Summary . . . . . . . . . . . . . . . . . . . . 5 5. Message Formats . . . . . . . . . . . . . . . . . . . . . . . . 6 5.1. Mobility Session Suspend Option . . . . . . . . . . . . . . 6 5.2. Status Codes . . . . . . . . . . . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 9. Normative References . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Muhanna, et al. Expires December 27, 2009 [Page 2] Internet-Draft Mobility Session Suspend in PMIPv6 June 2009 1. Introduction In some planned deployments of Proxy Mobile IPv6 (PMIPv6), the mobile node at times has to attach to a legacy network that supports circuit switched calls to be able to initiate and receive voice calls. This is because of a limitation in the access network that uses PMIPv6, where there is no support for circuit switched sessions and voice over IP is not available yet. When this happens, it is preferable to put the PMIPv6 mobility session on suspend instead of deleting the mobility session and having to set it up again. Therefore, an extension to the PMIPv6 protocol is needed to enable the suspend and resume of a mobility session. When the mobile node falls back to a legacy circuit switched network, the mobile access gateway receives an indication to suspend a particular mobility session, i.e., suspend sending downlink traffic to the mobile node. The indication to suspend the session is out of scope and not defined in this document. When the suspend indication is received, the mobile access gateway sends a Proxy Binding Update message to the local mobility anchor with the Mobility Session Suspend option, and with the Suspend flag set. See Section 5.1. When the local mobility anchor receives and successfully processes the Proxy Binding Update with the Mobility Session Suspend option, it sets a suspend flag in the binding cache entry (BCE) that corresponds to the mobility session. In addition, the local mobility anchor updates the mobile node routing entry to suspend forwarding the downlink traffic to the mobile node through the IP-in-IP tunnel pointing to the mobile node proxy Care-of-Address and instead starts dropping all downlink traffic. Then the local mobility anchor sends a successful Proxy Binding Acknowledgement with the Mobility Session Suspend option included with the S-flag set. It is very useful when the mobile node leaves the legacy network and comes back to the PMIPv6 access network to directly resume sending data traffic without service interruption. In other words, it is useful for the MAG and the LMA, when the PMIPv6 mobility session is suspended, to allow uplink traffic from the mobile node. This is useful to prevent any loss of uplink packets when the mobile node attaches to the PMIPv6 access network again. After the mobile node resumes its data session by sending uplink data traffic and the mobile access gateway receives an indication to resume the mobile node mobility session, the mobile access gateway sends a new Proxy Binding Update message with the Mobility Session Suspend option included and the S-flag cleared. When the local mobility anchor receives and successfully processes the Proxy Binding Update with the Mobility Session Suspend option with the S-flag Muhanna, et al. Expires December 27, 2009 [Page 3] Internet-Draft Mobility Session Suspend in PMIPv6 June 2009 cleared, the local mobility anchor validates that the suspend/resume flag in the mobile node BCE is set and if set, the local mobility anchor clears this flag and updates the mobile node routing entry to resume sending downlink traffic for this specific mobility session. The mobile access gateway and the local mobility anchor uses the same rules in [RFC5213] to identify the mobile node mobility session by including the proper mobility options. 2. Conventions & Terminology 2.1. Conventions used in this document 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 All the general mobility related terminology and abbreviations are to be interpreted as defined in Mobile IPv6 [RFC3775] and Proxy Mobile IPv6 [RFC5213] specifications. 3. Mobile Access Gateway Considerations 3.1. Extensions to the Conceptual Data Structure Every mobile access gateway maintains a Binding Update List (BUL) entry for each currently attached mobile node, as explained in Section 6.1 of the Proxy Mobile IPv6 specification [RFC5213]. To support this specification, the conceptual Binding Update List entry data structure must be extended with the following additional field. o A flag indicating whether the mobility session is suspended. 3.2. Operational Summary o If the mobile access gateway determines that a mobility session of a mobile node requires to be suspended, it sends a Proxy Binding Update message with the the Mobility Session Suspend option with the S-flag set to the local mobility anchor. o If the mobile access gateway determines that a mobile node mobility session needs to be suspended, the mobile access gateway updates the mobile node routing entry to start dropping any downlink traffic that is destined to the mobile node. However, Muhanna, et al. Expires December 27, 2009 [Page 4] Internet-Draft Mobility Session Suspend in PMIPv6 June 2009 the mobile access gateway sets the suspend flag in the Binding Update List entry after it receives a successful Proxy Binding Acknowledgement message with the Mobility Session Suspend option included and the S-flag set from the local mobility anchor. o If the mobile access gateway receives an indication to resume the mobile node's mobility session, the mobile access gateway sends a new Proxy Binding Update message with the Mobility Session Suspend option included and the S-flag cleared. In this case, the mobile access gateway updates the mobile node routing entry and clears the suspend flag in the mobile node Binding Update List entry only after receiving a successful Proxy Binding Acknowledgement from the local mobility anchor with the Mobility Session Suspend option included and the S-flag cleared. o If the mobile access gateway sends a Proxy Binding Update with the Mobility Session Suspend option included with the S-flag set and in response it receives a successful Proxy Binding Acknowledgement with the status code set to "success" and the Mobility Session Suspend option is not included, the mobile access gateway MUST assume that the local mobility anchor does not support the mobility session suspend feature as defined in this specification. In this case, the mobile access gateway SHOULD NOT include the Mobility Session Suspend option in any future Proxy Binding Update message to this local mobility anchor. The mobile access gateway may log an event. 4. Local Mobility Anchor Considerations 4.1. Extensions to the Binding Cache Entry If the local mobility anchor supports mobility session suspend as per this specification, the local mobility anchor needs to maintain an indication in the mobile node BCE. This requires that the BCE described in section 5.1 of the Proxy Mobile IPv6 specification [RFC5213] to be extended. To support this specification, the BCE must be extended with the following additional field. o A flag indicating whether the mobility session is suspended. 4.2. Operational Summary If the local mobility anchor successfully processes a Proxy Binding Update message with the Mobility Session Suspend option, it must perform the following actions. Muhanna, et al. Expires December 27, 2009 [Page 5] Internet-Draft Mobility Session Suspend in PMIPv6 June 2009 o If the S-flag is set, the local mobility anchor MUST set the suspend flag in the corresponding binding cache entry and MUST update the mobile node routing entry to drop all downlink traffic that is destined to this mobile node mobility session. In addition, the local mobility anchor MUST respond with a successful Proxy Binding Acknowledgement with the Mobility Session Suspend option included with the S-flag set. o If the S-flag is cleared, the local mobility anchor validates that the suspend flag of the mobile node BCE is set and responds with a successful Proxy Binding Acknowledgement with the Mobility Session Suspend option included with the S-flag cleared. o If the S-flag is cleared and the mobile node BCE has the suspend flag already cleared, the local mobility anchor SHOULD respond with a successful Proxy Binding Acknowledgement with status code is set to . o After the local mobility anchor responds with a successful Proxy Binding Acknowledgement with the Mobility Session Suspend option included with the S-Flag cleared, the local mobility anchor MUST clear the suspend flag in the mobile node BCE and MUST update the mobile node routing entry to resume sending downlink traffic that is destined to the mobile node mobility session. 5. Message Formats 5.1. Mobility Session Suspend Option A new mobility option, the Mobility Session Suspend option, is defined for use in the Proxy Binding Update and Proxy Binding Acknowledgment messages exchanged between the mobile access gateway and the local mobility anchor. This option can be used for suspending the mobile node mobility session at the mobile access gateway and the local mobility anchor to ensure that the delivery of downlink traffic is suspended until the local mobility anchor receives another Proxy Binding Update with the Mobility Session Suspend option with the S-flag cleared. The Mobility Session Suspend option has no alignment requirement. Its format is as follows: Muhanna, et al. Expires December 27, 2009 [Page 6] Internet-Draft Mobility Session Suspend in PMIPv6 June 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length |S| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Mobility Session Suspend Option Type Length 8-bit unsigned integer indicating the length in octets of the option excluding the type and length fields. This field is always set to 2. S-Flag Indicates that the mobile node mobility session needs to be suspended, i.e., suspend sending the downlink traffic of the mobile node's mobility session. When this flag is cleared, it means the mobile node mobility session can be resumed. Reserved These fields are unused. They MUST be initialized to zero by the sender and MUST be ignored by the receiver. 5.2. Status Codes The following status code value is defined for use in the Binding Acknowledgment message when using Proxy Mobile IPv6. MOBILITY-SESSION-NEVER-SUSPENDED (TBD less than 128) When the local mobility anchor receives a Proxy Binding Update with the Mobility Session Suspend option with the S-Flag cleared and the mobile node BCE already has the S-flag cleared, the local mobility anchor uses this code to indicate to the mobile access gateway that the Proxy Binding Update has been processed successfully but the mobility session was not previously suspended. Muhanna, et al. Expires December 27, 2009 [Page 7] Internet-Draft Mobility Session Suspend in PMIPv6 June 2009 6. IANA Considerations This specification defines a new Mobility Option, the Mobility Session Suspend Option, described in Section 5.1. This option is carried in the Mobility Header. The type value for this option needs to be assigned from the same numbering space as allocated for the other mobility options defined in the Mobile IPv6 specification [RFC3775]. This specification defines a new Binding Acknowledgement status code as described in Section 5.2 and requests that this code be allocated with numeric value in the range specified in Section 5.2 from the "Status Codes" registry of the Mobility IPv6 Parameters located at http://www.iana.org/assignments/mobility-parameters. 7. Security Considerations This specification does not introduce any new security requirements on the top of those documented in Proxy Mobile IPv6 [RFC5213]. 8. Acknowledgements The authors would like to thank Michael Brown for the useful discussion on the need of mobility session suspend functionality. 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. Muhanna, et al. Expires December 27, 2009 [Page 8] Internet-Draft Mobility Session Suspend in PMIPv6 June 2009 Authors' Addresses Ahmad Muhanna Nortel 2221 Lakeside Blvd. Richardson, TX 75082 USA Email: amuhanna@nortel.com Vijay Devarapalli 3950 North First Street San Jose, CA 95134 USA Email: vijay@wichorus.com Sri Gundavelli Cisco Systems 170 West Tasman Drive San Jose, CA 95134 USA Email: sgundave@cisco.com Muhanna, et al. Expires December 27, 2009 [Page 9]