Network Working Group D.Liu Internet Draft China Mobile Intended status: Standards Track J.SONG Expires: January 5, 2012 W.LUO ZTE July 3, 2011 PMIP Based Distributed Mobility Management Approach draft-liu-dmm-pmip-based-approach-00.txt 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), 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." 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Abstract Distributed mobility management (DMM) approach is needed, because the mobile networks are moving towards flat architectures. This document defines a PMIPv6 based distributed mobility management protocol. Liu, et. al Expires January 4, 2012 [Page 1] Internet-Draft Requirements of DMM July 2011 Table of Contents 1. Introduction ................................................... 2 2. Conventions used in this document .............................. 3 3. Overview of PMIP Based Distributed Mobility Management Approach .3 3.1. Basic Data Deliver Approaches ............................. 3 3.2. Handoff Approaches ........................................ 4 3.3. Local Mobility Anchor Locating Considerations ............. 6 4. Mobile Access Gateway Operation ................................ 6 4.1. Extensions to Binding Update List Entry Data Structure .... 6 4.2. Extended Operations for Mobile Access Gateway ............. 7 4.2.1. Receiving traffic generated by attached mobile node .. 7 4.2.2. Receiving traffic designated to attached mobile node . 7 5. Local Mobility Anchor Operation ................................ 8 5.1. Extensions to Binding Cache Entry Data Structure .......... 8 5.2. Extended Operations of Local Mobility Anchor .............. 8 6. Security Considerations ........................................ 8 7. IANA Considerations ............................................ 8 8. References ..................................................... 8 8.1. Normative References ...................................... 8 8.2. Informative References .................................... 8 1. Introduction As the mobile networks are moving towards flat architectures, the distributed mobility management (DMM) approaches are needed to relieve many disadvantages of using centralized mobility management in a flatten network described in [DMM-PS]. Both mobile access gateway and local mobility anchor specified in this draft are fully compatible with [RFC5213] only with limited extensions to enable PMIP based distributed mobility management approaches. The mobile access gateway specified in this draft is extended to support determining of IP address of correspondent node's mobile access gateway when receiving traffic from its attached mobile node to enable a optimized routing between two communicating parties. Meanwhile, the local mobility anchor specified in this draft is extended to support the query of IP address of mobile node's mobile access gateway according to mobile node's IP address. Furthermore, this draft also considers the approaches in handoff scenario to guarantee the session continuity. Liu, et. al Expires January 4, 2012 [Page 2] Internet-Draft Requirements of DMM July 2011 2. 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 RFC-2119 [RFC2119]. 3. Overview of PMIP Based Distributed Mobility Management Approach PMIP based Distributed Mobility Management approach does not change basic PMIP architecture defined in [RFC5213], only with limited extension to both mobile access gateway and local mobility anchor to support distributed approaches. 3.1. Basic Data Deliver Approaches +-----+ +------+ +-----+ +------+ +-----+ | MN1 | | MAG1 | | LMA | | MAG2 | | MN2 | +-----+ +------+ +-----+ +------+ +-----+ | | | | | | 1.attach and PMIP Reg. | 1.attach and PMIP Reg. | |<------------|----------->|<------------|------------>| | | | | | |2.uplink Data| | | | |============>| 3. PBQR | | | | |----------->| | | | | 4. PBQA | | | | |<-----------| | | | +----------------+ | | | | | 5.Recording PB | | | | | | of the MN2 | | | | | +----------------+ | | | | | 6.uplink data | | | |=========================>| | | | | |7.uplink data| | | | |============>| | | 8. Ongoing traffic | | |<===========>|<========================>|<===========>| | | | | | Figure1. Basic Data Delivery Approaches Figure1 shows basic data delivery approaches of PMIP based Distributed Mobility Management approaches specified in this draft. Liu, et. al Expires January 4, 2012 [Page 3] Internet-Draft Requirements of DMM July 2011 In this section, assuming both communication peers are mobile nodes denoted as MN1 and MN2 respectively. In the beginning, when mobile nodes enter Proxy Mobile IPv6 domain and attach to the access link, and if determines that the mobile nodes are authorized for network-based mobility service, the network performs standard PMIP approaches according to [RFC5213], i.e. PBU and PBA transaction, for both MN1 and MN2 to provide home prefixes for them respectively. When MN1 tries to establish a session with MN2, it sends IP packets denoted as uplink traffic to MN2, and the traffic will first arrive at MN1's mobile access gateway (MAG1). According to PMIP protocol specified in [RFC5213], MAG1 will forward the traffic to MN1's local mobility anchor (LMA) via a bi-directional tunnel between the two. In additional, as specified in this draft, MAG1 needs to determine how to forward the traffic in a optimized way to enable distributed approaches by querying LMA the IP address of the mobile access gateway to which the MN2 attaches currently (i.e. MAG2) according to the MN2's IP address which is the destination IP address of the traffic. For achieving this, MAG1 sends a PMIP Binding Query Request (PBQR) message to related LMA who holds the Binding Cache Entry (BCE) for MN2. Based on the IP address (i.e. HoA) of MN2, the LMA could derive IP address of MAG2 in corresponding BCE. Then the LMA sends a PMIP Binding Query Answer (PBQA) message with the IP address as a response to MAG1. Upon receiving the PBQA, MAG1 will record PMIP Binding information of MN2 including MN2's IP address (HoA) and MAG2's IP address (CoA) locally and set up its endpoint of a tunnel (e.g. IP in IP tunnel) to MAG2 and forward all follow-up traffic to MAG2 via the tunnel directly to bypass the LMA. When receiving encapsulated packet contains the traffic from MN1 in the tunnel, MAG2 will decapsulate the packet and forward the traffic to MN2 in access link. Note that, the date deliver approaches described above is only an specific example. 3.2. Handoff Approaches +---+ +----+ +----+ +---+ +----+ +---+ |MN1| |MAG1| |MAG3| |LMA| |MAG2| |MN2| +---+ +----+ +----+ +---+ +----+ +---+ Liu, et. al Expires January 4, 2012 [Page 4] Internet-Draft Requirements of DMM July 2011 | | | | | | | | 1. Ongoing traffic | | |<==========>|<==================================>|<==========>| | | | | | | | | 2.attach and PMIP Reg. | | | |<----------------------->|<--------->| | | | | | 3. Uplink traffic | | |========================>|======================>|===========>| | | | 4. Downlink Traffic | | | |<===================================|<===========| | |===========>| | | | |<========================| | | | | | | 5. PBCI | | | | |----------------------------------->| | | | | 6. PBCA | | | | |<-----------------------------------| | | | 7. Ongoing Downlink Traffic | | |<========================|<======================|<===========| | | | | | Figure 2. Handoff Approaches Figure 2 shows the signaling call flow for the MN1's handoff from the previously attached mobile access gateway (MAG1) to the newly attached mobile access gateway (MAG3). Before the HO, MN1 may have already established a session with its correspondent node (MN2). During the handoff, the network performs PMIP specified procedures for MN1 to maintain its HoA unchanged. The MAG3 on the new access link, upon detecting the MN1 on its access link, assigns a new CoA for MN1 and send PBU message to LMA for updating binding state. The LMA responses MAG3 with a PBA message in sequence according to [RFC5213]. If MN1 has active session with MN2 before the handoff, the downlink traffic from MN2 to MN1 may still be forwarded to MAG1 by MAG2 in the tunnel between the two. MAG1 may send a PMIP Binding Change Inform (PBCI) message to MAG2 with IP address of target mobile access gateway (MAG3) to update the IP address of MN1's mobile access gateway stored in MAG2 locally in order to prevent MAG2 from forwarding upcoming traffic to MAG1 but to MAG3 directly. Note that, the handoff approaches described above is only an specific example. Liu, et. al Expires January 4, 2012 [Page 5] Internet-Draft Requirements of DMM July 2011 3.3. Local Mobility Anchor Locating Considerations According to [RFC5213], only the local mobility anchor which is involved in PMIP registration for MN2 holds the MN2's Binding Cache Entry. MAG1 should determine to which local mobility anchor it should send a PBQR message. Every local mobility anchor is configured to hold one or more IPv6 prefix pools. In case MAG1 is aware of this IPv6 prefix pool configuration, e.g. from management plane, it could determine the corresponding local mobility anchor to which it should send the PBRQ message, according to the IP address of MN2. 4. Mobile Access Gateway Operation The mobile access gateway specified in this draft is fully compatible with the mobile access gateway defined in [RFC5213] only with limited additional functions. To support these additional functions, four new messages named PMIP Binding Query Request (PBQR), PMIP Binding Query Answer (PBQA), PMIP Binding Change Inform (PBCI) and PIMP Binding Change Acknowledgement(PBCA) for mobile access gateway are defined in this draft as extensions to [RFC5213]. 4.1. Extensions to Binding Update List Entry Data Structure As specified in section 6.1 of [RFC5213], every mobile access gateway MUST maintain a Binding Update List, and each entry in the Binding Update List represents a mobile node's mobility binding with its local mobility anchor. In this draft, the concept Binding Update List entry data structure needs to be extends with one additional field as following: * CN-Location, the IP address of the mobile access gateway to which the correspondent node attaches currently together with IP address of this correspondent node. This field enables the mobile access gateway to determine the location of correspondent node locally according to its IP address. Generally, one Binding Update List entry may have multiple CN-location fields depends on how many correspondent node the mobile node has. Liu, et. al Expires January 4, 2012 [Page 6] Internet-Draft Requirements of DMM July 2011 4.2. Extended Operations for Mobile Access Gateway 4.2.1. Receiving traffic generated by attached mobile node According to [RFC5213], whenever a mobile access gateway intercepts traffic generated by its attached mobile node which is a traffic sender, it shall check the corresponding Binding Update List entry to determine the local mobility anchor to which it should forward the traffic for that mobile node. As extensions in this draft, the mobile access gateway should also check CN-Location field in the corresponding Binding Update List entry locally to determine the IP address of correspondent node's mobile access gateway by using destination IP address of the traffic as input parameter. If this information cannot be determined locally, the mobile access gateway should query a corresponding LMA by sending a PBQR message with IP address of the correspondent node. When the mobile access gateway gets the IP address of the correspondent node's mobile access gateway in a PBQA message from the local mobility anchor, it should record the information into the CN- Location field of the corresponding Binding Update List entry for the mobile node. After the IP address of the correspondent node's mobile access gateway is determined, the mobile access gateway should set up a tunnel by using this IP address as endpoint and forward any follow-up traffic generated by the mobile node via the tunnel to the correspondent node's mobile access gateway directly. When the mobile access gateway receives a PBCI message with IP address of correspondent node's mobile access gateway, it should update the CN-Location filed of corresponding Binding Update List entry. 4.2.2. Receiving traffic designated to attached mobile node Whenever a mobile access gateway receives traffic designated to its attached mobile node which is the traffic receiver in a tunnel from correspondent node's mobile access gateway, the mobile access gateway should decapsulate the tunneled packet and send the traffic to the designated mobile node. In handoff scenario, mobile access gateway who plays the role of source mobile access gateway may inform IP address of the target mobile access gateway to the correspond mobile node's mobile access gateway by sending a PBCI message. Liu, et. al Expires January 4, 2012 [Page 7] Internet-Draft Requirements of DMM July 2011 5. Local Mobility Anchor Operation The local mobility anchor specified in this draft is fully compatible with the local mobility anchor defined in [RFC5213] only with limited additional functions. The only extension is the local mobility anchor defined in this draft supports the query for IP address of a mobile node's mobile access gateway based on this mobile node's IP address (HoA). To support these additional function, two new messages named PMIP Binding Query Request (PBQR) and PMIP Binding Query Answer (PBQA) for the local mobility anchor are defined in this draft as extensions to [RFC5213]. 5.1. Extensions to Binding Cache Entry Data Structure No extension to binding cache entry data structure for the local mobility anchor is needed in this draft. 5.2. Extended Operations of Local Mobility Anchor Extended operations of local mobility anchor are defined in this section as extensions to [RFC5213]. In case the local mobility anchor accepts a PBQR message from a mobile access gateway, it should locate the binding cache entry of mobile node which is identified by this mobile node's IP address carried in the PBQR message to acquire the IP address of this mobile node's mobile access gateway. 6. Security Considerations None. 7. IANA Considerations TBD 8. References 8.1. Normative References 8.2. Informative References [I-D. DMM-PS] Liu, et. al Expires January 4, 2012 [Page 8] Internet-Draft Requirements of DMM July 2011 Authors' Addresses Dapeng Liu China Mobile Unit2, 28 Xuanwumenxi Ave,Xuanwu District Beijing 100053 China Email: liudapeng@chinamobile.com Jun Song ZTE No.68,Zijinghua Road, Yuhuatai District Nanjing 210012 China Email: song.jun@zte.com.cn Wen Luo ZTE No.68,Zijinghua Road, Yuhuatai District Nanjing 210012 China Email: luo.wen@zte.com.cn Liu, et. al Expires January 4, 2012 [Page 9]