One document matched: draft-wu-netext-local-ro-00.txt


Network Working Group                                             Q.Wu 
                                                            B.Sarikaya 
Internet Draft                                     Huawei Technologies 
Intended status: Standard Track                          March 4, 2009 
Expires: September 2009 
                                   
 
                                      
             Proxy MIP extension for local routing optimization 
                   draft-wu-netext-local-ro-00.txt 


Status of this Memo 

   This Internet-Draft is submitted to IETF in full conformance with the 
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Copyright Notice 

   Copyright (c) 2009 IETF Trust and the persons identified as the 
   document authors. All rights reserved. 
 
 
 
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   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. 

Abstract 

   Proxy Mobile IPv6 allows the Mobility Access Gateway (MAG) to 
   optimize the media delivery by locally routing the packets within one 
   MAG, However it does not support optimization of the media delivery 
   by locally routing the packets between MAGs sharing the same LMA. 
   This document specifies extensions for Proxy MIP to support local 
   routing optimization through the interaction between the MAG and the 
   LMA.  

Table of Contents 

    
   1. Introduction.................................................3 
   2. Conventions used in this document............................3 
   3. Scenarios for local routing optimization.....................4 
      3.1. Intra-MAG local routing.................................4 
      3.2. Intra-LMA local routing.................................5 
   4. Local routing optimization protocol overview.................6 
      4.1. MAG initiated local routing optimization................6 
      4.2. LMA initiated local routing optimization................7 
   5. Conceptual Data Structure Extension..........................7 
      5.1. Binding Update List Extension...........................7 
   6. Local routing optimization message format....................8 
      6.1. Routing optimization mobility option....................8 
      6.2. Routing optimization Request message....................9 
      6.3. Routing optimization Response Message..................10 
   7. Process consideration.......................................12 
      7.1. Mobile Access Gateway Consideration....................12 
      7.2. Local Mobility Anchor Consideration....................14 
   8. IPv4 support................................................14 
   9. Security Considerations.....................................15 
   10. IANA Considerations........................................15 
   11. References.................................................15 
      11.1. Normative References..................................15 
      11.2. Informative References................................16 
    



 
 
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1. Introduction 

   Proxy Mobile IPv6 [RFC5213] can allow the Mobility Access Gateway 
   (MAG) to optimize the media delivery by locally routing the packets 
   within one MAG and by not reverse tunneling them to the mobile node's 
   local mobility anchor (LMA). However it does not address the case of 
   routing optimization between two MAGs sharing the same LMA. The 
   capability for local routing optimization provided in [RFC5213] 
   requires the MAG to support the EnableMAGLocalRouting flag and allow 
   the MAG to control local routing optimization behavior. However, 
   [RFC5213] does not define how local routing optimization capability 
   is detected, who initiates local routing optimization and how to 
   negotiate between the MAG and the LMA to determine whether the local 
   routing optimization is allowed.  

    

   This document describes a routing optimization mobility option for 
   proxy mobile ipv6 that is intended to assist the MAG to make specific 
   choice for local routing optimization with LMA involvement. The new 
   mobility routing optimization option may be used between the LMA and 
   the MAG to enable local forwarding with LMA involvement, in each 
   initial binding update that makes a new registration to the LMA, or 
   in other local forwarding control messages (e.g., as defined in 
   [I-D.localFwd]). As [RFC5213] warns, use of local routing may affect 
   accounting and traffic policies relating to the mobile node, home 
   agent routing policies, and security policies. The general aim of the 
   proposals in this document is to provide better manageability of  
   mobility services and mobility service provisioning from the point of  
   view of both operators and service providers within one PMIPv6 domain. 

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  

   The document uses the terminology specified in [RFC5213] and in 
   [RFC3775]. In addition, this document defines the following: 

   Local routing: Traffic between MN and CN does not pass through LMA 
   and is locally routed. 

   Routing Optimization Request (RORQ) A message initiated by the MAG or 
   LMA requesting the MAG to establish local routing optimization for a 
   pair of MNs who communicate with each other. 

 
 
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   Routing Optimization Response (RORP) A reply message from the MAG or 
   LMA to confirm local routing optimization results. 

3. Scenarios for local routing optimization 

   In this section, we introduce two scenarios that illustrate how the 
   route optimization technique can be applied to PMIPv6 and discuss 
   these techniques in details. 

3.1. Intra-MAG local routing 

                         +----------+ 
                         |          | 
                         |  LMA     | 
                         |          | 
                         +----------+ 
                              | 
                              | 
                         /----------\ 
                     /////          \\\\\ 
                    |      BACKBONE      | 
                    |       Network      | 
                     \\\\            //// 
                     /   \----------/   \ 
                    /                    \ 
              +----/--+               +---\----+ 
              |       |               |        | 
              | MAG1  |               |  MAG2  | 
              +------ +               +------- + 
               /     \ 
             /        \ 
           /           \ 
       +--/---+        +\-----+ 
       |      |        |      | 
       |  MN  |        |  CN  | 
       +------+        +------+ 
       Figure 1: Intra MAG Local Routing Scenario 
   Figure 1 shows intra-MAG local routing within a PMIPv6 domain, the 
   case dealt with in [RFC5213]. It is assumed that MN movement is 
   intra-MAG, and that the MN and CN belong to the same PMIPv6 domain. 
   Routing between the MN and CN in the absence of optimization requires 
   tunneling to the LMA and back again. Routing optimization establishes 
   a more direct path between the MN and CN via the MAG, thus reducing 
   the end-to-end delay in delivery of media.  

    

 
 
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3.2. Intra-LMA local routing 

                    +-----------+ 
                    |           | 
                    |   LMA     | 
                    |           | 
                    +-----------+ 
                          | 
                     -----|----- 
                  ///           \\\ 
                //                 \\ 
                |                   | 
               |      BACKBONE      | 
                |      Network      | 
                /\                 \/ 
               /  \\\           /// \ 
              /      -----------     \ 
             /                        \ 
            /                          \ 
     +-----------+                    +---------+ 
     |           |                    |         | 
     |    MAG1   |                    |MAG2     | 
     |           |                    |         | 
     +-----------+                    +---------+ 
     +--\--+                          +---/---+ 
     |     |                          |       | 
     | MN  |                          | CN    | 
     +-----+                          +-------+ 
      Figure 2: Intra LMA Local Routing Scenario 
   Figure 2 shows intra-LMA local routing within a PMIPv6 domain. If 
   movement of the MN is intra-MAG, previously-established routing 
   optimization is unaffected, so this scenario assumes that: 

   o the MN moves between MAGs sharing the same LMA, 

   o the CN is attached to a MAG also served by that LMA,  

   o and in its new position the MN is attached to a different MAG from 
   the CN.  

   As in the intra-MAG scenario, unoptimized routing involves tunneling 
   to the LMA and back again. There is an opportunity for routing 
   optimization in this scenario, too, by establishing a tunnel directly 
   between the two MAGs. [RFC5213] does not deal with this case. 

    

 
 
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4. Local routing optimization protocol overview 

   The protocol specified here assumes that the MAG and the LMA are 
   situated in one PMIP domain. The MAG has the capability to perceive 
   intra-MAG local routing (i.e., in the intra-MAG local routing 
   scenario, the MAG can detect whether the mobile node and 
   correspondent node attach to the same MAG by checking binding update 
   list). The LMA has the capability to perceive intra-LMA local routing 
   (i.e., in the intra-LMA local routing scenario, the LMA can detect 
   whether the MAGs to which MN and CN are attach belong to the same LMA 
   by checking its binding cache list). The flag 
   EnableDetectLocalRouting on the MAG and LMA may be used to control 
   this behavior. The decision to enable/disable detection of local 
   routing should be based on the policy configured on the MAG or LMA. 
   The specific details on how this is achieved are beyond of the scope 
   of this document. Subsequently there are two modes in which the local 
   routing optimization protocol operates. 

    

4.1. MAG initiated local routing optimization 

   When the MAG perceives intra-MAG local routing, it can initiate local 
   routing optimization to determine the value of the localMAGrouting 
   (defined in section 5) flag by message exchange between the MAG and 
   LMA. When the MAG can not perceive intra-MAG local routing but want 
   to check whether intra-LMA routing is allowed, it also can initiate 
   the local routing optimization. The message may be an initial binding 
   update message which contains the routing optimization mobility 
   option and home network prefix option for the correspondent node or a 
   newly defined routing optimization message. It will be used to 
   negotiate with LMA to determine whether or not the local routing 
   optimization between the mobile node and correspondent node is 
   supported. If the LMA does not allow the MAG bypass traffic from 
   itself, it will respond to the MAG that the local routing 
   optimization is not available. Otherwise it will set the 
   localMAGrouting flag on the MAG into value one by sending successful 
   response message.  

   After successful local routing optimization process, the MAG1 which 
   the MN is associated with may send PBU message to the MAG2 which the 
   CN is associated with. This PBU message sets the lifetime of the 
   binding of MN at MAG2. Similarly the MAG2 sends PBU message to the 
   MAG1. This PBU message sets the lifetime of the binding of CN at MAG1. 
   Each PBU MUST be acknowledged with PBAs.  PBU-PBA exchange is 
   repeated to extend the lifetime of the binding. 

 
 
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   For the data traffic, either of the MAGs can lookup local routing 
   flag and process traffic in terms of the value of LocalMAGrouting 
   flag. If the LocalMAGrouting flag is set to value one, the traffic 
   from MN will go directly to CN via MAG. If the localLMArouting flag 
   is set to value one, the traffic from MN will be forwarded directly 
   to the MAG associated with the CN. 

   In case of handover, registration entry for MN in MAG1's Binding 
   update list should be transferred to the new MAG.  The new MAG sends 
   PBUs to each MAG MN was in communication with route optimization 
   established.  This PBU- PBA exchange reestablishes optimal route path 
   between MN and its CNs. 

4.2. LMA initiated local routing optimization 

   When the LMA perceives intra-LMA local routing, it can initiate local 
   routing optimization to determine the value of localLMArouting flag 
   (defined in section 5) by message exchange between the MAG and LMA. 
   The message could be initial binding update message which contain 
   routing optimization mobility option or a newly defined routing 
   optimization message. It will be used to notify MAG to determine 
   whether or not the local routing optimization is supported. If the 
   LMA verifies there exists binding cache list of correspondent node 
   and mobile node and allow the MAG bypass traffic between mobile node 
   and correspondent node from itself, it will notify the MAG to set the 
   LocalLMArouting flag into value one, otherwise, it will respond to 
   MAG with failure information which indicate the intra-LMA routing 
   optimization is not supported. 

    

5. Conceptual Data Structure Extension 

5.1. Binding Update List Extension 

   Every mobile access gateway maintains a Binding Update List. Each 
   Entry in the Binding Update List represents a mobile node's mobility 
   binding with its local mobility anchor, as described in Section 6.1 
   of the PMIPv6 specification [RFC5213]. This specification extends the 
   Binding Update List Entry data structure with the following 
   additional fields: 

       LocalMAGRouting Flag indicating whether the media delivery 
   optimization is allowed by locally routing the packets within one MAG. 
   The flag is set to value 1 for local media delivery optimization is 
   allowed and vice versa. 

 
 
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       LocalLMARouting Flag indicating whether the media delivery 
   optimization is allowed by locally routing the packets from one MAG 
   to another within one LMA. The flag is set to value 1 for local media 
   delivery optimization is allowed and vice versa. 

       Home network prefix assigned to Correspondent Node 

       Proxy Care-of Address assigned to Correspondent Node 

6. Local routing optimization message format 

6.1. Routing optimization mobility option 

    
    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 = TBD   |   Length      |    Reserved               |ROI~ 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
                   Figure 3  Routing Optimization Mobility Option 
   Type TBD 

   Length 

   8-bit unsigned integer indicating the length of the option in octets, 
   excluding the type and length fields. This field MUST be set to 2. 

   Reserved (R) 

   This 8-bit field is unused for now. The value MUST be initialized to 
   0 by the sender and MUST be ignored by the receiver. 

   Routing Optimization Indication (ROI) 

   0: Reserved 

   1: The value of LocalMAGRouting  

   2: The value of LocalLMARouting 

   3: Routing optimization state is unknown or routing optimization is 
   not available. 




 
 
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6.2. Routing optimization Request message 

     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 
                                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
                                    |           Sequence #          | 
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    |R|ROI|  Reserved               |           Lifetime            | 
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    |                                                               | 
    .                                                               . 
    .                        Mobility options                       . 
    .                                                               . 
    |                                                               | 
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
          Figure 4: Routing Optimization Request Message 
   Sequence Number: A monotonically increasing integer. Set by a sending 
   node in a request message, and used to match a reply to the request. 

   'R' flag: Set to 0, indicates it is an routing optimization request 
   message. 

   Routing Optimization Indication (ROI) 

   00: Reserved 

   01: The value of LocalMAGRouting  

   10: The value of LocalLMARouting 

   11: Routing optimization state is unknown or routing optimization is 
   not available. 

   Lifetime: The requested time in seconds for which the sender wishes 
   to have local routing. 










 
 
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6.3. Routing optimization Response Message 

     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 
                                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
                                    |           Sequence #          | 
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    |R|ROI|  Reserved               |           Lifetime            | 
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    |                                                               | 
    .                                                               . 
    .                        Mobility options                       . 
    .                                                               . 
    |                                                               | 
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
          Figure 5: Routing Optimization Response Message 
   Sequence Number: A monotonically increasing integer. Set by a sending 
   node in a request message, and used to match a reply to the request. 

   'R' flag: Set to 0, indicates it is an routing optimization request 
   message. Set to 1, indicates it is an routing optimization response 
   message. 

   Routing Optimization Indication (ROI) 

   00: Reserved 

   01: The value of LocalMAGRouting  

   10: The value of LocalLMARouting 

   11: Routing optimization state is unknown or routing optimization is 
   not available. 

   Lifetime: The requested time in seconds for which the sender wishes 
   to have local routing. 

   Mobility options: Routing optimization mobility option described in 
   section 6.1 and MN-CN pair mobility option described in section 6.4 
   can be included. 

6.4. MN and CN pair mobility option 

A new option, MN-CN pair mobility option is defined for use with the 
Route Optimization Request and Response messages exchanged between LMA 
 
 
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and MAGs. This option is used by the LMA to enable local routing for MN 
to CN path from the destination MAG that receives the request message 
towards CN connected a different MAG whose address is given in option.  
The option MUST be used in pairs, one for MN and one for CN. The order 
is important. The LMA places the data for MN to which the destination 
MAG is connected first. 

 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      |P| Reserved    |Prefix Length  | 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
|                                                               | 
+                                                               + 
|                                                               | 
+                  Home Network Prefix                          + 
|                                                               | 
+                                                               + 
|                                                               | 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
|                                                               | 
+                                                               + 
|                                                               | 
+                      Proxy CoA                                + 
|                                                               | 
+                                                               + 
|                                                               | 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
|                     IPv4   HoA                                | 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
|                   IPv4 Proxy CoA                              | 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
               Figure 6: MN-CA pair mobility option 
P Flag 

   P flag is set for IPv4 support.  When set IPv4 HoA and IPv4 Proxy CoA 
    fields must be included for MN or CN. 

Reserved 

   This 7-bit field is unused for now.  The value MUST be initialized to 
    0 by the sender and MUST be ignored by the receiver. 

Prefix Length 

   8-bit unsigned integer indicating the prefix length of the IPv6 
    prefix contained in the option. 

 
 
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Home Network Prefix 

   A sixteen-byte field containing the mobile or corresponding node's 
    IPv6 Home Network Prefix. 

Proxy CoA 

   A sixteen-byte field containing the global address configured on the 
    egress interface of the mobile access gateway to which the mobile or 
    corresponding node is connected. 

IPv4 HoA 

   Optional 32-bit field containing IPv4 home address of the mobile or 
    corresponding node. 

IPv4 Proxy CoA 

   Optional 32-bit field containing IPv4 address that is configured on 
    the egress-interface of the mobile access gateway. 

7. Process consideration 

7.1. Mobile Access Gateway Consideration 

   The MAG may include the routing optimization mobility option and the 
   correspondent node's home network prefix option into initial binding 
   update message or create a new routing optimization request message 
   in which the above two options are contained. The routing 
   optimization mobility option is used to negotiate which kind of local 
   routing optimization is available. The correspondent node's home 
   network prefix option is used for the LMA to verify the validity of 
   local routing optimization path end points (in the intra-MAG local 
   routing scenario) or to request the LMA to determine proxy CoA-
   Address of correspondent node for local routing optimization (in the 
   intra-LMA local routing scenario). In the intra-MAG local routing 
   case, ROI field in routing optimization mobility option is set into 
   value 1 while in the intra-LMA local routing case, ROI field in 
   routing optimization mobility option is set into value 0 for mobile 
   node's MAG does not know whether traffic between MN and CN can be 
   locally routed within one LMA. 

   If the MAG receives initial binding acknowledge message with routing 
   optimization mobility option or routing optimization response message, 
   it will extract the ROI field from the routing optimization mobility 
   option or routing optimization response message and check the value 
   of it. If ROI field is 0, it indicates the LMA does not support this 
 
 
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   local routing optimization and the MAG should set LocalMAGRouting 
   flag to value 0 in the binding update list extension; if ROI field is 
   1, it indicates the LMA allow local routing in one MAG and bypass the 
   LMA and MAG should set LocalMAGRouting flag to value 1 in the binding 
   update list extension, if ROI field is 2, it indicates LMA has find 
   correspondent node's MAG address in terms of home network prefix of 
   CN and MAG should extract correspondent node's MAG address from 
   initial binding acknowledge message or routing optimization response 
   message and store it in binding update list extension with 
   correspondent node's home network prefix.  

   Upon the LocalMAGrouting flag or LocalLMArouting flag setup at the 
   MAGs, one MAG may send the proxy binding update message to another 
   MAG to establish corresponding binding cache associated with the MN 
   and CN. Upon receiving Proxy Binding Update message, the MAG checks 
   if the EnableLMALocalRouting flag is set to one.  If the 
   EnableLMALocalRouting flag is not set to one, the MAG MUST reject the 
   request and send a Proxy Binding Acknowledgement message with the 
   status field set to 129 (administratively prohibited). 

    Upon accepting Proxy Binding Update request, the MAG MUST create a 
    Binding Cache entry. The Source address of Proxy Binding Update is 
    copied to Proxy CoA field of the binding cache entry. The Mobile 
    node data (MN- Identifier, link-layer identifier, link-local address, 
    home network prefixes, etc.) are copied from the corresponding 
    fields of the proxy binding update. 

   Upon accepting Proxy Binding Update request for the first time from 
   another MAG, the MAG MUST establish a bi-directional tunnel between 
   the two MAGs.  The tunnel endpoints are the Proxy-CoA of this mobile 
   access gateway and the Proxy-CoA of the mobile access gateway that 
   sent Proxy Binding Update as can be obtained from the source address 
   of Proxy Binding Update.  This tunnel should be deleted when there 
   are no mobile nodes sharing it or when mobile access gateway receives 
   RORQ message from local mobility anchor with lifetime set to zero. 

   When using IPv4 transport, the endpoints of the bi-directional tunnel 
   are IPv4-Proxy-CoA of the mobile access gateway that sent Proxy 
   Binding Update as can be obtained from the source address of Proxy 
   Binding Update and IPv4-Proxy-CoA of this mobile access gateway with 
   the encapsulation mode as specified in [I-D.ietf-netlmm-pmip6-ipv4-
   support]. 

   For the data traffic between the MN and CN, on receiving a packet 
   from a mobile node connected to its access link, to a destination 
   that is directly connected or not directly connected, the MAG will 
   lookup local routing flag and process traffic in terms of 
 
 
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   LocalMAGrouting flag or LocalMAGrouting flag. If the 
   EnableLMALocalRouting flag is set to one and the destination address 
   matches one of the home network prefixes in the binding cache, the 
   packet must be forwarded to the Proxy CoA field in the binding cache 
   entry as a tunneled packet. For the packet from a mobile node 
   connected to its access link,to a destination that is also directly 
   connected to the same access link, if the EnableMAGLocalrouting flag 
   is set to one, the packet must go directly via the MAG. 

7.2. Local Mobility Anchor Consideration 

   For the case where the MAG initiates local routing, upon receiving 
   initial binding update message or routing optimization request 
   message, the LMA will check ROI field in the routing optimization 
   mobility option or routing optimization message. If ROI field is 1, 
   the LMA will check whether there exists binding cache list for CN and 
   whether MN's proxy CoA address is same as CN's proxy CoA address. If 
   ROI field is 0 and correspondent node's home network prefix included, 
   the LMA will check whether there exists binding cache list for CN in 
   terms of the correspondent node's home network prefix. If does, the 
   LMA will respond to the MAG with ROI field set to value 2.Otherwise, 
   the LMA will respond to the MAG with ROI field set to 0 in the 
   routing optimization mobility option to indicate the MAG that the 
   local routing optimization is not available. For the case where the 
   LMA initiates local routing, upon perceiving intra-LMA routing, the 
   LMA sends routing optimization request message with the ROI field set 
   to value 2. And then the LMA receives routing optimization reply 
   message from the corresponding MAG. 

8. IPv4 support 

    IPv4 support is needed in two cases: MN is IPv4 enabled and receives 
    IPv4 home address and the transport network between the LMA and the 
    MAG is an IPv4 network.  Local route optimization can be supported 
    if both IPv4 home address (IPv4-MN-HoA) and IPv4 Proxy Care-of 
    Address at the MAGs are global addresses. 

    Initially, both the MN and the CN configure IPv4 home addresses by 
    exchanging PBU/PBA as explained in [I-D.ietf-netlmm-pmip6-ipv4-
    support] with the LMA. 

    The LMA MUST include IPv4 IPv4-MN-HoA in routing optimization 
    request message for both MN and CN.  The LMA MAY include Home 
    Network Prefix in PBU if the MN or CN is assigned Home Network 
    Prefix. Both routing optimization request and routing optimization 
    response messages are IPv6 messages and are transported on LMA-MAG 
    tunnel as PBU and PBA are transported. 
 
 
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    The PBU and PBA exchanged between the MAGs are IPv6 messages and are 
    transported as unencapsulated IPv6 messages between MAGs. Data 
    messages between the MAGs after local routing is established are 
    transported in in IPv6 as IPv4 payload. 

    When IPv4 transport is used, RORQ, RORP, PBU and PBA messages are 
    transported as IPv6 messages using IPv4 or IPv4-UDP-ESP 
    encapsulation [I-D.ietf-netlmm-pmip6-ipv4-support]. IPv4-UDP and 
    IPv4-UDP-TLV modes are not used because no NAT boxes are supported 
    in local Routing Optimization protocol. 

    When IPv4 transport is used, IPv4 data packets are transported in an 
    IPv4 packet or encapsulated in IPv4-UDP-ESP encapsulation. 

9. Security Considerations 

   The protocol specified in this document can use the security 
   association between the LMA and the MAG to create security 
   association between MAGs to which MN and CN attach in the intra-LMA 
   local routing scenario. As regarding intra-MAG local routing scenario, 
   integrity protection can be considered and confidentiality using 
   IPsec is not necessary. 

10. IANA Considerations 

   This document has no actions for IANA. 

11. Acknowledgement 

The authors would like to thank Tom Taylor for his review and comments 
of this draft and all colleagues who have supported the advancement of 
this draft effort. 

12. References 

12.1. Normative References 

   [RFC3775] Johnson, D. and al. et, "Mobility Support in IPv6", RFC3775, 
             June 2004 

   [RFC5213] Gundavelli, S. and al. et, "Proxy Mobile IPv6", RFC5213, 
             May 2008. 

   [I-D.ietf-netlmm-pmip6-ipv4-support] 
             Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy 
             Mobile IPv6", draft-ietf-netlmm-pmip6-ipv4-support-09 
             (work in progress), January 2009. 

 
 
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12.2. Informative References 

   [I-D.LocalFwd] 
            Koodli,R., Chowdhury,K. "Local Forwarding in Proxy 
            Mobile IPv6", draft-koodli-netlmm-local-forwarding-00, 
            July 2008 










































 
 
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Authors' Addresses 

   Qin Wu 
   Huawei Technologies Co.,Ltd 
   Site B,Floor 12F,Huihong Mansion,No.91,Baixia Rd. 
   Nanjing 210001 
   China 
      
   Email: Sunseawq@huawei.com 
    

   Behcet Sarikaya 
   Huawei Technologies Co.,Ltd 
   1700 Alma Dr.Suite 500 
   Plano, TX 75075 
   USA 
      
   Email: sarikaya@ieee.org 




























 
 
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