JP5666988B2 - Handover method in proxy mobile IPv6 - Google Patents

Description

  The present invention relates to a handover method for multihomed connection in proxy mobile IPv6 (PMIPv6), and in particular, when one of a plurality of mobile terminal interfaces that are multihomed to a PMIPv6 domain is disconnected from an access line, the interface is changed. The present invention relates to a handover method for transferring communication that has passed through to another interface and continuing communication.

  In conventional MIPv6 (Mobile IP improved for IPv6), where mobility management is performed on a host basis (client basis), mobile terminals (MNs) are required to implement mobile IP control functions, so WLAN (Wireless LAN) , WiMAX (Worldwide Interoperability for Microwave Access) or mobile phone network etc. could not be managed. As a new mobility management method that does not require a special function for the mobile terminal MN or its interface by performing mobility management on a network basis in response to such a technical problem, PMIPv6 (Proxy Mobile IPv6) has been proposed.

  FIG. 7 is a block diagram schematically illustrating a configuration in which a multi-home compatible MN having two different radio interfaces IF1 and IF2 is multi-homed to a PMIPv6 domain in a conventional PMIPv6 network.

  Within the PMIPv6 domain, MAG (Mobile Access Gateway) that tracks MN access links and manages mobility-related signaling for each interface, and LMA (Local Mobility) that functions as MN HA (Home Agent) Anchor) is arranged, and a PMIPv6 tunnel is established between LMA and MAG1 and MAG2.

  In such a configuration, when the MAG1 detects that the first interface IF1 of the MN is connected to the access link, the terminal identifier (MN-ID) unique to the MN and the interface identifier (IF1 unique to the first interface IF1) -A proxy binding update request (PBU) message in which (ID) is described is transmitted to the LMA. Similarly, when MAG2 detects that the second interface IF2 of the MN is connected to the access link, a description of an identifier (MN-ID) unique to the MN and an identifier (IF2-ID) unique to the second interface IF2 are described. The PBU message sent is sent to the LMA.

  The LMA determines the relationship between various parameters including the MN identifier (MN-ID) and the identifiers of each interface (IF1-ID, IF2-ID) and the MAG that can reach each interface by BCE (Binding Cache Entry ) To manage.

  FIG. 8 is a diagram showing an example of LMA BCE in multi-home connection, where “Home prefix” is an address that uniquely identifies each interface IF1, IF2, “CoA” is a care-of address of each MAG1, MAG2, and “ "MN-ID" is an identifier unique to each MN, "IF-ID" is an interface identifier unique to each interface IF1 and IF2, and "Tunnel-ID" is unique to each PMIPv6 tunnel established between LMA / MAG The identifier “Access Type” represents the type of each wireless connection. In the illustrated example, the first interface IF1 is WLAN, the second interface IF2 is WiMAX (registered trademark), and the MN is simultaneously connected to the PMIPv6 domain through two different paths.

RFC5213, "Proxy Mobile IPv6", http://tools.ietf.org/html/rfc5213

  In PMIPv6, when the MN has two different wireless interfaces, the connection can be seamlessly switched between these two interfaces by handoff. An MN cannot be connected by multiple wireless access at the same time in communication with its opposite node (CN: Corresponding Node), and when the connection by one wireless access is started, the connection by the other wireless access is disconnected . This is because the address of the MN used in the connection before switching the connection needs to be used continuously after switching.

  Normally, in the MN, when the destination address of the arrived data packet is different from the input interface address, the data packet is regarded as an invalid packet and discarded. Therefore, in order to continue communication by switching between two different interfaces, the same address must be switched between the interfaces.

  In multi-homed connection, communication between the MN and the CN can be used properly between the two interfaces IF1 / IF2 by setting different addresses for the radio interfaces IF1 and IF2 of the MN. Here, differently using the interfaces IF1 and IF2 is to distinguish between the connection on the IF1 side and the connection on the IF2 side as a transfer path for communication from the CN to the MN.

  In IP (IPv4 and IPv6) communication, since the router sets the forwarding route based on the destination address of the packet, in order for the MN to communicate with the CN through multiple routes, each of the MN's interfaces IF1, IF2 and these It is necessary to register MAG1 and MAG2 corresponding to the transfer destination in association with LMA as BCE.

  In order to set a different address for each radio interface of the multi-homed MN, the LMA assigns a unique home network prefix for each interface. The IPv6 address of each wireless interface is often generated by concatenating the home network prefix with the interface ID in EUI-64 (64-bit identifier defined by IEEE) format calculated from the MAC address of each interface. The

  Even if one wireless interface is disconnected, in order to continue communication on the connection (hereinafter referred to as a flow), it is necessary to set the disconnected IPv6 address to the other interface. To do so, the LMA recognizes the disconnection of one interface, assigns the home network prefix assigned to that interface to the other wireless interface, and the MN uses the interface ID of the disconnected interface in EUI-64 format. Generate IPv6 address. However, when this procedure is performed, the combination of the existing technologies has the following two problems.

  (1) Since a different MAC address is assigned to each wireless interface of the MN, the MN cannot assign an appropriate IPv6 address to each interface even in a handoff between two interfaces.

  (2) Allocation of home network prefix to each interface of MN by LMA is performed in response to a PBU (Proxy Binding Update) request at MAG opportunity. For this reason, after disconnecting one wireless interface, in order to notify the other wireless interface of the additional home network Prefix, it is necessary to wait for the PBU from the MAG that maintains the connection with the other wireless interface. . However, since it takes time until the PBU request by the MAG after the interface is disconnected, it takes time to restore communication between the MN and the CN. In some cases, the MN or the CN ends the communication.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and when one of a plurality of interfaces of a mobile terminal multihomed to a PMIPv6 domain is disconnected from an access line, the flow is quickly transferred to another interface. It is another object of the present invention to provide a handover method capable of continuing communication.

  In order to achieve the above-described object, the present invention is configured such that a multi-homed mobile terminal having a plurality of wireless interfaces is connected to an LMA in a proxy mobile IPv6 domain via a MAG connected to each interface. The handover method for continuing communication by accommodating the flow accommodated in the disconnected interface in another maintained interface is characterized in that the following procedure is provided.

  Procedure 1: Generate an interface identifier IF-ID common to each interface for each MN.

  Procedure 2: Each interface of the MN notifies the IF-ID and the terminal identifier MN-ID to each connected MAG.

  Procedure 3: Each MAG notifies the LBU of the PBU in which the IF-ID and MN-ID and its care-of address are described, and registers it in its Binding List.

  Step 4: In response to the PBU, the LMA allocates a home network prefix HNP to each interface and registers the association between each HNP and IF-ID in the BCE.

  Procedure 5: The LMA notifies the corresponding MAG of the PBA in which the HNP is described.

  Step 6: The MAG updates the Binding List in response to the PBA.

  Step 7: Establish an IPv6 tunnel between LMA and each MAG.

  Procedure 8: Each MAG notifies the MN of the notified HNP router.

  Step 9: The MN generates an IPv6 address for each interface from the combination of the notified HNP and the interface identifier IF-ID and assigns it to each interface.

  Step 10: MAGa that detects disconnection with one interface IFa notifies the LMA of the PBU in which one home network prefix HNPa assigned to the interface IFa is described.

  Step 11: In response to the PBU, the LMA notifies HMAGa and MN-ID to the other MAGb that maintains the connection with the other interface IFb and requests transfer of the flow.

  Procedure 12: In response to the transfer request, another MAGb adds HNPa to the Binding List.

  Step 13: In response to the transfer request, the other MAGb sends the notified HNPa router notification to the other interface IFb.

  Step 14: The MN assigns an IPv6 address generated by combining the notified HNPa and the interface identifier IF-ID to the other interface IFb.

  Step 15: The LMA relays the packet addressed to the HNPa to another MAGb based on the BCE.

  Procedure 16: Another MAGb relays the packet addressed to the HNPa to the other interface IFb based on the Binding List.

  By providing the above-described configurations, the following effects are achieved according to the present invention.

  (a) By including the procedures 1 and 9 in particular, the MN can assign an IPv6 address to each of its interfaces regardless of its MAC address, so the IPv6 address used on one interface is Switch to another interface and continue to use it. As a result, the problem (1) is solved, and the IPv6 address assigned to the interface IFa that is disconnected from one MAGa is reassigned to the interface IFb that is maintained connected to the other MAGb. Thus, the flow of the disconnected interface IFa can be aggregated into the maintained flow of the interface IFb.

  (b) In particular, by including the procedures 10, 11, 12, and 13, when MAGa detects disconnection with the interface IFa, this is immediately notified to the LMA. Then, the home network prefix HNP assigned to the interface IFa is immediately notified to the other interface IFb in which the connection is maintained, so the IPv6 address of the disconnected communication is changed to the other in which the connection is maintained. Can be set immediately to interface IFb. As a result, the problem (2) is solved, and quick handoff is realized even in multihome connection.

It is the sequence flow which showed the procedure of the multihome connection in the PMIPv6 network to which this invention is applied. It is the figure which showed the registration content in the multi-home connection procedure of BCE managed by LMA. It is the sequence flow which showed the procedure of the handoff in the PMIPv6 network to which this invention is applied. It is the figure which showed the registration content in the handoff procedure of BCE managed by LMA. It is the sequence flow which showed the procedure of the multihome reconnection in the PMIPv6 network to which this invention is applied. It is the figure which showed the registration content in the multi-home reconnection procedure of BCE managed by LMA. It is the block diagram which showed an example of the multihome connection in the conventional PMIPv6 network. It is the figure which showed the registration content of BCE managed by LMA in the conventional multihome connection.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a PMIPv6 network to which the present invention is applied. A multi-homed mobile terminal MN having two different wireless interfaces IF1 (WLAN) and IF2 (WiMAX) is connected to each PMIPv6 domain with each wireless interface IF1 and IF2. It is the sequence flow which showed the procedure until multihome connection.

  At time t1, the first interface IF1 of the MN requests connection to the PMIPbv6 domain, and when this is detected by the MAG1 of the access link and a wireless connection is established, the MN has a 64-bit random interface identifier (IF-ID). Are generated by random numbers. This IF-ID uses the identifier standardized by IETF RFC 3041 (randomly generated IPv6 alternative interface identifier) as the IPv6 address assigned to the first and second interfaces IF1 and IF2. It is generated in advance and notified to MAG1 together with a terminal identifier (MN-ID) unique to the MN. In this embodiment, a network access identifier (NAI) is used as the MN-ID.

  At time t2, a router solicitation Rtr Sol (Router Solicitation) is transmitted from the first interface IF1 to MAG1. At time t3, the MAG1 to LMA that received the Rtr Sol, the MN-ID and IF-ID notified from the MN, and the MAG1 care-of address MAG1.PCoA (Proxy-CoA) described PBU (Proxy Binding Update) message is sent. At the same time, in MAG1, the MN and its first interface IF1 are registered in the Binding List.

  In the LMA, in response to the PBU, a 64-bit first home network prefix (HNP1) is set as a home address (HA) to be assigned to the first interface IF1, and an IPv6 established with the MAG1 is established. The first tunnel identifier (T1-ID) is set, and BCE (Binding Cache Entry) is updated.

  FIG. 2 (a) shows the registration contents of the BCE at that time, and the HNP1 and T1 such as the MN-ID, IF-ID, MAG1.PCoA, and radio access type (WLAN) notified by the PBU. -An entry linked to the ID has been added. In the multihome field, “OFF” indicating that the entry has not yet configured multihome connection is registered.

  At time t4, a PBA (Proxy Binding Acknowledgment) message in which HNP1 is described is returned from LMA to MAG1. In MAG1, the HNP1 is additionally registered in the corresponding entry of the Binding List based on the received PBA, and tunnel setting is performed. At time t5, a bidirectional IPv6 first tunnel (T1-ID) is established between MAG1 and LMA.

  At time t6, a router advertisement (Rtr Adv: Router Advertisement) in which the HNP1 is described is returned from the MAG1 to the first interface IF1 of the MN. At time t7, the 64-bit HNP1 allocated from the LMA and the 64-bit IF-ID are combined in the MN to generate a 128-bit IPv6 first address (HNP1 + IF-ID), which is 1 assigned to interface IF1.

  Further, when the second interface IF2 of the multihomed MN is connected to MAG2 at time t8, the same procedure as described above is repeated, and Rtr Sol is transmitted from the second interface IF2 to MAG2 at time t9. At time t10, PBU is transmitted from MAG2 to LMA. At the same time, in MAG2, the MN and its second interface IF1 are registered in the Binding List. In response to this update request, the LMA selects the second home network Prefix (HNP2) to be assigned to the second interface IF2, and the IPv6 second tunnel ID (T2-T2) established with the MAG2. ID) is set and BCE (Binding Cache Entry) is updated.

  FIG. 2B shows the registered contents of the BCE at that time. Here, since the home network prefixes (HNP1 and HNP2) linked to the two entries having the same IF-ID are different from each other, it is recognized that the two entries constitute a multihome connection, The home field has been updated to "ON".

  At time t11, the PBA in which the HNP2 is described is returned from the LMA to the MAG2. In MAG2, based on the received PBA, HNP2 is additionally registered in the corresponding entry in the Binding List, and tunnel setting is performed. At time t12, a bidirectional IPv6 second tunnel (T2-ID) is established between MAG2 and LMA.

  At time t13, Rtr Adv describing HNP2 is returned from MAG2 to the second interface IF2. At time t14, in the MN, the HNP2 allocated from the LMA and the IF-ID are combined to generate a 128-bit IPv6 second address (HNP2 + IF-ID), which is allocated to the second interface IF2. .

  Next, referring to the sequence flow of FIG. 3, when one connection is disconnected during packet transfer from the partner terminal (CN) to the multihomed MN, the flow is accommodated in the other interface where the connection is maintained. A handoff procedure for continuing communication will be described.

  At time t21, a packet transmitted from CN to HNP1 is received by the LMA, and transferred to MAG1 via the IPv6 first tunnel (T1-ID) based on the information registered in the BCE. MAG1 specifies the MN linked to the HNP1 and its first interface IF1 in its Binding List, and transfers the received packet to the first interface IF1 of the MN.

  When the connection between the first interface IF1 of the MN and the access link is disconnected at time t22, and this is detected by MAG1 at time t23, the deregistration request DeREG PBU (De-Registration Proxy Binding) is sent from MAG1 to LMA at time t24. Update) message is sent. In response to the reception of the DeREG PBU, the LMA starts buffering the packet addressed to the HNP1 from time t25.

  At time t26, a mobile session transfer request (MSM: (Mobility Session Migration) message with “NAI” as the MN-ID and “HNP1” as the home network prefix is transmitted from the LMA to MAG2. At time t27, MAG2 The MSM Ack message is returned from the LMA to the LMA At time t28, in the MAG2 that has received the MSM, an entry that links the HNP1 assigned to the first interface IF1 and the second interface IF2 of the MN is displayed in the Binding List. Added.

  At time t29, a PBA (Proxy Binding Ack) message is returned from LMA to MAG1 in response to the DeREG PBU message. At time t30, the entry relating to the first interface IF1 is deleted from the Binding List in MAG1 that has received the PBA. At time t31, BCE is updated in LMA.

  FIG. 4 is a diagram showing the recorded contents of the BCE updated at time t31, while the entry linking the first home network Prefix (HNP1) and the first MAG care-of address (MAG1.PCoA) is deleted. An entry that links the first home network Prefix (HNP1) and the care-of address (MAG2.PCoA) of the second MAG is newly added, and the multihome mode is changed from “ON” to “OFF”.

  At time t32, the first home network Prefix (HNP1) and the second home network Prefix (HNP2) are described from the MAG2 to the MN, and a router advertisement message with a multiple prefix option is transmitted. At time t33, the notified 64-bit HNP1 and the 64-bit random interface ID (IF-ID) are combined in the MN to generate an IPv6 address (HNP1 + IF-ID), which is the first active state. 2 Assigned to interface IF2 as the second IPv6 address.

  At time t34, an ICMPv6 Echo request message is transmitted from the LMA to the second interface IF2. LMAA (LMA address) is registered in the source address (Src) of this message, and IPv6 address generated by combining the HNP1 and IF-ID is registered in the destination address (Dst). Yes.

  At time t35, an ICMPv6 Echo response message is returned from the second interface IF2 of the MN to the LMA. The IPv6 address generated by combining the HNP1 and IF-ID is registered in the source address (Src) of this message, and the LMAA is registered in the destination address (Dst).

  At time t36, packets that have been buffered from time t25 are transmitted from LMA to HNP1. This packet is transferred to the second interface IF2 of the MN via the PMIPv6 second tunnel (T2-ID) and MAG2 according to BCE. At time t37, the packet transmitted from the CN to HNP1 is transferred from the LMA to the second interface IF2 of the MN via the PMIPv6 second tunnel (T2-ID) and MAG2.

  FIG. 5 is a sequence flow showing a procedure for recovering the connection between the disconnected first interface IF1 of the MN and the access line of MAG1 and returning to the multihome connection.

  At time t51, the packets transmitted from the CN to the two home network prefixes (addressed to HNP1 and addressed to HNP2) are both transferred to MAG2 via the LMA and PMIPv6 second tunnel (T2-ID), and It is transferred to the second interface IF2 of the MN by routing based on the Binding List.

  After that, at time t52, the first interface IF1 of the MN is reconnected to the PMIPbv6 domain, and when this is detected by MAG1 and the connection is reestablished between them, the random interface ID (IF-ID) and the MN are unique. The identifier (MN-ID) is notified to MAG1.

  At time t53, the router request Rtr Sol is transmitted from the first interface IF1 to MAG1. At time t54, the PBU in which the MN-ID, IF-ID, and MAG1.PCoA are described is transmitted from the MAG1 that has received the Rtr Sol to the LMA. In the LMA, in response to the PBU, at time t55, a third home network prefix (HNP3) to be assigned to the first interface IF1 is set, and the identifier of the IPv6 first tunnel established with the MAG1 (T1-ID) is set. At time t56, the BCE (Binding Cache Entry) is updated.

  FIG. 6 shows the registration contents of the BCE at that time, and the HNP3 and T1-ID such as the MN-ID, IF-ID, MAG1.PCoA, and radio access type (WLAN) notified by the PBU An entry to link is added. In addition, since the CoAs associated with the three entries with the same IF-ID are different, it is recognized that the three entries constitute a multihome connection, and the multihome field is updated to "ON". ing.

  At time t57, the PBA describing HNP3 is returned from LMA to MAG1. At time t58, route information and a tunnel are set in MAG1. As a result, a bidirectional IPv6 first tunnel is established between MAG1 and LMA at time t59. Further, HNP3 is additionally registered in the Binding List.

  At time t60, the router notification Rtr Adv (HNP3) in which the HNP3 is described is returned from the MAG1 to the first interface IF1. In the MN, an IPv6 third address is generated by combining the notified HNP3 and the random interface ID (IF-ID), and this is assigned to the first interface (WLAN). Accordingly, after that, the MN can resume the multihome connection by the first interface IF1 and the second interface IF2.

  BCE ... Binding Cache Entry, HA ... Home Agent, IF1-ID ... Interface Identifier, LMA ... Local Mobility Anchor, MAG ... Mobile Access Gateway, MN ... Mobile Terminal, MN-ID ... Terminal Identifier, PBA ... Proxy Binding Acknowledgment, PBU ... Proxy Binding Update, PMIPv6… Proxy Mobile IPv6

Claims (3)

A multi-homed mobile terminal equipped with multiple wireless interfaces is connected to the LMA in the proxy mobile IPv6 domain via the MAG connected to each interface, and the flow that was accommodated in the interface that was disconnected from the MAG In the handover method of continuing communication by accommodating in another maintained interface,
A procedure for generating a common interface identifier IF-ID for each interface IF for each mobile terminal;
Each interface IF notifies the IF-ID and terminal identifier MN-ID to each connected MAG,
Each MAG notifies the LBU of the notified IF-ID and MN-ID and PBU (Proxy Binding Update) in which its care-of address is described, and registers it in its Binding List;
In response to the PBU, the LMA assigns a home network prefix HNP to each interface IF, and registers the association between each HNP and IF-ID in a BCE (Binding Cache Entry);
The LMA notifies each corresponding MAG of the PBA (Proxy Binding Acknowledgment) in which the HNP is described, and
Each MAG responds to the PBA and adds the HNP to its own Binding List;
A procedure for constructing an IPv6 tunnel between the LMA and each MAG;
Each MAG performs a notification of the notified HNP router to a mobile terminal;
The mobile terminal generates an IPv6 address by combining each notified HNP and interface identifier IF-ID, and assigns it to each interface;
The MAGa that detects the disconnection with one interface IFa notifies the LMA of the PBU in which the one home network prefix HNPa assigned to the interface IFa is described, and
In response to the PBU, the LMA notifies the HNPa and MN-ID to the other MAGb that is still connected to the other interface IFb, and requests transfer of the flow;
In response to the transfer request, the other MAGb adds the HNPa to the Binding List;
In response to the transfer request, the other MAGb performs a notification of the notified HNPa router to the other interface IFb.
The mobile terminal assigns an IPv6 address generated by combining the notified HNPa and the interface identifier IF-ID to the other interface IFb.
The LMA relays a packet addressed to the HNPa to the other MAGb based on the BCE;
A handover method in proxy mobile IPv6, comprising: a procedure in which the other MAGb relays a packet addressed to the HNPa to the other interface IFb based on the Binding List. A procedure in which the LMA buffers a packet addressed to the disconnected interface IFa;
A procedure in which the LMA relays the buffered packet to another MAGb based on the BCE after the router notification of the HNPa assigned to the interface IFa is made to the other interface IFb. The handover method in proxy mobile IPv6 according to claim 1, comprising:   3. The handover method in proxy mobile IPv6 according to claim 1, wherein the interface identifier IF-ID is randomly generated in each mobile terminal.

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