Abstract:
The disclosure provides a method, system and apparatus for backuping HA/MAP in mobile IPv6 network. In the disclosure, at least two HAs/MAPs form a redundant backup group. The at least two HAs/MAPs elect an active HA/MAP and a standby HA/MAP via the VRRP. When the active HA/MAP interacts the signaling message with a mobile node, the HA/MAP in backup status obtains the signaling message interacted by both of them in real time. When the active HA/MAP is invalid, the standby HA/MAP may take over the work in time so that the stability of the active node device of the network is ensured. During the exchange of the active HA/MAP and the standby HA/MAP, the solution ensures a smooth transition of the service.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The application is a continuation of International Patent Application No. PCT/CN2006/002586, filed Sep. 29, 2006, which claims priority to Chinese Patent Application No. 200510100196.2 submitted with the State Intellectual Property Office of P.R.C. on Oct. 1, 2005, entitled “Method for Backuping HA/MAP in Mobile IPv6 Network,” both contents of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The disclosure relates to the communication field, and more particularly, to a method for backuping the home agent or mobile anchor point (HA/MAP) in the mobile IIPv6 network. 
       BACKGROUND OF THE INVENTION 
       [0003]    With the development of the network technique and the appearance of lots of mobile terminals, such as laptops, personal digital assistants (PDA), mobile telephones and mounted devices, an upsurge in the mobile computing is raised. More and more users may access the Internet via the public mobile wireless network by various terminals in any location. To meet the need of the mobile service, a mobile IP technique is introduced in the network layer. 
         [0004]    In the Mobile IP technique, a mobile node (MN) may perform the IP communication by using the initial IP address all the time in the movement. Therefore, an upper layer application carried in the IP network layer may be ensured uninterrupted and continuable. 
         [0005]    The operation principle of the Mobile IP is that when an MN is connected to its home network, the MN works in the same manner as other fixed nodes. If the MN finds itself moved to a foreign network, the care of address (CoA) on the foreign network is obtained by the stateful or stateless auto-configuration based on the received information announced by the router. Here, the MN owns the home address and the CoA at the same time. The MN registers its CoA to the home agent (HA) by a ‘binding update’ message. If the correspondence node (CN) of the MN does not know the CoA of the MN, the correspondence node sends the data packets to the home network of the MN according to the home address of the MN. The HA of the MN captures these data packets and transfers these data packets to the MN by using a tunnel mechanism according to the current CoA of the MN. The message sent by the MN to the CN is sent to the HA via a reverse tunnel, and is transferred to the CN by the HA. As the data packets between the CN and the MN are both transferred by the HA in that manner, the manner may be called ‘triangle route’ manner. 
         [0006]    In the ‘triangle route’ manner, in order to ensure the upper layer application carried in the IP network layer to be uninterrupted and continuable in movement. A plurality of HAs may be set on the home link. In a prior art, when the current active HA is invalid, the switching process of the HA and the MN is as follows. 
         [0007]    The MN detects the invalidation of the HA. Specifically, if the MN may not obtain the prefix of the home address from the HA or the MN may not complete the home registration with the HA, the MN detects the invalidation of the HA. In addition, if the MN fails to communicate with the outer CN via the HA, the MN may detect the invalidation of the HA. 
         [0008]    The MN sends an HA address request to obtain a redundant HA address when the MN detects the invalidation of the HA. After obtaining the HA address by the MN, the MN sends a home link prefix request to get its own home address. Subsequently, the MN completes the home registration. The MN re-completes the process of the registration and communication with other CNs. 
         [0009]    However, all the binding information retained in the invalid HA is lost. The real-time service is interrupted and the MN needs to re-establish the service connection, which costs greatly and consumes a lot of bandwidth. 
         [0010]    Another method of the redundant backup for the HA/MAP. The basic scheme is shown as follows. 
         [0011]    1. The HA on the same home link completes the election between the active HA/MAP and the standby HA/MAP by the virtual route redundancy protocol (VRRP). 
         [0012]    2. When the active HA/MAP performs message interaction with the MN, the active HA/MAP creates a binding request and a binding update message by expanding the VRRP message to complete the backup of the binding database record from the active HA/MAP to the standby MA/MAP. 
         [0013]    3. When the active HA/MAP is invalid, as the backup of the binding information is stored in the standby HA/MAP, the service flow (the triangle route) which is performing communication currently is not impacted and the standby HA/MAP may continually transfer the service between the MN and the CN. 
         [0014]    The method creates the binding request and the binding update message by the manner of expanding the VRRP message to complete the backup of the binding database record from the active HA/MAP to the standby HA/MAP. The quality of the communication between the MN and the CN may not be ensured because the backup is not performed in real time. 
         [0015]    In addition, as the key message of the security association (SA) has no backup (if the interaction is performed by using a dynamic key), when the CoA of the MN changes and needs to be re-registered by the HA, the MN needs to re-perform the key interaction with the new HA because the key negotiated before may not be retained. The process of the binding update of the MN is delayed. 
       SUMMARY OF THE INVENTION 
       [0016]    The disclosure provides a method, system and apparatus for backuping an HA/MAP in a mobile IPv6 network to realize the real-time backup of the HA/MAP and enable a standby HA/MAP to take over seamlessly when an active HA/MAP is invalid. 
         [0017]    A method for backuping a home agent or mobile anchor protocol (HA/MAP) in a mobile IPv6 network, at least two HAs/MAPs forming a redundant backup group includes following steps. 
         [0018]    The at least two HAs/MAPs elect an active HA/MAP and a standby HA/MAP. 
         [0019]    When the active HA/MAP performs a signaling message interaction with an MN, the standby HA/MAP obtains in real time a signaling message sent by the MN to the active HA/MAP and the signaling message sent by the active HA/MAP to the MN; or after performing the signaling message interaction with the MN, the active HA/MAP sends status information in real time to the standby HA/MAP via a synchronization message. 
         [0020]    The standby HA/MAP elects a new active HA/MAP when the active HA/MAP is invalid. 
         [0021]    Optionally, the step of obtaining in real time, by the standby HA/MAP, the signaling message sent by the MN to the active HA/MAP and a signaling message sent by the active HA/MAP to the MN specifically includes following steps. 
         [0022]    A backup information channel is established among the standby HA/MAP, the active HA/MAP and the MN. 
         [0023]    The standby HA/MAP obtains in real time the signaling message between the active HA/MAP and the MN via the backup information channel. The signaling message includes a binding update message and a key exchange message of a security association. 
         [0024]    Optionally, the step of establishing the backup information channel is: forming the backup information channel by connecting the active HA/MAP, the standby HA/MAP and the MN to an outer switch located outside each outer link interface. 
         [0025]    The step of obtaining in real time, by the standby HA/MAP, the signaling message between the active HA/MAP and the MN via the backup information channel specifically is that the outer switch copies the message sent by the MN to the active HA/MAP and the message sent by the active HA/MAP to the MN to the standby HA/MAP. 
         [0026]    Optionally, after the standby HA/MAP obtains in real time the signaling message sent by the MN to the active HA/MAP and the signaling message sent by the active HA/MAP to the MN, the method further includes: processing the signaling message obtained in real time. 
         [0027]    The step of processing the signaling message obtained in real time specifically includes following steps. 
         [0028]    A new record is established in a backup database and marked as temporarily unusable after the standby HA/MAP has obtained a binding update request sent by the MN. 
         [0029]    After that, the record is marked as usable or updated according to an obtained binding update acknowledgement message sent by the active HA/MAP. 
         [0030]    Optionally, if the binding update request of the MN includes a home address created by the MN, the active HA/MAP repeatedly performs an address examination for the binding update message; if the home address of the MN is different from the home address of other MNs and an address of a local link node, the binding update acknowledgement message is the binding update acknowledgement message sent by the active HA/MAP directly to the MN. 
         [0031]    If the home address of the MN is the same as the home address of other MNs and the address of the local link node, the binding update acknowledgement message is the binding update acknowledgement message including a suggested home address sent by the active HA/MAP to the MN. 
         [0032]    If the binding update request of the MN includes the home address created by the MN, the binding update acknowledgement message is the binding update acknowledgement message including the home address initiatively allocated for the MN and sent by the active HA/MAP to the MN. 
         [0033]    Optionally, the step of marking the record as usable or updating the record according to an obtained binding update acknowledgement message sent by the active HA/MAP specifically includes following steps. 
         [0034]    When there is no home address in the binding update acknowledgement message sent by the active HA/MAP, the standby HA/MAP marks the new record as usable in the database. 
         [0035]    When the binding update acknowledgement message sent by the active HA/MAP includes the home address initiatively allocated, the standby HA/MAP adds the allocated home address into the new record in the database. 
         [0036]    When the binding update acknowledgement message sent by the active HA/MAP includes the suggested home address, the standby HA/MAP updates the new record as the suggested home address in the database. 
         [0037]    Optionally, if the active HA/MAP creates the security association with the MN, the step of processing the signaling message obtained in real time specifically includes that the standby HA/MAP keeps real-time synchronization with a sending serial number and a receiving slip window of the active HA/MAP by analyzing the obtained signaling message between the active HA/MAP and the MN. 
         [0038]    Optionally, the method further includes following steps. 
         [0039]    When the HA/MAP resumes after invalidation, a current HA/MAP sends batch backup information to the HA/MAP; and 
         [0040]    The HA/MAP enters a real-time backup status after completing a batch backup. 
         [0041]    The step of sending, by a current HA/MAP, batch backup information to the HA/MAP specifically includes following steps. 
         [0042]    When the batch backup request sent by the HA/MAP includes the security policy database, the security association database, the Internet key exchange status information and the binding updated index information, a current active HA/MAP sends a backup response carrying a security policy database, a security association database, Internet key exchange status information and binding updated index information which are needed by the HA/MAP; when the batch backup request sent by the current HA/MAP does not includes backup information, needed by the current HA/MAP, the current active HA/MAP sends a backup response carrying the current security policy database, the security association database, the Internet key exchange status information and the binding updated index information to the HA/MAP. 
         [0043]    A downloaded security policy database, the security association database, the Internet key exchange status information and the binding updated index information are determined after receiving the backup response of the current active HA/MAP by the HA/MAP; the batch backup request is resent to the current HA/MAP; backup information is downloaded and sent to the standby HA/MAP according to a re-received request by the current HA/MAP. 
         [0044]    Optionally, the step of sending status information in real time to the standby HA/MAP via a synchronization message includes that the active HA/MAP synchronizes a key exchange status to the standby HA/MAP via the synchronization message when the active HA/MAP dynamically creates the security association with the MN. 
         [0045]    The step of synchronizing, by the active HA/MAP, a key exchange status to the standby HA/MAP via the synchronization message specifically includes following steps. 
         [0046]    When the MN and the active HA/MAP complete a first phase of the Internet key exchange, the active HA/MAP synchronizes a first phase status of the Internet key exchange to the standby HA/MAP. 
         [0047]    When the MN and the active HA/MAP complete a second phase of the Internet key exchange, the active HA/MAP synchronizes a second phase status or the second phase and the first phase status of the Internet key exchange to the standby HA/MAP. 
         [0048]    Optionally, the step of sending status information in real time to the standby HA/MAP via a synchronization message includes that the active HA/MAP backups binding cache information to the standby HA/MAP via the synchronization message. 
         [0049]    According to another aspect of the disclosure, a system for backuping a home agent or mobile anchor protocol (HA/MAP) in a mobile IPv6 network includes a redundant backup group formed by at least two HAs/MAPs and the at least HAs/MAPs includes an elected active HA/MAP and a standby HA/MAP; the standby HA/MAP is adapted to obtain in real time a signaling message sent by the active HA/MAP to a mobile node (MN) and the signaling message sent by the MN to the active HA/MAP or is adapted to obtain status information in real time sent by the active HA/MAP via a synchronization message. 
         [0050]    Optionally, the system further includes: 
         [0051]    a backup information channel established among the standby HA/MAP, the active HA/MAP and the MN and adapted to transmit a message obtained in real time by the standby HA/MAP; 
         [0052]    an outer switch located outside each outer link interface, connected to the active HA/MAP, the standby HA/MAP and the MN, and adapted to copy the message sent by the active HA/MAP to the MN and the message sent by the MN to the active HA/MAP to the standby HA/MAP. 
         [0053]    An apparatus for backuping a home agent or mobile anchor point (HA/MAP) in an IPv6 network includes: 
         [0054]    an interaction message obtaining unit, adapted to obtain a signaling message sent by a mobile node (MN) to an active HA/MAP and the signaling message sent by the active HA/MAP to the MN; and 
         [0055]    an interaction message sending unit, adapted to send in real time the obtained signaling message to a standby HA/MAP. 
         [0056]    Optionally, the interaction message obtaining unit and the interaction message sending unit are set in an outer switch located outside each outer link interface. 
         [0057]    Optionally, the apparatus further includes an interaction message processing unit set in an HA/MAP and adapted to process the signaling message from the interaction message sending unit when the HA/MAP is in a backup status. 
         [0058]    Optionally, the interaction message processing unit includes a binding update message processing unit and an IP security message processing unit. The binding update message processing unit is adapted to establish a new record in a backup database according to an obtained binding update request sent by the MN, mark the record as temporarily unusable, and mark the record as usable or update the record according to an obtained binding update acknowledgement message sent by the active HA/MAP. The IP security message processing unit is adapted to analyze an obtained IP security message between the active HA/MAP and the MN to keep real-time synchronization with a sending serial number and a receiving slip window of the active HA/MAP. 
         [0059]    Optionally, the apparatus further includes: 
         [0060]    a batch backup request unit, set in the HA/MAP and adapted to send a batch backup request for the HA/MAP when an invalid active HA/MAP resumes and is elected as the standby HA/MAP; 
         [0061]    a backup response unit, set in the HA/MAP and adapted to send a backup response to respond the batch backup request for a current active HA/MAP; 
         [0062]    a backup response processing unit, set in the HA/MAP and adapted to obtain index information after receiving the backup response and inform the batch backup request unit to send a re-batch backup request carrying the index information of the backup information needing to download; and 
         [0063]    a backup information sending unit, set in the HA/MAP and adapted to send the backup information when the current active HA/MAP has received the re-batch backup request. 
         [0064]    The disclosure makes the service information between the standby HA/MAP and the active HA/MAP real-time synchronous by the standby HA/MAP obtaining in real time the message interacted between the active HA/MAP and the MN or by the active HA/MAP sending in real time the backup information to the standby HA/MAP. Therefore, when the active HA/MAP is invalid, the standby HA/MAP may take over the work in real time, which ensures the stability of the active node devices in the network and minimally reduces the influence on the network operation by the single-point trouble. 
         [0065]    According to the disclosure, the batch backup between the standby HA/MAP and the active HA/MAP is realized. In the period of the active-backup exchange, the present scheme ensures the smooth transmission of the service and makes the foreign and local MNs not to feel the change of the service flow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0066]      FIG. 1  is a schematic diagram illustrating the scheme of the basic network organization in accordance with an embodiment of the disclosure; 
           [0067]      FIG. 2  is a schematic diagram illustrating the real-time backup in accordance with an embodiment of the disclosure; 
           [0068]      FIG. 3  is a schematic diagram illustrating that the standby HA/MAP obtaining in real time the signaling message in accordance with an embodiment of the disclosure; 
           [0069]      FIG. 4  is a schematic diagram illustrating the batch backup in accordance with an embodiment of the disclosure; and 
           [0070]      FIG. 5  is a block diagram illustrating the backup apparatus in accordance with an embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0071]    In order to make the objects, technical solutions and merits of the disclosure clearer, a further description of embodiments of the disclosure is given in conjunction with the accompanying drawings. 
         [0072]    Referring to  FIG. 1 , one embodiment of the backup system in accordance with the disclosure is applied in the mobile IPv6 network. On the home link of the MN  110 , HA/MAP  121 ,  122  and  123  form a redundant backup group. The HA/MAP  121 ,  122  and  123  elect HA/MAP  121  as an active HA/MAP and the HA/MAP  122 ,  123  as a standby HA/MAP. 
         [0073]    When the active HA/MAP  121  performs message interaction with the MN  110 , the HA/MAP  122 ,  123  in backup status obtain in real time the message sent by the MN  110  to the active HA/MAP  121  and the message sent by the active HA/MAP  121  to the MN  110  and process the message; or when the active HA/MAP  121  performs message interaction with the MN  110 , the active HA/MAP  121  synchronizes in real time the status information to the HA/MAP  122 ,  123  in the backup status by a synchronization message. 
         [0074]    Also referring to  FIG. 2  which is a schematic diagram illustrating the real-time backup in accordance with the embodiment of the standby Method in the disclosure, the real-time backup process includes the following steps. 
         [0075]    Step S 21 : On the home link of the MN, a plurality of HAs/MAPs forms the redundant backup group. Each HA/MAP elects the active HA/MAP by the VRRP protocol or a similar priority election protocol. The active HA/MAP communicates with an outer network by a virtual IPv6 address and a virtual medium access control address. The HA/MAP may share the global routable IP address to outside. 
         [0076]    When the active HA/MAP performs message interaction with the MN, the HA/MAP in the backup status obtains in real time the message sent by the MN to the active HA/MAP and the message sent by the active HA/MAP to the MN, calculates the message, processes the message, and stores the result. In one embodiment of the disclosure, the specific process for obtaining in real time the message and processing the message includes following steps. 
         [0077]    The configuration of the active HA/MAP is the same as the configuration of the standby HA/MAP, i.e. the security policy databases (SPD) of the active HA/MAP and the standby HA/MAP are the same. If the active HA/MAP and the standby HA/MAP establish the security association manually, the security association databases (SADB) of the active HA/MAP and the standby HA/MAP are also the same. 
         [0078]    When the active HA/MAP establishes the security association with the MN (MN) by using an Internet key exchange (IKE) (Step S 22 , S 23 ), the security association status (IKE/IPSec status) needs to be backuped to the standby HA/MAP (Step S 24 ). Meanwhile, the index relationship between the security policy database SPD and the security association also needs to be backuped. The active HA/MAP may backup the established IKE/IPSec status to the standby HA/MAP by the synchronization message. The standby Message used may be an expanding message of the VRRP for IPv6. 
         [0079]    The active HA/MAP may backup the established IKE/IPSec status to the standby HA/MAP by the synchronization message. The specific process is as follows. 
         [0080]    When the MN MN completes the first phase exchange of the IKE with the active HA/MAP, the active HA/MAP may synchronize the status of the first phase (including the DH exchanging public values, initiating the nonce and so on) of the IKE to the standby HA/MAP. 
         [0081]    When the MN MN completes the second phase exchange of the IKE with the active HA/MAP, the active HA/MAP may synchronize the status of the second phase or the status of the second phase and the first phase of the IKE to the standby HA/MAP. 
         [0082]    In addition, the standby HA/MAP also needs to synchronize the sending serial number and the receiving slip window of the key message of the security association of the active HA/MAP. The standby HA/MAP keeps synchronization by obtaining and analyzing the mobile signaling message between the active HA/MAP and the MN. The standby HA/MAP may perform a security filtering to the received signaling message, i.e. the standby HA/MAP only receives the signaling message between the active HA/MAP and the MN so as to keep synchronization with the sending serial number and the receiving slip window of the key message of the security association of the active HA/MAP. 
         [0083]    When the active HA/MAP performs the binding update with the MN, each HA/MAP in the backup status may also obtain the message sent by the MN to the active HA/MAP and the message sent by the active HA/MAP to the MN, calculate the binding update message, process the binding update message and stores the result. The specific process includes following steps. 
         [0084]    When the active HA/MAP has received a binding update request (Step S 25 ), the active HA/MAP sends different binding update acknowledge messages conditionally (Step S 27 ). If the home address created by the MN itself is not included, the active HA/MAP directly sends the binding update acknowledge message to the MN. If the home address created by the MN itself is included, the active HA/MAP needs to examine the home address repeatedly. The examination method includes: inquiring a local home link neighbor database, sending a repeat address examination message or inquiring a neighbor agent. If the repeat address examination is passed, the active HA/MAP directly sends the binding update acknowledge message to the MN. If the repeat address examination is not passed, the suggested home address needs to be included in the binding update acknowledge. 
         [0085]    After obtaining the binding update request (Step S 26 ), the standby HA/MAP establishes a new record in the backup database and marks the record as temporarily unusable; and then marks the record as usable or updating the record according to the obtained binding update acknowledge message sent by the active HA/MAP (Step S 28 ). When the home address field is not included in the binding update acknowledge message sent by the active HA/MAP, the standby HA/MAP marks the new record in the database as usable. When the allocated home address is included in the binding update acknowledge message sent by the active HA/MAP, the standby HA/MAP adds the allocated home address into the new record in the database. When the suggested home address is included in the binding update acknowledge message sent by the active HA/MAP, the standby HA/MAP updates the new record in the database to the suggested home address. 
         [0086]    In addition, the active HA/MAP may also directly send the binding cache information to the standby HA/MAP. 
         [0087]    The standby HA/MAP may obtain the signaling message between the active HA/MAP and the MN by establishing a backup information channel. One embodiment of the backup information channel is shown in  FIG. 3 . The backup information channel is established between each outer link interface  130  using the VRRP protocol. The signaling message sent by MN  110  to active HA/MAP  121  and the binding update message are copied by the switch  140  of the outer link to the standby HA/MAP  122 ,  123 . Meanwhile, the signaling message sent by the active HA/MAP  121  to the MN  110  and the binding update message are also copied by the switch  140  of the outer link to the standby HA/MAP  122 ,  123 . When the active HA/MAP is invalid (Step S 29 ), by the VRRP protocol, the standby HA/MAP elects a new active HA/MAP to take over the work of the active HA/MAP and act as the new active HA/MAP (Step S 30 ). The active HA/MAP may be invalid because of exception errors or maintaining requirement. 
         [0088]    If a previous active HA/MAP resumes, it may be elected as a new standby HA/MAP by the VRRP protocol. The HA/MAP has no information recorded in the security policy database, in the security association database and in the binding update database. The information needs to be obtained from the current active HA/MAP for completing the backup work. Although the previous active HA/MAP is the owner of the virtual IPv6 address, the previous active HA/MAP may be elected as a new active HA/MAP only after downloading the backup information in batch-bulk from the current active HA/MAP. 
         [0089]      FIG. 4  is a schematic diagram illustrating that the standby HA/MAP backups the message information of the current active HA/MAP in batch-bulk. The process of batch backup includes following steps. 
         [0090]    Step S 41 : When the previous active HA/MAP resumes, the previous active HA/MAP is elected as the new standby HA/MAP by the VRRP protocol. The standby HA/MAP initiates a batch backup request to the active HA/MAP; 
         [0091]    Step S 42 : When the active HA/MAP receives the batch backup request sent by the standby HA/MAP, the active HA/MAP sends a backup response. The specific process includes as follows. 
         [0092]    Firstly, the active HA/MAP determines whether the standby HA/MAP carries the index of the backup information needed. If the standby HA/MAP carries the index of the backup information needed, the current active HA/MAP sends the backup response carrying the security policy database, the security association database, the status information of the Internet key exchange and the index information of the binding update needed by the standby HA/MAP. When the batch backup request sent by the HA/MAP does not include the backup information needed, the current active HA/MAP sends the backup response carrying the current security policy database, the security association database, the status information of the Internet key exchange and the index information of the binding update to the HA/MAP. 
         [0093]    Step S 43 : When the HA/MAP receives the response of the current active HA/MAP, the HA/MAP determines to download security policy database, the security association database, the status information of the Internet key exchange and the index information of the binding update according to its own need and re-sends a batch backup request to the current active HA/MAP. 
         [0094]    Step S 44 : According to the re-received download request, the current active HA/MAP sends the backup information to the standby HA/MAP. 
         [0095]    After completing the batch backup, the standby HA/MAP enters the real-time backup status. 
         [0096]    Referring to  FIG. 5 , it is a block diagram illustrating the backup apparatus of the HA/MAP in accordance with an embodiment of the disclosure. 
         [0097]    The backup apparatus includes: an interaction message obtaining unit  510  adapted to obtain the signaling message sent by the MN to the active HA/MAP and the signaling message sent by the active HA/MAP to the MN; and an interaction message sending unit  520  adapted to send in real time the obtained signaling message to the standby HA/MAP. 
         [0098]    In one embodiment of the disclosure, the interaction message obtaining unit  510  and the interaction message sending unit  520  are set in the outer switch  600  located outside each outer link interface. 
         [0099]    The backup apparatus further includes an interaction message processing unit  530  set in the HA/MAP adapted to process the signaling message from the interaction message sending unit  520  when the HA/MAP is in the backup status. 
         [0100]    The interaction message processing unit  530  includes a binding update message processing unit  531  and an IP security message processing unit  532 . 
         [0101]    The binding update message processing unit  531  is adapted to establish a new record in the backup database according to the obtained binding update request sent by the MN and to mark the record as temporarily unusable; and mark the record as usable or update the record according to the obtained binding update acknowledgement message sent by the active HA/MAP. 
         [0102]    The IP security message processing unit  532  is adapted to analyze the obtained IP security message between the active HA/MAP and the MN to keep real-time synchronization with the sending serial number and the receiving slip window of the active HA/MAP. 
         [0103]    In addition, after resuming, an invalid previous active HA/MAP may be elected as a new standby HA/MAP by the VRRP protocol. The HA/MAP has no information recorded in the security policy database, in the security association database and in the binding update database. The previous active HA/MAP may be elected as a new active HA/MAP only after downloading the backup information from the current active HA/MAP in batch-bulk. In order to realize the batch backup, the backup apparatus further includes: 
         [0104]    a batch backup request unit  540  set in the HA/MAP and adapted to send a batch backup request for the HA/MAP when the invalid active HA/MAP resumes and is elected as the standby HA/MAP; 
         [0105]    a backup response unit  550  set in the HA/MAP and adapted to send a backup response to respond the batch backup request for the current active HA/MAP; 
         [0106]    a backup response processing unit  560  set in the HA/MAP and adapted to obtain the index information after receiving the backup response and inform the batch backup request unit  540  to send a re-batch backup request carrying the index information of backup information needing to be downloaded; and 
         [0107]    a backup information sending unit  570  set in the HA/MAP and adapted to send the backup information when the current active HA/MAP received the re-batch backup request. 
         [0108]    Though illustration and description of the present disclosure have been given with reference to embodiments thereof, it should be appreciated by persons of ordinary skill in the art that various changes in forms and details can be made without deviation from the scope of this disclosure, which are defined by the appended claims.