JP2003204350A - Load disperser, home agent, and mobile ip terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load disperser which is arranged so that the consistency preserving function of a server at the destination of connection may not be lost even if a terminal is a mobile IP terminal. <P>SOLUTION: This system abstracts identifying information peculiar to the mobile IP terminal from a packet having arrived, and decides a server at the destination of connection, based on this identifying information. Or, when the first packet addressed to one server arrives, this requests a home agent or the mobile terminal to inform itself of the change of the address of that mobile IP terminal when the care-of address of that mobile IP terminal is changed, and this decides a server at the destination of connection, using this informed care-of address as the identifying information. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a home agent and a mobile IP terminal, and more particularly to a load balancer, a home agent and a mobile IP terminal when the mobile IP terminal accesses a server. With the spread of the Internet, the roles of various servers such as Web servers are increasing, and server overload and response deterioration due to the concentration of access to the servers are becoming problems. As a countermeasure against this, a load balancer is used that evenly distributes received packets to multiple servers and distributes the load on the servers.

[0002]

2. Description of the Related Art There are various forms of conventionally known load balancers. An example of this is shown in FIG. LB is a load balancer that receives packets sent from the client CL via routers R1 and R3,
The received packet is distributed to the server S1 and the server S2 and transmitted.

Although the client CL shown in FIG. 20 is a fixed terminal, the mobile IP technology for managing the movement of the terminal on the IP (Internet Protocol) protocol is currently IETF (Internet E).
ngineering Task Force). This technology is for continuing communication even if the IP terminal moves, and a new care-of address (CoA
: Care of Address) and register this care-of address in a home agent (HA: Home Agent) or communication partner terminal to realize mobile communication.

FIG. 20 shows a case where the mobile IP terminal MN to which this technology is applied is changed from being connected to the router R1 to being connected to the router R2. The care-of address of the mobile IP terminal MN is also changed from CoA1 to CoA2. The home agent HA stores and manages the correspondence between the home address of the mobile IP terminal MN and the current care-of address.

Here, the load balancer LB determines the source address (SA: Source A) included in the IP header of the received packet.
ddress) or this source address and TCP (TransmissionCon
trol Protocol) Any one depending on the combination with the port number
I try to select one server as a connection destination. There is also a form in which the connection destination server is specified at a higher application level. For example, the connection destination URL (Unifo
A method of selecting a server according to the rm Resource Locator) is also possible.

Furthermore, SSL (Secure Sockets Layer;
Cryptographic protocol for ensuring TCP / IP communication security at the transport layer) Session ID and cookies (WW
It is also possible to select the connection destination server by identifying the character string information generated by the W server to identify the user, which is stored in both the server and the browser. Another important function of such a load balancer is a consistency maintaining function of the connection destination server for making a series of processes continuous.

[0007] For example, when load balancing of servers used for online shopping is performed, "consistency" for maintaining the association between the client and the server during a series of flow from selection of products to purchase and settlement. "Retention function" is essential. If the load balancer does not have such a consistency maintaining function, the connection is switched to another server in the middle of the series of processes, and the series of processes for electronic commerce cannot operate properly.

For this reason, most of the load balancers have a consistency maintaining function based on the IP header information.

[0009]

As shown in the network configuration example of FIG. 20, when the mobile IP terminal MN accesses the server and when the load of the server is distributed by the load distribution device, the mobile Every time the IP terminal moves, its IP address (care-of address) changes, so the source address changes. Therefore,
The source address or information in combination with the source address cannot be used to implement the consistency maintaining function of the connection destination server.

That is, when the mobile IP terminal MN is connected to the router R1, the care-of address CoA1 is set, and when the mobile IP terminal MN is moved and connected to the router R2, the care-of address CoA1 is set.
Packets with 2 as the source address (SA) are generated and transmitted. When the load balancer LB receives such a packet, the care-of address has been changed from CoA1 to CoA2, so if the source address (SA) is used as the search key, access is from the same mobile IP terminal MN. Despite this, there is a problem that the connection destination server cannot be guaranteed because the connection destination server is changed from S1 to S2 by erroneously recognizing that the access is from another mobile IP terminal. there were.

Therefore, the present invention provides a load balancer, a home agent and a mobile IP terminal in which the consistency maintaining function of the connected server during communication is not lost even if the terminal is a mobile IP terminal. To aim.

[0012]

According to the present invention, in a load balancer in a computer network in which a server and a mobile IP terminal communicate with each other,
It is possible to configure a load balancer including an extracting unit that extracts identification information unique to the mobile IP terminal and a determining unit that determines a connection destination server based on the identification information.

That is, in order to provide a load balancing function to the mobile IP terminal, the identification information unique to the mobile IP terminal is extracted from the arrival packet, and the packet is sent to the connection destination server based on the extracted identification information. I try to sort them out. As the identification information, first, the home address included in the header part of the IP packet transmitted by the moving mobile IP terminal can be used.

That is, IPv6 (Internet Protocol versi
The care-of address (source address) of the packet received by the load balancer changes every time it moves, as in the example of the packet format for the server from the terminal when using (on 6) (see Fig. 5), but the home address Are the same. Therefore, by using this home address to determine the connection destination server, the server connection can be maintained consistently.

As the identification information, information specified in a predetermined bit of the source address of the packet may be used. That is, the method for creating an IPv6 address is (1)
A stateless address generation method (IPv6 Stateless Address Autoconfigur
ation) and (2) a stateful address generation method (IPv6 Stateful Addr) that obtains permission when the terminal uses the address.
ess Autoconfiguration). Of these, when using the former stateless address method, the lower 64 bits (see FIG. 7) of the care-of address created by the mobile IP terminal is its own interface ID, for example, Ethernet (registered trademark). MAC (M
ediaAccess Control) A number that is a combination of addresses is used.

Since this interface ID has a unique value for each mobile IP terminal, the lower 64 bits of the source address of the packet received by the load balancer is used, or the lower 64 bits are combined with other information. It becomes possible to determine the connection destination server. Further, the security parameter index (SPI) when the packet is encrypted may be used as the identification information.

The IPv6 packet may be encrypted by IPsec (IP security protocol) for security measures of the packet itself. At that time, after the encryption range, the encryption cannot be decrypted unless there is an encryption key used end-to-end. In such cases, the security parameter index (SPI: see FIG. 10) can be used to ensure server connection consistency. This security parameter index SPI is
This is a number negotiated between end-to-end in order to show the relation between the encryption algorithm and the encryption key used between end-to-end, and is written in the head part of the encryption header.

Further, the load balancer according to the present invention, when the care-of address of the mobile IP terminal is changed with respect to the home agent when the first packet addressed to one server arrives, It can also be configured by means for requesting notification of the change and means for determining the connection destination server using the notified care-of address as identification information.

That is, the care-of address of the received packet is changed every time the mobile IP terminal moves, and the home agent manages the relationship between the care-of address and the home address. Therefore, when the load balancer receives the first packet including the care-of address, it instructs the home agent to notify the home agent of the new care-of address whenever the care-of address is changed. Even when no packet is generated, when the mobile IP terminal moves, the home agent notifies the load balancing apparatus of the changed care-of address.

As a result, the load balancer always knows the latest care-of address, and by using this to determine the connection destination server, the consistency of server connection can be ensured. In the above case, when the care-of address is changed to the home agent, the changed care-of address is notified to the load balancer, but the change of the care-of address is known to the mobile IP terminal itself. Considering this, when the care-of address in the arriving first packet is changed, the mobile IP terminal itself, instead of the home agent, is requested to notify the change of the care-of address, and the notified care-of address is sent. The connection destination server may be determined as the identification information.

Further, when the extracting means extracts a packet transmitted from the home link without having the destination option header when the packet arrives, the deciding means determines the source of the packet. The connection destination server may be determined using the address as identification information. That is, when the first packet arrives, if the packet is a packet transmitted from the home link (a packet transmitted from a mobile IP terminal not moving outside the home network), the source address of the packet is identified. The connection destination server may be determined as the information.

Further, the deciding means comprises a table storing the identification information of the connection destination server with the identification information of the transmission source address of the packet, that is, the identification information of the transmission source corresponding to the care-of address of the mobile IP terminal as a search key. The connection destination server can be determined by using the transmission source address of the packet. Furthermore, in response to a request from the load balancer, information on the binding cache (a table storing the correspondence between the care-of address and home address of the mobile IP terminal) managed by itself is periodically or A home agent characterized by notifying the load balancer when the care-of address of the IP terminal is changed can also be realized.

Further, in response to a request from the load balancer, the information of the binding cache managed by itself is periodically or when the care-of address of itself is changed, the load is changed. It is also possible to realize a mobile IP terminal characterized by notifying distributed devices.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a network embodiment (1) to which a load balancer according to the present invention is applied. In this embodiment, even when the mobile IP terminal MN moves, the router to which the mobile IP terminal MN is connected changes from the router R1 to R2, and the care-of address changes from CoA1 to CoA2, the unique identification of this mobile IP terminal MN By extracting the information (search key), if you have been connected to the server S1 until now, connect to the server S1 as it is and continue communication, thereby maintaining the consistency of the connection destination server. It was done.

The configuration of the load balancer LB shown in the network embodiment (1) of FIG. 1 is shown in the configuration (1) of the load balancer of FIG. Here, the load balancer LB is the IP
The v6 header information extraction unit 1, the load distribution table 2, the table control unit 3, and the distribution processing unit 4 are included. The IPv6 header information extraction unit 1 extracts the identification information of the mobile IP terminal MN from the received packet, and the table control unit 3 searches the load balancing table 2 using this identification information as a search key to determine the connection destination server. Then, the distribution processing unit 4 transmits the packet with the determined server as the destination.

Here, the load balancing table 2 is the mobile
A plurality of tables corresponding to the identification information of the IP terminal, that is, the type of the search key is included, and the table corresponding to the type of the search key used at that time is targeted for the search. Next, the operation of the load balancer will be described for each type of identification information of the mobile IP terminal.

First, as the identification information of the mobile IP terminal,
The case of using the home address will be described for each processing step with reference to the operation flowchart of FIG. First,
Header extraction is performed from the received packet (step T1).
Here, as shown in the format example of the IPv6 packet for the server from the terminal in FIG. 5, in order from the IPv6 header 10, the “next header” area storing the type code of the extension header arranged next is confirmed. Search for the extension header code “60” indicating the IPv6 destination option (step T
2).

If the destination option code "60" is found (YES), it indicates that the IPv6 destination option 20 exists in the area next to the IPv6 header section.
"201" which means that the option type indicating the type of the destination option 20 is the home address option
Or not (step T3). Here, if the option type is “201” (YES), this option is the home address option, which indicates that the mobile terminal MN is moving to a position different from the home address, and the home address is Stored in the home address option. This home address is the IP address on the link (home link) that was originally connected before the mobile IP terminal MN moved, and it remains unchanged no matter where the mobile IP terminal MN moves after that. By using this home address as identification information as a search key of the load balancing table (step T4), it is possible to maintain consistency of processing between the mobile IP terminal MN and the server.

On the other hand, when the destination option code "60" is not found in the judgment of step T2 (NO), or when the option type is not "201" in the judgment of step T3.
(NO) means that the mobile IP terminal MN has not moved from the home link, in which case the source address SA of the packet matches the home address, and the source address of the received packet is If SA is used as the identification information of the mobile IP terminal and it is used as the search key (step T5),
It is possible to maintain consistency of processing between the mobile IP terminal MN and the server.

On the basis of the search key set in the above step, the load balancing table 2 is searched in the table control A to determine the server of the connection destination (step T6), and the packet is addressed to the determined server as the destination. The data is sent (step T7), and the process ends. Next, the table control A will be described for each processing step with reference to the operation flowchart shown in FIG.

First, the target table in the load balancing table 2 is specified according to the type of search key, and the specified table is searched (step T61). If there is no entry that matches the search key as a result of the search (NO), the connection destination server is determined using the existing load balancing algorithm (step T64), and a new entry is created in the table based on the result. Register (step T65) and return to the caller.

If the entry already exists (YES),
Use the server identification information in that entry as the connection destination server
(Step T63), return to the caller. In the above description of the operation flowchart of FIG. 3, the description has been made according to the format example of FIG. 5, but the value of the next header code (“60”) and the option type code of the IPv6 destination header option described in FIG. Even if the value ("201") of, the header format, etc. are partially changed, only the processing procedure for extracting the source address and the home address, which are the identification information of the mobile IP terminal, is changed. It does not affect the essence.

FIG. 6 shows the configuration (1) of the load balancer of FIG.
An example of a table configuration in the case where the home address is used as a search key in the load balancing table 2 shown in FIG.
In this table, home address "2000.16"
With the search key as the search key, the identification information “S1” of the connection destination server corresponding to this home address and one-to-one is stored
In step T61 of the operation flowchart of the table control A shown in FIG. 4, this table is selected and becomes a search target.

The identification information of the connection destination server is the identification information of the server determined according to the load balancing algorithm according to the existing technology at the start of communication. As an algorithm for selecting a connection destination server, for example, there is a method of selecting a server by a round robin method or a method of selecting a server with a small load on the server, and the existing method can be used as it is.

When the home address shown in the example of the table structure of FIG. 6 is used as the search key, the entry is "2000".
Corresponds to the network ID (64 bits) in the IPv6 packet global address format shown in FIG. 7,
“16” is shown in a simplified form corresponding to the interface ID (64 bits). Next, a case where the lower 64 bits of the source address SA is used as the identification information of the mobile IP terminal will be described.

Care-of address Co of mobile IP terminal on the move
When A is generated by the stateless address generation method, the lower 64 bits of the mobile IPv6 global address shown in FIG. 7 can be used as the search key. As the configuration of the load balancer LB in this case, the configuration (1) of the load balancer of FIG. 2 can be used. In the case of the stateless address generation method described above, the lower 64 bits of the global address of the IPv6 packet uses the L2 address identifier such as a number combining the MAC address of the terminal itself, for example, in the case of Ethernet.

Therefore, since this address is unique for each terminal, in the operation flowchart using the home address of FIG. 3 as the search key, instead of extracting the home address, the source address to which the global address is set is set. If the lower 64 bits of SA are extracted and used as the search key of the load balancing table 2 and the table control A shown in FIG. 4 is executed and the packet is transmitted to the determined connection destination server, the mobile IP terminal MN It is possible to maintain consistency of processing between servers.

FIG. 8 shows an example of the configuration of the load balancing table selected by the table control A and to be searched. If the lower 64 bits of the source address SA is "16", it indicates that the connection destination server identification information is "S1". The identification information "S1" of the connection destination server is the identification information of the server determined by the load balancing algorithm according to the existing technology at the time of starting the communication as in the case described above.

Next, as the identification information of the mobile IP terminal,
The case where the security parameter index (SPI) is used will be described. If the IPv6 packet is encrypted, the security parameter index (SP
It is also possible to perform load balancing using I). That is,
As shown in the format example of the IPv6 packet for the server from the IPsec encrypted terminal in Fig. 10, when the IPv6 packet is encrypted, the ESP header is added as the extension header, and the security parameter index SPI Is stored. This SPI is identification information for identifying the security association that determines the security service content for safely communicating between two or more communication entities, and is unique for the communication session from the terminal to the server. Is assigned.
Therefore, by determining the connection destination server by using this SPI as the search key of the load balancing table, the mobile IP terminal MN
The consistency of processing between the server and the server can be secured. As the configuration of the load balancer LB in this case, the configuration (1) of the load balancer in FIG. 2 can be used.

FIG. 9 shows an operation flowchart in this case. First, the header is extracted from the received packet (step T11) .In this case, as shown in the format example of the IPv6 packet for the server from the IPsec encrypted terminal in FIG. The "next header" area in which the type code of the placed extension header is stored is confirmed, and the extension header code "50" indicating the ESP header (encryption header) is searched for (step T12).

If this code "50" is found (YES), the packet is encrypted, and as shown in the format example of the IPv6 packet for the server from the IPsec encrypted terminal in FIG. 10, IPv6 destination option 20 The extension header arranged next to is the ESP header 40. Since the security parameter index SPI is stored at the head of the ESP header 40, if this SPI is extracted and used as a search key when searching the load balancing table 2 (step T14), the mobile mobile phone as described above is used. This SPI remains unchanged while the communication session from the IP terminal MN to the server is open, and the mobile IP terminal MN
It is possible to maintain consistency of processing between the server and the server.

If the code "50" is not found (NO),
The source address because the packet is not encrypted
Use SA as the search key for the load balancing table (step T1
3). With the search key selected in the above steps, the table control A searches the load distribution table 2 to determine the connection destination server (step T15), and transmits the packet with the determined server as the destination (step T16). ).

FIG. 11 shows a configuration example of the load distribution table 2 when the SPI is used as the search key in this way.
In this example, the identification information "S1" of the connection destination server corresponding to the SPI "218" in a one-to-one relationship is stored. The identification information “S1” of the connection destination server is the identification information of the server determined by the load balancing algorithm according to the existing technology at the time of starting the communication as in the above.

Although the home address is included in the destination option in the above description, another extension header (eg, mobile IPv6 mobility option header) can be used. Further, in the above description, corresponding to the identification information of the mobile IP terminal to be used, when using the home address, when using the lower 64 bits of the source address, and divided into three cases when using SPI, In the operation flowcharts of FIGS. 3 and 9, when there is no header corresponding to the case in the received packet, a table search is simply performed using the source address SA as a search key, and the process ends. Can be combined with various processes. For example, first look for SPI in the header of the received packet.If there is no SPI, then look for the home address, and if not, look for the lower 64 bits of the source address. If not, the source address SA There is also a method of performing a table search by using as a search key. The present invention can be applied to any of these combinations.

FIGS. 12 and 13 show a network embodiment (2) to which the load balancer according to the present invention is applied. In this embodiment, information is exchanged between the home agent HA and the load balancer LB, and the mobile IP terminal MN
This is a method of changing the search key according to the movement of the. First, the operation when the load balancer LB receives the first packet from the mobile IP terminal MN will be described using the network embodiment (1) for receiving the first packet in FIG. (A1 to A5) will be described.

The IPv6 packet transmitted from the mobile IP terminal MN having the care-of address CoA1 is received by the load balancer LB via the routers R1 and R3 (sequence A1). The load balancer LB determines the mobile IP terminal from the received packet.
Source address SA (= CoA1) of MN and mobile IP terminal MN
The home address of is extracted (sequence A2).

Then, the connection destination server is determined by the existing load balancing algorithm, for example, the server S1 is determined and registered in the load balancing table, header rewriting processing is executed, and the packet is transmitted to the determined server S1 ( Sequence A
3). With the above sequence A3, the load balancer LB notifies the home agent HA managing the care-of address of the mobile IP terminal MN when the care-of address changes,
A CoA notification request for notifying this is sent (sequence A4). Home Agent HA is this CoA
Response to acceptance confirmation is returned in response to the notification request (sequence
A5).

Next, the operation when the mobile IP terminal MN moves corresponds to the operation sequence number (B1 to B7) described therein using the network example (2) when the MN moves in FIG. Attach and explain. The mobile IP terminal MN moves and changes the connection destination router from the router R1 (care-of address CoA1) to the router R2 (sequence B1), where the care-of address Co
Get A2 (sequence B2).

Then, the mobile IP terminal MN transmits a binding update indicating that the care-of address has changed from CoA1 to CoA2 to the home agent HA (sequence B3). The home agent HA that received the binding update updates the care-of address of the binding cache (a table that stores the correspondence between the home address and the care-of address of the mobile IP terminal) in its own station from CoA1 to CoA2 (sequence B4), and notices it. The load balancer LB is notified of the binding update indicating that the address has changed to CoA2 (sequence B
Five). FIG. 14 shows an example of the binding update message at this time.

The load balancer LB that has received the binding update creates an entry with the new care-of address CoA2 as the search key in the load balance table (sequence B6). At this time, leave the entry of CoA1 as it is, and read the connection destination server identification information in the entry of CoA1 and create a new entry of CoA2 so that the same connection destination server can be selected before and after the move. At this time, the read connection destination server identification information is stored as server identification information.

The load balancer LB receives the care-of address based on the care-of address CoA2 when receiving the packet thereafter.
The same server S1 as in CoA1 is selected as the connection destination server (sequence B7). A configuration (2) of the load balancer that executes such an operation is shown in FIG. 15. In this configuration, the CoA notification request generation unit 5 is different from the configuration (1) of the load balancer shown in FIG. The difference is that they are added.

FIG. 16 shows an operation flowchart of the configuration (2) of the load balancer LB, which will be described below for each processing step. First, the IPv6 header information extraction unit 1 extracts the header from the received packet as described above (step T21), and the received packet is sent to the mobile IP terminal M.
Whether IPv6 is sent directly from the N to the server or the binding update for notifying the change of the care-of address CoA sent from the home agent shown in sequence B5 of the network embodiment (2) of FIG.
The determination is made based on the option type (“198”) of the destination option (step T22).

As a result, the received packet is not a binding update (that is, mobile addressed to the server).
If the packet was sent by the IP terminal MN itself), (N
O), using the source address SA of this packet as a search key (step T23), the table control B searches the load balancing table 2 shown in the configuration (2) of the load balancing apparatus of FIG. Determine the destination server (step T2
4) Then, the packet is transmitted with the determined server as the destination (step T25), and the process is terminated.

FIG. 17 is an operation flowchart of the table control B for performing the connection destination server selection processing in step T24. In addition to the operation flow chart of table control A in Fig. 4, after creating the table entry, home agent HA
A processing step (step T245) of issuing a CoA notification request message to the destination is added. On the other hand, in step T22, when the received packet is a binding update (YES), the new IPv6 destination option set in the packet is set as shown in the message example of FIG.
CoA (new care-of address after mobile IP terminal MN moves)
Is used as a search key (step T26), and a new entry is created by the table control C (step T27).
), The processing ends.

The table control C for executing this new entry creation will be described for each processing step with reference to the operation flowchart of FIG. First, select the table corresponding to the type of search key from the load balancing table 2 (in this case, the table with SA as the search key), and use that table as the new care-of address (CoA2) set as the search key. Is searched (step T271), and it is determined whether a matching entry already exists (step T272).

As a result, if the entry corresponding to CoA2 has already been created (YES), no particular process is required, and the process returns to the calling source. On the other hand, when the entry corresponding to CoA2 is not created (NO), the old CoA
The table is searched by using as a search key, and the identification information of the server that has been connected so far is read (step T27).
3), create a new entry with the read identification information as stored data (step T274). This is to select the same server even if the same mobile IP terminal moves and the CoA changes.

In this way, since the identification information of the server used corresponding to the old care-of address is also copied to the entry of the new care-of address, even if the mobile IP terminal moves, it connects to the same server. It is possible to ensure consistency of server connection. FIG. 19 shows a configuration example of the load distribution table.

Here, the old care-of address CoA1 is "2000.1".
In 2 ”, when the server with the identification information“ S1 ”is selected as the connection destination, the binding update is received, and an example of the entry with the new care-of address CoA2“ 2001.12 ”is shown. In this table configuration example, the valid time is shown, but this valid time shows the valid time of the entry, and is subtracted at regular intervals, and when it becomes "0", the entry expires and the entry is deleted. It is a thing.

Therefore, two source addresses SA, old and new, coexist as search keys for a certain effective time for the same server address, and are newly added when the mobile IP terminal MN returns to the care-of address CoA1 again. Eliminates the need to create an entry. In the network embodiment (2) shown in FIGS. 12 and 13, the load balancer LB requests the home agent HA to change the care-of address, but the mobile IP terminal itself originally issued the care-of address. Since it knows the change, the same operation as described above will be performed even if a notification at the time of changing the care-of address is similarly requested to this mobile IP terminal.

(Supplementary Note 1) In a load balancer in a computer network in which a server and a mobile IP terminal communicate with each other, extraction means for extracting identification information unique to the mobile IP terminal from the arrived packet, and based on the identification information A load balancing apparatus, comprising: a determining unit that determines a connection destination server. (Supplementary note 2) The load balancer according to supplementary note 1, wherein the identification information is a home address included in a header of the packet. (Supplementary note 3) The load balancer according to supplementary note 1, wherein the identification information is defined in a predetermined bit of a source address of the packet. (Supplementary note 4) The load balancer according to supplementary note 1, wherein the identification information is a security parameter index when the packet is encrypted. (Supplementary note 5) In a load balancer in a computer network in which a server and a mobile IP terminal communicate,
When the first packet addressed to one server arrives, the home agent is informed of the means for requesting notification of the change of the care-of address when the care-of address of the mobile IP terminal is changed. And a means for determining a connection destination server using the care-of address as identification information. (Supplementary note 6) In a load balancer in a computer network in which a server and a mobile IP terminal communicate,
When the first packet addressed to one server arrives, when the care-of address is changed to the mobile IP terminal, a means for requesting notification of the change of the care-of address, and the noticed notification And a means for determining a connection destination server using the address as identification information. (Supplementary note 7) In the load balancer according to supplementary note 2, when the arrived packet is a packet transmitted from a home link of the mobile IP terminal, the extraction means extracts the source address of the packet as identification information. Then
The load balancer, wherein the deciding unit decides a connection destination server by using a transmission source address of the packet as identification information. (Additional remark 8) In the load balancer according to any one of additional remarks 1 to 4 and additional remark 7, the determining unit uses the identification information of the transmission source corresponding to the care-of address of the mobile IP terminal as a search key to connect to the connection destination server. A load balancer characterized by including a table storing identification information of the server, and determining a connection destination server by using a transmission source address of the arrived packet. (Supplementary Note 9) In the load balancer according to Supplementary Note 5 or Supplementary Note 6, the determining unit has a table that stores the identification information of the connection destination server using the source address corresponding to the care-of address as a search key and arrives. While determining the destination server using the source address of the packet,
When the table is notified of a new care-of address, an entry using the new care-of address as a search key is created and stored, and as a data to be stored, the connection destination server stored as the data of the entry of the old care-of address is identified. A load balancer characterized by storing information.

(Supplementary Note 10) In the load balancer according to Supplementary Note 9, the determining means stores the valid time in the data of the entry, periodically subtracts the valid time, and uses the entry. The load balancer is characterized in that the valid time is updated every time when the valid time arrives, and the entry is invalidated when the valid time expires.

(Supplementary note 11) The load balancer according to any one of supplementary notes 1 to 4, wherein a home agent of a mobile IP terminal is set as a connection destination instead of the server. (Supplementary Note 12) In a home agent in a computer network in which a server and a mobile IP terminal communicate with each other via a load balancing apparatus, in response to a request from the load balancing apparatus, information on a binding cache managed by itself is provided, A home agent, which notifies the load balancer periodically or when the care-of address of the mobile IP terminal is changed. (Supplementary Note 13) In a mobile IP terminal that communicates with a server via a load balancer, the information about the binding cache managed by itself is periodically or according to a request from the load balancer. A mobile IP terminal, which notifies the load balancer when a care-of address is changed.

[0063]

As described above, according to the load balancer, home agent, and mobile IP terminal of the present invention, the identification information unique to the mobile IP terminal is extracted from the arrived packet, and based on this identification information. Since the connection destination server is determined based on this, the consistency of the connection destination server is always maintained when the server is accessed from the mobile IP terminal.

When the first packet addressed to one server arrives, the home agent or the mobile IP terminal is notified of the change of the care-of address when the care-of address of the mobile IP terminal is changed. Even if the connection destination server is determined by using the notified care-of address as the identification information, the consistency of the connection destination server can be maintained in the same manner.

[Brief description of drawings]

FIG. 1 is a diagram showing a network embodiment (1) to which a load balancer according to the present invention is applied.

FIG. 2 is a block diagram showing a configuration (1) of a load balancer according to the present invention.

FIG. 3 is a flowchart showing an operation (when a home address is used as a search key) in the network embodiment (1) of the load balancer according to the present invention.

FIG. 4 is a table control A in the flowchart of FIG.
3 is a flowchart showing the operation of FIG.

FIG. 5 is a diagram showing a format example of an IPv6 packet for a server from a terminal used in the load balancer according to the present invention.

FIG. 6 is a diagram showing a configuration example of a load distribution table in the network embodiment (1) of the load distribution apparatus according to the present invention (when a home address is used as a search key).

FIG. 7 is a format diagram of a general global address of an IPv6 packet.

FIG. 8 is a diagram showing a configuration example of a load distribution table in the network embodiment (1) of the load distribution apparatus according to the present invention (when the SA lower 64 bits are used as the search key).

FIG. 9 is a flowchart showing an operation (when SPI is used as a search key) in the network embodiment (1) of the load balancer according to the present invention.

FIG. 10 is a diagram showing a format example of an IPv6 packet for a server from an IPsec encrypted terminal.

FIG. 11 is a diagram showing a load balancing table configuration example (when SPI is a search key) in the network embodiment (1) of the load balancing apparatus according to the present invention.

FIG. 12 is a block diagram showing a network embodiment (2) (when receiving a first packet) to which the load balancer according to the present invention is applied.

FIG. 13 is a block diagram showing a network embodiment (2) (when moving a mobile IP terminal) to which a load balancer according to the present invention is applied.

14 is a message example of a binding update message in the network embodiment (2) (when the mobile IP terminal moves) to which the load balancer of FIG. 13 is applied.

FIG. 15 is a block diagram showing a configuration in a network embodiment (2) of a load distribution apparatus according to the present invention.

FIG. 16 is a flowchart showing an operation (when a transmission source address is used as a search key) in the network embodiment (2) of the load distribution apparatus according to the present invention.

17 is a flowchart showing an operation of table control B in the flowchart of FIG.

FIG. 18 is a flowchart showing an operation of table control C in the flowchart of FIG.

FIG. 19 is a diagram showing a configuration of a load distribution table (when SA is a search key) in a network embodiment of the load distribution apparatus according to the present invention.

FIG. 20 is a diagram showing an example of a network configuration to which a load balancing device of a conventional technique is applied.

[Explanation of symbols]

LB Load balancer HA Home agent R1 to R3 Router S1, S2 Server CoA, CoA1, CoA2 Care-of address MN Mobile IP terminal SA Source address DA Destination address SPI security parameter index 1 IPv6 header information extractor 2 Load distribution table 3 Table control Part 4 Distribution processing part 5 CoA notification request generation part 10 IPv6 header 20 IPv6 destination option header 30 Upper layer data 40 ESP header 50 ESP authentication data A1 to A5 Network embodiment (2) (when receiving the first packet) Operation sequence numbers B1 to B7 In the operation sequence number diagram in the network embodiment (2) (when moving the MN), the same reference numerals indicate the same or corresponding parts.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiichi Nakatsugawa             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited F-term (reference) 5K030 HA08 HC09 HD06 HD09 JL01                       JT09 KA05 LB05 MA04                 5K067 AA23 BB21 DD17 EE02 EE10                       HH32

Claims (10)

[Claims] 1. A load balancer in a computer network in which a server and a mobile IP terminal communicate with each other, and extraction means for extracting identification information unique to the mobile IP terminal from an incoming packet, and a connection destination based on the identification information. A load balancer comprising: a determining unit that determines a server. 2. The load balancer according to claim 1, wherein the identification information is a home address included in a header of the packet. 3. The load balancer according to claim 1, wherein the identification information is defined in a predetermined bit of a source address of a packet. 4. The load balancer according to claim 1, wherein the identification information is a security parameter index when a packet is encrypted. 5. A load balancing apparatus in a computer network in which a server and a mobile IP terminal communicate with each other, when a first packet addressed to one server arrives, to a home agent managing a care-of address of the mobile IP terminal. , A means for requesting notification of the change of the care-of address when the care-of address of the mobile IP terminal is changed, and a means for determining a connection destination server using the notified care-of address as identification information. A load balancing device. 6. A load balancer in a computer network in which a server and a mobile IP terminal communicate with each other, when a first packet addressed to one server arrives, its care-of address is changed for the mobile IP terminal. In this case, the load balancer comprises: means for requesting notification of the change of the care-of address; and means for determining a connection destination server using the notified care-of address as identification information. 7. The load balancer according to claim 2, wherein the arrived packet is. When the packet is transmitted from the home link of the mobile IP terminal, the extracting means extracts the source address of the packet as identification information, and the determining means connects the source address of the packet as identification information to the connection destination. A load balancer characterized by determining a server. 8. The load balancer according to claim 1, wherein the determining unit searches for identification information of a transmission source corresponding to a care-of address of the mobile IP terminal as a search key. A load balancer characterized by comprising a table for storing identification information of a connection destination server, and determining a connection destination server by using a transmission source address of an arrived packet. 9. A home agent in a computer network in which a server and a mobile IP terminal communicate with each other via a load balancer, in response to a request from the load balancer, information on a binding cache managed by itself is provided. A home agent that notifies the load balancer periodically or when the care-of address of the mobile IP terminal is changed. 10. A mobile IP terminal that communicates with a server via a load balancer, in response to a request from the load balancer, information on a binding cache managed by itself, periodically or by itself. A mobile IP terminal, which notifies the load balancer when the care-of address of itself is changed.