JP2005027123A - Home agent device and home agent selection method for mobile terminal communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete method for realizing load distribution of a home agent and management of the home agent at the time of fault, which associates a care or address of a mobile node with a home address. <P>SOLUTION: The home agent device is provided with at least care of addresses and two or more home agent addresses which share the care of addresses and an address management table in which priority values by every two or more home agents are associated with operating states. Thus, since priority between the operating states (active or inactive) of each home agent and the home agents is set, the load distribution of the home agents by every care of address is realized by a way of setting the priority. In addition, the operating states are also grasped. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a load distribution technique of a home agent that is essential in network communication in mobile communication.
[0002]
[Prior art]
As a network technology that supports mobile communication, standardization of Mobile IP (Mobile IP (Inter-net Protocol v6)) is underway.
[0003]
Mobile IP (Mobile IP) requires mobility that conceals changes in the IP address caused by movement and the ability to always make a call so that the correspondent node can uniquely identify the IP address of the mobile node.
[0004]
Furthermore, it is necessary to assume IPv6, which is a new protocol, in order to cope with address exhaustion in the IPv4 environment, which is the current standard protocol of the Internet.
[0005]
In view of these points, a draft standard for Mobile IPv6 has been proposed. Under Mobile IPv6, the address assigned to the mobile terminal under the original home link (Home Link) before the movement of the mobile terminal is set as the home address (Home Address), and the node at the movement destination is the mobile node (Home Node). MN: Mobile Node), and the actual available address of the mobile terminal under this mobile node (visited link) is set as a care-of address (CoA), and this care-of address is set as the care-of address. The unique identification of the IP address of the mobile node is ensured by associating it with the home address.
[0006]
Then, in order to manage the home address and the care-of address in association with each other, a management device called a home agent (HA) is set, and the addresses before and after the movement are related by the home agent. .
[0007]
This home agent has a database called a binding cache, which associates the home address of the mobile node with the care-of address and registers the validity period thereof.
[0008]
Further, Mobile IPv6 (draft 23) proposes a mechanism (Home Agent Address Discovery Mechanism) in which a mobile node (MN) automatically and dynamically searches for a home agent in order to share functions between home agents.
[0009]
In mobile communication, Japanese Patent Application Laid-Open No. 2001-217866 and Japanese Patent Application Laid-Open No. 2001-169341 disclose techniques for enabling dynamic service change even during communication.
[0010]
In Patent Document 1, a service profile setting control unit and a service profile resetting control unit are provided in a home server connected to a home agent, and an event is generated based on a regulation condition in the service profile. This is a technique for extracting a new service profile and dynamically setting a new service profile for a network device, for example, a communication service quality and a charging method.
[0011]
Patent Document 2 provides a service control database so that control information can be customized for each user's mobile terminal, and the service profile is distributed only to the home agent of the mobile node and the external agent that accommodates the mobile agent. In this way, even if the number of mobile nodes increases, service control information to be set for each agent is relatively reduced so that value-added services can be provided to mobile terminals.
[0012]
[Patent Document 1]
JP 2001-217866 A [Patent Document 2]
JP 2001-169341 A
[Problems to be solved by the invention]
Although all of the above-mentioned patent documents attempt to control a dynamic communication environment by paying attention to mobile communication, the IP address of a mobile node that dynamically changes as a vehicle moves is taken as the home address. It did not adjust consistency.
[0014]
The present invention has been made paying attention to such points, and specifically realizes load distribution of a home agent that associates a care-of address of a mobile node with a home address and management at the time of failure of the home agent. The issue is to provide technology.
[0015]
[Means for Solving the Problems]
The first means of the present invention is a home agent device that associates a home address under a home link of a mobile terminal with a care-of address under a mobile node after movement, at least the care-of address and its care. A home agent device provided with an address management table in which addresses of two or more home agents that share an address, a priority value for each of the two or more home agents, and an operation state are associated with each other.
[0016]
Since the address management table can set the operating state of each home agent (active or inactive) and the priority order between the home agents, the care-of address of the home agent depends on how the priority order is set. Each load can be distributed. In addition, since the operating state can also be grasped, the mobile node side avoids the faulty home agent and selects an appropriate home agent, and the care-of address and home address for the mobile terminal under the mobile node. Can be associated with each other to realize access to the network.
[0017]
The home agent device as described above is suitable for a communication network that manages a large number of IP addresses (second means).
[0018]
According to a third means of the present invention, in the home agent device associating the home address under the home link of the mobile terminal with the care-of address under the mobile node after movement, at least the care-of address An address management table in which the addresses of two or more home agents that share the care-of address, the priority value for each of the two or more home agents, and the operation state are associated, and the home agent address via the network Home comprising control means for accepting a discovery request, accessing the address management table, and returning the status of the home agent corresponding to the care-of address to the mobile node as a home agent address discovery reply age It is a cement equipment.
[0019]
As described above, the third means can provide optimal home agent information on the premise of load distribution to the mobile node.
[0020]
The fourth means of the present invention includes at least a care-of address, addresses of two or more home agents that share the care-of address, a priority value for each of the two or more home agents, and an operation state. A home agent selection method for a network including a home agent device having an associated address management table, the step of receiving a home agent address discovery request from a mobile node, and based on the care-of address The priority value and the operation state for each home agent are returned to the mobile node as a home agent address discovery reply, and the mobile node adds the home agent whose home agent operation state is active and has a high priority. Select a scan as a home agent in charge of sharing a home agent selection method for the mobile terminal communication to allow access from the mobile terminal under the mobile node.
[0021]
Also in this fourth means, the operation state (active or inactive) of each home agent and the priority order between the home agents can be set by the address management table. Load distribution can be realized for each care-of address of the home agent. In addition, since the operating state can also be grasped, the mobile node side avoids the faulty home agent and selects an appropriate home agent, and the care-of address and home address for the mobile terminal under the mobile node. Can be associated with each other to realize access to the network.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
FIG. 1 is an explanatory diagram showing a network configuration of the present embodiment.
[0024]
In the figure, the terminal device (MT) 1 a is set with a home address of “A: B: C :: / 48”, for example, under the home link of the mobile node (MN) 2. In this figure, the terminal device (MT) 1a has moved to a visited link (Mobile Link) under the control of the mobile node (MN) 3. Under this mobile node (MN) 3, “X: Y: Z :: / 48” is assigned as an actual address.
[0025]
These mobile nodes (MN) 2 and 3 are connected to a network (NW). A plurality of home agents (HA 1 to n) are connected to the network (NW) 4 via a router 5.
[0026]
FIG. 2 shows the contents of the binding cache database (BCD), and FIG. 3 shows a block diagram of the configuration of the home agent (HA) in which the binding cache database (BCE) is accommodated.
[0027]
As shown in FIG. 3, the home agent (HA1) has a home agent management table (HAMT) and a binding cache database (BCD).
[0028]
The contents of the home agent management table (HAMT) are set by the home agent management table setting unit 303. Further, the home agent address discovery request processing unit 307 is accessed using the care-of address as a search key, and the search result is assembled into the format shown in FIG. 5 by the home agent address discovery discovery reply generation unit 305. The transmission unit 306 transmits the data.
[0029]
The binding cache database (BCD) is accessed by the home address request processing unit 304.
[0030]
As shown in FIG. 2, the binding cache database (BCD) has a care-of address (CoA) as a key and a corresponding home address and expiration date (Lifetime) registered therein. As the home address, the home address under the mobile node (MN) 2 of the terminal device (MT) 1 before movement is registered. The expiration date means the expiration date of the binding cash. The reason why the expiration date is set in this way is to prevent the binding cache area from being enlarged due to the care-of address (CoA) that is no longer needed. In FIG. 2, the care-of address (CoA) of “X: Y: Z :: / 48” means that it corresponds to the home address of “A: B: C :: / 48”. .
[0031]
When the home agent (HA1) receives a home address request using the care of address (CoA) as a search key from the mobile node (MN) 3, the request is analyzed through the reception unit 301 and the request analysis unit 302. Then, the home address request processing unit 304 accesses the binding cache database (BCD), and the mobile node (MN3) is notified of the home address corresponding to the care-of address (CoA). . Thus, the mobile node (MN3) can know the home address of the terminal device (MT) 1 under the link.
[0032]
As shown in FIG. 7, the home agent management table (HAMT) includes a care-of address (CoA) of the mobile node (MN), an address of a home agent (HA) that manages the care-of address, and a prefetch. The lance value and the operation status are registered. As the care-of address (CoA), the real address of the terminal device (MT) linked under the mobile node (MN) is registered. The address of the home agent (HA) indicates the address of the home agent (HA) that manages the care-of address (CoA). That is, in the case of FIG. 7, the home address of the terminal device having the real address “X: Y: Z :: / 48” as the mobile node uses the binding cache database (BCD) managed by the home agent (HA1). It shows that The priority value indicates a priority order, and a larger numerical value means a higher order. That is, in the case of FIG. 7, a request having the care of address (CoA) of “X: Y: Z :: / 48” as a key means that the home agent (HA1) is used preferentially, This means that (HA2) is used second. Similarly, a request having the care of address (CoA) of “X: Y: W :: / 48” as a key means that the home agent (HA2) is used preferentially, and the home agent (HA1). Is used second. The operation status is registered for each home agent. “Active” means a normal operation state, and “inactive” means a non-operation state. When the home agent management table (HAMT) is in a state as shown in FIG. 9, it means that the home agent (HA1) is not operating due to a failure and the home agent (HA2) is operating normally. .
[0033]
Next, updating of the home agent management table (HAMT) will be described.
[0034]
The home agent management table (HAMT) between home agents communicates between home agents by adding an active flag (F1 to Fn) of each home agent to the router advertisement request (RAR) from the router 5. By referring to the active flags (F1 to Fn), each home agent (HA) can recognize the home agent (HA) in which a failure has occurred. Specifically, as shown in FIG. 9, the home agent (HA2) has a failure in the home agent (HA1) because router advertisement (RA) that does not have the home agent information option does not arrive. Recognize that
[0035]
Next, processing when a home agent address discovery request (HAAD request) is transmitted from the mobile node (MN) 3 will be described.
[0036]
The mobile node (MN) 3 uses the IP address of the mobile terminal (MT) 1 under its link (mobile address after movement, here “X: Y: Z :: / 48”) as a search key. An agent address discovery request (HAAD request) is transmitted. This request is transmitted from the mobile node (MN) 3 to the router 5 via the network (NW) in the format shown in FIG. 4, and is sequentially transferred from the router 5 to each home agent (HA).
[0037]
In the home agent (HA) 1, the home agent address discovery request processing unit 307 searches the home agent management table (HAMT), and “X: Y: Z :: /” of the care-of address (CoA) is searched. 48 ”is an address managed by the home agent (HA1) and the home agent (HA2), both home agents are operating normally, and the self (home agent HA1) has a preference value. Therefore, the home agent address / discovery reply generation unit 305 assembles the addresses and preference values of both home agents into the format shown in FIG. 5 and sends them back to the mobile node (MN) 3.
[0038]
In this way, the mobile node (MN) 3 can recognize the home agents (HA1 and HA2) that manage the care-of address (CoA). Among them, the address of the home agent (HA1) having a high preference value is preferentially used.
[0039]
When the home agent (HA1) receives an agent address discovery request with the care-of address (CoA) set to “X: Y: W :: / 48”, the home agent management table (FIG. HAMT) and recognize that it is the home agents HA1 and HA2 that manage the address, but both home agents are operating normally and HA2 has a higher preference than the home agent HA1. When recognizing that it is a value, the home agent HA1 recognizes that it is not a request that it should respond to and terminates the process without responding.
[0040]
On the other hand, the home agent HA2 that has received the request with the same care-of address (CoA) at “X: Y: W :: / 48” refers to the table shown in FIG. 8 and manages the address. Recognize that they are home agents HA1 and HA2. Here, since both home agents are operating normally and HA2 (self) has a higher preference value than the home agent HA1, both home agents recognize that it is a request to be processed by themselves. The address of (HA1, HA2) and both preference values are assembled in the format shown in FIG. 5 by the home agent address / discovery reply generation unit 305 and returned to the source mobile node (MN) 3.
[0041]
In this way, the load distribution of the home agent (HA) can be realized by the care of address (CoA).
[0042]
On the other hand, when a failure occurs in the home agent (HA1), as described above, the contents of the home agent management table (HAMT) of the home agent (HA2) are updated as shown in FIG.
[0043]
In this state, even if the home agent (HA1) receives an agent address discovery request with the care-of address (CoA) set to “X: Y: W :: / 48”, the home agent HA1 fails. It is in a state where it cannot respond.
[0044]
When the home agent HA2 receives the same request as described above, it is the home agents HA1 and HA2 that correspond to the care-of address (CoA), but since HA1 is inactive, Regardless of the preference value, the home agent HA2 recognizes that it is a request that it should respond to, and returns an agent address discovery reply. At this time, the mobile node (MN) 3 may be notified of the information of both home agents (HA1, HA2), including that the home agent HA1 is not operating, or operates normally. Only the information of the home agent HA1 that is in charge may be notified.
[0045]
As described above, in this embodiment, by using the home agent management table (HAMT) shown in FIGS. 7 to 9, when a plurality of home agents are applicable, a home agent having a higher preference value is used. When a failure occurs in the top-level home agent, the next home agent that is operating normally can be used. Avoidance is possible.
[0046]
In the embodiment, for simplification of explanation, the load distribution and the processing at the time of failure occurrence have been described by taking two home agents (HA1, HA2) as an example, but it is of course applicable to three or more home agents. is there.
[0047]
【The invention's effect】
According to the present invention, when connecting a mobile terminal to an IPv6 network, the load distribution of the home agent that associates the care-of address of the mobile node with the home address and the management at the time of failure of the home agent are specifically described. Can be realized.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a network configuration of an embodiment of the present invention. FIG. 2 is an explanatory diagram showing contents of a binding cache database of a home agent. FIG. 3 is a functional block diagram of a home agent. FIG. 5 is an explanatory diagram showing the format of the HDDA reply. FIG. 6 is an explanatory diagram showing the format of the RA request. FIG. 7 is a diagram showing the contents of the address management table of the home agent 1 (HA1).
FIG. 8 is a diagram (2) showing the contents of the address management table of the home agent 2 (HA2)
FIG. 9 is a diagram showing the contents of the address management table of the home agent 2 (HA2) when a failure occurs in the home agent 1 (HA1).
1 Terminal equipment (MT)
2,3 Mobile node (MN)
4 Network (NW)
5 Router 301 Receiving Unit 302 Request Analyzing Unit 303 Home Agent Management Table Setting Unit 304 Home Address Request Processing Unit 305 Home Agent Address Discovery Reply Generation Unit 306 Transmitting Unit 307 Home Agent Address Discovery Request Processing Unit HA Home Agent BCD binding cache database HAMT home agent management table

Claims (4)

In a home agent device for associating a home address under a home link of a mobile terminal with a care-of address under a mobile node after movement,
It has an address management table that associates at least the care-of address, the addresses of two or more home agents that share the care-of address, the priority value for each of the two or more home agents, and the operation state. Home agent device. The home agent device according to claim 1, wherein the home agent device is connected to an IPv6 network via a router. In a home agent device for associating a home address under a home link of a mobile terminal with a care-of address under a mobile node after movement,
An address management table in which at least a care-of address and addresses of two or more home agents that share the care-of address, a priority value for each of the two or more home agents, and an operation state are associated with each other;
A home agent address discovery request is received via the network, the address management table is accessed, and the status of the home agent corresponding to the care-of address is sent to the mobile node as a home agent address discovery reply. A home agent device comprising control means for replying. It has an address management table that associates at least the care-of address, the addresses of two or more home agents that share the care-of address, the priority value for each of the two or more home agents, and the operation state. A home agent selection method for a network including a home agent device,
Receiving a home agent address discovery request from the mobile node;
A priority value and an operation state for each home agent based on the care-of address are returned to the mobile node as a home agent address discovery reply.
The mobile node selects an address of a home agent whose home agent is active and has a high priority as a home agent in charge of sharing, and allows the mobile node to permit access from a mobile terminal under the mobile node Home agent selection method for terminal communication.

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