Handoff notification and control method for mobile node

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a mobile IP (mobile IP) service, and more particularly to a mobile IP (mobile IP) service method for a handed-off mobile node (hereinafter abbreviated as MN).

【0002】

[Conventional technology]

Recently, while mobile communication and wireless LAN have become widespread, Internet connections centered on fixed terminals subordinate to Wide Area Network (hereinafter abbreviated as WAN) or Local Area Network (hereinafter abbreviated as LAN) have been reduced. , Internet connection using mobile terminals is gradually increasing, and research on the relevant technology is being actively promoted. Therefore, the Internet Engineering Task Force (IETF) and the ATM Forum have proposed a plan that can accommodate the Internet Protocol (hereinafter abbreviated as'IP') in the ATM network or mobile communication network, and standardization for it has been established. Has been done.

【0003】

Moreover, IP Version 4, which is used in most Internet environments, "should be located in a network that includes the IP address of the node in order for the node to receive the datagram transmitted to itself. If that position changes, the datagram cannot be transmitted. "

【0004】

The IETF is currently promoting RFC 2002 as a standardization plan to support the mobility of the node, which requires more extended technology to support the mobility of the node on the Internet. The draft standard (RFC2002) presents a technical plan that MNs connected to TCP / IP networks can be used without changing their IP addresses even if they move to other locations.

【0005】

FIG. 2 is a conceptual diagram showing a mobile IP (mobile IP) service based on the IETF's draft mobile IP (mobile IP) standard (RFC2002). As shown in FIG. 2, the mobile node (hereinafter abbreviated as'MN') 11 is a mobile IP host (IP host) and has a home IP address (Home IP Address). Send and receive data with.

【0006】

In addition, Foreign Agents (hereinafter abbreviated as'FA') 13 and 13'have a link connection with MN11 when the MN11 visits the visiting networks 12 and 12'. The IP packet destined for the MN11 is de-capsulated and transmitted.

【0007】

Further, the Home Agent (hereinafter abbreviated as'HA') 15 is located in the corresponding Home Network 14 of the MN11, manages the binding table of the MN11, and is described above. An IP packet destined for MN11 is transmitted by encapsulating (IP Packet). Performed to continuously support the handoff MN11 with mobile IP services during the mobile IP wireless communication method under the IETF Mobile IP Standards (RFC2002). The procedure can be explained by dividing it into three processes as follows. 1. Agent discovery process Mobility such as S1, HA15 or FA13, 13' The Agent) broadcasts an agent advertisement message to its own network areas 12 and 12', and the MN11 that receives the agent advertisement message determines in which network area it is located. That is, if MN11 starts transmitting a new advertising message that is different from the conventional one from any point in time, it means that MN11 has previously left the area of FA13 (Network 1) and moved to another area of FA13'(Network 2). means. The agent advertisement message is a kind of area display message sent by agents 13, 13', and 15 within its own network area, and the MN11 has the area in which it is located through the received agent advertisement message. You will be able to know which agent's area it is. 2. Registration process S2, if MN11 does not actually move to another network 12'area by the agent discovery process, MN11 and HA15 exchange registration request messages and registration response messages with each other. Care-of address Register Address) (COA) with HA15. Each registration message is sent and received through User Datagram Protocol (UDP) port 434 and includes the COA lifetime of MN11 and the like. The COA means the address of the agent of the network on which MN11 is located. 3. Routing and Tunneling Process When S3, MN11 is successfully registered in HA15, the datagram sent from the outside to MN11 is tunneled by HA15 to the COA of MN11. If the COA is assigned an FA address, the FA will perform a de-capsulation, and if the FA address is used as a Co-Located COA, the MN11 will be decapsulated. De-Capsulation will be performed. The tunnel (or IP tunnel) is an encapsulated datagram (Encapsulated). This is the path that datagram) travels. At this time, HA15 is the starting point of the tunnel, and the node that performs Encapsulation and de-capsulating becomes the end point of the tunnel. The De-capsulating node not only de-capsulating the datagram, but also de-capsulated the de-capsulated datagram as the final destination. An object that is transmitted to. If FA address is specified for COA, FA13, 13'is executed as a de-capsulating node, but if FA address is used as Co-Located COA, MN11 is decapsulated. It is performed as a rating node (De-capsulating node). The procedure for carrying out the registration process S2 is as follows. (a) MN11 transmits a registration request message to Agent 13'of the currently located network 12'. (b) The Agent 13', FA13', carries out a predetermined registration procedure and transmits the registration request message to HA15. (c) HA15 sends a registration permission response message or registration rejection response message to FA13'in response to the registration request. (d) FA13'transmits the received registration response message to MN11.

【0008】

FIG. 5 is a diagram of the registration procedure of the hand-off MN according to the conventional method.

【0009】

The registration process S2 will be described as follows based on FIGS. 2 and 5.

【0010】

That is, MN11 is from the service area (Network 1) of'old FA'(hereinafter abbreviated as'old FA') 13 to the service area (Network 2) of'new FA'(hereinafter abbreviated as'new FA') 13'. When moved (handed off) to, the MN11 transmits a registration request message (type = '1') to the agent 13'of the network 12'where it is currently located.

【0011】

Upon receiving the registration request message, FA13'registers MN11 in the visitor table and transmits the registration request message to HA15 again. S2 If FA13'disallows registration of MN11, FA13' will not transmit the registration request message of MN11 to HA15 and will enter the disallowed code (64 ~ 73, 80 ~) in the'code'field. Send a registration response message with 82 and 88) set to MN11. If the MN11 registration request is granted to FA13'but not to HA15, FA13' deletes the MN11 registration stored in the visitor table.

【0012】

Next, when the HA15 receives the registration request message of MN11, the binding table is updated with reference to the address value stored in the COA field of the registration request message. Of course, the execution of HA15 is when there is no error in the registration request of MN11. If HA15 disallows registration of MN11, HA15 sends a registration response message to MN11 via FA13'with a registration disapproval code (128-136) set in the'code'field.

【0013】

If MN11 is successfully registered with FA13'and HA15, an IP tunnel will be set up between FA13' and HA15. The HA15 then transmits the IP datagram received from the Internet host to the MN11 through the configured IP tunnel. At this time, the end point of the IP tunnel is FA13', and the address of the FA13' is called a core-of-address (COA).

【0014】

The HA15 encapsulates an IP datagram to generate an IP packet before transmitting the IP datagram to the IP tunnel. In addition, FA13'de-capsulates (IP Packet) the IP packet received through the IP tunnel and transmits it to MN11.

【0015】

The registration of MN11 stored in the FA13'visitor table is valid only during the lifetime set in the registration request message, and if re-registration is not performed until the end of the lifetime, the mobile binding of HA15 The registration of MN11 stored in the table and the visitor table of FA13'will be deleted, and MN11 will not be able to receive mobile IP (mobile IP) services.

【0016】

Through this process, the MN11 is routed to the IP Packet 11 from the Internet host, so that the MN11 can be used as a mobile IP service even after it has been relocated to another service area. Will be offered. In addition, the MN11 can continue to use its own Home IP address set for the first time as a mobile IP address regardless of the service area.

【0017】

FIG. 3 is an example diagram showing a registration request message and a registration response message. Hereinafter, each field of the registration request message and the registration response message shown in FIG. 3 and their set values will be described.

【0018】

If the setting value of the'Type'field of the registration request message is '1', it is a registration request message, and if it is '3', it is a registration response message.

【0019】

If the S in the registration request message is a simulated binding and the "S" bit is set ('1'), HA15 retains the previous Mobility binding of MN11. B is a Broadcast datagram, and when the'B'bit is set, HA15 transmits the Broadcast datagram received by the Home Network to MN15. D is De-Capsulation by MN11, which means that MN11 de-Capsulations the datagram when the'D'bit is set. That is, Co-Located COA is used as the mobile IP address of MN11. When using COA, MN11 registered in FA13'receives data depending on the address of FA13', but Co-Located The COA is used when the MN11 has a unique address (Local Address) linked to the network interface.

【0020】

M is the minimum encapsulation, and if the'M'bit is set, HA15 encapsulates the datagram transmitted to the MN11. Send. G is a 'GRE' encapsulation (Encapsulation), the 'G' bit is being set, HA 15 is datagrams to be transmitted to MN11 and (datagram) GRE encapsulation (Encapsula tion ) And send. When the'V'bit is set, mobilityAgents 13, 13', and 15 perform data transmission using the Van Jacobson header compression method on the link connected to the MN. rsv is a Reserved bit and is set to '0'. A predetermined time is set in the Life Time field, and the registration of MN11 is valid during the set time.

【0021】

The Home Address is the IP address of MN11, the Home Agent is the IP address of HA15, the COA is the IP address of the end of the tunnel, and the identification is the registration request and registration. A 64-bit number constructed by MN11 to match the response.

【0022】

The code of the registration response message indicates the result of the registration request. That is, HA15 or new FA13'sets the result (registration permission or registration disapproval) value for the registration request of MN11. A code value of '0' or '1' indicates permission to register, and "64-73", or "80-82" or "88" indicates disapproval of registration by FA, and "128-136". "Indicates that registration is not permitted by HA.

【0023】

The settings in the'Home Address'field and'Home Agent'field are similar to the registration request message, and the values set in the'Identifier field are in the MN11 registration request message. A 64-bit number that is set based on the identifyr field value and is used to match the registration request with the registration response and to prevent the registration message from being rejected.

【0024】

Therefore, HA15 that receives the registration request message of MN11 creates or modifies a binding table for MN11 by referring to the setting values of each field and bit included in the registration request message.

【0025】

As explained above, even if the position of MN11 is changed, FA13 cannot receive the report of the handoff fact of MN11 from HA15 or MN11, so FA13 will not be able to receive the notification of the handoff fact of MN11 until the set lifetime ends. It will have a visitor table for MN11, which will waste memory.

【0026】

In addition, as shown in Fig. 4, in the mobile wireless network, the Mobile Station (MS) 105 is receiving service in the service area of the Packet Station Serving Node (PDSN) 102. When moving to the PDSN102'area, the PDSN102 still occupies the MS105's visitor table and MS105's wireless link resources, and the BS103 manages information about the MS105 that has already been handed off and does not exist in its service area. As a result, the resources of PDSN102 and BS103 will be wasted. The BS 103 and 103'are objects that combine a base station transceiver (Base Station Transceiver), a base station controller (Base Station Controller), and a packet controller function (Packet Control Function), and in reality, all three objects are all three objects. It is an independent mobile communication equipment.

【0027】

Hereinafter, for convenience of description according to the present invention, the equipment will be simply expressed as BS103, 103'.

【0028】

As another example, if the MS105 handed off to the service area of PDSN102'is rehanded off to the service area of PDSN102 again before the end of its own lifetime registered in PDSN102, the binding table of PDSN102 is already available. Since it is registered in and the life timer setting time is still valid, PDSN102 and BS103 will not accept the registration request of MS105 even if MS105 sends a registration request message, and as a result, When the set time of the life timer ends, the MS105 is actually located in the service area of the BS103, but the BS103 does not recognize this, and the BS103'is still in its own service area. There is a'Registration Dead Lock'that will be recognized as being located in.

【0029】

[Problems to be Solved by the Invention]

However, in such a conventional mobile node handoff notification and control method, various methods and algorithms have been presented in order to solve the registration dead rack problem and the memory resource waste problem. There was the inconvenience that separate resources should be allocated for the algorithm to solve the point.

【0030】

The present invention has been made in view of such conventional problems, and is a'mobile node handoff notification and control method'for solving a registration dead rack of a handoff mobile node (Mobile Node). The purpose is to provide.

【0031】

It also notifies the previous FA of the fact of the mobile node handoff and provides a'mobile node handoff notification and control method'for efficiently managing the memory resources of the previous FA. The purpose is to do.

【0032】

[Means for solving problems]

The mobile node handoff notification and control system according to the present invention includes a mobile node (Mobile Node: hereinafter abbreviated as MN) that transmits a registration request message, and a mobile IP (mobile) to the MN before the handoff occurs. An old foreign agent (FA) that provides an IP) service, a new FA that provides a mobile IP service to the MN after a handoff occurs, and a new FA that provides a mobile IP service when a handoff occurs. When a registration request message is transmitted from the MN through (new FA), it includes a Home Agent (HA) that generates a deregistration message and transmits it to the old FA. Achieves the above-mentioned purpose.

【0033】

The old FA may delete the MN registration information stored in the visitor table by the registration cancellation message.

【0034】

The'type'of the deregistration request message may be similar to the registration request message.

【0035】

In the mobile node handoff notification and control system according to the present invention, the deregistration request message has a'type' field set to identify the message type and a lifetime setting the valid registration time of the MN. A field, a Home Address field that sets the IP address of the MN, a Home Agent field that sets the IP address of the HA, and a care-off address field that sets the IP address of the end point of the tunnel. (Care-Of Address field) and an identifier field (Identification field) set to match the registration request message and the registration response message are included and configured, thereby achieving the above-mentioned object.

【0036】

The HA may set the lifetime field of the deregistration request message to '0'.

【0037】

In the mobile node handoff notification and control system according to the present invention, the HA transmits a deregistration request message when the IP address of the MN is'Multiple Care-Of Address'. May be good.

【0038】

When a handoff occurs, the stage of transmitting a registration request message from MN to HA, the stage of transmitting a registration deregistration request message from the HA that received the registration request message to the old FA, and the stage of transmitting the deregistration request message according to the HA deregistration request. , The step of deleting the registration information of the corresponding MN stored in the visitor table of the old FA is sequentially performed, and the above-mentioned purpose is achieved by this.

【0039】

The registration cancellation message may have the same'type'set value as the registration request message.

【0040】

In the mobile node handoff notification and control method according to the present invention, the deregistration request message has a type'field set to identify the message type and a lifetime field set to set the valid registration time of the MN. And the Home Address field that sets the IP address of the MN, the Home Agent field that sets the IP address of the HA, and the care-off address field that sets the IP address of the end point of the tunnel. (Care-Of Address field) and an identifier field (Identification field) set to match the registration request message and the registration response message are included and configured, thereby achieving the above-mentioned object.

【0041】

The lifetime of the deregistration request message may be set to '0'.

【0042】

The HA does not have to transmit the deregistration request message when the IP address of the MN is'Multiple Care-Of Address'.

【0043】

The mobile node handoff notification and control method according to the present invention is a step of transmitting a registration request message from the MN to the new FA (new FA) and received by the new FA (new FA) when the handoff occurs. The stage of transmitting the registration request message to the HA, the stage of transmitting the registration deregistration request message of the same type as the registration request message from the HA that received the registration request message to the old FA, and the deregistration of the HA. According to the request, the step of deleting the registration information of the corresponding MN stored in the visitor table of the old FA is sequentially performed, thereby achieving the above-mentioned purpose.

【0044】

In the mobile node handoff notification and control method according to the present invention, the deregistration request message has a type'field set to identify the message type and a lifetime field set to set the valid registration time of the MN. And the Home Addrss field, which sets the IP address of the MN, the Home Agent field, which sets the IP address of the HA, and the Careoff Address field, which sets the IP address of the end point of the tunnel. The Care-Of Address field) and the Identification field set to match the registration request message and the registration response message are included and configured, thereby achieving the above-mentioned object.

【0045】

The HA may set the lifetime field of the deregistration request message to '0'.

【0046】

The HA does not have to transmit the deregistration request message when the IP address of the MN is'Multiple Care-Of Address'.

【0047】

In order to achieve such an object, in the'mobile node handoff notification and control method'related to the present invention, a registration request message is transmitted from the mobile node (Mobile Node) 11 to HA15 when a handoff occurs. The stage of transmitting the registration cancellation request message from HA15 that received the registration request message to old FA13', and the registration of the corresponding MN11 stored in the visitor table of old FA13' according to the registration cancellation request of HA15. It is characterized in that it is deleted and sequentially performed.

【0048】

Further, in the'mobile node handoff notification and control method'related to the present invention, the MN11 that receives the registration request message and the mobile IP (mobile IP) service are provided to the MN11 before the handoff occurs. When an old FA13 is used, a new FA13'that provides a mobile IP (mobile IP) service to the MN11 after a handoff occurs, and a registration request message is transmitted from the MN11 through the new FA13' when a handoff occurs. It is characterized by including HA15, which generates a registration deletion message and transmits it to old FA13'.

【0049】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

【0050】

In the mobile node handoff notification and control method according to the present invention, as shown in FIG. 1, when the mobile node (MobileNode) 11 is handed off, a stage of transmitting a registration request message to HA15 and a message are transmitted. Correspondence stored in the visitor table of old FA13 by the stage where the received HA15 transmits the deregistration request message to'old FA'(hereinafter abbreviated as'old FA') 13 and the deregistration request of HA15. It is characterized by sequentially performing the steps of deleting the registration of MN11.

【0051】

Hereinafter, the handoff notification and control method of the mobile node according to the present invention will be described with reference to FIGS. 1 and 2.

【0052】

As shown in Figure 2, when the MN11 leaves the service area of old FA13 (Network 1) and moves to the service area of new FA13'(Network 2), it will receive the agent advertisement message broadcast by new FA13'. ..

【0053】

Upon receiving the new agent advertisement message, MN11 transmits the registration request message to HA15 by the same method as before. Next, HA15 updates the binding table while transmitting a registration response message that permits registration to MN11. The above process is the same as the conventional method.

【0054】

HA15 then sends a deregistration message to old FA13 to inform it that MN11 has handed off. For the UDP field of the deregistration message, the registration request message (type = '1') is used as it is, and the lifetime field is set to '0'. The reason for setting the lifetime field to '0' is that the registration of MN11 set in the visitor table of old FA13 is valid only during the lifetime. By setting the lifetime field to '0', the lifetime ends. Upon receiving the registration cancellation message, the old FA13 can prevent the waste of resources due to the memory allocation in the old FA13 by deleting the registration of the corresponding MN11 in the visitor table.

【0055】

The MN11 sets the Home Address of the MN15 in the'Home Address'field of the deregistration message sent to the old FA13, and sets the HA15 address in the'Home Agent'field. Then, the address of old FA13 is set in the'COA'field, and the address of the'identifier'field of the registration request message is set in the same way as the'identifier'field setting value in the'identifier'field.

【0056】

Further, when HA15 transmits a registration cancellation message, it is determined whether or not to send the registration cancellation message by referring to the "D" bit and the "S" bit of the registration request message. If the "D" bit is set ("1"), HA15 does not transmit the deregistration message to old FA13.

【0057】

Also, the "S" bit does not transmit a deregistration message when set ('1'). When the "S" bit is set, the MN11 receives the IP datagram related to the Multiple simultaneous mobility binding. That is, the MN11 maintains the binding with the old FA13 as well as the new FA13'and receives the IP datagram in multiple paths.

【0058】

Hereinafter, an embodiment in which the'Mobile Node handoff notification and control method'related to the present invention is applied to the mobile communication (IMT-2000) system of FIG. 4 will be described.

【0059】

When the MS105 is in the service area of the PDSN102 and hands off to the service area of the PDSN102', the MS105 transmits a registration request message to the PDSN102'and the PDSN102'transmits the received registration request message to the HA101. The PDSN 102, 102'performs the same functions as the Foreign Agent 13, 13'.

【0060】

Upon receiving the registration request message, HA101 updates the registration of MS105 stored in the binding table, transmits a deregistration message that is a message with the life timer field set to '0', and transmits the deregistration message to oldPDSN102. The oldPDSN102 receives the message, deletes the registration of MS105 from the visitor table, and breaks the link connection. Other operation and execution conditions are the same as in the prior art.

【0061】

By the link disconnection, the BS103 subordinately linked to the PDSN102 can delete the information for the MS105 which is conventionally service-linked and effectively manage the link resource.

【0062】

Also, when the MS105 can be rehanded off to the service area of the PDSN102, it can be newly registered in the visitor table, so that the registration dead rack problem can be solved. A mobile node (hereinafter abbreviated as MN) that sends a registration request message, an old foreign agent (FA) that provides a mobile IP service to the MN before the handoff occurs, and a mobile IP service to the MN after the handoff occurs. Includes a new FA that provides, and a home agent (HA) that generates a deregistration message and transmits it to the old FA when a registration request message is transmitted from the MN through the new FA when a handoff occurs. Configure a handoff notification and control system for mobile nodes.

【0063】

[Effect of the invention]

As described above, in the'Mobile Node handoff notification and control method'related to the present invention, when the MN handoff occurs, the HA is deleted from the MN registration registered in the old FA. There is an effect that the waste of memory resources and the registration dead rack, which have been pointed out as problems in the past, can be solved easily but effectively.

[Simple explanation of drawings]

[Figure 1]

FIG. 1 is a flowchart showing a procedure for registering a hand-off MN according to the present invention.

[Figure 2]

FIG. 2 is a diagram showing a mobile IP (mobile IP) service network model (Network Model) according to the draft standard of the IETF mobile IP (mobile IP).

[Fig. 3]

FIG. 3 is an example diagram showing a registration request message and a registration response message.

[Fig. 4]

FIG. 4 is a configuration diagram showing a mobile communication network for conventional mobile IP (mobile IP) services.

[Fig. 5]

FIG. 5 is a flowchart showing the registration procedure of the conventionally hand-off MN.

[Explanation of symbols]

11 mobile node 12 Visit Network 1 12'Visit Network 2 13 Old Foreign Agent 13'New Foreign Agent 14 Home network 15 Home Agent 101 Home Agent 102 Packet Data Serving Node (PSDN) 102'Packet Data Serving Node (PSDN) 103 BS 103'BS 105 Mobile Station