KR20010068388A - Mobile Internet Protocol Routing Method - Google Patents

Abstract

PURPOSE: A mobile station IP(Internet Protocol) routing method is provided to effectively reduce a searching time by using an index for discriminating a mobile station host, and to notify the movement of the mobile station host by using a list of source hosts. CONSTITUTION: A mobile station host(16) requests a location register to a new foreign agent(130). The new foreign agent(13) notifies a home agent(11) and an old foreign agent(12) of the movement of the mobile station host(16), and updates information of the mobile station host(16). If the home agent(11) completes a register request for the mobile station host(16), the home agent(11) transmits a register completing message to the mobile station host(16) through the new foreign agent(13). The home agent(11) notifies source hosts(17) communicating with the mobile station host(16) of the movement of the mobile station host(16), and waits for an acknowledge signal. If the acknowledge signal is received from the source hosts(17), the home agent(11) transmits an information deleting message for the mobile station host(16) to the old foreign agent(12).

Description

Mobile Internet Protocol Routing Method

According to the present invention, when the foreign agent (FA) uses an index when searching for an Internet protocol in the tunneling of mobile station Internet protocol routing, the Internet protocol packet data due to handover reduces transmission errors and The present invention relates to a mobile station internet protocol routing method suitable for efficient buffer management.

Hereinafter, an internet protocol routing method of a conventional mobile station will be described with reference to the accompanying drawings.

1 is a diagram illustrating a conventional mobile station Internet protocol routing method.

The conventional mobile station Internet protocol routing shown in FIG. 1 represents a route optimization in mobile station IP, and the mobile engineering Internet protocol (hereinafter referred to as IP) working group Internet draft of the Internet Engineering Tack Force (IETF). In a method written in INTERNET DRAFT, it is proposed to reduce routing cost based on the Base Mobile IP Routing technique.

First of all, the network configuration in the route optimization of the conventional mobile station IP includes a mobile host (5) moving with a fixed IP address and a source host (6) for sending packet data to the mobile station host (5). ), A Home Agent (2) used as the default router of the network to which the mobile station host (5) was connected before moving, and a foreign agent registered for use as the default router in the visited network of the moved area. (Foreign Agent) (3). At this time, a router 4 is formed between the source host 6 and the backbone 1 made of the Internet.

Here, the source host 6 is a host for sending a packet to the mobile station host 5 while supporting mobile station IP communication, and the foreign agent 3 address of the region where the mobile station host 5 is located from the home agent 2. Receives the home address of the mobile station host 5 and uses it to encapsulate the foreign agent 3 address into a packet destined for the destination, and transmits packet data to the foreign agent 3 having the mobile station host 5. do.

The mobile station host 5 is a host moving with a fixed IP.

The foreign agent 3 is a basic router of the region where the mobile station host 5 of the Visited Network is currently located, and serves to send the actual data packet to the mobile station host 5 in the encapsulated packets sent from the home agent 2.

The home agent 2 is a router where the mobile station host 5 is originally located. When the mobile station host 5 is connected to another network and has a foreign agent 3, the home agent 2 In this case, the home agent (2) stores the home address of the mobile station host (5) and the foreign agent (3) address together to send packets arriving for the foreign agent to the mobile station host (5) Encapsulated with the address of (3), it is sent to the network where the mobile station host (5) is located.

The conventional mobile station Internet protocol routing method having such a configuration is as follows.

First, when the mobile station host 5 moves to another network, a registration request is made to the foreign agent 3 to register its current location with the home agent 2.

The foreign agent 3 then informs the home agent 2 of the address of the mobile station host 5 and conveys a message to the mobile station host 5 via the foreign agent 3 that the registration has been completed.

The source host 6 then transmits the data to the home agent 2 to send packet data to the mobile station host 5 in motion.

The home agent 2 transmits the foreign agent 3 address of the network where the mobile station host 5 is located to the source host 6, and for the packet that has already arrived, the packet having the foreign agent 3 as the destination address. Encapsulate it and send it.

Then, the encapsulated packets arriving at the foreign agent 3 are separated into actual IP packets and transmitted to the mobile station host 5.

Then, when the mobile station host 5 moves to another network, when a foreign agent (not shown) requests a registration from the newly moved area, the foreign agent 3 not only the home agent 2 but also the mobile station host 5 The foreign agent 3 before not moving informs the fact that the mobile station host 5 has moved.

The home agent 2 updates the information on the mobile station host 5 (the address of the foreign agent 3), and the previous foreign agent 3 releases the radio resource for the mobile station host 5 and newly moves. Maintain local foreign agent addresses.

When the packets sent from the source host 6 arrive at the foreign agent 3 in the previous region, the foreign agent 3 sends a binding warning message to the home agent 2 to the home agent 2. It causes the source host 6 that sent the packet to send a binding update message indicating the address of the new foreign agent that has changed. In the arriving packets, the foreign agent address of the newly moved region is found in the binding table by using the IP address of the actual IP data, and the packet is forwarded by encapsulating the address as a destination. do.

The source host 6 changes the binding information of the mobile station host 5 using a binding update message, and sends a packet to the changed foreign agent address.

Then, packets coming into the foreign agent of the newly moved area are finally delivered to the mobile station host 5.

At this time, the information about the mobile station host 5 that the source host 6 knows is automatically deleted if it is not used for a certain period of time.

In addition, the information of the mobile station host 5 moved to another network maintained by the previous foreign agent 3 is automatically deleted after a certain time.

That is, the home agent 2 is a foreign agent 3 in the area where the mobile host 5 has moved to the source host 6 along the line 'A'. ), The packets that have already arrived are encapsulated again into the foreign agent 3 address, arrive at the foreign agent 3 along the line 'B', and the data is sent to the mobile station host 5. On the other hand, since the source host 6 knows the address of the foreign agent in the region of the mobile station host 5, the source host 6 encapsulates using the foreign agent address and sends a packet to the foreign agent 'C' directly along the line 'C' to send the packet to the mobile station host. Transfer to (5).

In the conventional mobile station IP routing, when the packet data destined for the mobile station host arrives at the foreign agent, the actual IP data is extracted from the packets encapsulated by the IP-in-IP method, and the mapping of the radio resource assigned to the IP address is performed. If there are many IP addresses that need to be managed, there is a problem that it takes a lot of searching time to find such information. The information about the mobile station host has to be maintained for a certain period of time, which causes a problem of inefficiency of the buffer usage.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above-mentioned problems of the prior art, and reduces the internet protocol discovery time in a foreign agent by using an index when tunneling mobile station Internet protocol routing, and transmits IP packet data due to handover. It is to provide a mobile station Internet protocol routing method that can reduce errors and efficiently manage buffers in a foreign agent.

According to an aspect of the present invention for achieving the above object, the mobile station host requesting a registration registration as a new foreign agent (New Agent) to move, and transfers the home agent of the mobile station host from the new foreign agent Notifying the foreign agent of the mobile station host's movement and updating the mobile station host's information, and when the home agent completes the registration request with the mobile station host, a registration completion message to the mobile station host through the new foreign agent. Sending, the home agent notifying source hosts communicating with the mobile station host and waiting for an acknowledgment signal, and receiving the acknowledge signal from the source hosts. Once the former foreign agent A step of sending a delete message information for a mobile station host.

Preferably, the foreign agent FA maps an IP address of the mobile station host to an index to identify the mobile station host, and uses the foreign agent FA in searching for the IP of the mobile station host.

And when the mobile station host requests location registration as a new foreign agent, the new foreign agent has its own home agent, the address of a previous foreign agent, an index assigned by the previous foreign agent, and a recently communicating source host. Send a list of them.

According to the present invention as described above, it is possible to reduce the search time for identifying the mobile station host, and there is an advantage that efficient buffer management in the previous foreign agent is possible.

1 is a diagram illustrating a conventional mobile station internet protocol routing method.

2 is a diagram illustrating a routing method using an index table according to the present invention.

* Description of the symbols for the main parts of the drawings *

10 backbone (Internet) 11 home agent

12: Old Foreign Agent 13: New Foreign Agent

14,15 router 16: mobile station host

17: source host

Hereinafter, a configuration and an operation according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

2 is a diagram illustrating a routing method using an index table according to the present invention.

The network configuration in the present invention is the same as the conventional configuration, but there is a difference in the execution method in each node.

That is, a mobile host 16 having a fixed IP address, a source host 17 which sends packet data to the mobile host 16, and a mobile station host 16 Home Agent (11) used as the default router of the network that was connected before the move, and old and new Foreign Agents registered for use as the default router in the network of destinations in the traveled area (12) And 13).

Here, the backbone 10 and the router 14 are configured between the home agent 11 and the source host 17.

The source host 17 is a host for sending a packet to the mobile station host 16 while supporting mobile station IP communication, and is a foreign agent 12 in the region where the mobile station host 16 is located from the home agent 11. 13) The received address is used to encapsulate the foreign agent (12, 13) address into a packet destined for the destination, and directly to the foreign agent (12, 13) with the mobile station host (16). Send packet data.

Here, the mobile station host 16 is a host moving with a fixed IP. The mobile station host 16 maintains values such as a home agent 11 address, a foreign agent address, an index, and the like.

The foreign agent 12, 13 allocates an index to manage the mobile station host 16 when the mobile station host 16 requests registration, and assigns this index value to the home agent 11. To send. The real IP data is delivered to the mobile station host 16 in the encapsulated packet tunneled by the source host 17 or the home agent 11.

The home agent 11 is a router where the mobile station host 16 is originally located. When the mobile station host 16 connects to another network and has a new foreign agent 13, the home agent (11), where the home agent (11) is assigned at the home address of the mobile station host (16), foreign agent (Foreign agent) (13) address and foreign agent (Foreign agent) (13) Packets arriving to store the index together and send to the mobile station host 16 are encapsulated in the address of the foreign agent 13 and sent to the network where the mobile station host 16 is located.

First, when the mobile station host 16 wants to move to and connect from another network to which it belongs, it requests a foreign agent 12, 13 to register as a home agent 11. .

Foreign agent 12,13 then uses foreign agent 12 to manage mobile station host 16 using mobile station host's home address 11. Allocate an idle index in the index table of (13). At this time, the inverter field in the index table is changed and the registration request is made to the home agent 11 with the index value and the address of the mobile station host 16.

In this case, the inverter field is composed of 1 bit or 2 bits. The inverter field is changed from 0 to 1 or 1 to 0 whenever the index is released and reassigned. This inverter field is used to distinguish erroneously transmitted packets. In addition, when the index is assigned, it is allocated using a LRU (least recently used) method.

The home agent 11 binds the mobile station host 16 address, foreign agent 12, 13 address, index value, and inverter field in the registration request message received from the foreign agent 12, 13. Manage by binding.

When the home agent 11 completes the registration of the mobile station host 16, the home agent 11 transmits a message to the mobile station host 16 that the location registration is completed through the foreign agent 13.

When the source host 17 sends packet data to the mobile station host 16, it is delivered to the home agent 11, and the home agent 11 sends the above binding information to the source host 17 to send the source host 17. To send the packet directly. The destination address of the forwarded packet is replaced with an index value and an inverter field, and the packet is again encapsulated into an IP packet having the foreign agent 12, 13 as the destination address. To send).

From the encapsulated packet arriving at the foreign agent (12, 13), the data packet sent by the source host (17) is extracted and the inverter field and the index table of the packet are indexed using the index value in the destination address. The inverter fields in the table are compared and equal, and the packet is finally delivered to the mobile station host 16 with the actual IP address in the index table as the destination address of the data packet.

The mobile station host 16 manages a list of source hosts 17 in communication with it. This list is used when the mobile station host 16 has moved to another network as the source hosts 17 with which the mobile station host 16 has recently communicated.

And, if the mobile station host 16 moves to another network (for example, Old FA 12 to New FA 13), the mobile station host 16 is a foreign agent (Old FA) 12 of the previous region. The address, home agent 11, index value, list of source hosts 17 and the like are sent together when registering with the new FA 13 of the newly moved region.

The foreign agent 13 of the region newly moved by the mobile station host 16 allocates an idle index in the index table and changes the inverter field, and then not only the home agent 11 but also the previous region. It also forwards to the foreign agent 12 of the mobile station to inform the fact that the mobile station host (16). At this time, the binding update message to the home agent 11 includes a list of source hosts 17 received from the mobile station host 16.

The old FA 12 receives the wireless and wired resources allocated for the mobile station host 16 when notified of the mobile station 16's movement from the newly moved local FA. Release it. The index value of the new foreign agent 13 and the address value of the new foreign agent 13 are stored in the index table of the old foreign agent 12 to enter the old foreign agent 12. The packets are forwarded to the New foreign agent 13 using this information.

The home agent 11 then updates the binding information and notifies the mobile station host 16 of the result via the New foreign agent 13.

At this time, the source host 17 in the source list is notified of the location change of the mobile station host 16 and waits for an acknowledgment signal. If there is no acknowledgment signal, retransmit. If no acknowledgment signal is received, the old foreign agent 12 via the new foreign agent 13 tells the old foreign agent 12 to release the index for the mobile station host 16. Send it. The old foreign agent 12 then changes the inverter field of the index table and releases the index. However, when a confirmation signal is received, the old foreign agent 12 is deleted by the new foreign agent 13 from the mobile station host 16. At this time, the packets arriving at the Old foreign agent 16 along the 'D' line at the source host 17 are compared to the inverter field and transmitted to the New foreign agent 13 if they are the same, and the source host 17 transmits the updated information. The packet is directly sent to the new foreign agent 13 by using the packet.

Then, the source host occupied by the other mobile station host 16 in the index released by the old foreign agent 12, and the source host that has not been informed of the mobile station host 16 due to link fail or the like. When the data transmitted from (17) arrives at the Old foreign agent 12, the inverter fields are not matched with each other. The packet is then discarded and the source host 17, which detects no response from the mobile station host 16, communicates with the mobile station host 16 with reference to the home agent 11 again.

As described above, the present invention uses an index for identifying the mobile station host instead of comparing the IP corresponding to 4 bytes one by one to identify the mobile station host, thereby effectively reducing the searching time. When the mobile station host moves to another area, the buffer management can be efficiently performed by informing the mobile station host of the mobile station by using a list of source hosts communicating with the mobile station host.

Claims (3)

Requesting, by the mobile station host, to register a location with a new foreign agent to which it will move; Informing the home agent of the mobile station host and the previous foreign agent of the movement of the mobile station host in the new foreign agent and updating the information of the mobile station host; Sending a registration completion message to the mobile station host through the new foreign agent when the home agent completes a registration request for the mobile station host; The home agent notifying source hosts in communication with the mobile station host of the mobile station host and waiting for an acknowledgment signal; And transmitting an information deletion message for the mobile station host to the previous foreign agent when the acknowledgment signal is received from the source hosts. The method of claim 1, wherein the foreign agent FA maps the IP address of the mobile station host to an index to identify the mobile station host, and uses the mobile agent host for IP discovery of the mobile station host. The mobile station Internet protocol routing method using the (Inverter Field) to verify the integrity of the index. 2. The method of claim 1, wherein when the mobile station host requests location registration as a new foreign agent, the mobile station host's own home agent, the address of a previous foreign agent, an index assigned by the previous foreign agent, and A mobile station internet protocol routing method comprising transmitting a list of source hosts that are recently communicating.