JP3777173B2 - Home agent failure switching method, spare home agent, and program - Google Patents

Description

  The present invention relates to a method for switching home agents when a mobile IP home agent device fails.

  Mobile IP technology is a protocol that automatically detects the movement of a terminal between networks and enables communication in the network after the movement in the same manner as the network before the movement. There are two types of mobile IP technologies, mobile IPv4 technology and mobile IPv6 technology, depending on the IP version. Non-patent document 1 can be referred to for the former, and non-patent document 2 can be referred to for the latter. Hereinafter, Mobile IPv6 technology will be described.

  FIG. 5 shows a conventional example of mobile IPv6 technology.

  In the network 200, there are HA 210 and HA 250, which are home agents (hereinafter referred to as HA) compliant with the Mobile IPv6 protocol, and a router 220, and the HA 210 and HA 250 and the router 220 are connected by a link 240.

  The HA 210 has a binding cache table (hereinafter referred to as BCT) 211, the HA 250 has a BCT 251, and the router 220 has a neighbor cache table (hereinafter referred to as NCT) 221. The physical address of the HA 210 is assumed to be a physical address 212.

  The network 200 is a home network of the mobile terminal 230, and the mobile terminal 230 has a home address HoA 231 that is an IP address of the network 200. HA 210 and HA 250 have HA addresses HAA 213 and HAA 253, which are IP addresses of network 200, respectively.

  A router 310 is in the visited network 300 and is connected to the link 320. The router 220 and the router 310 are connected to the Internet 100. In addition, the communication partner terminal 110 is connected to the Internet 100.

  When the mobile terminal 230 connects to the link 320 in the visited network 300, the mobile terminal 230 changes the correspondence between the IP address in the visited network 300, that is, the care-of address (hereinafter referred to as CoA) CoA 331 and HoA 231. A mobile IPv6 signal packet (hereinafter referred to as a location registration packet) is registered in the HA 210 via the Internet 100 at regular intervals.

  When the HA 210 receives the CoA 331 location registration packet from the mobile terminal 230, the HA 210 sets correspondence between the HoA 231 and the CoA 331 in the BCT 211, and sends an IP packet addressed to the HoA 231 to the router 220 by the neighbor notification message. To send to the mobile terminal 230 a location registration response packet. The router 220 registers the correspondence between the HoA 231 and the physical address 212 in the NCT 221.

  In the example of FIG. 5, the case where there is one mobile terminal having the HoA of the network 200 is described. However, when there are a plurality of mobile terminals, the correspondence between the CoA to which each mobile terminal is connected and each HoA Is registered in the BCT 211.

  When the router 220 receives a user packet addressed to the HoA 231 from the communication partner terminal 110 via the Internet 100, the router 220 refers to the NCT 221 and transfers the user packet to the physical address 212. When the HA 210 receives the user packet addressed to the HoA 231, the HA 210 encapsulates the packet into an IP packet, and refers to the BCT 211 to specify the CoA 331 that is the IP address of the mobile terminal in the visited network corresponding to the HoA 231 in the destination header of the encapsulated user packet. To the router 220. Since the destination header is CoA331, according to normal IPv6 routing, the user packet is routed to the mobile terminal 230 connected to the visited network 300 via the router 220, the Internet 100, and the router 310.

  For details on the conventional Mobile IPv6 technology, Non-Patent Document 1 can be referred to.

  With this technology, the mobile terminal 230 can communicate with other terminals using the same HoA when moving from the home network 200 to the visited network 300 or when moving to another visited network.

  FIG. 6 shows a conventional technique for switching the HA used by the mobile terminal 230 when a failure occurs in the HA 210 in FIG. This technique is shown in Section 11.7.1 of Non-Patent Document 1. Note that the operation of the router 310 is normal IPv6 protocol processing, and is therefore omitted in FIG.

  As mentioned before, the mobile terminal 230 periodically transmits a location registration signal to the HA 210 and registers the CoA 331 of the mobile terminal 230 in the HA 210. When HA 210 receives a user packet addressed to HoA 231 that is the home address of mobile terminal 230 when there is a care-of address corresponding to mobile terminal 230, HA 210 encapsulates the packet into IP in IP (the IP packet is directly used as data). The packet is included in the packet) and transferred to the mobile terminal 230.

When a failure occurs in HA 210 (HA 1), signal packet processing and user packet processing become impossible, and a location registration response packet for a location registration packet transmitted from mobile terminal 230 to HA 210 does not return to mobile terminal 230. The mobile terminal 230 performs location registration with the HA 250. Upon receiving the location registration signal from the mobile terminal 230, the HA 250 notifies the router 220 to send a user packet addressed to the HoA 231 to the physical address 212 of the HA 250 by a neighbor notification message. A user packet addressed to HoA 231 is transmitted to HA 250. When the HA 250 receives the user packet addressed to the HoA 231, the HA 250 encapsulates the packet into IP in IP and transfers the packet to the mobile terminal 230. Communication between the communication partner terminal 110 and the mobile terminal 230 is not possible during a period from when the failure occurs in the HA 210 until the router 220 changes the user packet transfer destination addressed to the HoA 231 to the HA 250.
C. Perkins, Ed. P Mobility Support for IPv4, RFC 3220, August 2002, Internet <http://www.ietf.org/html.charters/mobileip-charter.html> David B. Johnson, Charles Perkins & Jari Arkko, 溺 obility Support in IPv6 ・ draft-ietf-mobileip-ipv6-22.txt, May 2003, Internet <http://www.ietf.org/html.charters/mobileip- charter.html>

  In the above-described prior art, when a HA failure occurs, the HA failure is detected at the mobile terminal, and the location registration information is re-registered from the mobile terminal to the replacement HA. Therefore, the HA failure occurs immediately after the location registration is normally completed. In such a case, communication between the communication partner terminal 110 and the mobile terminal 230 is impossible for the time until the location registration cycle + the mobile terminal determines that the HA has failed.

  Since the location registration period greatly affects the performance of the HA, a value of several minutes or more, and in some cases, a value of several hours or more may be used. For this reason, there is a possibility that the time during which communication is not possible becomes long.

  An object of the present invention is to provide a home agent failure switching method that greatly reduces the time during which communication is not possible when an HA failure occurs.

  The present invention adds the following means to the conventional mobile IP technology, and reduces the time during which communication cannot be performed between the mobile terminal and the communication terminal in the event of an HA failure compared to the conventional technology.

  (1) When the HA receives the location registration from the mobile terminal, if the care-of address changes, the care-of address is copied to the spare HA.

  (2) When the spare HA detects the failure of the HA, it sets the router to be connected so that the forwarding address of the IP address addressed to the failed HA is changed to the spare HA, and the spare HA processes the failed HA. Continue.

Specifically, the home agent failure switching method of the present invention includes:
Deploying a working HA and a spare HA;
Deploying routers directly connected to the working HA and the spare HA;
If care-of address in the position registration information received from the mobile terminals is changed, the steps of copying the care-of address before Symbol mobile terminal to the spare HA corresponding to the current for HA,
The working HA periodically monitored, when detecting a failure of the active HA, at least the working destination IP address destined packet and the IP address addressed packets of the mobile terminal that has registered its position in the developing for HA in HA, a step of rewriting the routing information in the router to change the addressed preliminary HA corresponding to the current HA,
The spare HA using the IP address of the working HA .

  In this method, since the care-of address must be copied only when the care-of address changes, the influence on the HA performance is small.

  There are the following two specific methods for the spare HA to detect a failure of the active HA.

  (Detection Method 1) The standby HA periodically communicates with the active HA that is operating the mobile IP process, monitors normality, and detects a failure of the active HA when there is no response.

  (Detection method 2) A failure monitoring device capable of communicating with both the standby HA and the active HA that is operating the mobile IP processing is provided, and the failure monitoring device periodically communicates with the active HA that is operating the mobile IP processing. The normality is monitored, and when there is no response, the failure of the active HA is detected, and the failure of the active HA is notified to the spare HA. When the spare HA receives a failure notification of the active HA from the failure monitoring device, the spare HA detects a failure of the active HA.

  In the case of the detection method 1, since it is not necessary to install a failure monitoring device necessary for the detection method 2, it can be realized more economically. On the other hand, in the case of the detection method 2, since a dedicated failure monitoring device is placed, more detailed failure monitoring can be performed compared to the detection method 1. In any case, since the failure of the HA is monitored by another HA or another device connected to the HA, it can be detected in a shorter time compared to the conventional technology monitored by a remote mobile terminal. is there.

  There are the following two methods for notifying the connected router so as to change the packet transfer destination to the spare HA, depending on the connection relationship between the connecting router and the home network.

  (Notification method 1) When the router to be connected is in the home network, transfer of the packet addressed to the IP address of the working HA that has failed and the packet addressed to the IP address of the mobile terminal that has been registered in the location of the failed HA The router is notified by the neighbor notification message so that the destination is changed to the spare HA.

  (Notification method 2) When the router to be connected is outside the home network, the packet addressed to the IP address of the active HA that has failed and the packet addressed to the IP address of the mobile terminal that has been registered in the location of the failed HA The router is notified by the routing information exchange means of the routing protocol so as to change the forwarding destination to the spare HA.

The invention of claim 1, 9, 14, the time communication is not possible between the remote terminal mobile terminal when HA failure, the failure of the HA, detected by other devices in g e beam network, failed addressed HA Since the time required to set the router to be connected so as to change the IP address transfer destination to the spare HA is sufficient, it is possible to greatly reduce the time during which communication is not possible when the HA fails.

The inventions of claims 4 and 10 can detect the failure of the working HA more economically.

The inventions of claims 5 and 11 can perform more detailed fault monitoring of the active HA .

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

(First embodiment)
FIG. 1 shows the system configuration of the first embodiment of the present invention. The only difference between the present embodiment and the conventional example of FIG. 5 is the IP address of the HA 250, except for the HA 210 and the HA 250, those having the same number have the same functions.

  FIG. 2 is a sequence diagram of the present embodiment. Since the operation of the router 310 is a normal IPv6 protocol process, it is omitted. Note that signals added in this embodiment with respect to the prior art of FIG. 5 are indicated by thick wavy lines.

  The sequence of FIG. 2 will be described below.

As mentioned in the background art, the mobile terminal 230 periodically transmits a location registration signal to the HA 210 and registers the CoA 331 of the mobile terminal 230 in the HA 210. When the HA 210 receives a location registration signal from the mobile terminal 230 for the first time, the HA 210 notifies the router 220 to send an IP packet addressed to the HoA 231 to the physical address 2 1 2 of the HA2 1 0 by a neighbor notification message. Further, when the care-of address in the location registration signal from the mobile terminal 230 changes, the HA 210 copies the care-of address to the HA 250. When there is a care-of address corresponding to the mobile terminal 230, the HA 210 receives the user packet addressed to the HoA 231 that is the home address of the mobile terminal 230, encapsulates the packet into IP in IP, and transfers the packet to the mobile terminal 230. To do.

  The HA 250 periodically communicates with the HA 210 in order to confirm the normality of the HA 210. If there is no response from the HA 210 (HA1), it is assumed that a failure has occurred in the HA 210, and the HA 250 sends the IP packet addressed to the HoA 231 and the IP packet addressed to the HAA 213 to the router 220 by the neighbor notification message. Notify you to send it to. However, when the HA 210 is operating using the HAA 213, the HA 250 does not use the HAA 213, and the HA 250 uses the HAA 213 for the first time after the failure of the HA 210 occurs.

  Thereafter, the router 220 transmits the IP packet addressed to the HoA 231 and the IP packet addressed to the HAA 213 and the packet to the HA 250. When the HA 250 receives the user packet addressed to the HoA 231, the HA 250 encapsulates the packet into IP in IP and transfers the packet to the mobile terminal 230. At this time, the same HAA 213 as the IP address of the HA 210 is used as the IP address of the HA 250.

  A packet addressed to the HAA 213 from the mobile terminal 230 is transferred to the HA 250 and processed by the HA 250. For this reason, in the present embodiment, the HA switching does not affect the processing on the mobile terminal 230 side, and no function addition to the mobile terminal 230 is necessary. Similarly, it is not necessary to add functions to the router 220 and the communication partner terminal 110 other than the HA 210 and HA 250.

  Communication between the communication partner terminal 110 and the mobile terminal 230 is not possible during a period from when the failure occurs in the HA 210 until the router 220 changes the user packet transfer destination addressed to the HoA 231 to the HA 250.

(Second Embodiment)
FIG. 3 shows the system configuration of the second embodiment of the present invention. In the second embodiment, the router to be connected is outside the home network 200. Comparing the second embodiment with the first embodiment, the HoA of the mobile terminal 230 and the HAA of the HA 210 have HoA 431 and HAA 413, which are IP addresses of the home network 400, not IP addresses of the home network 200, respectively. HA 210 and HA 250 have IPA 214 and IPA 254, which are IP addresses of network 200, respectively.

  In the sequence diagram of FIG. 4, the operation of the router 310 is abbreviated because it is a normal IPv6 protocol process. Note that signals added in the present embodiment with respect to the prior art of FIG. 6 are indicated by thick wavy lines.

  The sequence of FIG. 4 will be described below.

The HA 210 notifies the router 220 to send an IP packet addressed to the home network 400 to the IPA 214 by exchanging route information of a routing protocol (for example, RIPng or OSPF). As mentioned in the background art, the mobile terminal 230 periodically transmits a location registration signal to the HA 210 and registers the CoA 331 of the mobile terminal 230 in the HA 210. When the care-of address of the mobile terminal 230 changes, the HA 210 notifies the HA 250 of the care-of address. HA210, if there is a care-of address corresponding to the mobile terminal 230 receives a user packet destined HoA 4 31 is the home address of the mobile terminal 230, encapsulates the packet to IP in IP, the mobile terminal 230 Forward to.

The HA 250 periodically communicates with the HA 210 in order to confirm the normality of the HA 210. If there is no response from the HA 210, it is assumed that a failure has occurred in the HA 210, and the HA 250 sends an IP packet addressed to the home network 400 to the physical address 252 to the router 220 by exchanging route information of the routing protocol. Notice.

Thereafter, the router 220 transmits an IP packet addressed to the home network 400 to the HA 250. When the HA 250 receives the user packet addressed to the HoA 4 31, the HA 250 encapsulates the packet into IP in IP and transfers the packet to the mobile terminal 230. At this time, the HAA of the HA 250 uses the same HAA 413 as the HAA of the HA 210. A packet addressed to the HAA 4 13 from the mobile terminal 230 is transferred to the HA 250 and processed by the HA 250. For this reason, in the present embodiment, the HA switching does not affect the processing on the mobile terminal 230 side, and no function addition to the mobile terminal 230 is necessary. Similarly, it is not necessary to add functions to the router 220 and the communication partner terminal 110 other than the HA 210 and HA 250.

  Communication between the communication partner terminal 110 and the mobile terminal 230 is not possible during a period from when the failure occurs in the HA 210 until the router 220 changes the user packet transfer destination addressed to the HoA 231 to the HA 250.

  In this embodiment, HA 210 and HA 250 have different IP addresses in network 200, IPA 214 and IPA 254, and the forwarding destination of the IP packet addressed to home network 400 is switched from HA 210 to HA 250 by exchanging routing information of the routing protocol. However, it may be switched by the following method.

  When the HA 250 detects a failure of the HA 210, the HA 250 notifies the router 220 to change the transfer destination physical address of the packet addressed to the IPA 214 to the physical address 252 of the HA 250 by a neighbor notification message. However, when the HA 210 is operating using the IPA 214, the HA 250 does not use the IPA 214, and the HA 250 uses the IPA 214 for the first time after the HA 210 has failed.

  In this embodiment, the HA 250 monitors the normality of the HA 210, but the normality of all the HAs is monitored by other devices (not shown in FIGS. 1 and 3) connected to each HA to detect a failure. From time to time, the device may notify the spare HA.

  In the present embodiment, the case of mobile IPv6 is shown, but the case of mobile IPv4 can be similarly implemented.

  In this embodiment, when the care-of address in the location registration signal changes when the location registration signal is received, the care-of address is copied to the spare HA each time. The address information may be copied to the spare HA. In this case, the care-of address for some MNs may be different between the active HA and the spare HA at the time of switching due to a failure. Therefore, the care-of address of the MN is re-transferred from the MN to the spare HA according to the prior art. It is necessary to register. However, since the number of communication signals between the active HA and the spare HA can be reduced, the influence on the processing capability can be reduced.

  Further, in the present embodiment, there are two HAs, and one HA transfers a user packet and communicates with a mobile terminal, and shows a method in which the HA takes over processing to another HA when a failure occurs. When three or more HAs are present, the following example is carried out.

(1) Two sets of 1 + 1 spare HAs are grouped, and one HA transfers user packets and communicates with a mobile terminal in the same manner as in the above-described embodiment, and the HA takes over processing to the spare HA when a failure occurs. .

(2) n + 1 Preliminary System n HAs transfer user packets and communicate with mobile terminals, and if any of the HAs fails, the HA takes over the processing.

  In the present invention, it is possible to combine with a spare system other than those shown in the above embodiments ((1), (2)).

  In addition to what is implemented by dedicated hardware, the present invention records a program for realizing the function on a computer-readable recording medium, and the program recorded on the recording medium is a computer system. It may be read and executed. The computer-readable recording medium refers to a recording medium such as a floppy disk, a magneto-optical disk, a CD-ROM, or a storage device such as a hard disk device built in the computer system. Furthermore, a computer-readable recording medium is a server that dynamically holds a program (transmission medium or transmission wave) for a short period of time, as in the case of transmitting a program via the Internet, and a server in that case. Some of them hold programs for a certain period of time, such as volatile memory inside computer systems.

It is a system diagram of a 1st embodiment of the present invention. In 1st Embodiment, it is a figure which shows the sequence which switches HA at the time of HA failure. It is a system diagram of the 2nd embodiment of the present invention. In 2nd Embodiment, it is a figure which shows the sequence which switches HA at the time of HA failure. It is a figure which shows the prior art example of mobile IP technology. FIG. 6 is a diagram illustrating a sequence for switching HA when an HA failure occurs in the conventional example of FIG. 5.

Explanation of symbols

100 Internet 110 Communication partner terminal 200 Network 210 HA (Home Agent)
211 BCT (HA210)
212 Physical address of HA 210 213 HAA of HA 210
214 IPA (HA210)
220 (network 200) router 221 (router 220) NCT
230 Mobile terminal 231 HoA (of mobile terminal 230)
240 (network 200) link 250 HA
251 (HA250) BCT
252 Physical address of HA 250 253 HAA of HA 250
254 (HA250) IPA
300 Visited network 310 Router (of visited network 300) 320 Link (of visited network 300) 331 CoA (of mobile terminal 230)
400 Home network 413 HAA (HA210)
440 link (of home network 400)

Claims (14)

A method of switching home agents when a home agent performing mobile IP home agent processing fails.
Deploying a working home agent and a spare home agent;
Deploying a router directly connected to the working home agent and the spare home agent;
When the care-of address in the location registration information received from the mobile terminal has changed, copying the care-of address of the mobile terminal to a backup home agent corresponding to the active home agent;
When the working home agent is periodically monitored and a failure of the working home agent is detected , at least a packet addressed to the IP address of the working home agent and a packet addressed to the IP address of the mobile terminal registered in the position of the working home agent Rewriting routing information in the router to change the forwarding destination to a spare home agent corresponding to the working home agent;
A method of switching home agent failure, wherein the spare home agent uses an IP address of the working home agent .   The home agent failure switching method according to claim 1, wherein a change in the care-of address in the location registration information received from the mobile terminal is recognized by the active home agent.   The home agent failure switching method according to claim 1, wherein the working home agent copies the care-of address to the spare home agent. The home agent failure switching method according to any one of claims 1 to 3, wherein the active home agent is monitored and detected by a spare home agent. The failure monitoring device deployed so as to be able to communicate with both the active home agent and the backup home agent performs the monitoring and detection of the failure of the active home agent, and the failure monitoring device notifies the backup home agent of the failure of the current home agent. The home agent failure switching method according to any one of claims 1 to 3. A router so as to change the transfer destination of at least the packet addressed to the IP address of the current home agent and the packet addressed to the IP address of the mobile terminal registered in the current home agent to the backup home agent corresponding to the current home agent The home agent failure switching method according to claim 1, wherein the spare home agent gives an instruction to rewrite the routing information . 7. The home agent failure switching method according to claim 6, wherein a routing information change instruction from the spare home agent to the router is notified by a neighbor notification message. 7. The home agent failure switching method according to claim 6, wherein a routing information change instruction from the spare home agent to the router is notified by a routing information exchange unit of a routing protocol. A mobile home agent and a home agent in which a router is connected to each other via a link, and is a spare home agent that is a spare for the home agent,
When the care-of address in the location registration signal from the mobile terminal changes, the care-of address of the mobile terminal is copied by the active home agent,
Means for detecting a failure of the active home agent;
When the failure of the active home agent is detected, at least the transfer destination of the packet addressed to the IP address of the home agent that has failed and the packet addressed to the IP address of the mobile terminal that has been registered in the home agent that has failed is set as the spare home Means for notifying the router to change to an agent ;
A spare home agent having means for using the IP address of the working home agent. 10. The communication device according to claim 9 , further comprising means for periodically communicating with the working home agent that is operating mobile IP processing, monitoring normality, and detecting a failure of the working home agent when there is no response. Spare agent. Means for detecting a failure of the active home agent when receiving a failure notification of the active home agent from a failure monitoring device capable of communicating with both the spare home agent and the active home agent operating the mobile IP processing; The spare home agent according to claim 9 . Neighbor notification so as to change the forwarding destination of the packet addressed to the IP address of the failed active home agent and the packet addressed to the IP address of the mobile terminal registered in the location of the failed home agent to the spare home agent The spare home agent according to claim 9 , which notifies the router by a message. The routing protocol route so that the forwarding destination of the packet addressed to the IP address of the failed home agent and the packet addressed to the IP address of the mobile terminal registered in the failed home agent is changed to the spare home agent. The spare home agent according to any one of claims 9 to 11 , wherein the router is notified by information exchange means. A program for executing the function of the spare home agent according to any one of claims 9 to 13 on a computer.

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