Handover method for mobile terminal using ring network for transferring ethernet frames, in which mac address storage method for storing bit 1 in both memory storage areas accessed using lower address and intermediate address of source mac address of ethernet frame is applied to ring node device

Abstract

To achieve handover by transferring an Ethernet frame via a ring network.SOLUTION: When a packet from a mobile terminal arrives at a device for adding, dropping, and passing packets in a ring network, a bit 1 is stored in a first bit position of a memory area of an address location in SRAM accessed using the lower address of a source MAC address of the packet, and the bit 1 is stored in a fourth bit position of a memory area of an address location in the SRAM accessed using an intermediate address of the source MAC address of the packet, and the packet is sent to a counterclockwise ring. When the packet arrives at a device for adding, dropping, and passing packets, the bit 1 meaning an erasure reservation is stored in a third bit position of the memory area of the address location in the SRAM accessed using the lower address of the source MAC address of the packet.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a handover method for a mobile terminal using a ring network for transferring Ethernet frames, in which a MAC address storage method for storing bit 1 in both memory storage areas accessed by the lower address and intermediate address of the source MAC address of an Ethernet frame is applied to a ring node device. The present invention relates to a handover method for a mobile terminal using a ring network for transferring Ethernet frames, in which an Ethernet frame and a packet using the MAC address part of an IPv6 address as the MAC address of the MAC packet are used.

[0002] A conventional example of an address storage method is disclosed in Japanese Patent Application Laid-Open No. 2000-151617, "Table This conventional example is related to the storage circuit of MAC addresses, It consists of a first table consisting of a RAM or the like having a column address, a MAC address data area, and an index area, and a second table consisting of a RAM or the like having a row and column address, a MAC address data area, and an index area. In this conventional example, the entire 48 bits of a MAC address are stored at position A, which is specified in the memory of the first table by the lower bit string (for example, 16 bits). If another MAC address is already stored at position A, it is recorded at an empty address position B in the memory of the second table, and the recorded address position B is stored in the index area of ​​address position A of the first table. This is a method of specifying a recording area by nesting.

[0003] As a conventional technique for storing addresses, Patent Document 2, Japanese Patent Application Laid-Open No. 2004-15592, "MAC address pointer structure, MAC address rearrangement method." This conventional example is a method of storing multiple MAC addresses at the same address position in an entry table specified by a low-order bit string. If there is no free area, the MAC address is stored in an entry table specified by a low-order bit string different from the low-order bit string of the MAC address.

[0004] A typical conventional example of a ring network is a ring network using a master switch and a slave switch, as described in Patent Document 3. If one of the ring ports on the switch is a blocked port that does not pass frames, This prevents congestion caused by cluttering. If a fault occurs in the ring network, the monitoring frames sent from the master switch to the master switch will not arrive, and instead The master switch receives a failure notification frame from the slave switch at the failure point. The master switch unblocks the blocked port of the master switch to allow the frame to pass. Also, a blocked port is set on the failed transmission line side of one of the slave switches of the failure point, and the link The ring network continues to operate even after the ring network has recovered from a failure. Generally, in a conventional ring network, a MAC address table is used in the ring node device, so that in the event of a transmission line failure, the FDBs of all ring node devices in the ring are cleared and the FDBs are reconstructed by flooding.

[0005] An example of a handover method is Patent Document 4. This prior art is a method that has an IPv6 connection via a base station before switching via a gateway and a base station between a mobile terminal and an access router, and an IPv6 connection via a destination base station, and reduces the interruption time of packets via the connections when switching connections.

[0006] Non-patent document 2 describes a fast handover for Mobile IPv6. This is a method that uses FBU (Fast Binding Update) between an old access router and a mobile terminal to transmit a CoA (care of address) to an Internet terminal and enables movement to a new access router.

[0007] Non-Patent Document 3 is an example of a mobile network to which handover is applied. This is a network that uses a ring as the core network, with home agents distributed to each node of the ring. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2000-151617 A [Patent Document 2] JP 2004-15592 A [Patent Document 3] Retable No. 2008-068813 [Patent Document 4] Re-tabled publication No. 2017-195497 [Non-patent literature]

[0009] [Non-Patent Document 1] G.8032 “Ethernet Ring Protection Swithing” [Non-Patent Document 2] RFC4260, “Mobile IPv6 Fast handovers for 802.11 networks,” Website, https: / / datatracker.org / doc / html / rfc4260 [Non-Patent Document 3] H. Yokota et. Al, “Study on Decentralized Micro-mobility Magement for Large-scale Mobile Networks,” Journal of information Processing(JIP), Vol. 47 No.4, pp1239-1247, Apr. 2006. (in Japanese) Summary of the Invention [Problem to be solved by the invention]

[0010] The conventional address storage method disclosed in Japanese Patent Application Laid-Open No. 2000-151617 stores MAC addresses by nesting, which causes a problem that it takes a long time to trace the stored address destination by the address stored in the index.

[0011] In addition, in the conventional address storage method disclosed in Japanese Patent Application Laid-Open No. 2004-15592, the lower bits It is described that if there is no vacancy in the entry table position of the MAC address specified by the string, the MAC address will be stored in the entry table position of a different lower bit string. In that case, however, when selecting the position to store the MAC address, it is necessary to search the entry table positions specified by the two lower bit strings, and since there are multiple, discrete lower memory addresses at the same intermediate address position in the same entry table, it is necessary to compare all of these multiple lower memory addresses, which results in a long search time.

[0012] Conventional ring networks, such as Non-Patent Document 1 and Patent Document 3, store the destination MAC addresses of packets bound for the left-handed ring, the destination MAC addresses of packets bound for the right-handed ring, and the destination MAC addresses of packets sent out of the ring as MAC addresses and port numbers, which causes a problem of a large number of MAC addresses to be stored.In addition, when the MAC address table stores the entire 48 bits of the MAC address at the address position accessed by the memory with the lower address of the MAC address, or when the upper address is stored, if the MAC address cannot be stored, the destination MAC address of the packet to be transferred is not stored in the MAC address table (in the case of an unknown packet), and the packet is flooded.

[0013] Furthermore, in a conventional ring network, when searching for a connection destination, the entire destination MAC address is required, and searching using the lower address of the destination MAC address is not possible. Also, in a ring network, even if it is desired to store the source MAC address of a packet in an address table that specifies the passage of the packet so that a reverse packet can pass through a node device that stores a lower address equal to the lower address of the source MAC address, the storage process is not possible because the lower address of the destination MAC address does not indicate when the packet arrived at the destination. If the destination address is a fixed MAC address such as a server, it can be reached using the destination MAC address, but there is a problem that the device scale becomes large for terminals with many destinations.

[0014] Furthermore, the conventional handover technique disclosed in Patent Document 4 provides two IPv4 or IPv6 connections between an access router and a mobile terminal for switching, which requires identification of two IP connections, resulting in a drawback in that handover control becomes complicated.

[0015] In Non-Patent Document 2, handover is realized by transferring the FBU from the old access router to the new access router, but since a router is used for handover and waiting is performed at the router, there is a problem of a large delay time.

[0016] In addition, Non-Patent Document 3 distributes the load of location registration by distributing home agents, but distributing home agents poses the problem that an IP prefix address is required for each. When moving between base stations within a ring node, the IP prefix does not change, but when changing base stations, the IP prefix must be changed due to CoA (Care of Address), which is a problem that cannot be handled with 64-bit host addresses alone. When moving between ring nodes, the IP prefix naturally changes. Introducing IP addresses into the ring poses the problem that it makes it impossible to transfer Ethernet frames within one domain using MAC addresses.

[0017] The object of the present invention is to provide a method for achieving simple handover without using a conventional MAC address table by using a ring network in which a memory that stores the lower address and intermediate address of a MAC address in one bit is used in the ring node device. [Means for solving the problem]

[0018] The present invention has been made in consideration of the above-mentioned problems in the conventional art, and the means for solving the problems are as follows: first to ninth aspects of the present invention. A first aspect of the present invention is a system for enabling handover of a mobile terminal, comprising: a plurality of packet add, drop and pass devices inserted into a ring network, each of which has a U-shaped or normal end, like a fiord (Norwegian) for a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; a base station connected to the packet add, drop and pass devices; a mobile terminal under the base station having a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and a function of blocking the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router; and a vertex device through which a spare optical transmission path used in the event of a ring fault passes, said system transmitting packets from the mobile terminal as TCP or UDP Ethernet frames between the router and the server or the switch via the ring network, and as IP packets between the router and the server or the switch, for communication with a destination server for download services, video lectures, video conferences involving speech signals or content distribution, or for voice communication with a switch, means for transmitting a MAC address authentication packet transmission request packet to the source base station of the mobile terminal immediately before the mobile terminal accesses a destination base station approaching a router in the forward direction on a counterclockwise ring, the source base station confirming the MAC address of the mobile terminal in a MAC address table and then transmitting the MAC address authentication packet of the mobile terminal to the destination base station, and when the packet arrives at a packet add, drop and pass-through device connected to the source base station, transmitting the packet to the counterclockwise ring 1, and when the packet arrives at a packet add, drop and pass-through device connected to the destination base station of the mobile terminal, storing a bit 1 indicating advance reservation in a second bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, and storing a bit 1 indicating advance reservation in a fifth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, and transmitting a movement correspondence preparation packet having the MAC address of the mobile terminal as a destination MAC address to the clockwise ring; or Immediately before the mobile terminal accesses a destination base station approaching a router in the forward direction on the counterclockwise ring, it sends a MAC address authentication packet transmission request packet to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station. When the packet arrives at a device for adding, dropping and passing packets connected to the source base station, it sends the packet to the counterclockwise ring 1, and the packet arrives at a device for adding, dropping and passing packets connected to the destination base station of the mobile terminal. means for, when the packet arrives at the device, storing a bit 1 in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, storing a bit 1 in a fourth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, storing the MAC address of the mobile terminal in an address table that specifies the passage of the packet, and transmitting a mobility preparation packet having the MAC address of the mobile terminal as a destination MAC address to a clockwise ring; on the other hand, Immediately before the mobile terminal accesses a destination base station moving away from the router in the forward direction on the clockwise ring, it sends a MAC address authentication packet transmission request packet to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station, and when the packet arrives at a packet add, drop and pass-through device connected to the source base station, it stores a bit 1 indicating an erase reservation in the third bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, and a bit 1 indicating an advance reservation is stored in a sixth bit position of a storage area of ​​the address position of the memory accessed by the intermediate address of the MAC address, and the packet is sent to a clockwise ring 2, and when the packet arrives at a packet add, drop and pass-through device connected to the destination base station of the mobile terminal, a bit 1 indicating an advance reservation is stored in a second bit position of a storage area of ​​a designated address position of the memory accessed by the lower address and intermediate address accessed by the lower address of the MAC address of the mobile terminal, and a bit 1 indicating an advance reservation is stored in a fifth bit position of a storage area of ​​the address position of the memory accessed by the intermediate address of the source MAC address of the packet, a means for transmitting a mobility preparation packet having a MAC address of the mobile terminal as a destination MAC address to a clockwise ring; When a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, if the packet is a packet immediately after a change of a destination base station, and if the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, and a bit 1 is stored in a first bit position of a storage area at a specified address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in a second bit position of a storage area at a specified address position of a memory accessed by an intermediate address of the source MAC address of the packet. storing a bit 1 in the fourth bit position, and if a bit 1 indicating advance reservation is stored in the second bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address and accessed by a lower address of the source MAC address of the packet, erasing that bit, and if a bit 1 indicating advance reservation is stored in the fifth bit position of a storage area of ​​a designated address position of a memory accessed by an intermediate address of the source MAC address of the packet, erasing that bit, or if the packet does not use a bit indicating advance reservation, leaving it as it is, sending the packet onto the counterclockwise ring; On the other hand, when a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, if the packet is not a packet immediately after a change of destination base station, store a bit 1 in the first bit position of a storage area of ​​a designated address position in a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and store a bit 1 in the fourth bit position of a storage area of ​​a designated address position in the memory accessed by an intermediate address of the source MAC address of the packet, and send the packet to the counterclockwise ring; When the packet arrives at a packet add, drop, or pass-through device, When a bit 1 indicating an erasure reservation is stored in the third bit position of a storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by the lower address of the source MAC address of the packet, and a bit 1 indicating an erasure reservation is stored in the sixth bit position of a storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet, the bit 1s in the first and third bit positions of the storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by the lower address of the source MAC address of the packet, are erased, and a bit 1 indicating an erasure reservation is stored in the fourth bit position of a storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet. and clearing the bit 1 in the first bit position and the bit 1 in the sixth bit position, and, if a bit 1 is stored in the first bit of a storage area of ​​a specified address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and if a bit 1 is stored in the fourth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, storing the source MAC address of the packet in an address table that specifies the passage of the packet, and directing the packet on a counterclockwise ring to a vertex device in which a ring network interface NIC MAC address of a router to which a server or an exchange is connected via a router is stored as the destination MAC address of the packet; When a packet from a server or exchange is sent from a vertex device to a clockwise ring via a router and the packet arrives at a packet add, drop, or pass-through device, means for transmitting the packet forward in a clockwise ring when the destination MAC address of the packet is stored in an address table that specifies the passage of the packet, transmitting the packet out of the ring when the destination MAC address of the packet is not stored in the address table that specifies the passage of the packet and when a bit 1 is stored in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address that is accessed by a lower address of the destination MAC address of the packet and a bit 1 is stored in a fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the destination MAC address of the packet, and transmitting the packet forward in a clockwise ring when a bit 1 is not stored in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address that is accessed by a lower address of the destination MAC address of the packet and a bit 1 is stored in a fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the destination MAC address of the packet, When the base station receives a mobility preparation packet from the ring network, and a MAC address that is the same lower address as the lower address of the destination MAC address of the packet and is different from the destination MAC address of the packet is stored in the MAC address table, the base station sends a mobility preparation packet having the MAC address stored in the MAC address table as a source MAC address from the packet add, drop and pass through device connected to the base station to the counterclockwise ring, and when the packet arrives at the packet add, drop and pass through device, a means for storing the source MAC address of the packet in an address table for specifying the passage of the packet when a bit 1 indicating advance reservation is stored in a second bit position of a storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and a bit 1 indicating advance reservation is stored in a fifth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet; or If the packet does not use a method for storing bits indicating advance reservation, a means for storing the source MAC address of the packet in an address table that specifies the passage of the packet when a bit 1 is stored in a first bit position of a storage area of ​​a designated address position of the memory that is accessed by a lower address and an intermediate address and that is accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in a fourth bit position of a storage area of ​​an address position of the memory that is accessed by an intermediate address of the source MAC address of the packet; The system further comprises:

[0019] A second aspect of the present invention provides a system according to the first aspect of the present invention, comprising: The system is characterized in that the address table, which specifies the passage of the packet, is provided with a means for storing G*L*(L / EXP((24+kN)ln2))) / EXP((24+k)ln2) number of MAC addresses, where G is the number of terminals for packets transferred on the ring, L is the number of terminals ADDed from outside the ring to a device for adding, dropping and passing packets in the ring network, the number of address access bits to the memory is N bits, and the number of upper addresses of the MAC address which identify the lower 24 bits of the MAC address is 2 to the power of K within the system.

[0020] A third aspect of the present invention provides a system according to the first aspect of the present invention, The router has a home agent (HA) function and a CoA (Care of Address) termination function, and transfers data from the mobile terminal to the router via a base station and a ring network using a single domain Ethernet frame, with the IP address remaining unchanged during this time due to a tunnel within the MAC address.

[0021] A fourth aspect of the present invention provides a system according to the first aspect of the present invention, The system is characterized by using domestic IPv4 addresses between the router and the exchange without using NAT.

[0022] A fifth aspect of the present invention provides a system according to the first aspect of the present invention, When the MAC address authentication packet arrives at the destination base station of the mobile terminal, the MAC address of the mobile terminal is stored in a MAC address table, and a mobility preparation packet having the MAC address of the mobile terminal as a destination MAC address is sent to the clockwise ring a plurality of times from a packet add, drop and pass device connected to the destination base station, The system is characterized by comprising a means for setting up a radio channel to the mobile terminal, and storing packets destined for the mobile terminal until a radio channel reception preparation OK signal is received from the mobile terminal.

[0023] A sixth aspect of the present invention provides a system according to the first aspect of the present invention, The system is characterized in that the mobile terminal further comprises means for periodically accessing the receiving mail server and, if a response packet cannot be received from the receiving mail server, sending a retransmission packet to the receiving mail server.

[0024] A seventh aspect of the present invention is a method for enabling handover of a mobile terminal, comprising: inserting a plurality of packet add, drop and pass devices into a ring network, each of which has a U-shaped or normal end like a fiord (Norwegian) for a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; connecting a base station to the packet add, drop and pass devices; and allowing a mobile terminal under the base station to receive packets arriving from the counterclockwise ring of the ring network and forward them to a router and to block the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router, the method comprising the steps of: transmitting packets from the mobile terminal as TCP or UDP Ethernet frames between the mobile terminal and the router across the ring network, and transmitting packets as IP packets between the mobile terminal and the server or the switch via the router connected to a vertex device through which a spare optical transmission path passes, the spare optical transmission path being used in the event of a ring fault, for communication with a destination server for download services, video lectures, video conferences involving speech signals or content distribution, or for voice communication with a switch, the method comprising the steps of: a step of: sending a MAC address authentication packet transmission request packet to the source base station of the mobile terminal immediately before the mobile terminal accesses a destination base station approaching a router in the forward direction on the counterclockwise ring; the source base station confirms the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station; when the packet arrives at a packet add, drop and pass-through device connected to the source base station, sending the packet to the counterclockwise ring 1; when the packet arrives at a packet add, drop and pass-through device connected to the destination base station of the mobile terminal, storing a bit 1 indicating advance reservation in a second bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, and storing a bit 1 indicating advance reservation in a fifth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, and sending a movement correspondence preparation packet having the MAC address of the mobile terminal as a destination MAC address to the clockwise ring; or Immediately before the mobile terminal accesses a destination base station approaching a router in the forward direction on the counterclockwise ring, it sends a MAC address authentication packet transmission request packet to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station. When the packet arrives at a packet add, drop and pass device connected to the source base station, it sends the packet to the counterclockwise ring 1, and the packet arrives at a packet add, drop and pass device connected to the destination base station of the mobile terminal. when the packet arrives at the mobile terminal's MAC address, storing a bit 1 in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, storing a bit 1 in a fourth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, storing the MAC address of the mobile terminal in an address table that specifies the passage of a packet, and transmitting a mobility preparation packet having the MAC address of the mobile terminal as a destination MAC address to the clockwise ring; on the other hand, Immediately before the mobile terminal accesses a destination base station moving away from the router in the forward direction on the clockwise ring, it sends a MAC address authentication packet transmission request packet to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station, and when the packet arrives at a packet add, drop and pass-through device connected to the source base station, it stores a bit 1 indicating an erase reservation in the third bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, and a bit 1 indicating an advance reservation is stored in a sixth bit position of a storage area of ​​the address position of the memory accessed by the intermediate address of the MAC address, and the packet is sent to a clockwise ring 2, and when the packet arrives at a packet add, drop and pass-through device connected to the destination base station of the mobile terminal, a bit 1 indicating an advance reservation is stored in a second bit position of a storage area of ​​a designated address position of the memory accessed by the lower address and intermediate address accessed by the lower address of the MAC address of the mobile terminal, and a bit 1 indicating an advance reservation is stored in a fifth bit position of a storage area of ​​the address position of the memory accessed by the intermediate address of the source MAC address of the packet, sending a mobility preparation packet having a MAC address of the mobile terminal as a destination MAC address to a clockwise ring; When a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, if the packet is a packet immediately after a change of a destination base station, and if the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, and a bit 1 is stored in a first bit position of a storage area at a specified address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in a second bit position of a storage area at a specified address position of a memory accessed by an intermediate address of the source MAC address of the packet. storing a bit 1 in the fourth bit position, and if a bit 1 indicating advance reservation is stored in the second bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address and accessed by a lower address of the source MAC address of the packet, erasing that bit, and if a bit 1 indicating advance reservation is stored in the fifth bit position of a storage area of ​​a designated address position of a memory accessed by an intermediate address of the source MAC address of the packet, erasing that bit, or if the packet does not use a bit indicating advance reservation, leaving it as it is, sending the packet onto the counterclockwise ring; On the other hand, when a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, if the packet is not a packet immediately after a change of destination base station, store a bit 1 in the first bit position of a storage area of ​​a designated address position in a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and store a bit 1 in the fourth bit position of a storage area of ​​a designated address position in the memory accessed by an intermediate address of the source MAC address of the packet, and send the packet to the counterclockwise ring; When the packet arrives at a packet add, drop, or pass-through device, When a bit 1 indicating an erasure reservation is stored in the third bit position of a storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by the lower address of the source MAC address of the packet, and a bit 1 indicating an erasure reservation is stored in the sixth bit position of a storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet, the bit 1s in the first and third bit positions of the storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by the lower address of the source MAC address of the packet, are erased, and a bit 1 indicating an erasure reservation is stored in the fourth bit position of the storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet. and clearing the bit 1 in the first bit position and the bit 1 in the sixth bit position, and if a bit 1 is stored in the first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and if a bit 1 is stored in the fourth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, storing the source MAC address of the packet in an address table that specifies the passage of the packet, and directing the packet on a counterclockwise ring to a vertex device in which a ring network interface NIC MAC address of a router to which a server or an exchange is connected via a router is stored as the destination MAC address of the packet; When a packet from a server or exchange is sent from a vertex device to a clockwise ring via a router and the packet arrives at a packet add, drop, or pass-through device, sending the packet forward in a clockwise direction when the destination MAC address of the packet is stored in an address table that specifies the passage of the packet; sending the packet out of the ring when the destination MAC address of the packet is not stored in the address table that specifies the passage of the packet and when a bit 1 is stored in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address that is accessed by a lower address of the destination MAC address of the packet and a bit 1 is stored in a fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the destination MAC address of the packet; sending the packet forward in a clockwise direction when a bit 1 is not stored in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address that is accessed by a lower address of the destination MAC address of the packet and a bit 1 is stored in a fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the destination MAC address of the packet; When the base station receives a mobility preparation packet from the ring network, and a MAC address that is the same lower address as the lower address of the destination MAC address of the packet and is different from the destination MAC address of the packet is stored in the MAC address table, the base station sends a mobility preparation packet having the MAC address stored in the MAC address table as a source MAC address from the packet add, drop and pass through device connected to the base station to the counterclockwise ring, and when the packet arrives at the packet add, drop and pass through device, storing the source MAC address of the packet in an address table that specifies the passage of the packet when a bit 1 indicating advance reservation is stored in a second bit position of a storage area of ​​a specified address position of the memory that is accessed by a lower address and an intermediate address and that is accessed by a lower address of the source MAC address of the packet, and a bit 1 indicating advance reservation is stored in a fifth bit position of a storage area of ​​an address position of the memory that is accessed by an intermediate address of the source MAC address of the packet; or If the packet does not use a method for storing bits indicating advance reservation, storing the source MAC address of the packet in an address table that specifies the passage of the packet when a bit 1 is stored in a first bit position of a storage area of ​​a designated address position of the memory that is accessed by the lower address and an intermediate address and that is accessed by the lower address of the source MAC address of the packet, and a bit 1 is stored in a fourth bit position of a storage area of ​​an address position of the memory that is accessed by the intermediate address of the source MAC address of the packet; The method further comprises:

[0025] An eighth aspect of the present invention relates to a method according to the seventh aspect of the present invention, comprising: The method further comprises a step in which the mobile terminal periodically accesses the receiving mail server, and if it cannot receive a response packet from the receiving mail server, sends a retransmission packet to the receiving mail server.

[0026] A ninth aspect of the present invention relates to a method according to the seventh aspect of the present invention, comprising: The method is characterized in that the mobile terminal periodically accesses the receiving mail server with the packet number last received when accessing the receiving mail server, and brings back packets having numbers subsequent to the last received packet number and addressed to the mobile terminal from the receiving mail server. Effect of the Invention

[0027] As described above, the present invention has almost no packet loss or delay due to handover, can configure the mobile core network and subscriber network with one ring network, and uses SRAM for lower address and intermediate address designation memory for designating packet transmission outside the ring instead of a MAC address table, making operation simple and fast, and can realize a ring node device (device for adding, dropping and passing packets) with two SRAMs, which has the effect of reducing system costs. Another advantage of the present invention is that one-way UDP download is possible. The present invention also has the effect of realizing handover of a mobile terminal within one domain by a ring network using the above memory, which has the effect of reducing power consumption and system costs and enabling high-speed communication. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a diagram for explaining an example of handover operation of a mobile terminal in a packet forwarding system between a mobile terminal that forwards MAC packets through a base station connected to the packet add, drop and pass device of a double ring network having an SRAM for lower address and intermediate address designation memory for designating packet transmission outside the ring and an address table for designating packet passage according to a first embodiment of the present invention, the double ring network having a shape like a flattened inflated balloon at each end like a fiord (Norwegian word) in which multiple rings are connected by optical rings, and a server connected to the ring network via a router. [Diagram 2]FIG. 2 is a diagram for explaining an example of handover operation of a mobile terminal in a packet forwarding system between a mobile terminal that forwards MAC packets through a base station connected to the packet add, drop and pass device in a dual ring network in which multiple devices are connected by an optical ring, the mobile terminal forwarding MAC packets through a base station connected to the packet add, drop and pass device, and a server connected to the ring network via a router, in a packet forwarding system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] A first (A) embodiment of the present invention will be described with reference to Fig. 1. In this embodiment, a wireless base station is connected to the add, drop and pass devices of a double ring network, each of which has an SRAM for lower addresses and intermediate address designation memory for designating packet transmission outside the ring, and an address table for designating packet passage, and the end of each device is U-shaped or normal, like a fiord (Norwegian), and a mobile terminal under the wireless base station transfers information as a MAC packet to a router connected to the ring network, and the mobile terminal uses the ring network to transfer information between a server connected to the ring network or between a switchboard and the router. This system is also capable of one-way UDP download. The server is a mail receiving server or an Internet connection server.

[0030] In Fig. 1, 1 is an optical transmission line of a counterclockwise ring, 2 is an optical transmission line of a clockwise ring, 6-1, 6-2, and 6-3 are devices (ring node devices) for adding, dropping, and passing packets, 5 is a vertex device, 8 is an address table that specifies the passing of packets, 11 is an SRAM for lower addresses and intermediate addresses that specify packet transmission outside the ring, 13-1, 13-2, and 13-3 are mobile terminals, 14-1, 14-2, and 14-3 are wireless base stations (BS), 20 is a server, 22 is a home agent (HA), a router with a NAT function for Internet connection, 26 is a switch, and 27 is a home memory. Also, (1) to (37) indicate the transfer order of packets, which are abbreviated by letter symbols for MAC addresses transferred on the ring indicated by the dotted lead line, and I0, I1, I2, I3, and I7 are global IPv4 addresses that are dynamically set as IP addresses in terminals, or domestic IPv4 addresses of service providers. Or they are IPv6 addresses. The ring node devices 6-1, 6-2, 6-3 and apex devices in the ring network operate at Layer 2, but may have Layer 3 switch functions for monitoring, etc. In the case of one ring, ring node devices can be monitored by wire, so there is no need to monitor using IP addresses. When IPv6 addresses are used for base stations, the prefix portion of the IPv6 address is the same within the ring, and base stations are identified only by the MAC address portion of the IPv6 address. The OE conversion circuit, EO conversion circuit, input buffer, and output buffer are not shown in the figure.

[0031] The operation of Fig. 1 will be explained below. An example is shown in which the mobile terminal 13-2 for voice transmission has sent packet (1) Mn1r1r2γβα(I7) (M indicates an Ethernet packet, n1 indicates the wireless MAC address of the base station 14-1, r1r2 indicates the NIC MAC address of the ring network interface of the router 22, γβα indicates the upper MAC address γ, the intermediate MAC address β, and the lower MAC address α, which are the MAC addresses of the mobile terminal 13-2, and I7 indicates the IP address of the destination exchange) to the base station 14-1. When the packet reaches the add, drop and pass device 6-1 for a packet from the mobile terminal 13-2, the router 22 (r1r2 indicates the NICMAC address of the ring network interface of the router 22) stores bit 1 in the first bit of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the lower address α (e.g., the 1st bit to the 17th bit) of the source MAC address of the packet, stores bit 1 in the fourth bit of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the intermediate address β (e.g., the 18th bit to the 34th bit as the 1st bit to the 17th bit of the memory access address) of the source MAC address of the packet, and sends the packet toward the vertex device 5 (the add, drop and pass device for a packet) in which the NICMAC address of the upper ring network interface of the router 22 that connects to the server 20 via the working optical transmission line 1 of the counterclockwise ring is stored in the address table 12.

[0032] When the packet is transferred by (3) Mr1r2γβα (I7) on counterclockwise ring 1 as shown in the figure and arrives at device 6-2 for adding, dropping, and passing packets, a bit 1 is stored in the first bit of the storage area of ​​the address location of SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by the lower address α (e.g., the 1st bit to the 17th bit) of the source MAC address of the packet, and a bit 1 is stored in the first bit of the storage area of ​​the address location of SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by the intermediate address β (e.g., the 18th bit to the 34th bit as the memory access address 1st bit to the 17th bit) of the source MAC address of the packet. When bit 1 is stored in the fourth bit of the memory area of ​​the address location of the SRAM (11) for specifying the lower address and intermediate address specification memory, the source MAC address of the packet is stored in the address table that specifies the passage of the packet. However, in this case, since it is not stored, the packet is sent directly to the vertex device 5 on the counterclockwise ring 1, and when the packet arrives at the device for adding, dropping and passing the packet (vertex device 5), since the destination MAC address r1r2 of the packet is stored in the address table 12 for the router, the packet is dropped from the ring as (6)Mr1r2γβα(I7) toward the router 22 outside the ring. When the packet arrives at router 22, the source MAC address (γβα) and IP address (I3) of the packet are stored in an ARP table not shown in the figure, or the source MAC address (γβα) is placed in the option field of the IP header, and the IP packet is forwarded as shown in the figure by (7) IPI3I7 (IP indicates an IP address, I3 indicates the IP address of mobile terminal 13-2, and I7 indicates the IP address of the destination exchange 26), and reaches exchange 26.

[0033] Next, when the mobile terminal 13-1 receiving the mail reception service sends a packet (9) Mr1r2δβα(I0) (M indicates an Ethernet packet, r1r2 indicates the NIC MAC address of the ring network interface of the router 22, δβα indicates the upper MAC address δ, the intermediate MAC address β, and the lower MAC address α, which are the MAC addresses of the terminal device (e.g., mobile terminal) 13-1, and I0 indicates the IP address of the destination mail reception server 20 (a server that can be reached without using NAT)) to the device 6-1 for adding, dropping, and passing the packet via the base station 14-1, the lower address and intermediate address that specify the packet transmission outside the ring accessed by the lower address α of the source MAC address of the packet are A bit 1 is stored in the first bit position of the storage area of ​​the address location of the SRAM (11) for the address designation memory, a bit 1 is stored in the fourth bit position of the storage area of ​​the address location of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by the intermediate address β of the source MAC address of the packet, and the packet is sent to the address table 12 in which the NICMAC address of the ring network interface of the router 22 that connects to the server 20 or the switch 26 via the working optical transmission line 1 of the counterclockwise ring is stored.

[0034] When the packet is transferred by (10) Mr1r2δβα(I0) on counterclockwise ring 1 as shown in the figure and arrives at device 6-2 for adding, dropping, and passing packets, bit 1 is stored in the first bit position of the address position storage area of ​​SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the lower address α (e.g., bits 1 to 17) of the source MAC address of the packet, and the intermediate address β (e.g., bits 18 to 34 of the source MAC address of the packet) is stored in the first bit position of the address position storage area of ​​SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the lower address α (e.g., bits 1 to 17) of the source MAC address of the packet. In this case, the packet passes through the device 6-2 as is, and when the packet reaches the vertex device 5, whose destination MAC address r1r2 is stored in the address table 12 for the router, the packet is dropped from the ring as (13)Mr1r2δβα(I0) toward the router 22 outside the ring. When the packet reaches the router 22, the source MAC address (δβα) and IP address (I2) of the packet are stored in an ARP table (not shown), or the source MAC address (δβα) is put into the option field of the IP header, and the IP packet is forwarded by (14)IPI2I0 (IP indicates an IP address, I2 indicates the IP address of the mobile terminal 13-1, and I0 indicates the IP address of the destination server 20) as shown in the figure, and reaches the server 20.

[0035] Next, an example will be shown in which mobile terminal 13-2 moves from base station 14-1 to base station 14-2. When a MAC authentication packet transmission request packet (15)Mn2γβα(I7) (n2 indicates the wireless NIC MAC address of base station 14-2, and γβα indicates the MAC address of mobile terminal 13-2 (upper address γ, middle address β, lower address α)) from the mobile terminal 13-2 arrives at the source base station 14-1, the source base station checks the MAC address of the mobile terminal 13-2 in a MAC address table (not shown), and then transmits a MAC address authentication packet (16)MB2γβα() (B2 is the MAC address of base station 14-2) of the mobile terminal 13-2 to the destination base station 14-2. When the packet arrives at packet add, drop and pass device 6-1, it transmits the packet to the counterclockwise ring 1. When the packet arrives at the packet add, drop and pass device 6-2, a bit 1 indicating advance reservation is stored in the second bit position of the memory area of ​​the address location of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the lower address α of the MAC address of the mobile terminal 13-2, and a bit 1 indicating advance reservation is stored in the fifth bit position of the memory area of ​​the address location of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the intermediate address β of the source MAC address of the packet, and a mobility preparation packet (19) Mγβαr1r2() with the MAC address γβα as the destination MAC address is sent from the packet add, drop and pass device 6-2 to the clockwise ring 2. The packet (18) MB2γβα() is sent to the destination base station 14-2. The destination base station 14-2 stores the MAC address γβα of the mobile terminal in a MAC address table (not shown) and sends a mobility preparation packet (19)Mγβαr1r2() with the MAC address γβα as the destination MAC address from the packet add, drop, and pass device 6-2 to the clockwise ring 2.When the packet (20) Mγβαr1r2() arrives at the packet add, drop, and pass device 6-1, the destination MAC address γβα of the packet is not stored in the address table 8 that specifies the pass of the packet, and a bit 1 is stored in the first bit of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that specifies the packet transmission outside the ring and is accessed by the lower address α (e.g., the 1st bit to the 17th bit) of the destination MAC address of the packet, and a bit 1 is stored in the fourth bit of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that specifies the packet transmission outside the ring and is accessed by the intermediate address β of the source MAC address of the packet (e.g., the 18th bit to the 34th bit are the 1st bit to the 17th bit of the memory access address), so that the packet is sent outside the ring. When the mobility response preparation packet (21) Mγβαr1r2() arrives at base station 14-1, a MAC address δβα that is different from the destination MAC address of the packet and has the same lower address as the lower address a2 of the destination MAC address γβα of the packet is stored in the MAC address table, so a mobility response packet (22) Mr1r2δβα(I0) with the MAC address δβα stored in the MAC address table as the source MAC address is sent to counterclockwise ring 1 via packet add, drop and pass device 6-1.When the packet (23) Mr1r2δβα (I0) arrives at packet add, drop, and pass device 6-2, a bit 1 indicating advance reservation is stored in the second bit position of the storage area for the lower address and address position of SRAM (11) for intermediate address designation memory and lower address designating packet transmission outside the ring accessed by the lower address α (e.g., bits 1 to 17) of the source MAC address of the packet, and a bit 1 indicating advance reservation is stored in the fifth bit position of the storage area for the lower address and address position of SRAM (11) for intermediate address designation memory and lower address designating packet transmission outside the ring accessed by the intermediate address β of the source MAC address of the packet (e.g., bits 18 to 34 are the first to 17th bits of the memory access address), so that the source MAC address δβα of the packet is stored in address table 8 specifying the pass of the packet.

[0036] Next, when the MAC address authentication packet of the mobile terminal 13-2 arrives at the base station 14-2, a radio channel to the mobile terminal 13-2 is set, and no packet is sent to the mobile terminal 13-2 until the packet (25) Mr1r2γβα (I7) from the mobile terminal 13-2 arrives at the packet add, drop and pass device 6-2. When the packet arrives, the packet is a packet immediately after the destination base station is changed when the device is connected to a base station approaching the server 20 on the counterclockwise ring 1. Therefore, a bit 1 is stored in the first bit position of the address position storage area of ​​the SRAM (11) for the lower address and intermediate address designation memory that designates packet sending outside the ring accessed by the lower address α of the source MAC address of the packet, and the source MAC address of the packet is Bit 1 is stored in the fourth bit position of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate addressing memory that designates packet transmission outside the ring and is accessed by the intermediate address β of the MAC address, and bit 1 indicating advance reservation is erased in the second bit position of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate addressing memory that designates packet transmission outside the ring and is accessed by the lower address α of the source MAC address of the packet, and bit 1 indicating advance reservation is erased in the fifth bit position of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate addressing memory that designates packet transmission outside the ring and is accessed by the intermediate address β of the source MAC address of the packet. In the figure, the second and fifth bits are shown with horizontal lines to have been erased. The third bit is not shown in the figure.

[0037] The packet (26) Mr1r2γβα (I7) is sent as (27) Mr1r2γβα (I7) to the address table 12 which stores the NICMAC address of the upper ring network interface of the router 22 connected to the server 20 via the working optical transmission line 1 of the counterclockwise ring.

[0038] When the packet arrives at the packet add, drop and pass-through device (vertex device 5) on counterclockwise ring 1 as is, since the packet's destination MAC address r1r2 is stored in address table 12 for the router, the packet is dropped from the ring as (29)Mr1r2γβα(I7) and headed for router 22 outside the ring.

[0039] When the packet arrives at router 22, the source MAC address (γβα) and IP address (I3) of the packet are stored in an ARP table not shown in the figure, or the source MAC address (γβα) is placed in the option field of the IP header, and the IP packet is forwarded as shown in the figure by (30)IPI3I7 (IP indicates an IP address, I3 indicates the IP address of the terminal connected to terminal device 13-2, and I7 indicates the IP address of the destination exchange 26), and reaches exchange 26.

[0040] Next, when a response packet (31) IPI0I2 (IP indicates an IP address, I2 is the IPv6 address or IPv4 address of terminal device 13-1, and I0 is the IP address of server 20) for the mail reception service from server 20 arrives at router 22, if the packet is an IPv6 address, the destination MAC address paired with the destination IPv6 address I2 of the packet is copied from the MAC address portion of the destination IPv6 address, and the MAC packet (32) Mδβαr1r2 (I2) used as the MAC header address of the MAC packet is sent to the packet add, drop and pass-through device (vertex device 5) of the ring network. If the packet is an IPv4 address, the destination MAC address δβα paired with the destination IP address I2 of the packet is obtained from an ARP table (not shown in the figure), and a MAC packet (32)Mδβαr1r2(I2) using the MAC address in the optional field of the IP header as the destination MAC address and the NIC MAC address r1r2 of the ring network interface of router 22 as the source MAC address is sent to the device (vertex device 5) that adds, drops, and passes packets in the ring network.

[0041] When the MAC packet (32) Mδβαr1r2 (I2) arrives at the device for adding, dropping and passing packets (vertex device 5), the source MAC address of the packet is stored in the address table 12 for router connection, so the packet is sent to the clockwise ring 2.

[0042] When packet (34)Mδβαr1r2(I2) is forwarded through clockwise ring 2 and arrives at packet add, drop, and pass-through device 6-2, the packet is sent to clockwise ring 2 because the destination MAC address δβα of the packet is stored in address table 8, which specifies the pass-through of the packet.

[0043] When the packet (35)Mδβαr1r2(I2) is transferred to the clockwise ring 2 and arrives at the packet add, drop and pass device 6-1, the destination MAC address δβα of the packet is not stored in the address table 8 that specifies the packet pass, and bit 1 is stored in the first bit position of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that specifies the packet send out of the ring accessed by the lower address α of the destination MAC address of the packet, and bit 1 is stored in the fourth bit position of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that specifies the packet send out of the ring accessed by the intermediate address β of the destination MAC address of the packet, so the packet is sent out of the ring as (36)Mδβαr1r2(I2). When the packet arrives at the base station 14-1, the destination MAC address of the packet is stored in a MAC address table not shown in the figure, so the packet is headed for the destination mobile terminal 13-1.

[0044] Next, a first (B) embodiment of the present invention will be described with reference to FIG. 2. In this embodiment, a wireless base station is connected to the add, drop and pass device of a double ring network, each of which has an SRAM for lower addresses and intermediate address designation memory for designating packet transmission outside the ring and an address table for designating packet passage, and each end of the device is U-shaped or normal, like a fiord (Norwegian), in which optical transmission lines are connected. A mobile terminal under the wireless base station transfers information as a MAC packet to a router connected to the ring network, and this is an example of a handover operation of a TCP packet or a voice packet of a mobile terminal using a ring network in a packet transfer system between a server connected to the ring network via the router, or between a switchboard. This system is also capable of one-way UDP download. The server is a mail receiving server or an Internet connection server. The difference from FIG. 1 is that FIG. 1 shows a movement of a mobile terminal to a destination base station approaching a router in the forward direction on a counterclockwise ring, whereas FIG. 2 shows an example of a movement of a mobile terminal to a destination base station moving away from a router in the forward direction on a clockwise ring.

[0045] In FIG. 2, the elements with the numbers are the same as those in FIG. 1. Also, (1) to (31) indicate the order of packet transfers in which the MAC addresses are abbreviated with letter symbols to be transferred through the ring indicated by the dotted leader line, and I0, I1, I2, I3, and I7 are global IPv4 addresses that are dynamically set as IP addresses in terminals, or domestic IPv4 addresses of service providers. Or they are IPv6 addresses. The ring node devices 6-1, 6-2, and 6-3 and the apex device of the ring network operate at layer 2, but may have layer 3 switch functions for monitoring, etc. In the case of one ring, the ring node devices can be monitored by lines, so there is no need to monitor them using IP addresses. When an IPv6 address is used for a base station, the prefix part of the IPv6 address is the same within the ring, and the base station is identified only by the MAC address part of the IPv6 address. The OE conversion circuit, EO conversion circuit, input buffer, and output buffer are not shown in the figure.

[0046] The operation of Fig. 2 will be explained below. An example is shown in which the mobile terminal 13-2 for voice transmission has sent packet (1) Mn2r1r2γβα(I7) (M indicates an Ethernet packet, n2 indicates the wireless MAC address of the base station 14-2, r1r2 indicates the NIC MAC address of the ring network interface of the router 22, γβα indicates the upper MAC address γ, the intermediate MAC address β, and the lower MAC address α, which are the MAC addresses of the mobile terminal 13-2, and I7 indicates the IP address of the destination exchange) to the base station 14-2. When the packet reaches the add, drop and pass device 6-2 for a packet from the mobile terminal 13-2, the router 22 stores a bit 1 in the first bit of a storage area of ​​an address position of the SRAM (11) for a lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by a lower address α (e.g., the 1st bit to the 17th bit) of the source MAC address of the packet, stores a bit 1 in the fourth bit of a storage area of ​​an address position of the SRAM (11) for a lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by an intermediate address β (e.g., the 18th bit to the 34th bit are the 1st bit to the 17th bit of the memory access address) of the source MAC address of the packet, and sends the packet toward the vertex device 5 (a device for adding, dropping and passing a packet) in which the NICMAC address of the upper ring network interface of the router 22 that connects to the server 20 via the working optical transmission line 1 of the counterclockwise ring is stored in the address table 12.

[0047] When the packet is transferred by (3) Mr1r2γβα (I7) on counterclockwise ring 1 as shown in the figure and arrives at device 6-3 for adding, dropping and passing packets, a bit 1 is stored in the first bit of the storage area of ​​the address location of SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by the lower address α (e.g., the 1st bit to the 17th bit) of the source MAC address of the packet, and a bit 1 is stored in the first bit of the storage area of ​​the address location of SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by the intermediate address β (e.g., the 18th bit to the 34th bit as the memory access address 1st bit to the 17th bit) of the source MAC address of the packet. When bit 1 is stored in the fourth bit of the memory area of ​​the address location of the SRAM (11) for the lower address and intermediate address specification memory specifying the source MAC address of the packet, the source MAC address of the packet is stored in the address table specifying the passage of the packet. However, in this case, since it is not stored, the packet is sent directly to the vertex device 5 on the counterclockwise ring 1, and when the packet arrives at the device for adding, dropping and passing the packet (vertex device 5), since the destination MAC address r1r2 of the packet is stored in the address table 12 for the router, the packet is dropped from the ring as (5)Mr1r2γβα(I7) toward the router 22 outside the ring. When the packet arrives at router 22, the source MAC address (γβα) and IP address (I3) of the packet are stored in an ARP table not shown in the figure, or the source MAC address (γβα) is placed in the option field of the IP header, and the IP packet is forwarded as shown in the figure by (6) IPI3I7 (IP indicates an IP address, I3 indicates the IP address of mobile terminal 13-2, and I7 indicates the IP address of the destination exchange 26), and reaches exchange 26.

[0048] Next, when the mobile terminal 13-1 receiving the mail reception service sends a packet (8) Mr1r2δβα(I0) (M indicates an Ethernet packet, r1r2 indicates the NIC MAC address of the ring network interface of the router 22, δβα indicates the upper MAC address δ, the intermediate MAC address β, and the lower MAC address α, which are the MAC addresses of the mobile terminal (e.g., portable terminal) 13-1, and I0 indicates the IP address of the destination mail reception server 20 (a server that can be reached without using NAT)) to the add, drop, and pass-through device 6-1 via the base station 14-1, the lower address and intermediate address that specify the packet transmission outside the ring accessed by the lower address α of the source MAC address of the packet are A bit 1 is stored in the first bit position of the storage area of ​​the address location of the SRAM (11) for the address designation memory, a bit 1 is stored in the fourth bit position of the storage area of ​​the address location of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by the intermediate address β of the source MAC address of the packet, and the packet is sent to the address table 12 in which the NICMAC address of the ring network interface of the router 22 that connects to the server 20 or the switch 26 via the working optical transmission line 1 of the counterclockwise ring is stored.

[0049] When the packet is transferred through counterclockwise ring 1 by (9)Mr1r2δβα(I0) as shown in the figure and arrives at packet add, drop, and pass-through device 6-2, a bit 1 is stored in the first bit position of the memory area of ​​the address location of SRAM (11) for lower addresses and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the lower address α (e.g., the 1st to 17th bits) of the source MAC address of the packet, and a bit 1 is stored in the fourth bit position of the memory area of ​​the address location of SRAM (11) for lower addresses and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the intermediate address β (e.g., the 18th to 34th bits are the 1st to 17th bits of the memory access address) of the source MAC address of the packet, so that the source MAC address δβα of the packet is stored in address table 8 that designates the passage of the packet, and the packet is sent out to counterclockwise ring 1 as (10)Mr1r2δβα(I0). When the packet arrives at the vertex device 5, the destination MAC address r1r2 of the packet is stored in the address table 12 for the router, so the packet is dropped from the ring as (12)Mr1r2δβα(I0) toward the router 22 outside the ring. When the packet arrives at the router 22, the source MAC address (δβα) and IP address (I2) of the packet are stored in an ARP table (not shown), or the source MAC address (δβα) is placed in the option field of the IP header, and the IP packet is forwarded as shown in the figure by (13)IPI2I0 (IP indicates an IP address, I2 indicates the IP address of the mobile terminal 13-1, and I0 indicates the IP address of the destination server 20) to reach the server 20.

[0050] Next, an example will be shown in which the mobile terminal 13-2 moves from the base station 14-2 to the base station 14-1. When a MAC authentication packet transmission request packet (14)Mn2γβα(I7) (n2 indicates the wireless NIC MAC address of base station 14-2, and γβα indicates the MAC address of mobile terminal 13-2 (upper address γ, middle address β, lower address α)) from the mobile terminal 13-2 arrives at the source base station 14-2, the source base station checks the MAC address of the mobile terminal 13-2 in a MAC address table (not shown) and then transmits a MAC address authentication packet (15)MB1γβα() (B1 is the MAC address of base station 14-1) of the mobile terminal 13-2 to the destination base station 14-1. When the packet arrives at the packet add, drop and pass device 6-2, a bit 1 indicating an erase reservation is stored in the third bit position of the memory area of ​​the address location of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the lower address α of the MAC address of the mobile terminal 13-2, and a bit 1 indicating an erase reservation is stored in the sixth bit position of the memory area of ​​the address location of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the intermediate address β of the source MAC address of the packet, and the packet is sent to the clockwise ring. When the packet (17)MB1γβα() arrives at the destination base station 14-1, the destination base station 14-1 stores the MAC address γβα of the mobile terminal in a MAC address table (not shown) and sends a movement correspondence preparation packet Mγβαr1r2() with the MAC address γβα as the destination MAC address from the packet add, drop and pass device 6-1 to the clockwise ring 2.

[0051] Next, when the MAC address authentication packet of the mobile terminal 13-2 arrives at the base station 14-1, a radio channel to the mobile terminal 13-2 is set, and no packet is sent to the mobile terminal 13-2 until the packet (19) Mr1r2γβα (I7) from the mobile terminal 13-2 arrives at the packet add, drop and pass device 6-1. When the packet arrives, since the packet is a packet immediately after the destination base station is changed when the device is a device that connects to a destination base station in the direction away from the router 22 on the clockwise ring 1, a bit 1 is stored in the first bit position of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet sending outside the ring and that is accessed by the lower address α of the source MAC address of the packet, and a bit 1 is stored in the fourth bit position of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet sending outside the ring and that is accessed by the intermediate address β of the source MAC address of the packet.

[0052] The packet (21) Mr1r2γβα (I7) is sent as (22) Mr1r2γβα (I7) to the address table 12 which stores the NICMAC address of the upper ring network interface of the router 22 connected to the server 20 via the working optical transmission line 1 of the counterclockwise ring.

[0053] When the packet is transferred by (9) Mr1r2γβα(I0) on counterclockwise ring 1 as shown in the figure and arrives at device 6-2 for adding, dropping and passing packets, the packet is a packet immediately after a change of destination base station in the direction away from the router toward the front of the clockwise ring, so that a bit 1 indicating an erase reservation is stored in the third bit position of the address location storage area of ​​SRAM (11) for lower address and intermediate address designation memory designating packet transmission outside the ring accessed by lower address α (e.g., bits 1 to 17) of the source MAC address of the packet, and a bit 1 indicating an erase reservation is stored in the third bit position of the address location storage area of ​​SRAM (11) for lower address and intermediate address designation memory designating packet transmission outside the ring accessed by intermediate address β (e.g., bits 18 to 34 are the memory access address bits 1 to 17) of the source MAC address of the packet. Since a bit 1 indicating an erase reservation is stored in the sixth bit position of the memory area of ​​the address location of SRAM (11) for the lower address and intermediate address designation memory designating packet transmission outside the ring accessed by the lower address α (for example, the first to seventeenth bits) of the source MAC address of the packet, the bit 1s in the first and third bit positions are erased, and the bit 1s in the fourth and sixth bit positions of the memory area of ​​the address location of SRAM (11) for the lower address and intermediate address designation memory designating packet transmission outside the ring accessed by the intermediate address β (for example, the 18th to 34th bits are the first to 17th bits of the memory access address) of the source MAC address of the packet are erased, and the packet is sent to the counterclockwise ring 1. In the figure, the erased first, third, fourth, and sixth bits are indicated by horizontal lines. When the packet arrives at the packet add, drop and pass device (vertex device 5), the packet's destination MAC address r1r2 is stored in the address table 12 for the router, so the packet is dropped from the ring as (23)Mr1r2γβα(I7) and headed towards router 22 outside the ring.

[0054] When the packet arrives at router 22, the source MAC address (γβα) and IP address (I3) of the packet are stored in an ARP table not shown in the figure, or the source MAC address (γβα) is placed in the option field of the IP header, and the IP packet is forwarded as shown in the figure by (24) IPI3I7 (IP indicates an IP address, I3 indicates the IP address of the terminal connected to terminal device 13-2, and I7 indicates the IP address of the destination exchange 26), and reaches exchange 26.

[0055] Next, when a packet (25) IPI7I3 (IP indicates an IP address, I3 is the IPv6 address or IPv4 address of mobile terminal 13-2, and I7 is the IP address of exchange 26) that is not a communication initiation packet from exchange 26 arrives at router 22, if the packet is an IPv6 address, the destination MAC address paired with the destination IPv6 address I3 of the packet is copied from the MAC address portion of the destination IPv6 address, and the MAC packet (26) Mγβαr1r2 (I3) used as the MAC header address of the MAC packet is sent to the packet add, drop and pass-through device (vertex device 5) of the ring network. If the packet is an IPv4 address, the destination MAC address γβα paired with the destination IP address I3 of the packet is obtained from an ARP table (not shown in the figure), and a MAC packet (26)Mγβαr1r2(I3) using the MAC address in the option field of the IP header as the destination MAC address and the NIC MAC address r1r2 of the ring network interface of router 22 as the source MAC address is sent to the device (vertex device 5) that adds, drops, and passes packets in the ring network.

[0056] When the MAC packet (26) Mγβαr1r2 (I3) arrives at the packet add, drop and pass-through device (vertex device 5), the source MAC address of the packet is stored in the address table 12 for router connection, so the packet is sent to the clockwise ring 2.

[0057] When packet (28) Mγβαr1r2(I23) is transferred through clockwise ring 2 and arrives at packet add, drop, and pass-through device 6-2, the destination MAC address γβα of the packet is not stored in address table 8 specifying the passage of the packet, and bit 1 is stored in the first bit position of the storage area of ​​the address location of SRAM (11) for lower addresses and intermediate addressing memory specifying packet transmission outside the ring accessed by the lower address α of the destination MAC address of the packet, and bit 1 is not stored in the fourth bit position of the storage area of ​​the address location of SRAM (11) for lower addresses and intermediate addressing memory specifying packet transmission outside the ring accessed by the intermediate address β of the destination MAC address of the packet, so that the packet is sent to clockwise ring 2.

[0058] When the packet (29)Mγβαr1r2(I3) is transferred through the clockwise ring 2 and arrives at the packet add, drop and pass device 6-1, the destination MAC address γβα of the packet is not stored in the address table 8 that specifies the packet pass, and bit 1 is stored in the first bit position of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that specifies the packet send out of the ring accessed by the lower address α of the destination MAC address of the packet, and bit 1 is stored in the fourth bit position of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that specifies the packet send out of the ring accessed by the intermediate address β of the destination MAC address of the packet, so the packet is sent out of the ring as (30)Mγβαr1r2(I3). When the packet arrives at the base station 14-1, the destination MAC address of the packet is stored in a MAC address table not shown, so the packet is headed for the destination mobile terminal 13-2.

[0059] The switch 26 in the first embodiment (A) and the first embodiment (B) is a switch that routes IP packets using information in the home memory 27.

[0060] In the case of embodiment 1(A) and embodiment 1(B), when a mobile terminal is handed over, packets from the switch 26 reach the mobile terminal via the source base station until the channel setting from the destination base station to the mobile terminal is completed and the source MAC address of the packet immediately after the destination base station is changed is set in the packet add, drop and pass-through device connected to the destination base station, so that there is almost no packet loss when the mobile terminal is handed over.

[0061] In the first embodiment, bit 1 is stored in the first and second bits of the memory area of ​​an address position in SRAM that is accessed by a ring node device with a lower address of the destination MAC address of a packet (bit 1 to bit 17 counting from the least significant bit of the destination MAC address), and bit 1 is stored in the third and fourth bits of the memory area of ​​an address position in SRAM that is accessed by an intermediate address of the destination MAC address of the packet (bit 18 to bit 34 counting from the least significant bit of the destination MAC address), and the issue is the number of MAC addresses required to be stored in an address table that specifies the passage of a packet in a ring node device. Incidentally, if the number of packet terminals to be ADDed to the ring is 10,000, the number of terminals to be transferred on the ring is 500,000, the number of addressing bits in the SRAM is 17 bits, and NIC manufacturers of mobile terminals around the world manufacture NICs with 16 (4-bit) types of manufacturer numbers, then the number of MAC addresses required to be stored N = 500,000 * 10,000 * (10,000 / EXP((24+4-17)ln2))) / EXP(24+4)ln2) = 91, and therefore there is no problem in implementing the first embodiment.

[0062] Since the first embodiment can be configured using only existing SRAM, it can be easily adapted for use in a LAN. The first embodiment is also capable of storing the source MAC address of the location registration packet.

[0063] In the first embodiment, when a mobile terminal cannot receive a response packet to a periodic access packet to a receiving mail server, the mobile terminal sends a retransmission packet to the receiving mail server, or when accessing the receiving mail server, the mobile terminal accesses the server using the last packet number it has received and brings back packets from that number onwards.

[0064] Although the first embodiment is described on the assumption that SRAM is used, it can also be realized with MRAM. [Explanation of symbols]

[0065] 1. Counterclockwise ring optical transmission line 2. Clockwise ring optical transmission line 5 Vertex device 6-1, 6-2, 6-3 Packet Add, Drop and Pass Devices 8 Address table that specifies the passage of packets 11 SRAM for lower address and intermediate addressing memory for packet sending out of the ring 12 Address table for router connections 13-1, 13-2, 13-3, 13-4 Mobile terminals 14-1, 14-2, 14-3 Base station (BS) 20 Servers 22 Router 26 Switchboard

Claims

1. A system in which a plurality of packet add, drop and pass devices are inserted into a ring network, each of which has a U-shaped or normal end like a fiord (Norwegian) for a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1, a base station is connected to the packet add, drop and pass devices, and a mobile terminal under the base station has a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router, and a function of blocking the passage of packets having the NIC MAC address of the ring network interface of the router as a source MAC address, and in which packets from the mobile terminal travel between the router and a destination server via the router connected to a vertex device through which a spare optical transmission path to be used in the event of a ring fault passes, as TCP or UDP Ethernet frames between the router and the server or the switch, and as IP packets between the router and the server or the switch, enabling handover of the mobile terminal, means for transmitting a MAC address authentication packet transmission request packet to the source base station of the mobile terminal immediately before the mobile terminal accesses a destination base station approaching a router in the forward direction on a counterclockwise ring, the source base station confirming the MAC address of the mobile terminal in a MAC address table and then transmitting the MAC address authentication packet of the mobile terminal to the destination base station, when the packet arrives at a packet add, drop and pass-through device connected to the source base station, transmitting the packet to the counterclockwise ring 1, when the packet arrives at a packet add, drop and pass-through device connected to the destination base station of the mobile terminal, storing a bit 1 indicating advance reservation in a second bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, and storing a bit 1 indicating advance reservation in a fifth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, and transmitting a movement correspondence preparation packet having the MAC address of the mobile terminal as a destination MAC address to the clockwise ring; or Immediately before the mobile terminal accesses a destination base station approaching a router in the forward direction on the counterclockwise ring, it sends a MAC address authentication packet transmission request packet to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station. When the packet arrives at a device for adding, dropping and passing packets connected to the source base station, it sends the packet to the counterclockwise ring 1, and the packet arrives at a device for adding, dropping and passing packets connected to the destination base station of the mobile terminal. means for, when the packet arrives at the device, storing a bit 1 in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, storing a bit 1 in a fourth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, storing the MAC address of the mobile terminal in an address table that specifies the passage of the packet, and transmitting a mobility preparation packet having the MAC address of the mobile terminal as a destination MAC address to a clockwise ring; on the other hand, Immediately before the mobile terminal accesses a destination base station moving away from the router in the forward direction on the clockwise ring, it sends a MAC address authentication packet transmission request packet to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station, and when the packet arrives at a packet add, drop and pass-through device connected to the source base station, it stores a bit 1 indicating an erase reservation in the third bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, and a bit 1 indicating an advance reservation is stored in a sixth bit position of a storage area of ​​an address location of the memory accessed by the intermediate address of the MAC address, the packet is sent to clockwise ring 2, and when the packet arrives at a packet add, drop and pass-through device connected to the destination base station of the mobile terminal, a bit 1 indicating an advance reservation is stored in a second bit position of a storage area of ​​a designated address location of the memory accessed by the lower address and intermediate address accessed by the lower address of the MAC address of the mobile terminal, and a bit 1 indicating an advance reservation is stored in a fifth bit position of a storage area of ​​an address location of the memory accessed by the intermediate address of the source MAC address of the packet, a means for transmitting a mobility preparation packet having a MAC address of the mobile terminal as a destination MAC address to a clockwise ring; When a packet from the mobile terminal arrives at a packet add, drop and pass-through device of the ring network, if the packet is a packet immediately after a change of a destination base station, and if the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, and a bit 1 is stored in a first bit position of a storage area at a specified address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in a second bit position of a storage area at a specified address position of a memory accessed by an intermediate address of the source MAC address of the packet. store a bit 1 in the fourth bit position, and if a bit 1 indicating advance reservation is stored in the second bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address and accessed by a lower address of the source MAC address of the packet, erase that bit, and if a bit 1 indicating advance reservation is stored in the fifth bit position of a storage area of ​​a designated address position of a memory accessed by an intermediate address of the source MAC address of the packet, erase that bit, or if the packet does not use a bit indicating advance reservation, leave it as it is, and send the packet onto the counterclockwise ring; On the other hand, when a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, if the packet is not a packet immediately after a change of destination base station, a bit 1 is stored in the first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in the fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the source MAC address of the packet, and the packet is sent to the counterclockwise ring; When the packet arrives at a packet add, drop, or pass-through device, When a bit 1 indicating an erasure reservation is stored in the third bit position of a storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by the lower address of the source MAC address of the packet, and a bit 1 indicating an erasure reservation is stored in the sixth bit position of a storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet, the bit 1s in the first and third bit positions of the storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by the lower address of the source MAC address of the packet, are erased, and a bit 1 indicating an erasure reservation is stored in the fourth bit position of a storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet. and clearing the bit 1 in the first bit position and the bit 1 in the sixth bit position, and, if a bit 1 is stored in the first bit of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and if a bit 1 is stored in the fourth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, storing the source MAC address of the packet in an address table that specifies the passage of the packet, and directing the packet on a counterclockwise ring to a vertex device in which a ring network interface NIC MAC address of a router to which a server or an exchange is connected via a router is stored as the destination MAC address of the packet; When a packet from a server or exchange is sent from a vertex device to a clockwise ring via a router and the packet arrives at a packet add, drop, or pass-through device, means for sending the packet forward in a clockwise ring when the destination MAC address of the packet is stored in an address table that specifies the passage of the packet, sending the packet out of the ring when the destination MAC address of the packet is not stored in the address table that specifies the passage of the packet and when a bit 1 is stored in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address that is accessed by a lower address of the destination MAC address of the packet and a bit 1 is stored in a fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the destination MAC address of the packet, and sending the packet forward in a clockwise ring when a bit 1 is not stored in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address that is accessed by a lower address of the destination MAC address of the packet and a bit 1 is stored in a fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the destination MAC address of the packet, When the base station receives a mobility preparation packet from the ring network, and a MAC address that is the same lower address as the lower address of the destination MAC address of the packet and is different from the destination MAC address of the packet is stored in the MAC address table, the base station sends a mobility preparation packet having the MAC address stored in the MAC address table as a source MAC address from the packet add, drop and pass through device connected to the base station to the counterclockwise ring, and when the packet arrives at the packet add, drop and pass through device, a means for storing the source MAC address of the packet in an address table for specifying the passage of the packet when a bit 1 indicating advance reservation is stored in a second bit position of a storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and a bit 1 indicating advance reservation is stored in a fifth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet; or If the packet does not use a method for storing bits indicating advance reservation, a means for storing the source MAC address of the packet in an address table that specifies the passage of the packet when a bit 1 is stored in a first bit position of a storage area of ​​a designated address position of the memory that is accessed by a lower address and an intermediate address and that is accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in a fourth bit position of a storage area of ​​an address position of the memory that is accessed by an intermediate address of the source MAC address of the packet; The system further comprising:

2. The system according to claim 1, characterized in that the address table specifying the passage of the packet is provided with a means for storing a number of MAC addresses of G*L*(L / EXP((24+kN)ln2))) / EXP((24+k)ln2), where G is the number of terminals of packets transferred on the ring, L is the number of terminals ADDed from outside the ring to a packet add, drop and passage device of the ring network, the number of address access bits to the memory is N bits, and the number of upper addresses of the MAC address that identify the lower 24 bits of the MAC address is 2 to the power of K within the system.

3. The system described in claim 1, characterized in that the router has a home agent (HA) function and a CoA (Care of Address) termination function, and transfers data from the mobile terminal to the router via a base station and a ring network using an Ethernet frame of one domain, during which the IP address does not change due to a tunnel within the MAC address.

4. 2. The system according to claim 1, wherein a domestic IPv4 address is used between the router and the exchange without using a NAT.

5. When the MAC address authentication packet arrives at the destination base station of the mobile terminal, the MAC address of the mobile terminal is stored in a MAC address table, and a mobility preparation packet having the MAC address of the mobile terminal as a destination MAC address is sent to the clockwise ring a plurality of times from a packet add, drop and pass device connected to the destination base station, The system according to claim 1, further comprising a means for setting up a radio channel to the mobile terminal and storing packets destined for the mobile terminal until a radio channel reception preparation OK signal is received from the mobile terminal.

6. The system according to claim 1, characterized in that the mobile terminal further comprises means for periodically accessing the receiving mail server and, if it is unable to receive a response packet from the receiving mail server, sending a retransmission packet to the receiving mail server.

7. A method for enabling handover of a mobile terminal, comprising inserting a plurality of packet add, drop and pass devices into a ring network, each of which has a U-shaped or normal end like a fiord (Norwegian) for a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1, connecting a base station to the packet add, drop and pass devices, and having a mobile terminal under the base station receive packets arriving from the counterclockwise ring of the ring network and forward them to a router, and blocking the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router, the method comprising transmitting packets from the mobile terminal to a destination server via the router connected to a vertex device through which a spare optical transmission path passes, the mobile terminal communicating with a destination server for download services, video lectures, video conferences involving speech signals or content distribution, or communicating with a switch as voice communications, the method comprising transmitting packets from the mobile terminal to the router via the ring network as TCP or UDP Ethernet frames, and transmitting packets between the router and the server or switch as IP packets, the method comprising the steps of: a step of: sending a MAC address authentication packet transmission request packet to the source base station of the mobile terminal immediately before the mobile terminal accesses a destination base station approaching a router in the forward direction on the counterclockwise ring; the source base station confirms the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station; when the packet arrives at a packet add, drop and pass-through device connected to the source base station, sending the packet to the counterclockwise ring 1; when the packet arrives at a packet add, drop and pass-through device connected to the destination base station of the mobile terminal, storing a bit 1 indicating advance reservation in a second bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, and storing a bit 1 indicating advance reservation in a fifth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, and sending a movement correspondence preparation packet having the MAC address of the mobile terminal as a destination MAC address to the clockwise ring; or Immediately before the mobile terminal accesses a destination base station approaching a router in the forward direction on the counterclockwise ring, it sends a MAC address authentication packet transmission request packet to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station. When the packet arrives at a packet add, drop and pass device connected to the source base station, it sends the packet to the counterclockwise ring 1, and the packet arrives at a packet add, drop and pass device connected to the destination base station of the mobile terminal. when the packet arrives at the mobile terminal, storing a bit 1 in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, storing a bit 1 in a fourth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, storing the MAC address of the mobile terminal in an address table that specifies the passage of a packet, and sending a mobility preparation packet having the MAC address of the mobile terminal as a destination MAC address to the clockwise ring; on the other hand, Immediately before the mobile terminal accesses a destination base station moving away from the router in the forward direction on the clockwise ring, it sends a MAC address authentication packet transmission request packet to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and then sends the MAC address authentication packet of the mobile terminal to the destination base station, and when the packet arrives at a packet add, drop and pass-through device connected to the source base station, it stores a bit 1 indicating an erase reservation in the third bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the MAC address of the mobile terminal, and a bit 1 indicating an advance reservation is stored in a sixth bit position of a storage area of ​​an address location of the memory accessed by the intermediate address of the MAC address, the packet is sent to clockwise ring 2, and when the packet arrives at a packet add, drop and pass-through device connected to the destination base station of the mobile terminal, a bit 1 indicating an advance reservation is stored in a second bit position of a storage area of ​​a designated address location of the memory accessed by the lower address and intermediate address accessed by the lower address of the MAC address of the mobile terminal, and a bit 1 indicating an advance reservation is stored in a fifth bit position of a storage area of ​​an address location of the memory accessed by the intermediate address of the source MAC address of the packet, sending a mobility preparation packet having a MAC address of the mobile terminal as a destination MAC address to a clockwise ring; When a packet from the mobile terminal arrives at a packet add, drop and pass-through device of the ring network, if the packet is a packet immediately after a change of a destination base station, and if the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, and a bit 1 is stored in a first bit position of a storage area at a specified address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in a second bit position of a storage area at a specified address position of a memory accessed by an intermediate address of the source MAC address of the packet. store a bit 1 in the fourth bit position, and if a bit 1 indicating advance reservation is stored in the second bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address and accessed by a lower address of the source MAC address of the packet, erase that bit, and if a bit 1 indicating advance reservation is stored in the fifth bit position of a storage area of ​​a designated address position of a memory accessed by an intermediate address of the source MAC address of the packet, erase that bit, or if the packet does not use a bit indicating advance reservation, leave it as it is, and send the packet onto the counterclockwise ring; On the other hand, when a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, if the packet is not a packet immediately after a change of destination base station, a bit 1 is stored in the first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in the fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the source MAC address of the packet, and the packet is sent to the counterclockwise ring; When the packet arrives at a packet add, drop, or pass-through device, When a bit 1 indicating an erasure reservation is stored in the third bit position of a storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by the lower address of the source MAC address of the packet, and a bit 1 indicating an erasure reservation is stored in the sixth bit position of a storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet, the bit 1s in the first and third bit positions of the storage area of ​​a designated address position of the memory accessed by a lower address and an intermediate address, which is accessed by the lower address of the source MAC address of the packet, are erased, and a bit 1 indicating an erasure reservation is stored in the fourth bit position of a storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet. and clearing the bit 1 in the first bit position and the bit 1 in the sixth bit position, and if a bit 1 is stored in the first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address, which is accessed by a lower address of the source MAC address of the packet, and if a bit 1 is stored in the fourth bit position of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet, storing the source MAC address of the packet in an address table that specifies the passage of the packet, and directing the packet on a counterclockwise ring to a vertex device in which a ring network interface NIC MAC address of a router to which a server or an exchange is connected via a router is stored as a destination MAC address of the packet; When a packet from a server or exchange is sent from a vertex device to a clockwise ring via a router and the packet arrives at a packet add, drop, or pass-through device, sending the packet forward in a clockwise direction when the destination MAC address of the packet is stored in an address table that specifies the passage of the packet; sending the packet out of the ring when the destination MAC address of the packet is not stored in the address table that specifies the passage of the packet and when a bit 1 is stored in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address that is accessed by a lower address of the destination MAC address of the packet and a bit 1 is stored in a fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the destination MAC address of the packet; sending the packet forward in a clockwise direction when a bit 1 is not stored in a first bit position of a storage area of ​​a designated address position of a memory accessed by a lower address and an intermediate address that is accessed by a lower address of the destination MAC address of the packet and a bit 1 is stored in a fourth bit position of a storage area of ​​a designated address position of the memory accessed by an intermediate address of the destination MAC address of the packet; When the base station receives a mobility preparation packet from the ring network, and a MAC address that is the same lower address as the lower address of the destination MAC address of the packet and is different from the destination MAC address of the packet is stored in the MAC address table, the base station sends a mobility preparation packet having the MAC address stored in the MAC address table as a source MAC address from the packet add, drop and pass through device connected to the base station to the counterclockwise ring, and when the packet arrives at the packet add, drop and pass through device, storing the source MAC address of the packet in an address table that specifies the passage of the packet when a bit 1 indicating advance reservation is stored in a second bit position of a storage area of ​​a designated address position of the memory that is accessed by a lower address and an intermediate address and that is accessed by a lower address of the source MAC address of the packet, and a bit 1 indicating advance reservation is stored in a fifth bit position of a storage area of ​​an address position of the memory that is accessed by an intermediate address of the source MAC address of the packet; or If the packet does not use a method for storing bits indicating advance reservation, storing the source MAC address of the packet in an address table that specifies the passage of the packet when a bit 1 is stored in a first bit position of a storage area of ​​a designated address position of the memory that is accessed by the lower address and an intermediate address and that is accessed by the lower address of the source MAC address of the packet, and a bit 1 is stored in a fourth bit position of a storage area of ​​an address position of the memory that is accessed by the intermediate address of the source MAC address of the packet; The method of claim 1, further comprising:

8. The method according to claim 7, further comprising a step in which the mobile terminal periodically accesses the receiving mail server and, if it cannot receive a response packet from the receiving mail server, sends a retransmission packet to the receiving mail server.

9. The method according to claim 7, further comprising a step in which the mobile terminal periodically accesses a receiving mail server with the packet number last received when accessing the receiving mail server, and returns packets having numbers addressed to the mobile terminal subsequent to the last received packet number from the receiving mail server.

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