Handover method of mobile terminal using ring network for searching for drop connection destination of packet from ring network using lower address and intermediate address of destination mac address of ethernet frame

Abstract

To implement the handover of a mobile terminal with a simple method by transferring an Ethernet frame via a ring network.SOLUTION: When a packet arrives at a device for adding, dropping, and passing packets in a ring network, 1 is stored in a first bit of the address location of an SRAM, 1 is stored in a fifth bit of the address location of the SRAM accessed using an intermediate address of a transmission source MAC address, and the packet is sent to a counterclockwise ring. When the packet arrives at a device for adding, dropping, and passing packets, 1 is stored in a first bit of an address storage area of the SRAM accessed using a lower address of the transmission source MAC address. When 1 is stored in the fifth bit of the address location of the SRAM accessed using the intermediate address of the transmission source MAC address, 1 meaning duplicate lower address storage is stored in a third bit location of the address location of the SRAM accessed using the lower address of the transmission source MAC address.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a handover method for a mobile terminal in a system that searches for a drop destination from a ring network using the lower address and intermediate address of the destination MAC address of an Ethernet (registered trademark) frame, making use of the characteristics of a ring network in which an SRAM that stores the lower address and intermediate address of a MAC address is used in a device for adding, dropping and passing packets in the ring network. The present invention uses an Ethernet frame and a packet that uses the MAC address part of an IPv6 address as the MAC address of the MAC packet.

[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 return 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 failed 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. [Prior art documents] [Patent documents]

[0006] [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]

[0007] [Non-Patent Document 1] G.8032 “Ethernet Ring Protection Swithing” Summary of the Invention [Problem to be solved by the invention]

[0008] 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.

[0009] 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 stored addresses at the same address position in the same entry table, it is necessary to compare these multiple addresses, which results in a problem of long search times.

[0010] 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 outside the ring using MAC addresses and port numbers, which results in a large number of MAC addresses to be stored.When the MAC address table stores the entire 48 bits of the MAC address at the address position accessed by the memory using the lower address of the MAC address, or when the upper address is stored, if the MAC address cannot be stored, a drawback is that when the destination MAC address of a packet to be forwarded is not stored in the MAC address table, the packet is flooded.

[0011] In addition, because an FDB (Forwarding Database) based on a MAC address table is used, when a loopback packet returns to the source ring node device in the event of a ring transmission path failure, the source MAC address of the packet has the port number stored as the port number outside the ring, so in RPR, the port number of the destination MAC address of the packet is set to the ring downstream transmission path port, making it possible to transition to steering; however, in a normal Ethernet ring, the arrival ring port and source MAC address are stored as a pair in the MAC address table, so there is a problem that it is not possible to transition to steering operation. In addition, a blocking point is adopted in the ring as an STP to avoid congestion caused by flooding when recovering from a fault in the ring network. However, because of this blocking point, a method of transitioning from wrapping to steering, such as RPR, cannot be used, and it becomes necessary to re-store the FDB by flooding.

[0012] 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. When the destination address is fixed, such as a server, it can be reached using the destination MAC address, but this is not possible for a terminal with many destinations.

[0013] Furthermore, the conventional handover technique disclosed in Patent Document 4 provides two IP6 connections between an access router and a mobile terminal for switching, which requires identification of the two IPv6 connections, resulting in a drawback in that handover control becomes complicated.

[0014] An object of the present invention is to provide a method for realizing a simple handover without using a conventional MAC address table, by using a ring network in which a lower address memory for storing lower addresses of a MAC address is used in a ring node device. [Means for solving the problem]

[0015] The present invention has been made in consideration of the above problems in the conventional technology, and the means for solving the problems are as follows: Aspect 1 to Aspect 6 of the present invention. A first aspect of the present invention is a system in which a plurality of packet add, drop and pass devices are inserted into a ring network of 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 a packet arriving from the counterclockwise ring of the ring network and transferring it to a router, and a function of blocking the passage of a packet having a NIC MAC address of a ring network interface of the router as a source MAC address when the source MAC address of the packet is stored in a MAC address table of the device itself, and in which packets from the mobile terminal travel between the ring network and the router as TCP or Ethernet (registered trademark) frames for voice communication or video conference communication involving speech signals, and between the router and the server or exchange as IP packets, in order to communicate with a destination server via the router connected to the ring node device, When a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, regardless of whether the packet is a packet immediately after the mobile terminal moves to a destination base station or not, store a bit 1 indicating low-order address storage in a first bit position of a storage area of ​​an address position of the SRAM which is accessed by a low-order address of the source MAC address of the packet and which is set to all bits 0 at the time of initial setting, store a bit 1 which is the even parity of the bit 1 in the first bit position in a second bit position, store a bit 1 indicating intermediate address storage in a fifth bit position of a storage area of ​​an address position of the SRAM which is accessed by an intermediate address of the source MAC address of the packet, store a bit 1 which is the even parity of the bit 1 in the fifth bit position in a sixth bit position, and transmit the packet to a counterclockwise ring; When the packet arrives at a packet add, drop and pass device, if bit 1 indicating low address storage is stored in the first bit position and bit 1 is stored in the second bit position of a storage area of ​​an address location of the SRAM that is accessed with the low address of the source MAC address of the packet and is set to all bits 0 at the time of initialization, and bit 1 is stored in the fifth bit position and bit 1 indicating intermediate address storage is stored in the sixth bit position, then bit 1 indicating duplicate low address storage is stored in the third bit position of the storage area of ​​the address location of the SRAM that is accessed with the low address of the source MAC address of the packet, and the even parity of bit 1 in the third bit position is stored in the fourth bit position, a means for directing the packet via a router to a ring node device in which a NIC MAC address of the router is stored as a destination MAC address of the packet; When a packet from a server arrives at a ring node device in which the NIC MAC address of the router is stored as the source MAC address of the packet via a router, the packet is sent to the clockwise ring, and when the packet arrives at a packet add, drop, or pass-through device, means for copying the packet and sending the copied packet to the front of the ring in a clockwise direction and sending the original packet of the copied packet out of the ring when bit 1 indicating low-order address storage is stored in the third bit position of a storage area of ​​an address position of the SRAM that is set to all bits 0 at initial setting when accessed by the low-order address of the destination MAC address of the packet, and bit 1 is stored in the fourth bit position, bit 1 indicating low-order address storage is stored in the first bit position of a storage area of ​​an address position of the SRAM that is set to all bits 0 at initial setting when accessed by the low-order address of the destination MAC address of the packet, bit 1 is stored in the second bit position, bit 1 is not stored in the third bit position, bit 1 is not stored in the fourth bit position, and bit 1 is stored in the fifth bit position of a storage area of ​​an address position of the SRAM that is accessed by an intermediate address of the destination MAC address of the packet, and bit 1 is stored in the sixth bit position, and means for sending the packet out of the ring when bit 1 indicating low-order address storage is stored in the fifth bit position of a storage area of ​​an address position of the SRAM that is set to all bits 0 at initial setting when accessed by the low-order address of the destination MAC address of the packet,

[0016] A second aspect of the present invention is a system according to the first aspect of the present invention, characterized in that the mobile terminal comprises means for sending a re-access packet to the receiving mail server when the mobile terminal is unable to receive a response packet to an access packet to the receiving mail server.

[0017] A third aspect of the present invention is a system according to the first aspect of the present invention, comprising: When the lower address of the source MAC address of the packet and the bit string of the intermediate address are the same, the system changes the bit string of the intermediate address to a bit string in which the upper and lower bits are swapped, and stores and reads the bit string in the SRAM for the lower address and intermediate address designation memory.

[0018] A fourth aspect of the present invention is a system according to the first aspect of the present invention, This system is characterized in that when the bit string of the lower address of the source MAC address of the packet and the intermediate address are the same, one bit of the bit string of the NIC address maker of the intermediate address is changed, and the lower address and intermediate address are stored in and read from the SRAM for the intermediate address designation memory.

[0019] A fifth aspect of the present invention is a method for transmitting packets from a mobile terminal to a ring node device on a ring network, the method comprising: inserting a plurality of packet add, drop and pass devices in a ring network of 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, in a case where a mobile terminal under the base station has a function of receiving a packet arriving from a counterclockwise ring of the ring network and transferring it to a router, and a function of blocking the passage of a packet having a NIC MAC address of a ring network interface of the router as a source MAC address when the source MAC address of the packet is stored in a MAC address table of the device itself, the method comprising the steps of: transmitting packets from the mobile terminal to a ring node device on the ring network, the ring node device being connected to the ring node device; transmitting packets from the mobile terminal to a destination server via the ring node device as TCP or audio communication or video conference communication accompanied by a voice signal, the method comprising the steps of: transmitting packets from the mobile terminal to the router as Ethernet frames for video conference communication accompanied by a voice signal across the ring network, and transmitting packets between the router and the server or exchange as IP packets; When a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, regardless of whether the packet is a packet immediately after the mobile terminal moves to a destination base station or not, store a bit 1 indicating low-order address storage in a first bit position of a storage area of ​​an address position of the SRAM which is accessed by a low-order address of the source MAC address of the packet and which is set to all bits 0 at the time of initial setting, store a bit 1 which is the even parity of the bit 1 in the first bit position in a second bit position, store a bit 1 indicating intermediate address storage in a fifth bit position of a storage area of ​​an address position of the SRAM which is accessed by an intermediate address of the source MAC address of the packet, store a bit 1 which is the even parity of the bit 1 in the fifth bit position in a sixth bit position, and transmit the packet to a counterclockwise ring; When the packet arrives at a packet add, drop and pass device, if bit 1 indicating low address storage is stored in the first bit position and bit 1 is stored in the second bit position of a storage area of ​​an address location of the SRAM that is accessed with the low address of the source MAC address of the packet and is set to all bits 0 at the time of initialization, and bit 1 is stored in the fifth bit position and bit 1 indicating intermediate address storage is stored in the sixth bit position, then bit 1 indicating duplicate low address storage is stored in the third bit position of the storage area of ​​the address location of the SRAM that is accessed with the low address of the source MAC address of the packet, and the even parity of bit 1 in the third bit position is stored in the fourth bit position, a step of directing the packet by the server via a router to a ring node device in which a NIC MAC address of the router is stored as a destination MAC address of the packet; When a packet from a server arrives at a ring node device in which the NIC MAC address of the router is stored as the source MAC address of the packet via a router, the packet is sent to the clockwise ring, and when the packet arrives at a packet add, drop, or pass-through device, and if bit 1 indicating duplicate lower address storage is stored in the third bit position of a storage area of ​​an address position of the SRAM which is set to all bits 0 at the time of initial setting and which is accessed by the lower address of the destination MAC address of the packet, and bit 1 is stored in the fourth bit position, copying the packet and sending the copied packet to the front of the ring in a clockwise direction and sending the original packet of the copied packet out of the ring, if bit 1 indicating lower address storage is stored in the first bit position of a storage area of ​​an address position of the SRAM which is set to all bits 0 at the time of initial setting and which is accessed by the lower address of the destination MAC address of the packet, bit 1 is stored in the second bit position, bit 1 is not stored in the third bit position, bit 1 is not stored in the fourth bit position, and bit 1 is stored in the fifth bit position of a storage area of ​​an address position of the SRAM which is accessed by the intermediate address of the destination MAC address of the packet, and bit 1 indicating intermediate address storage is stored in the fifth bit position and bit 1 is stored in the sixth bit position, sending the packet out of the ring in the other cases.

[0020] A sixth aspect of the present invention provides a method according to the fifth aspect of the present invention, comprising the steps of: The method is characterized by comprising a step of sending a re-access packet to the receiving mail server when the mobile terminal cannot receive a response packet to the access packet to the receiving mail server. Effect of the Invention

[0021] As described above, the present invention uses an SRAM that is set to all bits 0 at the time of initialization for lower address and intermediate address designation memory that designates packet transmission outside the ring, instead of a MAC address table, and if there is an SRAM whose lower address and intermediate address are the same as the source MAC address of the packet while the packet is heading toward the apex device on the counterclockwise ring, the duplicate lower address bits are stored in that SRAM, and an address table that designates packet passage is not used, so that operation is simple and fast, and a ring node device (device for adding, dropping and passing packets) can be realized with a single SRAM, thereby reducing system costs. Also, the present invention is a method for realizing handover of a mobile terminal within one domain by a ring network using the above memory, which has the effects of reducing power consumption and system costs and enabling high-speed communication. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram for explaining an example of handover operation of a packet forwarding system between a mobile terminal that forwards MAC packets through a base station connected to the packet adding, dropping and passing device in a dual ring network in which multiple devices are connected by an optical ring, and a server connected to the ring network via a router, the packet adding, dropping and passing device having an SRAM that sets all bits to 0 during initialization for a lower address and intermediate addressing memory that designates packet transmission outside the ring in the first embodiment of the present invention; [Figure 2A] An example of an operation flow diagram of a packet adding, dropping and passing device according to a first embodiment of the present invention. [Figure 2B] An example of an operation flow diagram of a packet adding, dropping and passing device according to a first embodiment of the present invention. [Figure 2C] An example of an operation flow diagram of a packet adding, dropping and passing device according to a first embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] A first embodiment of the present invention will be described with reference to Fig. 1. This embodiment 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 forwarding system in which a base station is connected to a packet adding, dropping and passing device of a double ring network in which a plurality of devices have SRAMs that are set to all bits 0 at the time of initial setting for a lower address and an intermediate address designation memory that designates packet transmission outside the ring, and the devices have a mobile terminal under the base station that transfers information as a MAC packet to a router connected to the ring network, and the mobile terminal transfers information between the mobile terminal and a server connected to the ring network via the router. The server is a mail receiving server or an Internet connection server.

[0024] 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, 6-3, and 6-4 are devices (ring node devices) for adding, dropping, and passing packets, 11 is an SRAM that is set to all bits 0 at the time of initial setting for lower addresses and intermediate address designation memory that designate packet transmission outside the ring, 13-1, 13-2, and 13-3 are mobile terminals, 14-1, 14-2, and 14-3 are base stations (BS), 20 is a server, and 22 is a router. In addition, (1) to (40) indicate the transfer order of packets in which the MAC addresses transferred on the ring indicated by the dotted lead line are abbreviated by letter symbols, and I0, I1, I2, and I3 are global IPv4 addresses that are dynamically set as IP addresses in the terminals, or domestic IPv4 addresses of the service provider. Or they are IPv6 addresses. The OE conversion circuit, EO conversion circuit, input buffer, and output buffer are not shown in the figure.

[0025] The operation of FIG. 1 will be explained below. An example is shown in which the mobile terminal 13-2 for receiving mail sends packet (1) Mn1γβα(I0) (M indicates an Ethernet packet, n1 indicates the wireless MAC address of the base station 14-1, γβα indicates the upper MAC address γ, the middle MAC address β, and the lower MAC address α, which are the MAC addresses of the mobile terminal 13-2, and I0 indicates the IP address of the destination server) to the base station 14-1. When the packet arrives at the device 6-1 for adding, dropping and passing a packet from the terminal 13-2, the lower address α (for example, the 1st bit to the 17th bit) of the source MAC address of the packet is accessed, and the address location of the SRAM (11) which is set to all bits 0 at the time of initialization for the lower address and intermediate address designation memory, stores bit 1, which means lower address storage, in the 1st bit, stores p (bit 1) in the 2nd bit as the even parity of the 1st bit, and stores intermediate address β (for example, the 18th bit to the 34th bit) of the source MAC address of the packet in the 1st bit of the memory. A bit 1 indicating intermediate address storage is stored in the fifth bit of the memory area of ​​the address position of the SRAM (11) which is set to all bits 0 at the time of initialization for the lower address and intermediate address designation memory which designates packet transmission outside the ring accessed by the current optical transmission line 1 of the counterclockwise ring, and p (bit 1) is stored in the sixth bit as the even parity of the fifth bit. When α and β have the same bit string, one bit of the NIC manufacturer of β is changed and stored, and the packet is sent to the address table 12 of the packet add, drop and pass-through device 6-4 in which the NIC MAC address of the upper ring network interface of the router 22 connected to the server 20 is stored via the current optical transmission line 1 of the counterclockwise ring.

[0026] When the packet is transferred by (3) Mr1r2γβα(I0) through 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 and second bits of the memory area of ​​the address location of SRAM (11) which is set to all bits 0 at the initial setting for the lower address and intermediate address designation memory which 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, and a bit 1 is stored in the first and second bits of the memory area of ​​the address location of SRAM (11) which is set to all bits 0 at the initial setting for the lower address and intermediate address designation memory which 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) of the source MAC address of the packet. When bit 1 is stored in the third and fourth bits of the memory area of ​​the address location of RAM (11), if α and β have the same bit string, and one bit of the NIC manufacturer of β is changed and stored, then in the memory area of ​​the address location of SRAM (11), which is set to all bits 0 at the time of initialization for the lower address and intermediate address specification memory that specifies packet transmission outside the ring accessed by the lower address α (for example, the 1st to 17th bits) of the source MAC address of the packet, bit 1 indicating duplicate lower address storage is stored in the third bit, and the even parity p (bit 1) of the third bit is stored in the fourth bit, but since the 1st and 5th bits are not stored, the packet is sent as is to packet add, drop and pass-through device 6-4 (vertex device 5) on counterclockwise ring 1. When the packet arrives at packet add, drop, and pass-through device 6-4 (vertex device), since the destination MAC address r1r2 of the packet is stored in address table 12 for router connection, the packet is dropped from the ring as (6)Mr1r2γβα(I0) toward 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 options field of the IP header, and the IP packet is forwarded as shown in the figure by (7) IPI3I0 (IP indicates an IP address, I3 indicates the IP address of mobile terminal 13-2, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0027] Next, an example will be shown in which mobile terminal 13-1 receiving a telework service sends packet (9) Mr1r2δβα(I0) (M indicates an Ethernet packet, r1r2 indicates the NIC MAC address of the ring network interface of router 22, δβα indicates the upper MAC address δ, intermediate MAC address β, and lower MAC address α, which are the MAC addresses of terminal device 13-1, and I0 indicates the IP address of the destination server) to device 6-1 for adding, dropping, and passing packets via base station 14-1. When the packet arrives at device 6-1 for adding, dropping, and passing packets, bit 1 indicating lower address storage is stored in the first bit of the storage area of ​​the address position of SRAM (11) for the lower address and intermediate address designation memory designating packet sending outside the ring accessed by the lower address α of the source MAC address of the packet, and p (bit 1) is stored in the second bit as the even parity of the first bit, and the lower address and intermediate address designating packet sending outside the ring accessed by the intermediate address β of the source MAC address of the packet are stored in the second bit. Then, bit 1, which indicates intermediate address storage, is stored in the fifth bit of the storage area of ​​the address position of the SRAM (11) for the intermediate address designation memory, and p (bit 1) is stored in the sixth bit as the even parity of the fifth bit. If α and β have the same bit string, one bit of the NIC manufacturer of β is changed and stored, or the bit order of β is swapped up and down, and the packet is sent to address table 12 in which the NIC MAC address of the ring network interface of router 22 connected to server 20 is stored via current optical transmission line 1 of the counterclockwise ring.

[0028] When the packet is transferred to the counterclockwise ring 1 by (10) Mr1r2 δβα (I0) as shown in the figure and arrives at the device 6-2 for adding, dropping and passing packets, the packet passes through the device 6-2 and arrives at the device 6-4 (vertex device) for adding, dropping and passing packets whose destination MAC address r1r2 is stored in the address table 12 for router connection, and the packet is dropped from the ring as (13) Mr1r2 δβα (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 put in the option field of the IP header, and the IP packet is transferred 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.

[0029] 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 packet (15)Mn2γβα(I0) (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 mobile terminal 13-2 arrives at base station 14-2, there is a packet immediately after the destination base station is changed when packet add, drop and pass through device 6-2 connected to the destination base station is a device that connects to a base station approaching server 20 on counterclockwise ring 1, and this packet is sent to packet add, drop and pass through device 6-2 as (16)Mr1r2γβα(I0). When the packet from the mobile terminal 13-2 reaches the add, drop and pass-through device 6-2, the device stores bit 1, which indicates lower address storage, 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, which is accessed by the lower address α of the source MAC address of the packet and designates packet transmission outside the ring, and stores p (bit 1) in the second bit as the even parity of the first bit, stores bit 1, which indicates intermediate address storage, in the fifth bit of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory, which is accessed by the intermediate address β of the source MAC address of the packet and designates packet transmission outside the ring, and stores p (bit 1) in the sixth bit as the even parity of the fifth bit, and transmits the packet to the address table 12 in which the NICMAC address of the ring network interface of the router 22, which connects to the server 20 via the working optical transmission line 1 of the counterclockwise ring, is stored.

[0030] When the packet arrives at packet add, drop, and pass-through device 6-4 (vertex device) on counterclockwise ring 1 as is, since the destination MAC address r1r2 of the packet is stored in address table 12 for router connection, the packet is dropped from the ring as (19)Mr1r2γβα(I0) and headed for router 22 outside the ring.

[0031] 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 (20)IPI3I0 (IP indicates an IP address, I3 indicates the IP address of mobile terminal 13-2, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0032] Next, when a response packet (21) IPI0I2 (IP indicates an IP address, I2 is the IPv6 address or IPv4 address of mobile terminal 13-1, and I0 is the IP address of server 20) for the upload packet 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 (22) Mδβαr1r2 (I2) used as the MAC header address of the MAC packet is sent to packet add, drop, and pass-through device 6-4 (apex device) 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 (22)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 device 6-4 (vertex device) for adding, dropping, and passing packets in the ring network.

[0033] When the MAC packet (22) Mδβαr1r2 (I2) arrives at packet add, drop and pass-through device 6-4 (vertex device), the source MAC address of the packet is stored in address table 12 for router connection, so the packet is sent to clockwise ring 2.

[0034] When a packet (23) Mδβαr1r2 (I2) is transferred through clockwise ring 2 and arrives at packet add, drop and pass-through device 6-2, the first bit of the address location 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 of the destination MAC address of the packet stores bit 1, which means lower address storage, and p (bit 1) is stored in the second bit as the even parity of the first bit, and Since bit 1, which indicates duplicate lower address storage, is not stored, the fourth bit is bit 0, bit 1, which indicates intermediate address storage, is stored in the fifth bit of the address location storage area of ​​SRAM (11) for lower address and intermediate address designation memory that specifies packet transmission outside the ring accessed by intermediate address β of the destination MAC address of the packet, and p (bit 1) is stored in the sixth bit as the even parity of the fifth bit, the packet is sent outside the ring as (25)Mδβαr1r2(I2). When the packet arrives at base station 14-2, the destination MAC address of the packet is not stored in a MAC address table (not shown), so the packet is discarded.

[0035] Next, when the mobile terminal 13-1 transmits a retransmission packet (26) Mn1δβα(I0) (M indicates an Ethernet packet, n1 indicates the MAC address of the base station 14-1, 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 13-1, and I0 indicates the IP address of the destination server) to the packet add, drop, and pass-through device 6-1 via the base station 14-1, a bit 1 indicating lower address storage is stored 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 which designates packet transmission outside the ring and is accessed by the lower address α of the source MAC address of the packet, and a bit 1 is stored in the second bit as the even parity of the first bit, A bit 1 is stored in the fifth bit of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address specification memory that specifies packet transmission outside the ring, which is accessed by the intermediate address β of the source MAC address of the packet, and p (bit 1) is stored in the sixth bit as the even parity of the fifth bit. If α and β have the same bit string, one bit of the NIC manufacturer of β is changed and stored, or the bit order of β is swapped up and down, and the packet is sent to the address table 12 in which the NIC MAC address of the ring network interface of the router 22 that connects to the server 20 via the current optical transmission line 1 of the counterclockwise ring is stored.

[0036] When the packet is transferred by (28) Mr1r2δβα(I0) through 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 and second bits 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 lower address α (e.g., bits 1 to 17) of the source MAC address of the packet, and a bit 1 is stored in the first and second bits 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 intermediate address β (e.g., bits 18 to 34 are taken as bits 1 to 17 of the memory) of the source MAC address of the packet. When bit 1 is stored in the fifth and sixth bits of the area, and when α and β are the same bit string, and when β is stored with one bit of the NIC manufacturer changed, the third bit of the storage area of ​​the address position of the SRAM (11) that is set to all bits 0 at the time of initialization for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the lower address α (for example, from the first bit to the 17th bit) of the source MAC address of the packet, stores bit 1 meaning duplicate lower address storage in the third bit, stores even parity p (bit 1) in the fourth bit, and sends the packet toward the packet add, drop and pass-through device 6-4 (vertex device) whose destination MAC address r1r2 is stored in the address table 12 for router connection. When the packet arrives at the packet add, drop and pass-through device 6-4 (vertex device), the packet is dropped from the ring as (31)Mr1r2δβα(I0) toward the router 22 outside the ring. When the packet arrives at 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 inserted into an option field in the IP header, and the IP packet is forwarded to router 22 as (32)IPI2I0 (IP indicates an IP address, I2 indicates the IP address of mobile terminal 13-1, and I0 indicates the IP address of server 20, which is the destination).) as shown in the figure, and arrives at the server 20.

[0037] Next, when a response packet (33) 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) of the retransmitted packet (32) from server 20 arrives at router 22, if the packet is an IPv6 address, the destination MAC address of the packet's destination IPv6 address I2 is copied from the MAC address portion of the destination IPv6 address, and a MAC packet (34) Mδβαr1r2 (I2) used as the MAC header address of the MAC packet is sent to packet add, drop, and pass-through device 6-4 (apex device) 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 (34)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 device 6-4 (apex device) for adding, dropping, and passing packets in the ring network.

[0038] When the MAC packet (34) Mδβαr1r2 (I2) arrives at packet add, drop and pass-through device 6-4 (vertex device), the source MAC address of the packet is stored in address table 12 for router connection, so the packet is sent to clockwise ring 2.

[0039] When a packet (35)Mδβαr1r2(I2) is transferred through the clockwise ring 2 and arrives at the packet add, drop and pass device 6-2, the packet is copied and the copy packet is sent to the clockwise ring 2 as (38)Mδβαr1r2(I2), and the original copy packet is sent to the outside of the ring as (37)Mδβαr1r2(I2). When the packet sent to the outside of the ring arrives at the base station 14-2, the destination MAC address δβα of the packet is not stored in the MAC address table (not shown), so the packet is discarded.

[0040] When the packet (38) Mδβαr1r2 (I2) is transferred through the clockwise ring 2 and arrives at the packet add, drop and pass-through device 6-1, the first bit 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 and is accessed by the lower address α (for example, the 1st bit to the 17th bit) of the destination MAC address of the packet is stored as bit 1, which means lower address storage, as well as parity p (bit 1) as the second bit and duplicate lower address storage as the third bit. The packet is sent out of the ring because bit 1, which indicates intermediate address storage, is not stored, the 4th bit is bit 0, and bit 1, which indicates intermediate address storage, is stored in the 5th 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, which is accessed by the intermediate address β (for example, bits 18 to 34 are the 1st to 17th bits of the memory) of the source MAC address of the packet, and parity p (bit 1) is stored in the 6th bit, so the packet is sent out of the ring. 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 heads to the destination mobile terminal 13-1 as (40)Mδβαn1(I2) (n1 is the wireless NIC address of the base station 14-1).

[0041] Next, Fig. 2A, Fig. 2B, and Fig. 2C show an example of an operation flow diagram of the device for adding, dropping, and passing packets in the first embodiment. In Fig. 2A, 100 judges whether a packet has arrived from the clockwise ring, and if YES, judges whether bit 1, which means a duplicate lower address storage, is stored in the third bit of the data storage area of ​​the address position of the memory for packet dropping (SRAM for lower addresses and intermediate address designation memory for specifying packet sending outside the ring) accessed by the lower address of the destination MAC address of the received packet of 101, and parity p (bit 1) is stored in the fourth bit, and if YES, copies the received packet of 102, sends the copy packet forward on the clockwise ring, sends the original packet of the copy packet out of the ring, and returns to (a). If NO, transition is made to (c).

[0042] In Fig. 2B, the memory for packet dropping (SRAM for lower addresses and intermediate address designation memory for specifying packet sending outside the ring) accessed by the lower address of the destination MAC address of the received packet of 103 has a data storage area in which bit 1 meaning lower address storage is stored in the first bit, the parity p (bit 1) of the first bit is stored in the second bit, bit 1 meaning duplicate lower address storage is not stored in the third bit, the fourth bit is bit 0, bit 1 meaning intermediate address storage is stored in the fifth bit of the data storage area of ​​the memory for packet dropping accessed by the intermediate address of the destination MAC address of the received packet, and parity p (bit 1) is stored in the sixth bit. If the answer is YES, the received packet of 104 is sent out of the ring and the process returns to (a). If the answer is NO, the received packet is shifted to the front of the ring in a clockwise direction and the process returns to (a).

[0043] In FIG. 2C, 106 judges whether a packet has arrived from the ADD line, and if Yes, stores bit 1 indicating lower address storage in the first bit of a data storage area of ​​an address position of memory for packet dropping (SRAM for lower address memory and intermediate address specification memory for specifying packet transmission outside the ring) accessed by the lower address of the source MAC address of the received packet of 107, stores even parity p (bit 1) of the first bit in the second bit, stores bit 1 indicating intermediate address storage in the fifth bit of a data storage area of ​​an address position of memory for packet dropping accessed by the intermediate address of the source MAC address of the received packet, stores parity p (bit 1) in the sixth bit, sends the received packet of 108 to the front of the ring in a counterclockwise direction, and returns to (a). If the answer is NO in 106, it is determined whether a packet has arrived from the counterclockwise ring in 109. If the answer is YES, a bit 1 indicating lower address storage is stored in the first bit of the data storage area of ​​the address position of the memory for packet dropping (SRAM for the lower address memory and intermediate address designation memory for specifying packet transmission outside the ring) accessed by the lower address of the source MAC address of the received packet in 110, and even parity p (bit 1) is stored in the second bit. Also, data storage of the address position of the memory for packet dropping accessed by the intermediate address of the source MAC address of the received packet is performed. It is determined whether bit 1, which means intermediate address storage, is stored in the fifth bit of the area, and whether even parity p (bit 1) is stored in the sixth bit. If the answer is YES, bit 1, which means duplicate lower address storage, is stored in the third bit of the data storage area of ​​the address position of the memory for packet dropping (the SRAM for the lower address memory for specifying packet transmission outside the ring and the intermediate address specification memory) accessed by the lower address of the source MAC address of the received packet of 111, and even parity p (bit 1) is stored in the fourth bit. The received packet of 112 is sent to the front of the ring in a counterclockwise direction, and the process transitions to (a). If the answer is NO at 109, the process returns to (a). If the answer is NO at 110, the process transitions to 112.

[0044] When each bit is stored in the memory area of ​​the SRAM, which is set to all bits 0 during the initial setting, the even parity of each bit is inserted and written before each subsequent stored bit, and when the first bit and the second bit, the third bit and the fourth bit, and the fifth bit and the sixth bit do not match during reading, the even parity is used to detect a memory error.

[0045] In the first embodiment, bit 1 is stored in the first and second bits of the storage area of ​​the address position of the SRAM accessed by the lower address of the destination MAC address of the packet in the ring node device, and bit 1 is stored in the fifth and sixth bits of the storage area of ​​the address position of the SRAM accessed by the intermediate address of the destination MAC address of the packet in the ring node device, and the number of stored MAC addresses in the address table that specifies the passage of the packet is an issue. In the first embodiment, this corresponds to the number of duplicate lower addresses. 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 100,000, and the number of addressing bits of the SRAM is 17 bits, then 10,000*100,000*10,000 / EXP(17ln2) / EXP(17ln2)=580, and there is no problem in realizing the first embodiment. In addition, the method of using 24-bit lower address memory may cause problems with skew and hazards in the logic circuit of the decoder ASIC. If a decoder memory is used to avoid this, it will become a ROM, which will slow down the operation. In addition, since the first embodiment can be configured using only existing memory, it is easy to introduce into a LAN.

[0046] In the first embodiment, when the mobile terminal cannot receive a response packet of the access packet to the receiving mail server of the mobile terminal, the mobile terminal sends a re-access packet to the receiving mail server. Also, since the base station has an intermediate TCP circuit, the re-transmission packet is sent to the server side.

[0047] In the case of a ring fault in the first embodiment, it can be handled without flooding by steering or both-ring loopback. In the case of both-ring loopback, when a ring network fault occurs, the add, drop and pass devices of the packet on both sides of the fault point loop back, and when the loopback occurs, a loopback bit is added, and the packet with the loopback bit added passes through all the devices up to the second loopback point, and the loopback bit is removed at the second loopback. [Explanation of symbols]

[0048] 1. Counterclockwise ring optical transmission line 2. Clockwise ring optical transmission line 6-1, 6-2, 6-3, 6-4 Packet Add, Drop and Pass Devices 11 SRAM that is set to all bits 0 at initialization for lower address and intermediate addressing memory that specifies packet transmission outside the ring 12 Address table for router connections 13-1, 13-2, 13-3 Mobile terminals 14-1,14-2,14-3 Base Station (BS) 20 Servers 22 Router

Claims

1. a ring node device on a ring network connected to the ring node device has a function of receiving a packet arriving from a counterclockwise ring of the ring network and forwarding the packet to a router, and a function of blocking the passage of a packet having a NIC MAC address of a ring network interface of the router as a source MAC address when the source MAC address of the packet is stored in a MAC address table of the ring node device, and a packet from the mobile terminal travels between the mobile terminal and the router via the ring network as a TCP or voice communication or an Ethernet (registered trademark) frame for video conference communication accompanied by a voice signal, and between the router and the server or exchange as an IP packet, When a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, regardless of whether the packet is a packet immediately after the mobile terminal moves to a destination base station or not, a bit 1 indicating low-order address storage is stored in a first bit position of a storage area of ​​an address position of an SRAM which is accessed by a low-order address of the source MAC address of the packet and which is set to all bits 0 at the time of initialization, a bit 1 which is even parity of the bit 1 in the first bit position is stored in a second bit position, and a bit 1 which is even parity of the bit 1 in the first bit position is stored in a second bit position, and a bit 1 indicating intermediate address storage is stored in a fifth bit position of a storage area of ​​an address position of the SRAM which is accessed by an intermediate address of the source MAC address of the packet, and a bit 1 which is even parity of the bit 1 in the fifth bit position is stored in a sixth bit position, and the packet is sent to a counterclockwise ring; When the packet arrives at a packet add, drop and pass device, if bit 1 indicating low address storage is stored in the first bit position and bit 1 is stored in the second bit position of a memory area of ​​an address location of the SRAM accessed with a low address of the source MAC address of the packet and set to all bits 0 at the time of initialization, and bit 1 is stored in the fifth bit position of a memory area of ​​an address location of the SRAM accessed with an intermediate address of the source MAC address of the packet, and bit 1 is stored in the sixth bit position, then bit 1 indicating duplicate low address storage is stored in the third bit position of the memory area of ​​the address location of the SRAM accessed with the low address of the source MAC address of the packet, and the even parity of bit 1 in the third bit position is stored in the fourth bit position, a means for directing the packet via a router to a ring node device in which a NIC MAC address of the router is stored as a destination MAC address of the packet; When a packet from a server arrives at a ring node device in which the NIC MAC address of the router is stored as the source MAC address of the packet via a router, the packet is sent to the clockwise ring, and when the packet arrives at a packet add, drop, or pass-through device, means for copying the packet and sending the copied packet to the front of the ring in a clockwise direction and sending the original packet of the copied packet out of the ring, when a bit 1 indicating duplicate lower address storage is stored in a third bit position of a storage area of ​​an address position of an SRAM which is set to all bits 0 at initial setting and which 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, and when a bit 1 indicating lower address storage is stored in a first bit position of a storage area of ​​an address position of an SRAM which is set to all bits 0 at initial setting and which is accessed by a lower address of the destination MAC address of the packet, a bit 1 is stored in the second bit position, a bit 1 is not stored in the third bit position, a bit 1 is not stored in the fourth bit position, and a bit 1 is stored in the fifth bit position of a storage area of ​​an address position of the SRAM which is accessed by an intermediate address of the destination MAC address of the packet, and a bit 1 is stored in a sixth bit position,

2. 2. The system according to claim 1, wherein said mobile terminal transmits a re-access packet to the receiving mail server when it cannot receive a response packet to the access packet to the receiving mail server.

3. The system according to claim 1, characterized in that when the bit strings of the lower address and intermediate address of the source MAC address of the packet are the same, the bit string of the intermediate address is changed to a bit string in which the upper and lower bits are swapped, and the lower address and intermediate address are stored in and read from an SRAM for the lower address and intermediate address designation memory.

4. The system described in claim 1, characterized in that when the bit strings of the lower address of the source MAC address of the packet and the intermediate address are the same, one bit of the bit string of the NIC address maker of the intermediate address is changed, and the lower address and intermediate address are stored in and read from an SRAM for the intermediate address designation memory.

5. a ring node device on a ring network connected to the ring node device has a function of receiving a packet arriving from the left-handed ring of the ring network and transferring the packet to a router, and a function of blocking the passage of a packet having a NIC MAC address of a ring network interface of the router as a source MAC address when the source MAC address of the packet is stored in a MAC address table of the ring node device, the method comprising: inserting a plurality of packet add, drop and pass devices in a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; and passing packets from the mobile terminal to and from the ring node device on the ring network as TCP or Ethernet (registered trademark) frames for voice communication or video conference communication accompanied by a voice signal between the mobile terminal and a destination server via the ring node device, the method comprising the steps of: When a packet from the mobile terminal arrives at a packet add, drop and pass through device of the ring network, regardless of whether the packet is a packet immediately after the mobile terminal moves to a destination base station or not, a bit 1 indicating low-order address storage is stored in a first bit position of a storage area of ​​an address position of an SRAM which is accessed by a low-order address of the source MAC address of the packet and which is set to all bits 0 at the time of initialization, a bit 1 which is even parity of the bit 1 in the first bit position is stored in a second bit position, and a bit 1 which is even parity of the bit 1 in the first bit position is stored in a second bit position, and a bit 1 indicating intermediate address storage is stored in a fifth bit position of a storage area of ​​an address position of the SRAM which is accessed by an intermediate address of the source MAC address of the packet, and a bit 1 which is even parity of the bit 1 in the fifth bit position is stored in a sixth bit position, and the packet is sent to a counterclockwise ring; When the packet arrives at a packet add, drop and pass device, if bit 1 indicating low address storage is stored in the first bit position and bit 1 is stored in the second bit position of a memory area of ​​an address location of the SRAM accessed with a low address of the source MAC address of the packet and set to all bits 0 at the time of initialization, and bit 1 is stored in the fifth bit position of a memory area of ​​an address location of the SRAM accessed with an intermediate address of the source MAC address of the packet, and bit 1 is stored in the sixth bit position, then bit 1 indicating duplicate low address storage is stored in the third bit position of the memory area of ​​the address location of the SRAM accessed with the low address of the source MAC address of the packet, and the even parity of bit 1 in the third bit position is stored in the fourth bit position, a step of directing the packet by the server via a router to a ring node device in which a NIC MAC address of the router is stored as a destination MAC address of the packet; When a packet from a server arrives at a ring node device in which the NIC MAC address of the router is stored as the source MAC address of the packet via a router, the packet is sent to the clockwise ring, and when the packet arrives at a packet add, drop, or pass-through device, and if a bit 1 indicating duplicate lower address storage is stored in a third bit position of a storage area of ​​an address location of an SRAM which is set to all bits 0 at initial setting and which is accessed by a lower address of the destination MAC address of the packet, and a bit 1 is stored in the fourth bit position, copying the packet and sending the copied packet to the front of the ring in a clockwise direction and sending the original packet of the copied packet out of the ring, if a bit 1 indicating lower address storage is stored in a first bit position of a storage area of ​​an address location of an SRAM which is set to all bits 0 at initial setting and which is accessed by a lower address of the destination MAC address of the packet, a bit 1 is stored in the second bit position, a bit 1 is not stored in the third bit position, a bit 1 is not stored in the fourth bit position, and a bit 1 is stored in the fifth bit position of a storage area of ​​an address location of the SRAM which is accessed by an intermediate address of the destination MAC address of the packet, and a bit 1 is stored in the sixth bit position, sending the packet out of the ring, and otherwise sending the packet to the front of the ring in a clockwise direction.

6. 6. The method according to claim 5, further comprising the step of: sending a re-access packet to the receiving mail server when the mobile terminal cannot receive a response packet to the access packet to the receiving mail server.

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