Handover method for mobile terminal in ring network using SRAM in ring node device that stores lower address of destination mac address of ethernet frame and bit 1 that indicates intermediate address

Abstract

To provide an apparatus and a method for forwarding packets over a ring network.SOLUTION: When a packet from a mobile terminal arrives at an add / drop / pass-through device in a ring network, a 1 is stored in the first and second bits of an SRAM accessed with a lower address of the MAC address selected by bit 0 of the least significant bit of the source MAC address of the packet, and a 1 is stored in the third and fourth bits of an SRAM accessed with an intermediate address of the source MAC address, and the packet is sent to the counterclockwise ring, in a case in which the packet arrives at an add / drop / pass-through device, when a 1 is stored in the first and second bits of an SRAM accessed with a lower address of the source MAC address and a 1 is stored in the third and fourth bits of an SRAM accessed with an intermediate address of the source MAC address, the source MAC address is stored in an address table that specifies passage, and the packet is sent to the server on the counterclockwise ring.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a handover method for a mobile terminal in a ring network using an SRAM in a ring node device that stores a lower address of a destination MAC address of an Ethernet frame and bit 1 that indicates an intermediate address. 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] Furthermore, 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 MAC 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 by using a ring network that utilizes a ring node device configured with only two SRAMs as memory, without using a MAC address table. [Means for solving the problem]

[0015] The present invention has been made in consideration of the above problems in the conventional art, and the means for solving the problems are as follows: first to fifth aspects of the present invention. A first aspect of the present invention is a ring node device of a system in which a packet via a ring node device, which is ADDed by an ADD line, travels via the ring from a router connected to the ring to a server, and a packet from the server is transferred to the ADD line, the ring node device storing a bit 1 in a first bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by a lower address of a source MAC address of a packet from the ADD line is bit 0, and storing a bit 1 of even parity in the second bit position, storing a bit 1 in a third bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet is bit 0, and storing a bit 1 of even parity in the fourth bit, storing a bit 1 in a fifth bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by the lower address of the source MAC address of the packet is bit 1, and storing a bit 1 of even parity in the sixth bit, a bit 1 is stored in a seventh bit position which is selected when the least significant bit of the lower address of a storage area of ​​an address location of the memory to be accessed is bit 1, and bit 1 of the even parity is stored in the eighth bit position; the packet is sent to a server, and bit 1 is stored in a first bit position which is selected when the least significant bit of the lower address of a storage area of ​​an address location of the memory to be accessed with the lower address of a source MAC address of a packet arriving at the own ring node device from downstream on the ring is bit 0, and bit 1 of the even parity is stored in the second bit position; and a bit 1 is stored in a third bit position which is selected when the least significant bit of the lower address of a storage area of ​​an address location of the memory to be accessed with an intermediate address of the source MAC address of the packet is bit 0, and bit 1 of the even parity is stored in the fourth bit;means for storing the source MAC address of the packet in an address table that specifies the passage of the packet and sending the packet to a server via a trunk or a ring when a bit 1 is stored in a fifth bit position that is selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by a lower address of the source MAC address of the packet is bit 1, and a bit 1 of even parity is stored in the sixth bit, and when a bit 1 is stored in a seventh bit position that is selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet is bit 1, and a bit 1 of even parity is stored in the eighth bit position; When a packet from a server arrives at its own ring node from the ring, if the destination MAC address of the packet is stored in an address table that specifies the passage of the packet, the packet is sent in the downstream direction of the ring. If the destination MAC address of the packet is not stored in the address table that specifies the passage of the packet, and if the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by a lower address of the destination MAC address of the packet is bit 0, a bit 1 is stored in a first bit position that is selected when the least significant bit of the lower address of the storage area of ​​an address position of a memory accessed by an intermediate address of the destination MAC address of the packet is bit 0, a bit 1 of even parity is stored in a second bit position that is selected when the least significant bit of the lower address of the storage area of ​​an address position of a memory accessed by an intermediate address of the destination MAC address of the packet is bit 0, a means for sending the packet to an ADD line if a bit 1 is stored in a third bit position that is selected when the least significant bit is bit 0, bit 1 of even parity is stored in the fourth bit, bit 1 is stored in a fifth bit position that is selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by a lower address of the destination MAC address of the packet is bit 1, bit 1 of even parity is stored in the sixth bit, and bit 1 of even parity is stored in a seventh bit position that is selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by an intermediate address of the destination MAC address of the packet is bit 1, and bit 1 of even parity is stored in an eighth bit position, and means for sending the packet downstream on the ring in other cases.

[0016] A second aspect of the present invention is a ring node apparatus according to the first aspect of the present invention, This ring node device is characterized in that if the source terminal of a packet from the ADD line is divided into n parts by the value of a bit string at a specific position of the source MAC address, and bit 1 representing the lower address of the source MAC address and bit 1 representing the intermediate address are stored in the memory, the number of source MAC addresses that need to be stored in the address table that specifies the passage of packets is reduced to 1 / n.

[0017] A third aspect of the present invention is a ring node apparatus according to the first aspect of the present invention, 2. The ring node apparatus according to claim 1, wherein an Ethernet frame from a terminal or an Ethernet frame from a mobile terminal is added to the ADD line.

[0018] A fourth aspect of the present invention is a method for transmitting packets from a mobile terminal to a destination server via a ring node device connected to the 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 blocking the passage of a packet having a source MAC address that is the NIC MAC address of a ring network interface of the router 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 the ring node device via the ring network as Ethernet frames of TCP and UDP for call signals, etc., and transmitting packets between the router and the server or exchange as IP packets, the method comprising the steps of: 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; When a packet from the mobile terminal arrives at an add, drop and pass-through device of the ring network, regardless of whether the packet is a packet immediately after a change of the destination base station or not, storing bit 1 in a first bit position selected when the least significant bit of a lower address of a storage area of ​​an address location of a memory accessed by the lower address of the source MAC address of the packet is bit 0, storing bit 1 of even parity in the second bit position, and storing bit 1 in a third bit position selected when the least significant bit of the lower address of a storage area of ​​an address location of the memory accessed by the intermediate address of the source MAC address of the packet is bit 0, storing bit 1 of even parity in the fourth bit, storing bit 1 in a fifth bit position selected when the least significant bit of the lower address of a storage area of ​​an address location of a memory accessed by the lower address of the source MAC address of the packet is bit 1, storing bit 1 of even parity in the sixth bit, and storing bit 1 in a seventh bit position selected when the least significant bit of the lower address of a storage area of ​​an address location of the memory accessed by the intermediate address of the source MAC address of the packet is bit 1, a step of storing bit 1 of the even parity in a first bit position selected when the least significant bit of the lower address of a memory area of ​​an address location of a memory accessed with a lower address of a source MAC address of a packet arriving at an add, drop and pass-through device of the packet from the counterclockwise ring is bit 0, bit 1 of the even parity is stored in a second bit position, bit 1 is stored in a third bit position selected when the least significant bit of the lower address of a memory area of ​​an address location of a memory accessed with an intermediate address of the source MAC address of the packet is bit 0, bit 1 of the even parity is stored in a fourth bit, bit 1 is stored in a fifth bit position selected when the least significant bit of the lower address of a memory area of ​​an address location of a memory accessed with the lower address of the source MAC address of the packet is bit 1, and bit 1 of the even parity is stored in a sixth bit,storing a bit 1 in a seventh bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet is a bit 1, and a bit 1 of even parity is stored in an eighth bit position; storing the source MAC address of the packet in an address table that specifies the passage of the packet, and sending the packet toward a server on a counterclockwise ring; When a packet from a server arrives at a packet add, drop, and pass-through device from a clockwise ring, if the destination MAC address of the packet is stored in an address table that specifies the pass-through of the packet, the packet is sent in the downstream direction of the ring; if the destination MAC address of the packet is not stored in the address table that specifies the pass-through of the packet, and if the least significant bit of the lower address of a storage area of ​​an address location in memory accessed by a lower address of the destination MAC address of the packet is bit 0, a bit 1 is stored in a first bit position that is selected when the least significant bit of the lower address of the storage area of ​​an address location in memory accessed by an intermediate address of the destination MAC address of the packet is bit 0, a bit 1 of even parity is stored in a second bit position that is selected when the least significant bit of the lower address of the storage area of ​​an address location in memory accessed by an intermediate address of the destination MAC address of the packet is bit 0 a bit 1 is stored in a third bit position selected when the least significant bit of the lower address of a memory area of ​​an address position of the memory accessed by a lower address of the destination MAC address of the packet is bit 1, a bit 1 is stored in a fifth bit position selected when the least significant bit of the lower address of the memory area of ​​an address position of the memory accessed by a lower address of the destination MAC address of the packet is bit 1, a bit 1 is stored in a sixth bit position selected when the least significant bit of the lower address of the memory area of ​​an address position of the memory accessed by a middle address of the destination MAC address of the packet is bit 1, and a bit 1 is stored in an eighth bit position selected when the least significant bit of the lower address of the memory area of ​​an address position of the memory accessed by a middle address of the destination MAC address of the packet is bit 1,

[0019] A fifth aspect of the present invention relates to a method according to the fourth aspect of the present invention, comprising: The method is characterized in that the mobile terminal accesses a 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. Effect of the Invention

[0020] As described above, the present invention uses an SRAM for lower address and intermediate address designation memory for designating packet transmission outside the ring instead of a MAC address table, and by dividing the source terminal of a packet of an ADD line from a wireless base station by n using the value of a bit string at a specific position of the source MAC address and storing bit 1 representing the lower address and bit 1 representing the intermediate address of the source MAC address in the memory, the number of source MAC addresses that need to be stored in the address table for designating packet passage is reduced to 1 / n, making operation simple and fast, and requiring only two SRAMs for the memory of a ring node device (device for adding, dropping and passing packets), thus reducing system costs. Also, the present invention is a method for realizing handover of a mobile terminal within a 1MAC 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]

[0021] [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 add, drop and pass 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 add, drop and pass device having an SRAM for lower address and intermediate address designation memory that designates packet transmission outside the ring in the first embodiment of the present invention and an address table that designates packet passing; [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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] A first embodiment of the present invention will be described with reference to Fig. 1. This embodiment is an example of 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 lower address for specifying packet transmission outside the ring and an SRAM for an intermediate address specifying memory and an address table for specifying packet passing are connected by an optical transmission line, a mobile terminal under a base station transfers information as a MAC packet to a router connected to the ring network, and a server connected to the ring network via the router. The server is a mail receiving server or an Internet connection server.

[0023] 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, 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, 13-3, and 13-4 are mobile terminals, 14-1, 14-2, and 14-3 are base stations (BS), 20 is a server, 22 is a router, and 26 is a switch. In addition, (1) to (39) indicate the transfer order of packets, which are abbreviated as MAC addresses in letter symbols to be transferred on the ring indicated by the dotted lead line, 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 service providers. Or they are IPv6 addresses. The OE conversion circuit, EO conversion circuit, input buffer, and output buffer are not shown in the figure.

[0024] The operation of FIG. 1 will be explained below. An example is shown in which the mobile terminal 13-2 for sending 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 a packet arrives at the add, drop and pass device 6-1 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 a bit 1 is stored in the 1st bit of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory for designating packet transmission outside the ring, and the intermediate address β (for example, the 18th bit to the 34th bit) of the source MAC address of the packet is accessed, and a bit 1 is stored in the 2nd bit as the even parity of the 1st bit. A bit 1 is stored in the third bit of the storage 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 accessed by the address 17 (bits 1 to 17), and a bit 1 is stored in the fourth bit as the even parity of the third 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 currently used optical transmission line 1 of the counterclockwise ring.

[0025] When the packet is transferred by (3) Mr1r2γβα(I0) through counterclockwise ring 1 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 and second bits 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 with 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 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 with 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. If bit 1 is stored in the third and fourth bits of the memory area of ​​the address location of the SRAM (11) for α, if α and β have the same bit string, and if the NIC manufacturer of β is stored with one bit changed, the source MAC address of the packet is stored in the address table that specifies the passage of the packet, but 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 packet add, drop and passage device 6-4 (vertex device), 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(I0) 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 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.

[0026] Next, when a mobile terminal 13-1 receiving a telework service transmits 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 13-1, and I0 indicates the IP address of the destination server) to the device 6-1 for adding, dropping, and passing the packet via the base station 14-1, a bit 1 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 that designates packet transmission outside the ring, which is accessed by the lower address α of the source MAC address of the packet, and a bit 0 is stored in the second bit as the even parity of the first bit. A bit 1 is stored in the third bit of the storage 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 accessed by the intermediate address β of the source MAC address of the packet, a bit 1 is stored in the fourth bit as the even parity of the third bit, and 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 is connected to the server 20 via the current optical transmission line 1 of the counterclockwise ring is stored.

[0027] When the packet is forwarded on the counterclockwise ring 1 by (10) Mr1 r2 δ β α (I0) as shown in the figure and arrives at the packet add, drop and pass device 6-2, the packet passes through the device 6-2 and arrives at the packet add, drop and pass device 6-4 (vertex device) where the destination MAC address r1 r2 of the packet is stored in the address table 12 for the router, the packet is dropped from the ring as (13) Mr1 r2 δ β α (I0) toward the router 22 outside the ring. When the packet arrives at the router 22, the source MAC address (δ β α) and IP address (I2) of the packet are stored in an ARP table (not shown) or the source MAC address (δ β α) is put in the option field of the IP header, and the IP packet is forwarded by (14) IPI2 I0 (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.

[0028] 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, a bit 1 is stored in the 5th bit, which is selected when the least significant bit of the lower address θ of the storage 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 with the lower address θ of the source MAC address γηθ of the packet from the previous mobile terminal 13-4, and a bit 1 is stored in the 6th bit as the even parity of the 5th bit. Also, since a bit 1 is stored in the 7th bit, which is selected when the least significant bit of the lower address θ of the storage 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 with the intermediate address η of the source MAC address of the packet, the packet is accessed with the lower address α of the source MAC address γβα of the packet. a bit 1 is stored in the first bit, which is selected when the least significant bit of the lower address α of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address specification memory specifying packet transmission outside the ring accessed by the intermediate address β of the source MAC address of the packet is bit 0, a bit 1 is stored in the third bit, which is selected when the least significant bit of the lower address α of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address specification memory specifying packet transmission outside the ring accessed by the intermediate address β of the source MAC address of the packet is bit 0, a bit 1 is stored in the fourth bit, which is selected when the least significant bit of the lower address α of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address specification memory specifying packet transmission outside the ring accessed by the intermediate address β of the source MAC address of the packet is bit 1, and a bit 1 is stored in the fourth bit, which is selected when the least significant bit of the

[0029] When the packet arrives at packet add, drop, and pass-through device 6-4 (vertex device) 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 (19)Mr1r2γβα(I0) and headed for router 22 outside the ring.

[0030] 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 the terminal connected to terminal device 13-2, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0031] Next, when a response packet (21) 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 upload packet 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 (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.

[0032] 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.

[0033] When a packet (23) M δ β α r1 r2 (I2) is transferred through the clockwise ring 2 and arrives at the packet add, drop and pass-through device 6-2, if the destination MAC address δ β α of the packet is not stored in the address table 8 that specifies the packet pass-through, and if the least significant bit of the lower address α of the address position storage area of ​​the SRAM (11) for the lower address memory that specifies the packet transmission outside the ring accessed by the lower address α of the destination MAC address of the packet is bit 0, then the first bit selected is bit 0. A bit 1 is stored in the third bit selected by the least significant bit of the lower address α of the memory area of ​​the address position of the SRAM (11) for the lower address memory that specifies packet transmission outside the ring accessed by the intermediate address β of the destination MAC address of the packet, and a bit 1 is stored in the fourth bit as the even parity of the third bit, so that 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.

[0034] 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 middle 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 is stored in the first bit of the memory area of ​​the address position of the SRAM (11) for the lower address and middle 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, and the packet A bit 1 is stored in the third bit of the storage 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 accessed by the intermediate address β of the source MAC address of the packet, and a bit 1 is stored in the fourth bit as the even parity of the third 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 is connected to the server 20 via the current optical transmission line 1 of the counterclockwise ring is stored.

[0035] When the packet is transferred by (28)Mr1r2δβα(I0) through counterclockwise ring 1 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 selected by bit 0 of the least significant bit of the lower address α of the storage area of ​​the address position of SRAM (11) for the lower address and intermediate address designation memory that is accessed by the lower address α (for example, the 1st bit to the 17th bit) of the source MAC address of the packet and that designates packet transmission outside the ring, and a bit 1 is stored in the second bit as the even parity of the first bit, and a bit 1 is stored in the third bit selected by bit 0 of the least significant bit of the lower address α of the storage area of ​​the address position of SRAM (11) for the lower address and intermediate address designation memory that is accessed by the intermediate address β of the source MAC address of the packet and that designates packet transmission outside the ring, and a bit 1 is stored in the fourth bit position as the even parity. Therefore, the source MAC address δβα of the packet is stored in the address table that designates packet passage. When the packet arrives at the packet add, drop and transit device 6-4 (vertex device) where 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 (31)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 put into the option field of the IP header, and the IP packet is forwarded as shown in the figure by (32)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.

[0036] 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.

[0037] 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.

[0038] When packet (35)Mδβαr1r2(I2) is forwarded through clockwise ring 2 and arrives at packet add, drop, and pass-through device 6-2 as (36)Mδβαr1r2(I2), 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. When the packet (37)Mδβαr1r2 (I2) is transferred through the clockwise ring 2 and arrives at the packet add, drop, and pass-through device 6-1, the destination MAC address δβα of the packet is not stored in the address table 8 specifying the pass-through of the packet, and a bit 1 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 specifying packet transmission outside the ring, which is accessed by the lower address α of the destination MAC address of the packet, and a bit 1 is stored in the second bit as the even parity of the first bit, and a bit 1 is stored in the third bit of the storage area of ​​the address position of SRAM (11) for the lower address and intermediate address designation memory specifying packet transmission outside the ring, which is accessed by the intermediate address β of the destination MAC address of the packet, and a bit 1 is stored in the fourth bit as the even parity of the third bit, so that the packet is sent out of the ring as (38)Mδβαr1r2 (I2). When the packet arrives at 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 destination mobile terminal 13-1.

[0039] Next, Fig. 2A and Fig. 2B 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, 101 judges whether the destination MAC address of the received packet is stored in the address table that specifies the passing of the packet, and if NO, if the least significant bit of the destination MAC address of the received packet in 102 is bit 0, it judges whether bit 1 is stored in the first and second bits of the data storage area of ​​the address position of the memory for packet dropping (SRAM for the lower address and intermediate address specification memory that specifies the packet sending out of the ring) accessed by the lower address of the MAC address, and whether bit 1 is stored in the third and fourth bits of the data storage area of ​​the address position of the memory for packet dropping accessed by the intermediate address of the destination MAC address of the received packet, and if YES, it sends the received packet in 103 out of the ring and returns to (a). If NO, it sends the received packet in 104 forward to the clockwise ring and returns to (a). If NO at 100, it transitions to (b). If the answer is YES at 101, the process transitions to 104. In FIG. 2B, 106 judges whether a packet has arrived from the ADD line, and if the answer is Yes, regardless of whether the received packet at 107 is a packet immediately after changing the destination base station or not, if the least significant bit of the source MAC address of the received packet is bit 0, 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 (the lower address memory for specifying packet transmission outside the ring and the SRAM for the intermediate address specification memory) accessed by the lower address of the MAC address, and the parity p (bit 1) is stored in the second bit, bit 1 indicating intermediate address storage is stored in the third bit of the data storage area of ​​the address position of the memory for packet dropping accessed by the intermediate address of the source MAC address of the received packet, and the parity p (bit 1) is stored in the fourth bit, the received packet at 108 is sent out counterclockwise to the front of the ring, and the process returns to (a). If NO in 106, it is determined whether a packet has arrived from the counterclockwise ring in 109. If YES, when the least significant bit of the source MAC address of the received packet in 110 is bit 0, it is determined whether bit 1 is stored in the first bit of the data storage area of ​​the address position of the memory for packet drop (the lower address memory for specifying packet transmission outside the ring and the SRAM for the intermediate address specification memory) accessed with the lower address of the MAC address, and whether the parity p (bit 1) is stored in the second bit, and whether bit 1 is stored in the third bit of the data storage area of ​​the address position of the memory for packet drop accessed with the intermediate address of the source MAC address of the received packet, and whether the parity p (bit 1) is stored in the fourth bit. If YES, it is determined whether the source MAC address of the received packet in 111 is stored in the address table for specifying the passage of the packet, and the received packet in 112 is sent forward to the counterclockwise ring, and the process transitions to (a). If NO in 109, it returns to (a). If NO in 110, it transitions to 112.

[0040] In the first embodiment, a bit 1 is stored in a first bit, which is selected when the least significant bit of the lower address α of a storage area of ​​an address position of an 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 of the source MAC address of the packet, is bit 0; a bit 1 is stored in a third bit, which is selected when the least significant bit of the lower address α of a storage area of ​​an address position of an 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 of the source MAC address of the packet, is bit 0; The number of MAC addresses stored in the address table specifying the passage of packets in the ring node device becomes an issue when bit 1 is stored in the 5th bit, which is selected when the least significant bit of the lower address α of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address specification memory specifying packet transmission outside the ring accessed with the intermediate address β of the source MAC address of the packet is bit 1, and bit 1 is stored in the 7th bit, which is selected when the least significant bit of the lower address α of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address specification memory specifying packet transmission outside the ring accessed with the intermediate address β of the source MAC address of the packet is bit 1. 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 SRAM access bits is 17, and the number of terminals to be added to the ring is divided into two as described above, the number of MAC addresses n required to be stored in the address table specifying the passage of packets is as follows: Since n = 100000 * 5000 * 5000 / EXP (17ln2) / EXP (17ln2) * 2 = 291, there is no problem in realizing the first embodiment. If the source terminal of a packet from the ADD line is divided into n parts by the value of the bit string at a specific position of the source MAC address, and bit 1 representing the lower address of the source MAC address and bit 1 representing the intermediate address are stored in the memory, the number of source MAC addresses that need to be stored in the address table specifying the passage of packets will be reduced to 1 / n.

[0041] In the first embodiment, when the mobile terminal cannot receive a response packet to an access packet to a receiving mail server of the mobile terminal, a retransmission packet is sent to the receiving mail server.

[0042] 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]

[0043] 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 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 ring node device of a network in which a packet via a ring node device, which is added by an ADD line, travels from a vertex device connected to a ring to a server via a ring and a packet from the server is transferred to the ADD line, stores a bit 1 in a first bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by a lower address of a source MAC address of a packet from the ADD line is bit 0, stores a bit 1 of even parity in the second bit position, stores a bit 1 in a third bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by an intermediate address of the source MAC address of the packet is bit 0, stores a bit 1 of even parity in the fourth bit, stores a bit 1 in a fifth bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by the lower address of the source MAC address of the packet is bit 1, stores a bit 1 of even parity in the sixth bit, and stores an address of the intermediate address of the source MAC address of the packet. a bit 1 is stored in a seventh bit position which is selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory to be accessed is bit 1, and bit 1 of the even parity is stored in the eighth bit position; the packet is sent to a server, and bit 1 is stored in a first bit position which is selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory to be accessed with the lower address of a source MAC address of a packet arriving at the own ring node device from downstream on the ring is bit 0, and bit 1 of the even parity is stored in the second bit position; and a bit 1 is stored in a third bit position which is selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory to be accessed with an intermediate address of the source MAC address of the packet is bit 0, and bit 1 of the even parity is stored in the fourth bit;a means for storing a source MAC address of the packet in an address table that specifies the passage of the packet and sending the packet to a server via a trunk or a ring when a bit 1 is stored in a fifth bit position that is selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by a lower address of the source MAC address of the packet is bit 1, and a bit 1 of even parity is stored in the sixth bit, and when a bit 1 is stored in a seventh bit position that is selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet is bit 1, and a bit 1 of even parity is stored in the eighth bit position; When a packet from a server arrives at its own ring node from the ring, if the destination MAC address of the packet is stored in an address table that specifies the passage of the packet, the packet is sent in the downstream direction of the ring. If the destination MAC address of the packet is not stored in the address table that specifies the passage of the packet, and if the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by a lower address of the destination MAC address of the packet is bit 0, a bit 1 is stored in a first bit position that is selected when the least significant bit of the lower address of the storage area of ​​an address position of a memory accessed by an intermediate address of the destination MAC address of the packet is bit 0, a bit 1 of even parity is stored in a second bit position that is selected when the least significant bit of the lower address of the storage area of ​​an address position of a memory accessed by an intermediate address of the destination MAC address of the packet is bit 0, a means for sending the packet to an ADD line if a bit 1 is stored in a third bit position selected when the least significant bit is bit 0, bit 1 of even parity is stored in the fourth bit, bit 1 is stored in a fifth bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by a lower address of the destination MAC address of the packet is bit 1, bit 1 of even parity is stored in the sixth bit, and bit 1 of even parity is stored in a seventh bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of a memory accessed by an intermediate address of the destination MAC address of the packet is bit 1, and bit 1 of even parity is stored in an eighth bit position, and

2. The ring node device according to claim 1, characterized in that if the source terminal of a packet from the ADD line is divided into n by the value of a bit string at a specific position of the source MAC address, and bit 1 representing the lower address of the source MAC address and bit 1 representing an intermediate address are stored in the memory, the number of source MAC addresses that need to be stored in the address table that specifies the passage of packets is reduced to 1 / n.

3. 2. The ring node apparatus according to claim 1, wherein an Ethernet frame from a terminal or an Ethernet frame from a mobile terminal is added to the ADD line.

4. a ring node device on a ring network connected to the ring node device on the ring network, the ring node device having 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 of the packet 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 and UDP Ethernet frames for call signals or the like across the ring network and as IP packets between the router and the server or exchange, in order to communicate with a destination server via the ring node device connected to the router for email communication, video conference involving call signals or content distribution, the method comprising: When a packet from the mobile terminal arrives at an add, drop and pass device of the packet of the ring network, regardless of whether the packet is a packet immediately after changing the destination base station or not, storing bit 1 in a first bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by the lower address of the source MAC address of the packet is bit 0, storing bit 1 of even parity in the second bit position, and storing bit 1 in a third bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet is bit 0, storing bit 1 of even parity in the fourth bit, storing bit 1 in a fifth bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by the lower address of the source MAC address of the packet is bit 1, storing bit 1 of even parity in the sixth bit, and storing bit 1 in a seventh bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by the intermediate address of the source MAC address of the packet is bit 1, a step of storing bit 1 of the even parity in a first bit position selected when the least significant bit of the lower address of a memory area of ​​an address position of a memory accessed with a lower address of a source MAC address of a packet arriving at an add, drop and pass-through device of the packet from the counterclockwise ring is bit 0, bit 1 of the even parity is stored in a second bit position, bit 1 is stored in a third bit position selected when the least significant bit of the lower address of a memory area of ​​an address position of a memory accessed with an intermediate address of the source MAC address of the packet is bit 0, bit 1 of the even parity is stored in a fourth bit, bit 1 is stored in a fifth bit position selected when the least significant bit of the lower address of a memory area of ​​an address position of a memory accessed with the lower address of the source MAC address of the packet is bit 1, and bit 1 of the even parity is stored in a sixth bit,storing a bit 1 in a seventh bit position selected when the least significant bit of the lower address of a storage area of ​​an address position of the memory accessed by an intermediate address of the source MAC address of the packet is bit 1, and a bit 1 of even parity is stored in an eighth bit position; storing the source MAC address of the packet in an address table that specifies the passage of the packet, and sending the packet toward a server on a counterclockwise ring; When a packet from a server arrives at a packet add, drop, and pass-through device from a clockwise ring, if the destination MAC address of the packet is stored in an address table that specifies the pass-through of the packet, the packet is sent in the downstream direction of the ring; if the destination MAC address of the packet is not stored in the address table that specifies the pass-through of the packet, and if the least significant bit of the lower address of a storage area of ​​an address location of a memory accessed by a lower address of the destination MAC address of the packet is bit 0, a bit 1 is stored in a first bit position, a bit 1 of even parity is stored in a second bit position, and the least significant bit of the lower address of a storage area of ​​an address location of a memory accessed by an intermediate address of the destination MAC address of the packet is bit 0, a a bit 1 is stored in a third bit position selected when the least significant bit of the lower address of a storage area of ​​an address location of the memory accessed by a lower address of the destination MAC address of the packet is bit 1, a bit 1 is stored in a fifth bit position selected when the least significant bit of the lower address of the storage area of ​​the address location of the memory accessed by a lower address of the destination MAC address of the packet is bit 1, a bit 1 is stored in a sixth bit position selected when the least significant bit of the lower address of the storage area of ​​the address location of the memory accessed by an intermediate address of the destination MAC address of the packet is bit 1, and a bit 1 is stored in an eighth bit position selected when the least significant bit of the lower address of the storage area of ​​the address location of the memory accessed by a middle address of the destination MAC address of the packet is bit 1,

5. 5. The method according to claim 4, wherein the mobile terminal accesses a 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.

Images