Handover using ring network that searches for drop connection destination of packet from ring network at low-order address of destination mac address of ethernet frame, and fault recovery method for ring network

Abstract

To provide a system and method that quickly and inexpensively perform fault recovery of a ring transmission path involved in handover of a wireless system.SOLUTION: In the event of a ring network failure, a packet on a counterclockwise ring transmission path in contact with a transmission path failure point is looped back, when the packet which has been looped back is not a steered packet and a transmission source MAC address is stored in an address table specifying passage, the MAC address is not erased, when the same low-order address as the low-order address of the transmission source MAC address is stored in the address table specifying passage, the MAC address is erased, and in cases other than the above cases, the above is left as is, and when the low-order address of the transmission source MAC address is stored so as to specify packet transmission to the outside the ring, the destination MAC address is stored in a ring transmission path port address table at a downstream exit, and the packet is sent to the front of a clockwise ring.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a network handover and ring fault recovery method for searching for a drop destination from a ring network by the lower address of the destination MAC address of an Ethernet (registered trademark) frame, making use of the characteristics of a ring network in which a lower address memory that stores the lower address of a MAC address is used in a device for adding, dropping and passing packets of 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 master switch will not arrive, and instead The master switch receives a failure notification frame from the slave switch at the failure point. The master switch unblocks the blocked port of the master switch to allow the frame to pass. Also, a blocked port is set on the failed transmission line side of one of the slave switches of the failure point, and the link The ring network continues to operate even after the ring network has recovered from a failure. Generally, in a conventional ring network, a MAC address table is used in the ring node device, so that in the event of a transmission line failure, the FDBs of all ring node devices in the ring are cleared and the FDBs are reconstructed by flooding.

[0005] An example of a handover method is Patent Document 4. This prior art is a method that has an IPv6 connection via a base station before switching via a gateway and a base station between a mobile terminal and an access router, and an IPv6 connection via a destination base station, and reduces the interruption time of packets via the connections when switching connections. [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] The object of the present invention is to provide a method for recovering from a ring fault in a ring network in which a lower address memory that stores lower addresses of a MAC address is used in a ring node device, thereby realizing a simple handover without using a conventional MAC address table. [Means for solving the problem]

[0015] The present invention has been made in consideration of the above-mentioned problems of the prior art, and the means for solving the problems are as follows: These are the first to eighth aspects of the present invention. A first aspect of the present invention is a system in which a plurality of devices for adding, dropping and passing packets are inserted into a ring network of an optical transmission path 2 for a clockwise ring and an optical transmission path 1 for a counterclockwise ring, a base station is connected to the devices for adding, dropping and passing packets, and a mobile terminal under the base station has a function of receiving packets arriving from the counterclockwise ring of the ring network or from the clockwise ring when a fault occurs in the ring network, and transferring the packets 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, in order to communicate with a destination server via the router for television lectures, television conferences involving telephone signals, and content distribution, and in which packets are passed between the mobile terminal and the router across the ring network as TCP or UDP Ethernet frames for telephone signals, and between the router and the server or exchange as IP packets, When a packet from the terminal or mobile terminal arrives at a packet add, drop and pass device of the ring network, If the packet is a packet immediately after the mobile terminal changes its destination base station, or if the packet is a communication start packet of the terminal, and if the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, If the lower address of the source MAC address of the packet is not stored in the lower address memory 7 that specifies packet transmission outside the ring, A lower address of the source MAC address of the packet is stored in a lower address memory 7 for specifying packet transmission outside the ring, and the source MAC address of the packet is stored in a temporary storage address table, On the other hand, if the packet is not a packet immediately after the mobile terminal changes the base station destination, or if the packet is not a communication start packet of the terminal, If the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, and if a lower address of the source MAC address of the packet is stored in lower address memory 7 that specifies the transmission of the packet outside the ring, the lower address of the source MAC address of the packet is stored in the lower address memory that specifies the transmission of the packet outside the ring, and the packet is transmitted to the counterclockwise ring; When the forwarded packet arrives at a packet add, drop, and pass-through device from the counterclockwise ring, means for storing the source MAC address of the packet in an address table 8 that specifies the passage of the packet when the lower address of the source MAC address of the packet is stored in a lower address memory 7 that specifies the packet transmission outside the ring, and for transferring the packet directly to a router 22 connected to a server 20 via an optical transmission line in other cases; When a packet from the server 20 arrives at the apex device 5 of the ring network via the router 22, the packet is sent to the clockwise ring, When the packet arrives at a packet add, drop, and pass-through device, if the destination MAC address of the packet is stored in a temporary storage address table, the packet is sent to a base station outside the ring, if a MAC address with a lower address that is the same as the lower address of the destination MAC address of the packet is stored in the temporary storage address table, the MAC address stored in the temporary storage address table is erased, the destination MAC address of the packet is stored in an address table that specifies the pass-through of the packet, and the packet is sent to the front of the clockwise ring, otherwise, 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 to the front of the clockwise ring. means for transmitting the packet to the front of the clockwise ring if the destination MAC address of the packet is not stored in an address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying packet transmission outside the ring, and means for transmitting the packet to the front of the clockwise ring if the destination MAC address of the packet is not stored in an address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying packet transmission outside the ring.

[0016] In a second aspect of the present invention, in the system according to the first aspect of the present invention, when a ring network fault occurs, a packet on the left-handed ring transmission line of a device for adding, dropping and passing packets adjacent to the fault point is looped back to an input buffer on the receiving side of the right-handed ring, and when a packet whose destination MAC address is the NIC MAC address of the ring network interface of the router 22 arrives from the receiving side of the right-handed ring to a sequencer circuit of the device for adding, dropping and passing packets, If the packet does not hold a steering packet bit, and the source MAC address of the packet is not stored in the address table that specifies the passage of the packet, and a MAC address with the same lower address as the lower address of the source MAC address of the packet is stored in the address table that specifies the passage of the packet, a steering packet bit is added to the packet, and the destination MAC address of the packet is stored in the ring transmission line port address table in the front of the clockwise ring, or the add, drop and pass device of the packet is set in a steering state, and the packet is sent to the front of the clockwise ring, and the packet is added to the address table that specifies the passage of the packet. When the packet arrives at a drop and pass device, if the packet holds a steering packet bit and the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet transmission outside the ring, the source MAC address of the packet is stored in an address table that specifies packet passing, and if the packet does not hold a steering packet bit, the destination MAC address of the packet is stored as is in a ring transmission line port address table in front of the clockwise ring, or the add, drop and pass device of the packet is placed in a steering state, and the packet is sent out to the front of the clockwise ring, On the other hand, when the packet arrives at a device for adding, dropping, and passing a packet from outside the ring, if the destination MAC address of the packet is stored in the ring transmission line port address table, or if the device for adding, dropping, and passing the packet is in a steering state, a steering packet bit is added to the packet and the packet is sent to the front of the clockwise ring; when the packet arrives at a device for adding, dropping, and passing a packet from the clockwise ring, if the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet sending outside the ring, the source MAC address of the packet is stored in an address table that specifies packet passing, and the packet is sent to the front of the clockwise ring; When the packet arrives at a vertex device from the clockwise ring, store the lower address of the source MAC address of the packet in a lower address memory, and forward the packet to a server or switch via the router 22; When a packet from a server or exchange arrives at a vertex device via a router 22, if the lower address of the destination MAC address of the packet is stored in the lower address memory, the packet is forwarded on the counterclockwise ring with a steering packet bit added, whereas if the lower address of the destination MAC address of the packet is not stored in the lower address memory, the packet is forwarded on the clockwise ring without a steering packet bit added; When a packet having a steering packet to be transferred on a counterclockwise ring arrives at a packet add, drop and pass device, if the destination MAC address of the packet is stored in a temporary storage address table, the packet is sent to a base station outside the ring, if a MAC address with a lower address that is the same as the lower address of the destination MAC address of the packet is stored in the temporary storage address table, the MAC address stored in the temporary storage address table is erased, the destination MAC address of the packet is stored in an address table that specifies the packet's pass, and the packet is sent to the front of the counterclockwise ring, and if the destination MAC address of the packet is not stored in the temporary storage address table, and sending the packet to the front of the counterclockwise ring if the destination MAC address of the packet is not stored in the address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying packet transmission outside the ring, sending the packet out of the ring, and sending the packet to the front of the counterclockwise ring if the destination MAC address of the packet is not stored in the address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying packet transmission outside the ring. The system further comprises:

[0017] A third aspect of the present invention provides a system according to the first aspect of the present invention, This system is characterized in that, in the event of a ring network failure, the system loops back the packets at the add, drop and pass devices on both sides of the failure point, and when the packets loop back, a loopback bit is added, and the packets with the loopback bit added pass through all devices up to the point where they loop back a second time, and further comprises a means for removing the loopback bit at the second loopback.

[0018] A fourth aspect of the present invention provides a system according to the first aspect of the present invention, In the packet add, drop and pass device, 8-bit parallel data of a packet arriving from a clockwise ring and 10 bits of the first bit of a frame and the last bit of a frame are input to an input FIFO, and when the first bit of the frame is read from the FIFO by a sequencer circuit, a 550-byte timer and a 1500-byte timer are started to operate, and if the last bit of the frame is read before the 550-byte timer times out, reading from the FIFO is stopped, and the 1500-byte timer is reset by a timeout pulse of the 550-byte timer, and and means for resetting all JKFFs of the sequencer circuit and resuming reading of the FIFO regardless of the end of the sequence of the path, while stopping operation of the 550 byte timer if the end bit of the frame is not read before the 550 byte timer times out, and stopping reading from the FIFO if the end bit of the frame is read before the 1500 byte timer times out, and resetting all JKFFs of the sequencer circuit and resuming reading of the FIFO regardless of the end of the sequence of the sequencer circuit.

[0019] A fifth aspect of the present invention provides a system according to the first aspect of the present invention, The sequencer circuit of the packet adding, dropping and passing device is characterized by having a means for placing packets arriving from a clockwise ring in an input FIFO, copying the packets at the FIFO output and placing them in the output memory of the clockwise ring and in a drop memory outside the ring, and discarding packets in the memory on the opposite side to the destination of the packets instructed by the sequencer.

[0020] A sixth aspect of the present invention provides a system according to the second aspect of the present invention, This system is characterized in that if the source MAC address of the looped back packet is not stored in an address table that specifies the passage of a packet, the source MAC address of the packet is stored in an address table that specifies the passage of a packet of a second packet add, drop, and pass-through device, in which the lower address of the source MAC address of the packet is stored in a lower address memory that specifies the transmission of the packet outside the ring.

[0021] A seventh aspect of the present invention provides a system according to the first aspect of the present invention, The system is characterized in that the mobile terminal comprises means for transmitting an RTCP response packet when an RTCP packet is received.

[0022] An eighth aspect of the present invention is a method for transmitting packets as TCP or UDP Ethernet frames for speech signals or the like between a mobile terminal and the router 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 router for television lectures, television conferences involving speech signals, and content distribution, comprising: inserting a plurality of packet add, drop and pass devices in a ring network of an optical transmission path 2 for a clockwise ring and an optical transmission path 1 for a counterclockwise ring; connecting a base station to the packet add, drop and pass devices; and having a function for a mobile terminal under the base station to receive packets arriving from the counterclockwise ring of the ring network, or from the clockwise ring when a fault occurs in the ring network, and to forward the packets to a router, and to block the passage of packets 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 packets is stored in a MAC address table of the device itself, the method comprising the steps of: When a packet from the terminal or mobile terminal arrives at a packet add, drop and pass device of the ring network, If the packet is a packet immediately after the mobile terminal changes its destination base station, or if the packet is a communication start packet of the terminal, and if the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, If the lower address of the source MAC address of the packet is not stored in the lower address memory 7 that specifies packet transmission outside the ring, A lower address of the source MAC address of the packet is stored in a lower address memory 7 for specifying packet transmission outside the ring, and the source MAC address of the packet is stored in a temporary storage address table, On the other hand, if the packet is not a packet immediately after the mobile terminal changes the base station destination, or if the packet is not a communication start packet of the terminal, If the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, and if a lower address of the source MAC address of the packet is stored in lower address memory 7 that specifies the transmission of the packet outside the ring, the lower address of the source MAC address of the packet is stored in the lower address memory that specifies the transmission of the packet outside the ring, and the packet is transmitted to the counterclockwise ring; When the forwarded packet arrives at a packet add, drop, and pass-through device from the counterclockwise ring, a step of storing the source MAC address of the packet in an address table 8 that specifies the passage of the packet when the lower address of the source MAC address of the packet is stored in a lower address memory 7 that specifies the packet transmission outside the ring, and otherwise forwarding the packet as it is to a router 22 to which a server 20 is connected via an optical transmission line; When a packet from the server 20 arrives at the apex device 5 of the ring network via the router 22, the packet is sent to the clockwise ring, When the packet arrives at a packet add, drop and pass-through device, if the destination MAC address of the packet is stored in a temporary storage address table, the packet is sent to a base station outside the ring, if a MAC address with a lower address that is the same as the lower address of the destination MAC address of the packet is stored in the temporary storage address table, the MAC address stored in the temporary storage address table is erased, the destination MAC address of the packet is stored in an address table that specifies the pass-through of the packet, and the packet is sent forward to the front of the clockwise ring, and if the destination MAC address of the packet does not match the address table that specifies the pass-through of the packet, the packet is sent forward to the front of the clockwise ring. sending the packet forward on the clockwise ring if the destination MAC address of the packet is not stored in an address table specifying packet passage and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying packet transmission outside the ring, sending the packet out of the ring if the destination MAC address of the packet is not stored in an address table specifying packet passage and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying packet transmission outside the ring, and sending the packet forward on the clockwise ring if the destination MAC address of the packet is not stored in an address table specifying packet passage and a lower address of the destination MAC address of the packet is not stored in a lower address memory specifying packet transmission outside the ring, moreover, In the event of a ring network failure, a packet on the left-handed ring transmission line of a device for adding, dropping and passing packets adjacent to the failure point is looped back to an input buffer on the receiving side of the right-handed ring, and when a packet whose destination MAC address is the NIC MAC address of the ring network interface of the router 22 arrives from the receiving side of the right-handed ring to a sequencer circuit of a device for adding, dropping and passing packets, If the packet does not hold a steering packet bit, and the source MAC address of the packet is not stored in the address table that specifies the passage of the packet, and a MAC address with the same lower address as the lower address of the source MAC address of the packet is stored in the address table that specifies the passage of the packet, a steering packet bit is added to the packet, and the destination MAC address of the packet is stored in the ring transmission line port address table in the front of the clockwise ring, or the add, drop and pass device of the packet is set in a steering state, and the packet is sent to the front of the clockwise ring, and the packet is added to the address table that specifies the passage of the packet. When the packet arrives at a drop and pass device, if the packet holds a steering packet bit and the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet transmission outside the ring, the source MAC address of the packet is stored in an address table that specifies packet passing, and if the packet does not hold a steering packet bit, the destination MAC address of the packet is stored as is in a ring transmission line port address table in front of the clockwise ring, or the add, drop and pass device of the packet is placed in a steering state, and the packet is sent out to the front of the clockwise ring, On the other hand, when the packet arrives at a device for adding, dropping, and passing a packet from outside the ring, if the destination MAC address of the packet is stored in the ring transmission line port address table, or if the device for adding, dropping, and passing the packet is in a steering state, a steering packet bit is added to the packet and the packet is sent to the front of the clockwise ring; when the packet arrives at a device for adding, dropping, and passing a packet from the clockwise ring, if the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet sending outside the ring, the source MAC address of the packet is stored in an address table that specifies packet passing, and the packet is sent to the front of the clockwise ring; When the packet arrives at a vertex device from the clockwise ring, store the lower address of the source MAC address of the packet in a lower address memory, and forward the packet to a server or switch via the router 22; When a packet from a server or exchange arrives at a vertex device via a router 22, if the lower address of the destination MAC address of the packet is stored in the lower address memory, the packet is forwarded on the counterclockwise ring with a steering packet bit added, whereas if the lower address of the destination MAC address of the packet is not stored in the lower address memory, the packet is forwarded on the clockwise ring without a steering packet bit added; When a packet having a steering packet to be transferred on a counterclockwise ring arrives at a packet add, drop and pass-through device, if the destination MAC address of the packet is stored in a temporary storage address table, the packet is sent to a base station outside the ring, if a MAC address with a lower address that is the same as the lower address of the destination MAC address of the packet is stored in the temporary storage address table, the MAC address stored in the temporary storage address table is erased, the destination MAC address of the packet is stored in an address table that specifies the packet's pass-through, and the packet is sent to the front of the counterclockwise ring, and if the destination MAC address of the packet is not stored in the temporary storage address table, the packet is sent to the base station outside the ring. sending the packet forward on the counterclockwise ring if the destination MAC address of the packet is stored in an address table specifying the passage of the packet, sending the packet out of the ring if the destination MAC address of the packet is not stored in the address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying the transmission of the packet out of the ring, and sending the packet forward on the counterclockwise ring if the destination MAC address of the packet is not stored in the address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying the transmission of the packet out of the ring; or The method includes steps of looping back packets at add, drop and pass devices on both sides of a fault point, adding a loopback bit when the packet is looped back, passing the packet with the loopback bit through all devices up to the point where the packet is looped back a second time, and removing the loopback bit at the second loopback. Effect of the Invention

[0023] As described above, the present invention has the advantage that no flooding is required even when a ring transmission line fault occurs, so that congestion does not occur even if the Ethernet domain is large. In addition, the present invention has the advantage that congestion is unlikely to occur because a loopback recovery can be immediately switched to a steering mode when a ring transmission line fault occurs. In addition, the present invention has the advantage that the operation is simple and fast because the device for adding, dropping, and passing packets is operated by a sequencer, and the system cost can be reduced because a lower MAC address memory is used instead of a conventional MAC address table. In addition, the present invention has the advantage that the power consumption and system cost can be reduced and high-speed communication can be achieved by a method for realizing handover of a mobile terminal within one domain by a ring network using the above memory. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a diagram for explaining an example of a ring transmission line failure recovery operation of a packet forwarding system between a terminal that forwards MAC packets through a base station connected to the packet add / drop / pass device having a lower address memory that specifies packet transmission outside the ring, an address table that specifies packet passage, a temporary storage address table, and a ring transmission line port address table in a first embodiment of the present invention, and a server connected to the ring network via a router and a terminal that forwards MAC packets through a base station connected to the packet add / drop / pass device in a dual ring network in which multiple rings are connected by an optical ring; [Figure 2A]FIG. 1 is a diagram showing the operation flow of a device for adding, dropping, and passing packets in a first embodiment of the present invention. [Figure 2B] FIG. 1 is a diagram showing the operation flow of a device for adding, dropping, and passing packets in a first embodiment of the present invention. [Figure 2C] FIG. 1 is a diagram showing the operation flow of a device for adding, dropping, and passing packets in a first embodiment of the present invention. [Figure 3A] FIG. 1 shows a sequencer circuit of a packet adding, dropping and passing device according to a first embodiment of the present invention. [Figure 3B] FIG. 1 shows a sequencer circuit of a packet adding, dropping and passing device according to a first embodiment of the present invention. [Figure 4] FIG. 1 shows a sequencer driving circuit of a packet adding, dropping and passing device according to a first embodiment of the present invention. [Diagram 5] FIG. 1 is a diagram showing a sequencer driving circuit of a device for adding, dropping and passing packets when steering is set to both loopback operations when a ring network failure occurs in the first embodiment of the present invention; [Figure 6] FIG. 1 is a diagram showing the principle of storing lower addresses in a lower address memory that specifies packet transmission outside a ring used in a packet adding, dropping and passing device according to a first embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] A first embodiment of the present invention will be described with reference to Fig. 1. This embodiment is an example of the operation of a ring transmission line failure recovery method for handover in which a mobile terminal accommodated in a base station connected to a packet add, drop and pass device of a double ring network, which is formed by connecting a plurality of devices with a lower address memory for specifying packet transmission outside the ring, an address table for specifying packet passage, a temporary storage address table, and a ring transmission line port address table, is transferred as a MAC packet to a router connected to the ring network, and a packet transfer system between the mobile terminal and a server connected to the ring network via the router is also capable of receiving TCP packets and UDP one-way packets from the mobile terminal using the ring network. The server is an Internet connection server or a content server. From the NIC of the ring network interface of the router 22 through the ring network to the NIC of the wireless interface of the base station is one MAC domain. The content server may be a cloud center.

[0026] In Fig. 1, 1 is an optical transmission line of a counterclockwise ring, 2 is an optical transmission line of a clockwise ring, 5 is a vertex device, 6-1, 6-2, and 6-3 are devices for adding, dropping, and passing packets, 7 is a lower address memory that specifies packet transmission outside the ring, 8 is an address table that specifies packet passing, 9 is a ring transmission line port address table, 11 is a temporary storage address table, 13-1, 13-2, and 13-3 are TCP mobile terminals or UDP mobile terminals, 14-1, 14-2, and 14-3 are base stations, 20 is a content server or a service provider's Internet connection server, and 22 is a router. Also, (1) to (35) 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, I3, and I4 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.

[0027] The operation of Fig. 1 will be explained below. An example is shown in which UDP mobile terminal 13-2 for voice or game data communication sends packet (1) Mn1a3a2(I0) (M indicates an Ethernet packet, n1 indicates the wireless MAC address of the interface of base station 14-1, a3a2 indicates the upper MAC address a3 and the lower MAC address a2 which are the MAC addresses of UDP terminal 13-2, and I0 indicates the IP address of server 20 which is the destination) to base station 14-1. Base station 14-1 sends (2) Mr1r2a3a2(I0) via wired line as an Ethernet packet to packet add, drop and pass device 6-2. When the packet from the UDP mobile terminal 13-2 reaches the add, drop and pass-through device 6-1, the lower address a2 of the source MAC address of the packet is stored in the lower address memory 7 that specifies packet transmission outside the ring, and the packet is sent toward the vertex device 5 via the working optical transmission path 1 of the counterclockwise ring. When the packet arrives at the add, drop and pass-through device 6-2 as shown in the figure by (3) Mr1 r2 a3 a2 (I0), since the lower address a2 of the source MAC address of the packet is not stored in the lower address memory 7 that specifies packet transmission outside the ring, the packet is transferred as it is through the counterclockwise ring 1 to the add, drop and pass-through device 6-3 of the packet by (4) Mr1 r2 a3 a2 (I0). ), the lower address a2 of the source MAC address of the packet is not stored in the lower address memory 7 that specifies packet transmission outside the ring, so the packet is forwarded as is through the counterclockwise ring 1. When the packet arrives at the vertex device 5, the destination MAC address r1r2 of the packet is stored in the MAC address table 25-1, so the name of the counterclockwise ring 1 through which the packet has been forwarded is stored in the address table 25-1 together with the source MAC address a3a2, or the lower address a2 of the source MAC address a3a2 of the packet is stored in the lower address memory together with the counterclockwise ring name 1, and the packet (5)Mr1r2a3a2(I0) is sent outside the ring as (6)Mr1r2a3a2(I0) and headed for the router 22.

[0028] When the packet (6) Mr1r2a3a2 (I0) arrives at router 22, the source MAC address a3a2 and source IP address I3 of the packet are stored in the ARP table, the output port corresponding to the destination IP address I0 of the packet is found, and the packet is sent to that port. The packet is then transferred as shown in the figure by (7) IPI3I0 (IP indicates an IP address, I3 indicates the source IP address of mobile terminal 13-2, and I0 indicates the IP address of server 20, which is the destination) to reach server 20.

[0029] Next, an example is shown in which UDP mobile terminal 13-1, which is connected to a video conference server via an Internet connection server and receives a video conference service, sends packet (8)Mn1a1a2(I0) (M indicates an Ethernet packet, n1 indicates the wireless MAC address of base station 14-1, a1a2 indicates the upper MAC address a1 and the lower MAC address a2 which are the MAC addresses of UDP mobile terminal 13-1, and I0 indicates the IP address of destination server 20) to base station 14-1. Base station 14-1 sends (9)Mr1r2a1a2(I0) to packet add, drop and pass device 6-1 as a wired Ethernet packet. When the packet from UDP mobile terminal 13-1 reaches add, drop and pass-through device 6-1, the lower address a2 of the source MAC address of the packet is stored in lower address memory 7 which specifies packet transmission outside the ring, and the packet is sent toward vertex device 5 via current optical transmission path 1 of the counterclockwise ring. The packet is then forwarded by (10) Mr1r2a1a2 (I0) as shown in the figure, and arrives at packet add, drop and pass-through device 6-2. When the packet (10) Mr1r2a1a2 (I0) arrives at the packet add, drop and pass device 6-2 on the working optical transmission path 1 of the counterclockwise ring, the lower address of the source MAC address of the packet is not stored in the lower address memory 7 that specifies packet transmission outside the ring, so the packet is sent as it is to the vertex device 5 as (11) Mr1r2a1a2 (I0) via the optical transmission path 1 of the counterclockwise ring. When the packet arrives at the vertex device 5 via the packet add, drop and pass device 6-3 on the optical transmission path 1 of the counterclockwise ring, the destination MAC address r1r2 of the packet is stored in the MAC address table 25-1, so the counterclockwise ring name 1 from which the packet has been transferred and the source MAC address a1a2 are stored in the address table 25-1, or the lower address a2 of the source MAC address a1a2 of the packet is stored in the lower address memory together with the counterclockwise ring name 1, and the packet is sent outside the ring toward the router 22.

[0030] When the packet (13) Mr1r2a1a2 (I0) arrives at router 22, if the packet is a communication initiation packet, the source MAC address a1a2 and source IP address I2 of the packet are stored in the ARP table, the output port corresponding to the destination IP address I0 of the packet is found, and the packet is sent to that port. The packet is transferred as shown in the figure by (14) IPI2I0 (IP indicates an IP address, I2 indicates the source IP address of mobile terminal 13-1, and I0 indicates the IP address of server 20, which is the destination) to reach server 20.

[0031] Next, when the UDP mobile terminal 13-2 determines its approach to the destination base station 14-2, which is advertising a base station signal from the LTE (IEEE802.16e) base station 14-1 to nearby mobile terminals, by comparing the received radio wave strength from the base stations 14-1 and 14-2, or by detecting its approach to the base station 14-2 by identifying its location using the GPS function of the mobile terminal 13-2, it sends a request packet (15) Mn1a3a2 (I0) to send a MAC address authentication packet to the source base station 14-1 of the mobile terminal 13-2. Since the MAC address of the mobile terminal 13-2 is stored in a MAC address table (not shown) of its own base station, the source base station 14-1 confirms the MAC address of the mobile terminal 13-2, stores an erasure preparation bit in the MAC address storage location of the mobile terminal in the MAC address table, and sends a MAC address authentication packet having a MAC address confirmation source signal to the destination base station 14-2 of the mobile terminal 13-2 via packet add, drop and pass device 6-1 connected to its own base station and packet add, drop and pass device 6-2 connected to the destination base station of the mobile terminal 13-2. When the authentication packet arrives at the destination base station 14-2 of the mobile terminal 13-2, the base station 14-2 authenticates the MAC address of the wireless channel setting request packet for the mobile terminal that arrived from the mobile terminal 13-2, and sets up a wireless channel for the mobile terminal 13-2. Since both the mobile terminal and the base station are time-synchronized with the nearest GPS satellite with an error of 39 nsec even if the position error is 10 m, the signal from the mobile terminal to the base station is TDM multiplexed transmission with a guard time. The same time slot is used for voice, but the UDP uplink packet is a TDM reserved variable time slot. The IPv6 address of the base station 14-2 is used as the attachment address, and the MAC address a3a2 of the mobile terminal 13-2 is stored in a MAC address table (not shown), and the care-of address is sent to the mobile terminal 13-2 together with an authentication signal. When a packet (16)Mn2a3a2(B2)(I0) (n2 indicates the wireless NIC MAC address of base station 14-2, and B2 corresponds to the MAC address of base station 14-2, which is the MAC address portion of the IPv6 care-of address) from mobile terminal 13-2 that received the packet from destination base station 14-2 arrives at base station 14-2, the packet is a packet immediately after the destination base station has been 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. Therefore, a signal m indicating that the packet is a packet immediately after the move is inserted into the packet, and the packet is sent to packet add, drop and pass through device 6-2 as (17)Mr1r2a3a2(B2)m(I0). When the packet (17) Mr1r2a3a2(B2)m(I0) from UDP mobile terminal 13-2 reaches add, drop and pass-through device 6-2, the lower address a2 of the source MAC address of the packet is not stored in lower address memory 7 which specifies packet transmission outside the ring, so the lower address a2 of the source MAC address of the packet is stored in lower address memory 7 which specifies packet transmission outside the ring, and the source MAC address a3a2 of the packet is stored in temporary memory address table 11, and the packet is sent toward the apex device via optical transmission path 1 of the counterclockwise ring.When the packet (18) Mr1r2a3a2 (I0) arrives at the packet add, drop and pass device 6-3, the packet is transferred as shown in the figure by (19) Mr1r2a3a2 (I0) via the optical transmission path 1 of the counterclockwise ring and sent toward the vertex device 5. When the packet (19) Mr1r2a3a2 (I0) arrives at the receiving circuit 25-1 of the vertex device 5, the destination MAC address r1r2 of the packet is stored in the MAC address table 25-1, so the counterclockwise ring name 1 from which the packet has been transferred and the source MAC address a3a2 are stored in the address table 25-1, or the lower address a2 of the source MAC address a3a2 of the packet is stored in the lower address memory together with the counterclockwise ring name 1, and the packet is sent outside the ring and headed for the router 22. The packet is sent outside the ring as (20) Mr1r2a3a2 (I0) and headed for the router 22.

[0032] When the packet (20) Mr1r2a3a2 (I0) arrives at the router 22, it is not a communication initiation packet or a response packet to a communication initiation packet, and therefore the source MAC address a3a2 and source IP address I3 of the packet are stored in the ARP table, so the packet is taken into the router 22, an output port corresponding to the destination of the destination IP address I0 of the packet is found, and the packet is sent to that port. The IP packet of the packet is sent to the server 20. The packet is transferred as shown in the figure by IPI3I0 (IP indicates an IP address, I3 indicates the source IP address of the mobile terminal 13-2, and I0 indicates the IP address of the content server 20 of the destination game packet) and reaches the server 20.

[0033] Next, when a packet (21) IPI0I2 (IP indicates an IP address, I2 is the IPv6 address or IPv4 address of the terminal 13-1, and I0 is the IP address of the video conference server) that is not a communication initiation packet arrives at the router 22 from the video conference server, if the packet is an IPv6 address, the destination MAC address a1a2 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) Ma1a2r1r2 (I2) used as the MAC header address of the MAC packet is sent to the apex device 5 of the ring network. If the packet is an IPv4 address, the destination MAC address a1a2 paired with the destination IP address I2 of the packet is found from an ARP table (not shown), and the MAC packet (22) Ma1a2r1r2 (I2) used as the MAC header address of the MAC packet is sent to the apex device 5 of the ring network. When the packet arrives at the vertex device 5, the destination MAC address of the packet is stored in the MAC address table 25-1, and the counterclockwise ring name 1 is stored in that MAC address storage location, or the lower address a2 of the destination MAC address a1a2 of the packet is stored in the lower address memory together with the counterclockwise ring name 1, so the packet is sent to the optical transmission path 2 of the clockwise ring, which is the opposite ring of the left ring name 1.

[0034] When the packet (23) Ma1a2r1r2 (I2) is transferred on the clockwise ring 2 and arrives at the packet add, drop, and pass-through device 6-3, the packet is sent to the clockwise ring 2 because the lower address a2 of the destination MAC address of the packet (23) Ma1a2r1r2 (I2) is not stored in the lower address memory 7 that specifies the sending of the packet outside the ring. When the packet (24)Ma1a2r1r2(I2) arrives at the packet add, drop and pass device 6-2, the destination MAC address of the packet is not stored in the temporary storage address table, and the MAC address a3a2, which has the same lower address as the lower address of the lower address of the destination MAC address of the packet, is stored in the temporary storage address table 11, so the MAC address a3a2 is erased, the destination MAC address a1a2 of the packet is stored in the address table 8 that specifies the packet pass, and the packet is sent to the clockwise ring as (26)Ma1a2r1r2(I2). In the figure, the deletion of the MAC address a3a2 is indicated by a horizontal line.

[0035] When the packet (26)Ma1a2r1r2(I2) arrives at the packet add, drop and pass device 6-1, the destination MAC address of the packet is not stored in the short-time address table, and the MAC address of the same lower address as the lower address of the lower address of the destination MAC address of the packet is not stored in the temporary storage address table 11, the destination MAC address a1a2 of the packet (26)Ma1a2r1r2(I2) is not stored in the address table 8 that specifies the passing of the packet, and the lower address of the destination MAC address of the packet is stored in the lower address memory 7 that specifies the sending of the packet outside the ring, so the packet is sent outside the ring. When the packet arrives at the base station 14-1, the destination MAC address a1a2 of the packet (27)Ma1a2r1r2(I2) is stored in a MAC address table not shown in the figure, so the packet is sent to the mobile terminal 13-1 as (28)Ma1a2n1(I2).

[0036] Next, the operation when a transmission line failure occurs at symbol 30 between the packet add, drop and pass devices 6-2 and 6-3 and the packet is looped back to the clockwise ring at the exit of the counterclockwise ring at the packet add, drop and pass device 6-2 is shown. The loopback may be at the optical signal level or the electrical signal level. When a fault occurs in the ring network, the packet on the counterclockwise ring transmission line adjacent to the transmission line fault point is looped back at symbol 40. When the looped back packet (31) Mr1r2a1a2 (I0) arrives at the packet add, drop and pass-through device 6-2 from the clockwise ring, If the packet does not retain the steered packet bit and the source MAC address a1a2 of the packet is stored in the address table 8 that specifies the passage of the packet, the MAC address a1a2 is not erased, but if a MAC address with the same lower address as the lower address of the source MAC address of the packet is stored in the address table that specifies the passage of the packet, the MAC address is erased and a steering bit is added to the packet, and the destination MAC address r1r2 of the packet is stored in the ring transmission line port address table 9 of the downstream exit of the packet without changing anything other than the above, and the packet is directed to the packet add / drop and passage device 6-1 as (32)Mr1r2a1a2(I0).

[0037] When the loopback packet arrives at the packet add / drop and pass device 6-1, the destination MAC address r1r2 of the packet is stored in the ring transmission line port address table 9 of the downstream exit of the packet, and the MAC address of the same lower address as the lower address of the source MA address of the packet is stored in the address table 8 specifying the packet pass in the case of the packet after passing through the add, drop and pass device of the packet, since the steering bit is added to the packet, if the lower address of the source MAC address of the packet is stored in the lower address memory specifying the packet transmission outside the ring, the source MAC address of the packet is stored in the address table specifying the packet pass, but since this packet is different, it is not stored in the address table 8. When the packet arrives at the ring node device 5 as (33)Mr1r2a1a2(I0), the destination MAC address r1r2 of the packet is stored in the MAC address table 25-1, so the source MAC address a1a2 of the packet and the clockwise ring name 2 from which the packet has been transferred are stored in a pair in the MAC address table 25-1. In the figure, the ring name 1 of MAC address a1a2 is crossed out and port number 2 is stored.

[0038] Next, when the mobile terminal 13-2 transmits a packet (34)Mn2a3a2(I0) to the base station 14-2 and the packet Mr1r2a3a2(I0) arrives at the packet add, drop and pass-through device 6-2, since the destination MAC address r1r2 of the packet is stored in the ring transmission line port address table 9, a steering packet bit is added to the packet and the packet is transmitted to the rightward ring 2 via the input FIFO on the rightward ring receiving side. When the packet arrives at packet add, drop and pass device 6-1, the lower address of the source MAC address of the packet is stored in the lower address memory that specifies packet transmission outside the ring, so the source MAC address a3a2 of the packet is stored in the address table that specifies the packet's pass, and when the packet arrives at ring node device 5 as (35)Mr1r2a3a2(I0), the destination MAC address r1r2 of the packet is stored in MAC address table 25-1, so the source MAC address a3a2 of the packet and the clockwise ring name 2 from which the packet was transferred are stored as a pair in MAC address table 25-1. In the figure, ring name 1 of MAC address a3a2 has been crossed out and ring name 2 has been stored. The ring name of a packet with a destination MAC address of a1a2 or a3a2 arriving at vertex device 5 from the router is read as 2 from MAC address table 25-1, so the packet is sent to counterclockwise ring 1. A steering packet bit is added to a packet sent to the counterclockwise ring. When a packet with a destination MAC address of a1a2 and a steering packet bit arrives at packet add, drop, and pass device 6-1 on the counterclockwise ring, the destination MAC address of the packet is not stored in the address table that specifies the passing of the packet, a MAC address with the same lower address as the lower address of the destination MAC address of the packet is not stored in the short-time address table, and the lower address of the destination MAC address of the packet is stored in the lower address memory that specifies the sending of the packet outside the ring, so the packet is sent outside the ring.

[0039] When switching back after a transmission line failure is restored, the OAM packet from the apex device clears the stored addresses in the ring transmission line port address table 9 of the add, drop and pass-through devices for all packets in the ring, and the ring names used for the MAC addresses of all mobile terminals in the MAC address table 25-1 of the apex device are changed to counterclockwise ring name 1.

[0040] In addition, when the wireless section uses TCP, the response from the mobile terminal will be NAK, but between the base station and the server, an ACK packet will be sent from the base station's TCP circuit. On the other hand, when the wireless section uses UDP, the bandwidth of the upstream signal in the wireless section is narrowed down to a lower speed compared to the downstream signal, so an immediate response from the mobile terminal cannot be expected.

[0041] Next, the operation flow of the device for adding, dropping and passing packets in the first embodiment is shown in Figures 2A, 2B and 2C, the sequencer circuit is shown in Figures 3A and 3B, and the sequencer drive circuit is shown in Figure 4. Next, the operation of Figures 2A, 2B and 2C will be described. In Figures 2A, 2B and 2C, the address table 8 that specifies the passing of a packet is described as a pass address table, the lower address memory 7 that specifies the sending of a packet outside the ring is described as a drop lower address memory, the temporary storage address table 11 is described as a short time memorized drop address table, and a packet having a steering packet bit is described as a steering packet. Among the flow symbols describing the operations in the flow diagram, (b1), (b2), (b3), (c1), (c2), (c3), etc., and B1, B2, B3, C1, C2, etc., described outside the flow symbols, are entered in sequence diagram 3, and (b1), (b2), (b3), (c1), (c2), (c3), etc. indicate the time positions in sequence diagram 3 where the corresponding operations described in Figure 2 are performed, and B1, B2, B3, C1, C2, etc. are described in correspondence with Figure 2 as input signals to the AND gate in sequence diagram 3. In Fig. 2A, 100 receives a packet from the clockwise ring and indicates whether there is no steering packet as (b1), a signal for YES is (B1), and a signal for NO is (F1), 101 indicates whether the destination MAC address of the packet other than the steering packet is stored in the temporary storage address table as (b2), a signal for YES is (B2), and a signal for NO is (C1), 102 drops the received packet other than the steering packet from the ring to the home base station (b3). 103 indicates whether the lower address MAC address m1 that matches the destination MAC lower address of the packet other than the steering packet is stored in the temporary storage address table as (c2), a signal for YES is (C2), and a signal for NO is (D1), 104 erases the MAC address m1 from the temporary storage address table, stores the destination MAC address of the received packet other than the steering packet in the address table that specifies the passage of the packet, and sends the packet forward to the clockwise ring (c3). 105 indicates as (d2) whether the destination MAC address of the received packet excluding the steering packet is stored in the address table that specifies the passage of the packet, the signal for YES is (D2) and the signal for NO is (E1), and 106 sends the received packet forward on the clockwise ring (d3). 107 indicates as (e2) whether the destination MAC lower address of the packet excluding the steering packet is stored in the lower address memory that specifies the packet transmission outside the ring, the signal for YES is (E2) and the signal for NO is (a), and 108 sends the received packet from the ring to the dependent base station (e3).

[0042] Numeral 110 indicates as (f2) whether a packet other than a steering packet has arrived from the base station, and if YES, the signal is (F2) and if NO, the signal is (H1). Numeral 111 indicates as (f3) whether the source MAC lower address of the received packet is stored in the lower address memory which specifies packet transmission outside the ring, and if NO, the signal is (F3) and if YES, the signal is (G1). Numeral 112 stores the source MAC lower address of the received packet in the lower address memory which specifies packet transmission outside the ring, stores the source MAC address of the received packet in a temporary storage address table, and erases the source MAC address of the received packet from the address table which specifies packet passage (f5). Numeral 114 stores the source MAC lower address of the received packet in a lower address memory that specifies packet transmission outside the ring, indicates as (g2) whether the source MAC address of the received packet has been deleted from the address table that specifies the passage of the packet, and sets the output signal to (G2). Numeral 115 sends the received packet to the front of the counterclockwise ring (g3). Numeral 116 indicates as (h2) whether a packet has been received from the counterclockwise ring, and sets the signal if YES to (H2). If NO, transitions to (a) upon timer out. Numeral 117 indicates as (h3) whether the source MAC lower address of the received packet has been stored in the lower address memory that specifies packet transmission outside the ring, and sets the signal if YES to (H3). If NO, transitions to 119. Numeral 118 stores the source MAC address of the received packet in the address table that specifies the passage of the packet (h4), sets the output signal to (H4), and 119 sends the received packet to the front of the counterclockwise ring (h5). The time-out signal (a) of the timer 130 is not related to the above flow, and the timer value is set so that it times out after the above flow operation is completed.

[0043] Next, the operation of FIG. 3A, part of the sequence diagram, will be described. 450 is a JKFF, and 451 is an AND circuit. All JKFFs are reset by a timeout signal (a). When a timer-out signal (a) is input to JKFFs 450-1 and 452-1, the Q bars of JKFFs 450-1, 450-2, and 450-3 become 1, and the signal B1 after the operation (b1) of 452-1 is input to the AND circuit 451-1, so that the output signal of the AND circuit 451-1 is input to J of JKFF 450-1, and the output becomes 1. The operation (b2) of 452-2 is performed at the output 1, and the output signal B2 is input to the AND circuit 451-2, and the output 1 is input to J of JKFF 450-2, so that the output of JKFF 450-2 becomes 1, and the operation (b3) of 452-3 is performed at the output 1. Since the NOT signal of Q output 1 and Q-bar output of JKFF 450-2 is input to AND circuit 451-6, the output signal C1 is input to J of JKFF 450-4, the operation of (c2) of 453-2 is performed at output 1, and the output signal C2 is input to the AND circuit, the operation of (c3) of 453-3 is performed at output 1. Signal F1 is generated from the output of JKFF 450-1 in the same manner as signal C1. Signal D1 is generated from the output of JKFF 450-4 in the same manner as signal C1. Next, the operation of FIG. 3B, part of the sequence diagram, will be described. 450 is a JKFF, and 454 is an AND circuit. All JKFFs are reset by a timeout signal (a). When the signal D1 is input to the AND circuit 454-1, the other input of the AND circuit 451-1 is input with the Q bar output of the JKFF 450-7, so the output becomes 1, the output signal is input to J of the JKFF 450-6, and the Q output becomes 1. The operation of (d2) of 455-2 is performed by the Q output 1, and the output signal D2 is input to the AND circuit 454-2, and the output 1 is input to J of the JKFF 450-7, so the output of the JKFF 450-7 becomes 1, and the operation of (d3) of 455-3 is performed by the output 1. The NOT signal of the Q output 1 and Q-bar output of JKFF 450-6 is input to AND circuit 460-5, so the output signal E1 is input to J of JKFF 450-8, the operation of (e2) of 456-2 is performed at output 1, and the output signal E2 is input to the AND circuit, the operation of (e3) of 456-3 is performed at output 1. The signal (a) of AND circuit 454-5 is made by ANDing the NOT signal of the Q output and Q-bar output of JKFF 450-8, but is not connected anywhere. Other branch sequencer diagrams are not shown in FIG. 3, but they would have a similar form to the above.

[0044] Next, the operation of the sequencer driving circuit shown in FIG. 4 will be described. FIG. 4 is an example of a device for adding, dropping and passing packets in a steering state when a ring transmission line failure occurs. When the destination MAC address of a packet added from the base station on the ADD line is stored in the ring transmission line port address table in front of the right-handed ring, or when the device for adding, dropping and passing packets is in steering mode, a steering packet with steering packet bits is input to the right-handed ring received packet input FIFO 400 and the steering packet FIFO 420 in parallel. The output of FIFO 400 is 8-bit parallel data 405, packet start bit 406 and packet end bit 407, and the output of FIFO 420 is 8-bit parallel data 425, packet start bit 426 and packet end bit 427. FIFO 420 operates with 8-bit parallel clock 1, and FIFO 400 operates with 8-bit parallel clock 2, with the clock 1 and the clock 2 shifted by half a clock. A signal 426 indicating that the start bit of a packet has been read from the FIFO 420 and a signal 407 indicating that the end bit of a packet has been read from the FIFO 400 are ORed in an OR circuit 416 to generate a read clock 2 stop signal 413 for the FIFO 400. Similarly, a signal 406 indicating that the start bit of a packet has been read from the FIFO 400 and a signal 427 indicating that the end bit of a packet has been read from the FIFO 420 are ORed in an OR circuit 428 to generate a read clock 1 stop signal for the FIFO 420. A signal 409 indicating the start bit of a packet in the FIFO 400 or a signal 419 indicating the start bit of a packet in the FIFO 420 serves as a start signal for the 550-byte timer and the 1512-byte timer. If the end bit signal of the packet (either 427 or 407) is input to the 550-byte timer before the 550-byte timer times out, the 550-byte timer outputs a timeout signal 411 to stop the operation of the 1512-byte timer.On the other hand, if the end-of-packet bit signal (either 427 or 407) is not input to the 550-byte timer before the 550-byte timer times out, the 550-byte timer does not output a timeout signal 411, and a timeout signal 412 from the 1512-byte timer is input to the OR circuit 403. The OR signal of signals 411 and 412 becomes a reset signal (a) for all JKFFs in the sequencer circuit, and also becomes a read resume signal for FIFO 400 and FIFO 420.

[0045] Next, a sequencer driver circuit of a device for adding, dropping and passing packets when looping back on both sides of a fault point without steering when a ring network fault occurs will be described with reference to Fig. 5. A clockwise ring received packet is input to an input FIFO 500. The output of the FIFO 500 is 8-bit parallel data 520, a packet start bit 521 and a packet end bit 522. The FIFO 500 operates with an 8-bit parallel clock, and a signal 522 obtained by reading the end bit of the packet from the FIFO 500 becomes a stop signal for the read clock of the FIFO 500. The signal 521 of the first bit of the packet of the FIFO 500 becomes start signals 510 and 511 of the 550-byte timer and the 1512-byte timer. The signal 521 of the first bit of the packet of the FIFO 500 becomes a set signal for the latch circuits 503-1 and 503-3. If the bit signal 522 at the end of the packet is input to the AND circuit 504-1 before the 550-byte timer times out and the latch circuit 503-2 is set at the output, the timeout signal of the 550-byte timer resets the latch circuits 503-1 and 503-3 via the AND circuit 504-2, so the timeout signal of the 1512-byte timer stops at the AND circuit 504-3. On the other hand, if the bit signal 522 at the end of the packet does not set the latch circuit 503-2 before the 550-byte timer times out, the timeout signal of the 550-byte timer is stopped at the AND circuit 504-2 and does not reset the latch circuit 503-2, so the timeout signal 412 of the 1512-byte timer passes through the AND circuit 504-3 and is input to the OR circuit 505. An OR signal 512 of the output signal of the AND circuit 504-2 and the output signal of the AND circuit 504-3 serves as a reset signal (a) for all JKFFs in the sequencer circuit, and also serves as a read restart signal for the FIFO 500.

[0046] The configuration method of the lower address memory that specifies the packet add, drop and pass device's packet send out of the ring in the first embodiment is disclosed in Chapter 3 "Address memory method using data memory area as address" on page 44 of "Proposal of MAC operation type tree-shaped ring network that forwards packets having only source terminal address in both directions" in Communication Method vol 113 No, 207, September 12-13, 2013 of the Institute of Electronics, Information and Communication Engineers Technical Report (IEICE Technical Report CS2013-28-CS2013-40) and in Chapter 3 "Packet's add, drop and pass equipment" in "Handovers using ring network composed of ring node equipment including lower MAC address memory, and top equipment" in Session 10-5 of ICETC2022 at https: / / www.ieice.org / publications / proceedings. It is also disclosed in JP 2019-097045 (Address memory method). This method can also be configured as shown in FIG. 6 as a principle diagram. In FIG. 6, the output of 32 bits 70 of the SRAM output data is latched by latch circuit 55, and the latch output signal, bit 0 write signal 59, and output 60 obtained by decoding the lower 5 bits 58 of the lower MAC address by decoder 53 are input to logic circuit 54, which sends the signal to the outside and writes it from the CPU to the SRAM. [Explanation of symbols]

[0047] 1. Counterclockwise ring optical transmission line 2. Clockwise ring optical transmission line 5 Vertex device 6-1, 6-2, 6-3 Packet Add, Drop and Pass Devices 7 Lower address memory that specifies packet transmission outside the ring 8 Address table that specifies the passage of packets 11 Temporary Storage Address Table 13-1, 13-2, 13-3 Mobile terminals 14-1,14-2,14-3 Base station 15. Mobile terminal movement 20 Servers 22 Router 25-1 MAC address table of apex device

Claims

1. A system in which a plurality of devices for adding, dropping and passing packets are inserted into a ring network of an optical transmission path 2 of a clockwise ring and an optical transmission path 1 of a counterclockwise ring, a base station is connected to the devices for adding, dropping and passing packets, and a mobile terminal under the base station receives packets arriving from the counterclockwise ring of the ring network, or from the clockwise ring when a fault occurs in the ring network, and transfers the packets to a router, and blocks 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, for communication with a destination server via the router connected to the router for television lectures, television conferences involving telephone signals, and content distribution, and in which data travels between the mobile terminal and the router across the ring network as TCP or UDP Ethernet (registered trademark) frames for telephone signals, etc., and between the router and the server or exchange as IP packets, When a packet from the terminal or mobile terminal arrives at a packet add, drop and pass device of the ring network, If the packet is a packet immediately after the mobile terminal changes its destination base station, or if the terminal starts communication, and if the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, If the lower address of the source MAC address of the packet is not stored in the lower address memory 7 that specifies packet transmission outside the ring, A lower address of the source MAC address of the packet is stored in a lower address memory 7 for specifying packet transmission outside the ring, and the source MAC address of the packet is stored in a temporary storage address table, On the other hand, if the packet is not a packet immediately after the mobile terminal changes the base station destination, or if the packet is not a communication start packet of the terminal, If the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, and if a lower address of the source MAC address of the packet is stored in lower address memory 7 that specifies the transmission of the packet outside the ring, the lower address of the source MAC address of the packet is stored in the lower address memory that specifies the transmission of the packet outside the ring, and the packet is transmitted to the counterclockwise ring; When the forwarded packet arrives at a packet add, drop, and pass-through device from the counterclockwise ring, means for storing the source MAC address of the packet in an address table 8 that specifies the passage of the packet when the lower address of the source MAC address of the packet is stored in a lower address memory 7 that specifies the packet transmission outside the ring, and for transferring the packet directly forward to a router 22 to which a server 20 is connected via an optical transmission line in the other cases; When a packet from the server 20 arrives at the apex device 5 of the ring network via the router 22, the packet is sent to the clockwise ring, When the packet arrives at a packet add, drop, and pass-through device, if the destination MAC address of the packet is stored in a temporary storage address table, the packet is sent to a base station outside the ring, if a MAC address with a lower address that is the same as the lower address of the destination MAC address of the packet is stored in the temporary storage address table, the MAC address stored in the temporary storage address table is erased, the destination MAC address of the packet is stored in an address table that specifies the packet's pass-through, and the packet is sent to the front of the clockwise ring, otherwise, if the destination MAC address of the packet is stored in an address table that specifies the packet's pass-through, means for transmitting the packet to the front of the clockwise ring if the destination MAC address of the packet is not stored in an address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying packet transmission outside the ring, and means for transmitting the packet to the front of the clockwise ring if the destination MAC address of the packet is not stored in an address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying packet transmission outside the ring.

2. In the event of a ring network failure, packets on the left-handed ring transmission line of the device that adds, drops, and passes packets adjacent to the failure point are looped back to the input buffer on the receiving side of the right-handed ring, and when a packet whose destination MAC address is the NIC MAC address of the ring network interface of the router 22 arrives from the receiving side of the right-handed ring to the sequencer circuit of the device that adds, drops, and passes packets, If the packet does not hold a steering packet bit, and the source MAC address of the packet is not stored in the address table that specifies the passage of the packet, and a MAC address with the same lower address as the lower address of the source MAC address of the packet is stored in the address table that specifies the passage of the packet, a steering packet bit is added to the packet, and the destination MAC address of the packet is stored in the ring transmission line port address table in the front of the clockwise ring, or the add, drop and pass device of the packet is set in a steering state, and the packet is sent to the front of the clockwise ring, and the packet is added to the address table that specifies the passage of the packet. When the packet arrives at a drop and pass device, if the packet holds a steering packet bit and the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet transmission outside the ring, the source MAC address of the packet is stored in an address table that specifies packet passing, and if the packet does not hold a steering packet bit, the destination MAC address of the packet is stored as is in a ring transmission line port address table in front of the clockwise ring, or the add, drop and pass device of the packet is placed in a steering state, and the packet is sent out to the front of the clockwise ring, On the other hand, when the packet arrives at a device for adding, dropping, and passing a packet from outside the ring, if the destination MAC address of the packet is stored in the ring transmission line port address table, or if the device for adding, dropping, and passing the packet is in a steering state, a steering packet bit is added to the packet and the packet is sent to the front of the clockwise ring; when the packet arrives at a device for adding, dropping, and passing a packet from the clockwise ring, if the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet sending outside the ring, the source MAC address of the packet is stored in an address table that specifies packet passing, and the packet is sent to the front of the clockwise ring; When the packet arrives at a vertex device from the clockwise ring, store the lower address of the source MAC address of the packet in a lower address memory, and forward the packet to a server or switch via the router 22; When a packet from a server or exchange arrives at a vertex device via a router 22, if the lower address of the destination MAC address of the packet is stored in the lower address memory, the packet is forwarded on the counterclockwise ring with a steering packet bit added, whereas if the lower address of the destination MAC address of the packet is not stored in the lower address memory, the packet is forwarded on the clockwise ring without a steering packet bit added; When a packet having a steering packet to be transferred on a counterclockwise ring arrives at a packet add, drop and pass device, if the destination MAC address of the packet is stored in a temporary storage address table, the packet is sent to a base station outside the ring, if a MAC address with a lower address that is the same as the lower address of the destination MAC address of the packet is stored in the temporary storage address table, the MAC address stored in the temporary storage address table is erased, the destination MAC address of the packet is stored in an address table that specifies the packet's pass, and the packet is sent to the front of the counterclockwise ring, and if the destination MAC address of the packet is not the packet a means for transmitting the packet to the front of the counterclockwise ring when the destination MAC address of the packet is stored in an address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying the transmission of the packet to the outside of the ring, the means for transmitting the packet to the front of the counterclockwise ring when the destination MAC address of the packet is not stored in the ... The system of claim 1 further comprising:

3. The system according to claim 1, further comprising means for looping back packets at add, drop and pass devices on both sides of the failure point when the ring network fails, adding a loopback bit when the packet is looped back, allowing the packet with the loopback bit to pass through all devices up to the point where it loops back a second time, and removing the loopback bit at the second loopback.

4. In the packet add, drop and pass device, 8-bit parallel data of a packet arriving from a clockwise ring and 10 bits of the first bit of a frame and the last bit of a frame are input to an input FIFO, and when the first bit of the frame is read from the FIFO by a sequencer circuit, a 550-byte timer and a 1500-byte timer are started to operate, and if the last bit of the frame is read before the 550-byte timer times out, reading from the FIFO is stopped, the 1500-byte timer is reset by a timeout pulse of the 550-byte timer, and the sequencer circuit is started. and means for resetting all JKFFs of said sequencer circuit and resuming reading of said FIFO regardless of the end of a sequence in said sequencer circuit, while stopping operation of said 550 byte timer if an end of frame bit is not read before a 550 byte timer times out, and stopping reading from said FIFO if an end of frame bit is read before a 1500 byte timer times out, and resetting all JKFFs of said sequencer circuit and resuming reading of said FIFO regardless of the end of a sequence in said sequencer circuit.

5. 2. The system according to claim 1, wherein the sequencer circuit of the packet add, drop and pass device includes means for placing packets arriving from the clockwise ring in an input FIFO, copying packets at the FIFO output and placing them in an output memory of the clockwise ring and a drop memory outside the ring, and discarding packets in the memory on the opposite side to which the sequencer has instructed the packet to go.

6. The system described in claim 2, characterized in that if the source MAC address of the looped back packet is not stored in an address table that specifies the passage of a packet, the source MAC address of the packet is stored in an address table that specifies the passage of a packet of a second packet add, drop and pass device, in which the lower address of the source MAC address of the packet is stored in a lower address memory that specifies the transmission of the packet outside the ring.

7. 2. The system according to claim 1, wherein the mobile terminal comprises means for transmitting an RTCP response packet when the mobile terminal receives an RTCP packet.

8. A method for transmitting packets as TCP or UDP Ethernet frames for speech signals or the like between a mobile terminal and the router 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 router connected to a vertex device on the ring network, for television lectures, television conferences involving speech signals, and content distribution, comprising: inserting a plurality of devices for adding, dropping and passing packets into a ring network of an optical transmission path 2 for a clockwise ring and an optical transmission path 1 for a counterclockwise ring; connecting a base station to the devices for adding, dropping and passing packets; and having a function for a mobile terminal under the base station to receive packets arriving from the counterclockwise ring of the ring network, or from the clockwise ring when a fault occurs in the ring network, and to forward the packets to a router, and to block the passage of packets 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 packets is stored in a MAC address table of the device itself, the method comprising the steps of: When a packet from the terminal or mobile terminal arrives at a packet add, drop and pass device of the ring network, If the packet is a packet immediately after the mobile terminal changes its destination base station, or if the terminal starts communication, and if the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, If the lower address of the source MAC address of the packet is not stored in the lower address memory 7 that specifies packet transmission outside the ring, A lower address of the source MAC address of the packet is stored in a lower address memory 7 for specifying packet transmission outside the ring, and the source MAC address of the packet is stored in a temporary storage address table, On the other hand, if the packet is not a packet immediately after the mobile terminal changes the base station destination, or if the packet is not a communication start packet of the terminal, If the source MAC address of the packet is stored in an address table that specifies the passage of the packet, the MAC address is erased, and if a lower address of the source MAC address of the packet is stored in lower address memory 7 that specifies the transmission of the packet outside the ring, the lower address of the source MAC address of the packet is stored in the lower address memory that specifies the transmission of the packet outside the ring, and the packet is transmitted to the counterclockwise ring; When the forwarded packet arrives at a packet add, drop, and pass-through device from the counterclockwise ring, a step of storing the source MAC address of the packet in an address table 8 that specifies the passage of the packet when the lower address of the source MAC address of the packet is stored in a lower address memory 7 that specifies the packet transmission outside the ring, and otherwise forwarding the packet as it is to a router 22 to which a server 20 is connected via an optical transmission line; When a packet from the server 20 arrives at the apex device 5 of the ring network via the router 22, the packet is sent to the clockwise ring, When the packet arrives at a packet add, drop and pass device, if the destination MAC address of the packet is stored in a temporary storage address table, the packet is sent to a base station outside the ring, if a MAC address with a lower address that is the same as the lower address of the destination MAC address of the packet is stored in the temporary storage address table, the MAC address stored in the temporary storage address table is erased, the destination MAC address of the packet is stored in an address table that specifies the packet's pass, and the packet is sent forward to the front of the clockwise ring, and if the destination MAC address of the packet is not stored in the address table that specifies the packet's pass, the packet is sent forward to the front of the clockwise ring. sending the packet forward on the clockwise ring if the destination MAC address of the packet is not stored in an address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying the transmission of the packet outside the ring, sending the packet out of the ring if the destination MAC address of the packet is not stored in an address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying the transmission of the packet outside the ring, moreover, In the event of a ring network failure, packets on the left-handed ring transmission line of the device that adds, drops, and passes packets adjacent to the failure point are looped back to the input buffer on the receiving side of the right-handed ring, and when a packet whose destination MAC address is the NIC MAC address of the ring network interface of the router 22 arrives from the receiving side of the right-handed ring to the sequencer circuit of the device that adds, drops, and passes packets, If the packet does not hold a steering packet bit, and the source MAC address of the packet is not stored in the address table that specifies the passage of the packet, and a MAC address with the same lower address as the lower address of the source MAC address of the packet is stored in the address table that specifies the passage of the packet, a steering packet bit is added to the packet, and the destination MAC address of the packet is stored in the ring transmission line port address table in the front of the clockwise ring, or the add, drop and pass device of the packet is set in a steering state, and the packet is sent to the front of the clockwise ring, and the packet is added to the address table that specifies the passage of the packet. When the packet arrives at a drop and pass device, if the packet holds a steering packet bit and the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet transmission outside the ring, the source MAC address of the packet is stored in an address table that specifies packet passing, and if the packet does not hold a steering packet bit, the destination MAC address of the packet is stored as is in a ring transmission line port address table in front of the clockwise ring, or the add, drop and pass device of the packet is placed in a steering state, and the packet is sent out to the front of the clockwise ring, On the other hand, when the packet arrives at a device for adding, dropping, and passing a packet from outside the ring, if the destination MAC address of the packet is stored in the ring transmission line port address table, or if the device for adding, dropping, and passing the packet is in a steering state, a steering packet bit is added to the packet and the packet is sent to the front of the clockwise ring; when the packet arrives at a device for adding, dropping, and passing a packet from the clockwise ring, if the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet sending outside the ring, the source MAC address of the packet is stored in an address table that specifies packet passing, and the packet is sent to the front of the clockwise ring; When the packet arrives at a vertex device from the clockwise ring, store the lower address of the source MAC address of the packet in a lower address memory, and forward the packet to a server or switch via the router 22; When a packet from a server or exchange arrives at a vertex device via a router 22, if the lower address of the destination MAC address of the packet is stored in the lower address memory, the packet is forwarded on the counterclockwise ring with a steering packet bit added, whereas if the lower address of the destination MAC address of the packet is not stored in the lower address memory, the packet is forwarded on the clockwise ring without a steering packet bit added; When a packet having a steering packet to be transferred on a counterclockwise ring arrives at a packet add, drop, and pass-through device, if the destination MAC address of the packet is stored in a temporary storage address table, the packet is sent to a base station outside the ring, if a MAC address with a lower address that is the same as the lower address of the destination MAC address of the packet is stored in the temporary storage address table, the MAC address stored in the temporary storage address table is erased, the destination MAC address of the packet is stored in an address table that specifies the packet's pass-through, and the packet is sent to the front of the counterclockwise ring, and if the destination MAC address of the packet is not stored in the temporary storage address table, the packet is sent to the base station outside the ring. sending the packet forward on the counterclockwise ring if the destination MAC address of the packet is stored in an address table specifying the passage of the packet, sending the packet out of the ring if the destination MAC address of the packet is not stored in the address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying the transmission of the packet out of the ring, and sending the packet forward on the counterclockwise ring if the destination MAC address of the packet is not stored in the address table specifying the passage of the packet and a lower address of the destination MAC address of the packet is stored in a lower address memory specifying the transmission of the packet out of the ring; or A step of looping back the packets at the add, drop and pass devices on both sides of the failure point, adding a loopback bit when the packets are looped back, passing the packets with the loopback bit through all the devices up to the point where the packets are looped back a second time, and removing the loopback bit at the second loopback.

23. A method comprising:

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