Handover of mobile terminal in ethernet communication system, and device for adding, dropping and passing power-saving ethernet frames used therefor

Abstract

To realize handover by using a ring network that transfers Ethernet frames.SOLUTION: A ring node device uses only a lower address memory that stores the lower address of the MAC address and specifies frame transmission outside a ring, and a duplicated use lower address memory, and attaches an unnecessary lower address deletion bit to a communication start frame or a frame immediately after changing the destination base station, and transfers it on the counterclockwise ring, and when the lower address of the source MAC address of the frame arrives at a ring node device stored in the lower address memory that specifies frame transmission outside the ring of the ring node device or the duplicated use lower address memory, the lower address is deleted, the frame is copied, and the copy frame is sent outside the ring. The base station stores the lower address of the MAC address in the duplicated use lower address memory of the ring node device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to handover of mobile terminals in an Ethernet communication system and to devices (ring node devices) used therefor for adding, dropping, and passing power-saving Ethernet frames, and to handover of a network that searches for a drop connection destination from a ring network using the lower address of the destination MAC address of an Ethernet (registered trademark) frame, taking advantage of the characteristics of a ring network in which a lower address memory that stores the lower addresses of MAC addresses is used in devices for adding, dropping, and passing frames of the ring network. This invention uses packets that use the MAC address portion of an Ethernet frame and an IPv6 address as the MAC address of the MAC packet.

[0002] A conventional example of a MAC address storage method is Patent Document 1, Japanese Patent Application Laid-Open No. 2000-151617, entitled "Table Creation and Search Device." This conventional example relates to a MAC address storage circuit, and comprises a first table consisting of RAM or the like having row and column addresses, a MAC address data area, and an index area, and a second table consisting of RAM or the like having row and column addresses, a MAC address data area, and an index area. In this conventional example, the entire 48 bits of a MAC address are stored at location A specified in the memory of the first table by a low-order bit string (e.g., 16 bits). If another MAC address is already stored at location A, it is recorded at an empty address location B in the memory of the second table, and the recorded address location B is then stored in the index area of ​​address location A of the first table. This is a method of specifying storage areas by nesting.

[0003] Furthermore, a conventional MAC address storage method is disclosed in Patent Document 2, Japanese Patent Application Laid-Open No. 2004-15592, entitled "MAC Address Pointer Structure, MAC Address Rearrangement Method." This conventional example is a method for storing multiple MAC addresses at the same address location 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 example of a conventional ring network is a ring network using a master switch and a slave switch, as shown in Patent Document 3. One of the ring ports on the switch is a blocked port that does not allow frames to pass through. This prevents congestion due to clutter. If a failure occurs in the ring network, the monitoring frames that leave the master switch and return to the master switch will not arrive, and instead The failure notification frame arrives at the master switch from the slave switch at the point of failure. 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 path side of one of the slave switches at the failure point, and the link The ring network continues to operate even after the ring network has recovered from a failure. Generally, in conventional ring networks, ring node devices use MAC address tables. In the event of a transmission path failure, the FDBs of all ring node devices in the ring are cleared and reconstructed through flooding. In conventional WANs, the router is the company's exit point, resulting in congestion and slow data transfer within the WAN. Using MAC for data transfer within the WAN raises the issue of fairness between companies and the fairness of fees. Optical paths can accommodate only about 10 paths, and AWGs are expensive, but they do not have the problem of TCP congestion. If only large companies can afford optical path fees, MAC multiplexing is an option, but it does not solve the congestion problem. If there is no congestion, MAC multiplexing is also an option. This proposal aims to achieve high-speed data transfer by eliminating intra-company routers and forwarding data only using MAC. Since companies vary in quality, MAC multiplexing is desirable, but MAC congestion-free data transfer is only possible at around 10G. Each company uses a VLAN to manage bandwidth reservations at the apex device.

[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 between a mobile terminal (user equipment (UE)) and an access router, and an IPv6 connection via a destination base station, and reduces the interruption time of frames via the connections when switching connections.

[0006] An example of a handover method is Non-Patent Document 2. This prior art is a method for realizing high-speed handover of Layer 3 by transferring a Fast Binding Update (FBU) and a reverse FBU having an old Care of Address (CoA) and a new CoA of the target access point (AP) between an old access router and a mobile node.

[0007] Non-Patent Document 3 provides an example of a handover method. This prior art is an example of an LTE Layer 3 handover, and involves transferring a Fast Binding Update (FBU) and a reverse FBU between the old access router and the mobile node, which contain the old Care of Address (CoA) and the new CoA of the target base station (BS), achieving a high-speed Layer 3 handover over a Layer 2 handover. The old base station advertises information about surrounding base stations to the mobile node, and the mobile node uses this information to send information about the new base station to the old base station. The old base station then confirms the new access router and sends an FBU to the old access router. After exchanging information with the new access router, the old access router sends packets destined for the mobile node to the new access router. Upon receiving notification after the mobile node's Layer 2 handover, the new access router sends packets stored in its buffer to the mobile node via the new base station.

[0008] An example of a handover method is Non-Patent Document 4. This prior art is an improvement of Non-Patent Document 3, and shortens the time it takes for an old access router to identify a new access router before receiving an FBU. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2000-151617 [Patent Document 2] Japanese Patent Publication No. 2004-15592 [Patent Document 3] Retable No. 2008-068813 [Patent Document 4] Re-tabled publication No. 2017-195497 [Non-patent literature]

[0010] [Non-Patent Document 1] G.8032 “Ethernet Ring Protection Swithing” [Non-patent document 2] RFC4260, ``Mobile IPv6 Fast handovers for 802.11 networks,'' Website, https: / / datatracker.org / doc / html / rfc4260. [Non-patent document 3] RFC5270, ``Mobile IPv6 Fast handovers over 802.16e networks,'' Website, https: / / datatracker.ictf.org / doc / html / rfc5270. [Non-patent document 4] S. Masoud Seyyedoshohadei, et al. ``An Integrated Scheme to Improve Performance of Fast Mobile IPv6 Handover in IEEE 802.16e Network,'' Proceedings of the 2009 IEEE 9th Malaysia International Conference on Communications 15-17 Dec. 2009 Kuala Lumpur Malaysia Summary of the Invention [Problem to be solved by the invention]

[0011] The conventional address storage method disclosed in Japanese Patent Application Laid-Open No. 2000-151617 stores MAC addresses using nesting, which has the drawback of taking a long time to trace the stored address. Also, it must store 48 bits, which is a drawback in that it cannot store a large number of MAC addresses.

[0012] In addition, the conventional address storage method disclosed in Japanese Patent Application Laid-Open No. 2004-15592 uses the lower bits It is stated that if there is no free space in the entry table position of the MAC address specified by the lower bit string, the MAC address will be stored in the entry table position of a different lower bit string, but in that case, when selecting the position to store the MAC address, the entry table positions specified by the two lower bit strings must be searched, and since there are multiple stored addresses at the same address position in the same entry table, these multiple addresses must be compared, which causes the problem of time-consuming searches. Also, 48 bits must be stored, which has the disadvantage of not being able to store many MAC addresses.

[0013] Conventional ring networks, such as those described in Non-Patent Document 1 and Patent Document 3, store the destination MAC addresses of frames bound for the left-handed ring, the destination MAC addresses of frames bound for the right-handed ring, and the destination MAC addresses of frames sent outside the ring using MAC addresses and port numbers, which means that a large number of MAC addresses must be stored.When the MAC address table stores the entire 48 bits of the MAC address at the address location accessed by 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 if the destination MAC address of a frame to be transferred is not stored in the MAC address table, the frame is flooded.

[0014] Furthermore, because it uses a forwarding database (FDB) based on a MAC address table, when a loopback frame returns to the source ring node device in the event of a ring transmission path failure, the source MAC address of the frame is stored as the port number outside the ring. Therefore, by setting the port number of the destination MAC address of the frame to the ring downstream transmission path port, RPR can transition to steering. However, in a typical Ethernet ring, the arrival ring port and source MAC address are stored as a pair in the MAC address table, making it impossible to transition to steering operation. Conventional MAC address tables operate at high speed, with a 1M-bit memory class of around 8,000 MAC addresses, and a 64M memory would slow down the speed. Furthermore, increasing speed through miniaturization leads to the problem of vulnerability to noise, which is related to shielding. In addition, a block point is used in the ring as an STP to avoid congestion caused by flooding when recovering from a ring network failure. However, because of this block point, a method of transitioning from wrapping to steering, such as RPR, cannot be used, and the FDB must be re-stored by flooding. Furthermore, conventional MAC address tables have a timer function for storing addresses to erase unnecessary stored addresses and reduce the number of stored addresses, which causes an increase in power consumption.

[0015] Furthermore, in a conventional ring network, when searching for a connection destination, the entire destination MAC address is required, and searching using the lower addresses of the destination MAC address is not possible. Furthermore, in a ring network, even if it is desired to store the source MAC address of a frame in an address table that specifies the frame passage so that a reverse direction frame 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 frame will arrive 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 terminals with many destinations.

[0016] Furthermore, the conventional handover technique disclosed in Patent Document 4 sets up two IPv6 connections between the access router and the mobile terminal (user equipment (UE)) and switches between them, which has the drawback of requiring identification of the two IPv6 connections and making handover control complicated.

[0017] All of Non-Patent Documents 2 to 4 involve a layer 3 handover on a layer 2 handover, which involves IP address conversion, and therefore has the drawback of causing a large handover delay.

[0018] The object of this invention is to show a method for realizing simple handover with low power consumption without using the conventional MAC address table by using an Ethernet ring network in which the lower address memory of the MAC address is used in the ring node device, in order to expand Layer 2 handover within a subnet by enlarging one MAC domain and thereby realizing handover with fewer opportunities for IP address conversion using CoA. [Means for solving the problem]

[0019] The present invention has been made in consideration of the problems of the prior art. To reduce power consumption, instead of the conventional MAC address table, the ring node device uses only a lower address memory and a duplicated-use lower address memory that store lower addresses of MAC addresses and specify frame transmission outside the ring. Furthermore, the timer function of the addresses stored in these memories is eliminated. To achieve this, an unnecessary lower address deletion bit is attached to a communication start frame or a frame immediately after a change of destination base station, and the frame is transmitted counterclockwise around the ring. When the frame's source MAC lower address arrives at a ring node device whose source MAC lower address is stored in the lower address memory or duplicated-use lower address memory that specifies frame transmission outside the ring, the lower address is deleted, the frame is copied, and the copy frame is transmitted outside the ring. When the base station receives a copy frame with the unnecessary lower address deletion bit attached from the ring, if another MAC address with the same lower address as the source MAC address of the frame is stored in the MAC address table, the base station stores the lower address of the MAC address in the duplicated-use lower address memory of the ring node device.

[0020] Specific solutions of the present invention are the first to twelfth aspects of the present invention described below. A first aspect of the present invention is a communications system in which a plurality of frame add, drop and pass devices are inserted into a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1, base stations are connected to the frame add, drop and pass devices, and a mobile terminal under the control of the base station has a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and a function of blocking the passage of packets having the NIC MAC address of the ring network interface of the router as a source MAC address, so that packets from the mobile terminal travel between the router and the ring network as Ethernet (registered trademark) frames and between the router and the server or exchange as IP packets across the ring network, When a frame from the mobile terminal arrives at a device for adding, dropping, and passing frames in a ring network, regardless of whether the frame is a frame immediately after a change of the destination base station or not, or whether the frame is a communication initiation frame or not, means for storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending a frame outside the ring, if the lower address of the source MAC address of the frame is not stored in a deletion lower address memory (hereinafter referred to as a duplicated use lower address memory), and if the lower address of the source MAC address of the frame is not stored in a lower address memory that specifies sending a frame outside the ring, and attaching an unnecessary lower address deletion bit to the frame, and sending the frame with the unnecessary lower address deletion bit attached to the counterclockwise ring; means for storing the lower address of the source MAC address of the frame in a duplicated use lower address memory, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending a frame outside the ring, and sending the frame to the counterclockwise ring without attaching an unnecessary lower address deletion bit to the frame; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, or / and if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and if an unnecessary lower address deletion bit is attached to the frame, delete the lower address from the lower address memory, delete the lower address from the duplicated use lower address memory, copy the frame, drop the copy frame from the ring and send it to the base station, and send the original frame of the copy frame to the counterclockwise ring, On the other hand, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, the lower address in the lower address memory that specifies sending the frame outside the ring is deleted, and the lower address is stored in a duplicated use lower address memory, means for transferring the frame on the counterclockwise ring as is, other than the above, and directing the frame to the router via the vertex device; When a frame arrives at the apex device from the server via the router and is sent to the clockwise ring, and arrives at the frame add, drop, and pass-through device, means for copying the frame and sending the copy frame forward in a clockwise direction on the ring if the lower address of the destination MAC address of the frame is stored in a duplicated use lower address memory, and sending the original frame of the copy frame out of the ring; means for sending the frame forward in a clockwise direction on the ring if the lower address of the destination MAC address of the frame is not stored in the duplicated use lower address memory and if the lower address of the destination MAC address of the frame is not stored in a lower address memory that specifies frame sending out of the ring; and means for sending the frame out of the ring if the lower address of the destination MAC address of the frame is stored in a lower address memory that specifies frame sending out of the ring; This communication system is characterized in that when a frame with an unnecessary lower address erasure bit attached arrives from a frame adding, dropping, and passing device connected to the base station, if a MAC address with the same lower address as the lower address of the source MAC address of the frame is stored in the MAC address table, the base station returns the frame to the frame adding, dropping, and passing device connected to the base station, and stores the lower address of the source MAC address of the frame with the unnecessary lower address erasure bit attached in a duplicated use lower address memory.

[0021] A second aspect of the present invention is a communication system according to the first aspect of the present invention, The communication system includes means for sending a MAC address authentication packet request frame to the source base station of the mobile terminal just before the mobile terminal accesses a destination base station approaching a router on a counterclockwise ring, the source base station confirming the MAC address of the mobile terminal in a MAC address table and sending the MAC address authentication packet of the mobile terminal to the destination base station, and when the MAC address authentication packet arrives at a device for adding, dropping and passing frames connected to the destination base station, if the lower address of the MAC address of the mobile terminal is stored in a duplicated use lower address memory, or / and the lower address of the MAC address of the mobile terminal is stored in a duplicated use lower address memory of a device for adding, dropping and passing frames along the way, or / and another MAC address with the same lower address as the lower address of the MAC address of the mobile terminal is stored in the MAC address table of the source base station, and the MAC address authentication packet arrives at a device for adding, dropping and passing frames connected to the destination base station, the communication system includes means for storing the lower address of the MAC address of the mobile terminal in a duplicated use lower address memory.

[0022] A third aspect of the present invention provides a communication system according to the first aspect of the present invention, When a location registration frame from the mobile terminal arrives at a device for adding, dropping, and passing frames, the lower address of the source MAC address of the frame is stored in a location registration lower address memory, and the frame is directed to the apex device via a through loop on the counterclockwise ring; when an incoming frame or communication initiation frame from the clockwise ring arrives at a device for adding, dropping, and passing frames, if the lower address of the destination MAC address of the frame is stored in the location registration lower address memory, the system is provided with means for copying the frame, sending the copy frame to the clockwise ring, and sending the original frame of the copy frame out of the ring.

[0023] A fourth aspect of the present invention is a communication system according to the first aspect of the present invention, The communication system is characterized in that the frame adding, dropping and passing device does not have a timer function for storing addresses in memory.

[0024] A fifth aspect of the present invention provides a communication system according to the first aspect of the present invention, The frame is a communication system in which the frame is an Ethernet frame carrying a TCP packet or a download unidirectional UDP packet.

[0025] A sixth aspect of the present invention is A frame add, drop and pass device, comprising: When a frame from a mobile terminal arrives at the add, drop, or pass-through device of the frame, means for storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending a frame outside the ring when the lower address of the source MAC address of the frame is not stored in a duplicate use lower address memory and when the lower address of the source MAC address of the frame is not stored in a lower address memory that specifies sending a frame outside the ring, and attaching an unnecessary lower address erasure bit to the frame and sending the frame with the unnecessary lower address erasure bit attached to the counterclockwise ring; means for storing the lower address of the source MAC address of the frame in a duplicate use lower address memory when the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending a frame outside the ring, and sending the frame to the counterclockwise ring without attaching an unnecessary lower address erasure bit to the frame; means for storing the lower address of the source MAC address of a frame in a duplicated use lower address memory and discarding the frame when the frame to which an unnecessary lower address deletion bit is added from a base station arrives at an add, drop or pass-through device of the frame; When a frame from the counterclockwise ring arrives at the add, drop, or pass-through device for that frame, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, or / and if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and if an unnecessary lower address deletion bit is attached to the frame, delete the lower address from the lower address memory, delete the lower address from the duplicated use lower address memory, copy the frame, drop the copy frame from the ring and send it to the base station, and send the original frame of the copy frame to the counterclockwise ring, On the other hand, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, the lower address in the lower address memory that specifies sending the frame outside the ring is deleted, and the lower address is stored in a duplicated use lower address memory, means for transmitting the frame to the counterclockwise ring as is, except for the above; When a frame from the clockwise ring arrives at the add, drop, or pass-through device for that frame, a means for copying the frame and sending the copy frame forward in the clockwise direction on the ring if the lower address of the destination MAC address of the frame is stored in a duplicated use lower address memory, and sending the original frame of the copy frame out of the ring; for sending the frame forward in the clockwise direction on the ring if the lower address of the destination MAC address of the frame is not stored in the duplicated use lower address memory and is not stored in a lower address memory that specifies frame sending out of the ring; and for sending the frame out of the ring if the lower address of the destination MAC address of the frame is stored in a lower address memory that specifies frame sending out of the ring.

[0026] A seventh aspect of the present invention is a communication system according to the first aspect of the present invention, The frame add, drop and pass device inputs 8-bit parallel data of a frame arriving from the clockwise ring and 10 bits of the frame's start bit and end bit into an input FIFO, and when the sequencer circuit reads the frame's start bit from the FIFO, it starts a 550-byte timer and a 1500-byte timer, and when the frame's end bit is read before the 550-byte timer times out, it stops reading from the FIFO, resets the 1500-byte timer with the timeout pulse of the 550-byte timer, and means for resetting all JKFFs in the sequencer circuit and restarting reading of the FIFO regardless of the end of the sequence of the sequencer circuit, while stopping operation of the 550-byte timer if the end-of-frame bit is not read before the 550-byte timer times out, and stopping reading from the FIFO if the end-of-frame bit is read before the 1500-byte timer times out, and resetting all JKFFs in the sequencer circuit and restarting reading of the FIFO regardless of the end of the sequence of the sequencer circuit.

[0027] An eighth aspect of the present invention is a communication system according to the first aspect of the present invention, The method of configuring the lower address memory for specifying the sending of a frame outside the ring of the frame add, drop and pass device is such that, when storing the lower address of the source MAC address of a frame, parallel data of the logical sum of the latch output signals of each bit of parallel data read from a plurality of cells at a position addressed by the lower part of the lower address of the source MAC address of the frame and each bit of parallel data obtained by decoding the upper part of the lower address of the source MAC address is stored at the address specified position of the SRAM, and bit 1 of the upper part of the lower address of the source MAC address is inserted and stored as bit 1, which means the lower address storage; When outputting a signal indicating whether the lower address of the source MAC address of the frame is stored or not, a logical sum output of all bits of parallel data obtained by logically multiplying the latch output signal of each bit of parallel data read from a plurality of cells at a position addressed by the lower part of the lower address of the source MAC address of the frame and the latch output signal of each bit of parallel data obtained by decoding the upper part of the lower address of the source MAC address is sent, and when the output is bit 1, it is determined that the lower address of the source MAC address of the frame is stored, and when the output is bit 0, it is determined that the lower address of the source MAC address of the frame is not stored, When deleting the lower address of the source MAC address of the frame, a latch signal of parallel data obtained by logically multiplying each bit of parallel data read from a plurality of cells at a position addressed by the lower part of the lower address of the source MAC address of the frame and the bit inversion bits of each bit of parallel data obtained by decoding the upper part of the lower address of the source MAC address is stored at the address specified position in the SRAM, thereby inserting and storing bit 0, which means no lower address storage, at the position of decoded bit 1, in the lower part of the lower address of the source MAC address. This is a method of configuring a lower address memory that specifies sending of frames outside the ring of a frame add, drop, and pass device.

[0028] A ninth aspect of the present invention is A method for transmitting packets from a mobile terminal to a destination server or exchange via a router connected to a vertex device on the ring network, the router having a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and a function of blocking the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router, the method comprising: inserting a plurality of frame add, drop and pass devices into a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; connecting a base station to the frame add, drop and pass devices; and transmitting packets from the mobile terminal to a vertex device on the ring network via the router as Ethernet (registered trademark) frames across the ring network and as IP packets between the router and the server or exchange, the method comprising: When a frame from the mobile terminal arrives at a device for adding, dropping, and passing frames in a ring network, regardless of whether the frame is a frame immediately after a change of the destination base station or not, or whether the frame is a communication initiation frame or not, a step of storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring, if the lower address of the source MAC address of the frame is not stored in a duplicate use lower address memory, and if the lower address of the source MAC address of the frame is not stored in a lower address memory that specifies sending the frame outside the ring, storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring, and attaching an unnecessary lower address erasure bit to the frame, and sending the frame with the unnecessary lower address erasure bit attached to the counterclockwise ring; otherwise, if the lower address of the source MAC address of the frame is stored in a duplicate use lower address memory, storing the lower address of the source MAC address of the frame in a duplicate use lower address memory, and if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring, and sending the frame to the counterclockwise ring without attaching an unnecessary lower address erasure bit to the frame; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, or / and if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and if an unnecessary lower address deletion bit is attached to the frame, delete the lower address from the lower address memory, delete the lower address from the duplicated use lower address memory, copy the frame, drop the copy frame from the ring and send it to the base station, and send the original frame of the copy frame to the counterclockwise ring, On the other hand, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, the lower address in the lower address memory that specifies sending the frame outside the ring is deleted, and the lower address is stored in a duplicated use lower address memory, otherwise, forwarding the frame on the counterclockwise ring as is, and directing it to the router via the vertex device; When a frame arrives at the apex device from the server via the router and is sent to the clockwise ring, and arrives at the frame add, drop, and pass-through device, a step of copying the frame and sending the copy frame forward in a clockwise direction on the ring if the lower address of the destination MAC address of the frame is stored in a duplicated use lower address memory, and sending the original frame of the copy frame out of the ring, sending the frame forward in a clockwise direction on the ring if the lower address of the destination MAC address of the frame is not stored in the duplicated use lower address memory and if the lower address of the destination MAC address of the frame is not stored in a lower address memory that specifies frame sending out of the ring, and sending the frame out of the ring if the lower address of the destination MAC address of the frame is stored in a lower address memory that specifies frame sending out of the ring; The method is characterized by the step of, when the base station receives a frame with an unnecessary lower address erasure bit attached from a frame adding, dropping and passing device connected to the base station, and if a MAC address with the same lower address as the lower address of the source MAC address of the frame is stored in the MAC address table, returning the frame to the frame adding, dropping and passing device connected to the base station, and storing the lower address of the source MAC address of the frame with the unnecessary lower address erasure bit attached in a duplicated use lower address memory.

[0029] A tenth aspect of the present invention is A method for transmitting packets from a mobile terminal to a destination server or exchange via a router connected to a vertex device on the ring network, the router having a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and a function of blocking the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router, the method comprising: inserting a plurality of frame add, drop and pass devices into a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; connecting a base station to the frame add, drop and pass devices; and transmitting packets from the mobile terminal to a vertex device on the ring network via the router as Ethernet (registered trademark) frames across the ring network and as IP packets between the router and the server or exchange, the method comprising: When a frame from the mobile terminal arrives at a device for adding, dropping, and passing frames in a ring network, regardless of whether the frame is a frame immediately after a change of the destination base station or not, or whether the frame is a communication initiation frame or not, a step of storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring, if the lower address of the source MAC address of the frame is not stored in a duplicate use lower address memory, and if the lower address of the source MAC address of the frame is not stored in a lower address memory that specifies sending the frame outside the ring, storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring, and attaching an unnecessary lower address erasure bit to the frame, and sending the frame with the unnecessary lower address erasure bit attached to the counterclockwise ring; otherwise, if the lower address of the source MAC address of the frame is stored in a duplicate use lower address memory, storing the lower address of the source MAC address of the frame in a duplicate use lower address memory, and if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring, and sending the frame to the counterclockwise ring without attaching an unnecessary lower address erasure bit to the frame; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, or / and if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and an unnecessary lower address deletion bit is attached to the frame, delete the lower address from the lower address memory and the duplicated use lower address memory, and send the frame to the counterclockwise ring; On the other hand, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, the lower address in the lower address memory that specifies sending the frame outside the ring is deleted, and the lower address is stored in a duplicated use lower address memory, otherwise, forwarding the frame on the counterclockwise ring as is, and directing it to the router via the vertex device; When a frame arrives at the apex device from the server via the router and is sent to the clockwise ring, and arrives at the frame add, drop, and pass-through device, if the lower address of the destination MAC address of the frame is stored in a duplicated use lower address memory, copying the frame and sending the copy frame forward in a clockwise direction on the ring and sending the original frame of the copy frame out of the ring; if the lower address of the destination MAC address of the frame is not stored in the duplicated use lower address memory and the lower address of the destination MAC address of the frame is not stored in a lower address memory that specifies sending the frame out of the ring, sending the frame forward in a clockwise direction on the ring; if the lower address of the destination MAC address of the frame is stored in a lower address memory that specifies sending the frame out of the ring, sending the frame out of the ring.

[0030] An eleventh aspect of the present invention is a method according to the tenth aspect of the present invention, comprising: the communicating mobile terminal or a base station to which the communicating mobile terminal belongs periodically sends a one-way route setting frame having the MAC address of the mobile terminal as a source MAC address to a frame add, drop and pass-through device connected to the base station, and when the frame arrives at the frame add, drop and pass-through device, if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies frame transmission outside the ring, the lower address of the source MAC address of the frame is stored in a lower address memory that specifies frame transmission outside the ring, and the frame is sent to the counterclockwise ring without adding an unnecessary lower address deletion bit to the frame; When the frame arrives at a frame add, drop, or pass-through device, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, delete the lower address of the source MAC address of the frame from the lower address memory that specifies sending the frame outside the ring, and store the lower address in a duplicated use lower address memory, otherwise, the method further comprises the step of forwarding the frame on the counterclockwise ring as is, toward the router via the vertex device.

[0031] A twelfth aspect of the present invention is a communication system according to either the ninth or tenth aspect of the present invention, When a location registration frame from the mobile terminal arrives at a device for adding, dropping, and passing frames, the method includes the steps of storing the lower address of the source MAC address of the frame in a location registration lower address memory, and directing the frame to the apex device via the counterclockwise ring, and when an incoming frame or communication initiation frame from the clockwise ring arrives at a device for adding, dropping, and passing frames, if the lower address of the destination MAC address of the frame is stored in the location registration lower address memory, copying the frame, sending the copy frame to the clockwise ring, and sending the original frame of the copy frame out of the ring. [Effects of the Invention]

[0032] As explained above, the present invention uses, instead of a MAC address table, a lower address memory and a duplicated-use lower address memory that specify frame transmission outside the ring, and when the lower address of the source MAC address of a frame arriving at a device (ring node device) for adding, dropping, and passing frames from the counterclockwise ring is stored in the lower address memory that specifies frame transmission outside the ring, if the frame is a frame that has just been sent to the destination base station, the lower address is simply erased from the lower address memory, and on the other hand, if the frame is not a frame that has just been sent to the destination base station, the lower address is erased from the lower address memory and the lower address of the source MAC address of the frame is stored in the duplicated-use lower address memory.This configuration makes operation simple and fast, and the ring node device (device for adding, dropping, and passing frames) can be implemented with just two memories, and the memory of the ring node device does not have a timer function for the stored MAC addresses, which has the effect of reducing power consumption and system costs. Furthermore, the present invention is a method for realizing handover of a mobile terminal within one MAC domain using a ring network using the above-mentioned memory, which has the effect of reducing power consumption and system costs and enabling high-speed communication. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a diagram illustrating an example of handover operation in a communication system between a mobile terminal (user equipment UE) that transfers MAC frames to a router connected to a vertex device of a ring network through a base station connected to the frame add, drop and pass device having a lower address memory and a duplicated use lower address memory that specify frame transmission outside the ring according to a first embodiment of the present invention, and a server connected to the ring network via the router, in a dual ring network in which a plurality of such devices are connected in a ring shape by an optical transmission path. [Figure 2] FIG. 2 is a diagram illustrating an example of handover operation in a communication system between a mobile terminal (user equipment UE) that transfers MAC frames to a router connected to a vertex device of a ring network through a base station connected to the frame add, drop and pass device having a lower address memory and a duplicated use lower address memory that specify frame transmission outside the ring according to a second embodiment of the present invention, and a server connected to the ring network via the router, in a dual ring network in which a plurality of such devices are connected in a ring shape by an optical transmission path. [Figure 3A] FIG. 2 is a diagram for explaining the operational flow of the device for adding, dropping, and passing frames according to the first and second embodiments of the present invention. [Figure 3B] FIG. 2 is a diagram for explaining the operational flow of the device for adding, dropping, and passing frames according to the first and second embodiments of the present invention. [Figure 3C1] FIG. 2 is a diagram for explaining the operational flow of the device for adding, dropping, and passing frames according to the first and second embodiments of the present invention. [Figure 3C2] FIG. 10 is a diagram for explaining another operational flow of the frame adding, dropping and passing device according to the first embodiment of the present invention. [Figure 4] FIG. 2 is a diagram for explaining an example of the configuration of a sequencer in a device for adding, dropping, and passing frames according to the first and second embodiments of the present invention. [Figure 5] FIG. 2 is a diagram for explaining an example of the configuration of a drive circuit for a sequencer in a frame adding, dropping and passing device according to the first and second embodiments of the present invention. [Figure 6] FIG. 10 is a diagram for explaining the configuration method of the lower address memory and the overlapping use lower address memory that specify frame transmission outside the ring used in the frame adding, dropping and passing devices of the first and second embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] A first embodiment of the present invention will be described with reference to Figure 1. This embodiment illustrates an example of handover operation of a TCP frame or voice frame of a mobile terminal (user equipment UE) using a ring network in a communication system in which a wireless base station (eNB) is connected to a frame adding, dropping, and passing device of a double ring network, in which multiple optical transmission paths connect the frame adding, dropping, and passing devices having a lower address memory that specifies frame transmission outside the ring and a duplicated use lower address memory. A mobile terminal (user equipment UE) under the base station transfers information as a MAC frame to a router connected to the ring network, and then transfers the information as an IP packet between the router and a server connected to the ring network. The frame can also be a UDP frame. The server is a mail receiving server or an Internet connection server.

[0035] In Figure 1, 1 is a transmission path for the counterclockwise ring, 2 is a transmission path for the clockwise ring, 5 is a vertex device, 6-1, 6-2, and 6-3 are devices for adding, dropping, and passing frames (ring node devices), 7 is a lower address memory that specifies frame transmission outside the ring, 10 is a duplicated use lower address memory (deletion lower address memory), 12 is an address table for router connection, 13-1, 13-2, and 13-3 are mobile terminals (user devices UE), 14-1, 14-2, and 14-3 are base stations (eNB / BS), 15 is movement of the mobile terminal, 20 is a server, 22 is a router, 26 is a switch, and 27 is a home memory. Also, (1) to (31) indicate the transmission order of frames in which MAC addresses are abbreviated using letter symbols (a1a2, a3a2 are not ASCII codes) transmitted through the ring indicated by the dotted line, and I0, I1, I2, and I3 are global IPv4 addresses dynamically assigned to terminals, or domestic IPv4 addresses of service providers, or IPv6 addresses. The lower address memory (7) and overlapping lower address memory (10), which specify frame transmission outside the ring, have all the aforementioned bits set to 0 at initial setting. The OE conversion circuit, EO conversion circuit, input buffer, and output buffer are not shown in the diagram.

[0036] The operation of FIG. 1 will be explained below. An example is shown in which a mobile terminal (user equipment UE of a portable terminal) 13-2 for game communication sends frame (1) Mn2a3a2(I0) (M indicates an Ethernet frame, n2 indicates the wireless MAC address of the base station 14-2, a3a2 indicates the upper MAC address a3 and the lower MAC address a2 which are the MAC addresses of the mobile terminal 13-2, and I0 indicates the IP address of the destination server 20) to the base station 14-2. Here, a2 is not an ASCII code. When the frame arrives at the device 6-2 for adding, dropping and passing frames from the terminal 13-2, the lower address of the source MAC address of the frame is not stored in the duplicated use lower address memory (delete lower address memory) (10) and the lower address of the source MAC address of the frame is not stored in the lower address memory (7-1) for specifying the frame transmission outside the ring, the lower address of the source MAC address of the frame is stored in the lower address memory (7) for specifying the frame transmission outside the ring, and An unnecessary lower address elimination bit is attached to the frame, and if the lower address of the source MAC address of the frame is stored in the duplicated use lower address memory (10) in a case other than the above, the lower address of the source MAC address of the frame is stored in the duplicated use lower address memory (10), and if the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, and the unnecessary lower address elimination bit is not attached to the frame, and the frame is sent to the counterclockwise ring.The figure shows a case where the lower address of the source MAC address of the frame is not stored in the duplicated use lower address memory (10) and is not stored in the lower address memory (7) that specifies sending the frame outside the ring, so the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, an unnecessary lower address deletion bit is attached to the frame, and the frame is sent to the counterclockwise ring. In the figure, for convenience, the lower address a2 is stored in the lower address memory (7) which specifies the frame transmission outside the ring.

[0037] The frame is sent to vertex device 5 on counterclockwise ring 1, and when the frame arrives at vertex device 5, the frame's destination MAC address r1r2 is stored in address table 12 for the router, so the frame is dropped from the ring as (5) Mr1r2a3a2(I0) toward router 22 outside the ring. When the frame arrives at router 22, the frame's source MAC address (a3a2) and IP address (I3) are stored in an ARP table (not shown), or the source MAC address (a3a2) is placed in the options field of the IP header, and the IP frame is forwarded as shown in the figure by (6) IP I3 I0 (IP indicates an IP address, where I3 indicates the IP address of mobile terminal 13-2 and I0 indicates the IP address of server 20, which is the destination), until it reaches server 20.

[0038] Next, an example will be shown in which mobile terminal 13-2 moves from base station 14-2 to base station 14-1. Just before the mobile terminal 13-2 accesses the destination base station 14-1, it sends a MAC address authentication frame transmission request frame (7)Mn2a3a2() (n2 is the wireless MAC address of the base station 14-2) of the mobile terminal 13-2 to the source base station 14-2, and the source base station 14-2 checks the MAC address a3a2 of the mobile terminal 13-2 in the MAC address table of the base station 14-2 (not shown) and sends a MAC address authentication IP packet (8), (9), (10)MB1B2(a3a2) (B1 is the NIC MAC address of the destination base station 14-1 selected from the phase modulation angle of the (beam) PSK, and a3a2 is contained in the option field of the IP header) or a MAC address authentication frame MB1a3a2 of the mobile terminal 13-2 to the destination base station 14-1. If an FBU packet is sent when moving between rings, a packet with MAC address B1a3a2 wrapped in CoA (the IPv6 prefix of the router in the new ring and the MAC address of the new base station) is sent as a MAC packet addressed to the NIC MAC address of the router in the old ring. In the case of movement within a ring, when the MAC address authentication IP packet arrives at frame add, drop, and passage device 6-1, the destination MAC address B1 of the frame is stored together with the destination port number in a MAC address table (not shown in the figure) that stores only base station NIC MAC addresses, so the frame is sent to the destination base station 14-1. When the MAC address authentication frame arrives at the destination base station 14-1, the MAC address of the mobile terminal (user equipment UE) 13-2 is stored in a MAC address table (not shown), a channel is set for the mobile terminal (user equipment UE) 13-2, and the frame Ma3a2n1() is sent to the mobile terminal (user equipment UE) 13-2.

[0039] When a frame (11)Mn1a3a2(I0) (n1 indicates the wireless MAC address of the base station 14-1, and a3a2 indicates the MAC address of the mobile terminal (user equipment) 13-2) from the mobile terminal 13-2 arrives at the base station 14-1, the frame is sent to the frame adding, dropping and passing device 6-1 as (12)Mr1r2a3a2(I0) immediately after the destination base station is changed when the frame adding, dropping and passing device 6-1 connected to the destination base station is a device that connects to a base station away from the router 22 on the counterclockwise ring 1. When the frame from the mobile terminal (user equipment) 13-2 reaches the frame add, drop and pass device (ring node device) 6-1, if the lower address of the source MAC address of the frame is not stored in the duplicated use lower address memory (10) and if the lower address of the source MAC address of the frame is not stored in the lower address memory (7) that specifies sending the frame outside the ring, the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, an unnecessary lower address deletion bit is attached to the frame, and the frame is sent to the counterclockwise ring. The frame is sent to the vertex device 5 having the address table 12 in which the NICMAC address of the upper ring network interface of the router 22 connected to the server 20 is stored via the current transmission line 1 of the counterclockwise ring.

[0040] When the frame is transferred by (13) Mr1r2a3a2 (I0) through counterclockwise ring 1 as shown in the figure and arrives at frame add, drop and pass-through device 6-2, it is determined that the frame is a frame immediately after the destination base station has been changed, an unnecessary lower address deletion bit has been added to the frame, and the lower address (e.g., the least significant bit to the 22nd bit) of the source MAC address of the frame is stored in the lower address memory (7) that specifies the frame's transmission outside the ring, so the lower address (e.g., the least significant bit to the 22nd bit) of the source MAC address of the frame is deleted from the lower address memory (7) that specifies the frame's transmission outside the ring. If the unnecessary lower address deletion bit is not attached to the frame, the lower address (e.g., the least significant bit through the 22nd bit) of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, so the lower address (e.g., the least significant bit through the 22nd bit) of the source MAC address of the frame is deleted from the lower address memory (7) that specifies sending the frame outside the ring, and the lower address of the source MAC address of the frame is stored in the overlapping use lower address memory (10). In the figure, a horizontal line is drawn through the lower address a2 in the lower address memory (7) that specifies sending the frame outside the ring, indicating that it has been deleted. When the frame being forwarded on counterclockwise ring 1 arrives at vertex device 5, the frame's destination MAC address r1r2 is stored in address table 12 for the router, so the frame is dropped from the ring as (16)Mr1r2a3a2(I0) and headed to router 22 outside the ring.

[0041] When the frame arrives at router 22, the source MAC address (a3a2) and IP address (I3) of the frame are stored in an ARP table (not shown), or the source MAC address (a3a2) is placed in the option field of the IP header, and the IP frame is forwarded as shown in the figure by (17)IPI3I0 (IP indicates an IP address, I3 indicates the IP address of the terminal connected to terminal device 13-2, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0042] Next, when a mobile terminal (tablet user device UE) 13-1 receiving a UDP download service sends frame (19) Mr1r2a1a2(I0) (M indicates an Ethernet frame, r1r2 indicates the NIC MAC address of the ring network interface of the router 22, a1a2 indicates the upper MAC address a1 and the lower MAC address a2, which are the MAC addresses of the terminal device 13-1, and I0 indicates the IP address of the destination server) via the base station 14-1 to the frame adding, dropping and passing device 6-1, when the frame from the mobile terminal arrives at the frame adding, dropping and passing device 6-1 in the ring network, since the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies frame sending outside the ring, the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies frame sending outside the ring, and the frame is sent to the counterclockwise ring without adding an unnecessary lower address deletion bit to the frame. The frame is sent to the vertex device 5 having the address table 12 in which the NICMAC address of the ring network interface of the router 22 connected to the server 20 is stored via the counterclockwise ring working transmission line 1 .

[0043] When the frame is forwarded by (20) Mr1r2a1a2(I0) on counterclockwise ring 1 as shown in the figure and arrives at frame add, drop, and pass-through device 6-2, the frame is sent directly to the counterclockwise ring because the lower addresses (e.g., the least significant bit through the 22nd bit) of the frame's source MAC address are not stored in lower address memory (7) that specifies frame transmission outside the ring. When the frame arrives at vertex device 5, where the frame's destination MAC address r1r2 is stored in address table 12 for router connections, the frame is dropped from the ring as (23) Mr1r2a1a2(I0) toward router 22 outside the ring. When the frame arrives at router 22, the source MAC address (a1a2) and IP address (I2) of the frame are stored in an ARP table (not shown), or the source MAC address (a1a2) is placed in the options field of the IP header, and the IP frame is forwarded as shown in the figure by (24)IPI2I0 (IP indicates an IP address, I2 indicates the IP address of mobile terminal (user equipment) 13-1, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0044] Next, when an IP packet (25) IPI0I2 (IP indicates an IP address, I2 is the IPv6 address or IPv4 address of terminal device 13-1, and I0 is the IP address of server 20) from server 20 arrives at router 22, if the IP packet is an IPv6 address, the destination MAC address paired with the destination IPv6 address I2 of the packet is copied from the MAC address portion of the destination IPv6 address, and a MAC frame (26) Ma1a2r1r2 (I2) using this as the MAC header address of the MAC frame is sent to vertex 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 is used as the destination MAC header address of the MAC frame, or the MAC address a1a2 in the option field of the IP header is used as the destination MAC address, and a MAC frame (26)Ma1a2r1r2(I2) using the NIC MAC address r1r2 of the ring network interface of the router 22 as the source MAC address is sent to the vertex device 5 of the ring network. When the MAC frame (26) Ma1a2r1r2 (I2) arrives at the vertex device 5, the frame is sent to the clockwise ring 2 because the source MAC address of the frame is stored in the address table 12 for router connection.

[0045] When frame (28) Ma1a2r1r2 (I2) is transferred through clockwise ring 2 and arrives at frame add, drop and pass-through device 6-2, if the lower address of the frame's destination MAC address is stored in duplicated use lower address memory (10), the frame is copied and the copy frame is sent forward on the clockwise ring, and the original copy frame is sent out of the ring. However, in the figure, the lower address of the frame's destination MAC address is not stored in duplicated use lower address memory (10), and the lower address of the frame's destination MAC address is not stored in lower address memory (7) that specifies sending the frame out of the ring, so the frame is sent forward on the clockwise ring.

[0046] When the frame (29) Ma1a2r1r2 (I2) is transferred through the clockwise ring 2 and arrives at the frame add, drop and pass-through device 6-1, if the lower address of the frame's destination MAC address is stored in the duplicated use lower address memory (10), the frame is copied and the copy frame is sent to the front of the clockwise ring, and the original copy frame is sent out of the ring. If the lower address of the frame's destination MAC address is not stored in the duplicated use lower address memory (10) and the lower address of the frame's destination MAC address is not stored in the lower address memory (7-1) that specifies frame sending out of the ring, the frame is sent to the front of the clockwise ring. However, in the figure, the lower address of the frame's destination MAC address is stored in the lower address memory that specifies frame sending out of the ring, so the frame is sent out of the ring as (30) Ma1a2r1r2 (I2). Since the destination MAC address a1a2 of the frame sent to the base station 14-1 outside the ring is stored in a MAC address table not shown in the figure, the frame (31)Ma1a2n1(I2) (n1 is the wireless MAC address of the base station 14-1) reaches the mobile terminal (user equipment UE) 13-1.

[0047] Next, a second embodiment of the present invention will be described with reference to Figure 2. This embodiment is an example of handover operation of TCP frames or voice frames of a mobile terminal (user equipment UE) using a ring network in a communication system in which a wireless base station (eNB) is connected to frame add, drop, and pass-through devices in a dual ring network, in which multiple optical transmission paths connect the frame add, drop, and pass-through devices having a lower address memory that specifies frame transmission outside the ring and a duplicated use lower address memory. A mobile terminal (user equipment UE) under the base station transfers information as a MAC frame to a router connected to the ring network, and then transfers the information as an IP packet between the router and a server connected to the ring network. The frame can also be UDP. The server is a mail receiving server or an Internet connection server. This embodiment differs from Figure 1 in that in Figure 1 the mobile terminal moves to the destination base station in a direction away from the router on a counterclockwise ring, whereas in Figure 2 the mobile terminal moves to the destination base station in a direction towards the router on a counterclockwise ring.

[0048] In Figure 2, the circuits with the numbers indicated on the figure operate in the same way as in Figure 1.

[0049] The operation of FIG. 2 will be explained below. An example is shown in which a mobile terminal (user equipment UE, a portable terminal) 13-2 for game communication sends frame (1) Mn1a3a2(I0) (M indicates an Ethernet frame, n1 indicates the wireless MAC address of the base station 14-1, a3a2 indicates the upper MAC address a3 and the lower MAC address a2, which are the MAC addresses of the mobile terminal (user equipment UE) 13-2, and I0 indicates the IP address of the destination server 20) to the base station 14-1. Here, a2 is not an ASCII code. The above Ethernet frame (2) Mr1r2a3a2(I0)( When the frame arrives at the add, drop and pass device 6-1 from the terminal 13-2, the frame is not a location registration frame, so if the lower address of the source MAC address of the frame is not stored in the duplicated use lower address memory (10) and if the lower address of the source MAC address of the frame is not stored in the lower address memory (7) that specifies sending the frame outside the ring, the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, and if the lower address of the source MAC address of the frame is not stored in the lower address memory (7) that specifies sending the frame outside the ring, A required lower address erasure bit is attached, and if the lower address of the source MAC address of the frame is stored in the duplicated use lower address memory (10) in a case other than the above, the lower address of the source MAC address of the frame is stored in the duplicated use lower address memory (10), and if the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies frame transmission outside the ring, the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies frame transmission outside the ring, and the unnecessary lower address erasure bit is not attached to the frame, and the frame is transmitted to the counterclockwise ring.The figure shows a case where the lower address of the source MAC address of the frame is not stored in the duplicated use lower address memory (10) and is not stored in the lower address memory (7) that specifies sending the frame outside the ring, so the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, an unnecessary lower address deletion bit is attached to the frame, and the frame is sent to the counterclockwise ring. The figure shows a case where the lower address a2 (for example, the least significant bit to the 22nd bit) of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring.

[0050] The frame is sent to vertex device 5 on counterclockwise ring 1, and when the frame arrives at vertex device 5, the frame's destination MAC address r1r2 is stored in address table 12 for the router, so the frame is dropped from the ring as (6) Mr1r2a3a2(I0) toward router 22 outside the ring. When the frame arrives at router 22, the frame's source MAC address (a3a2) and IP address (I3) are stored in an ARP table (not shown), or the source MAC address (a3a2) is placed in the options field of the IP header, and the IP frame is forwarded as shown in the figure by (7) IP13I0 (IP indicates an IP address, I3 indicates the IP address of mobile terminal (user equipment) 13-2, and I0 indicates the IP address of the destination server 20), until it reaches server 20.

[0051] Next, an example will be shown in which the mobile terminal (user equipment UE) 13-2 moves from the base station 14-1 to the base station 14-2. Just before the mobile terminal (user equipment UE) 13-2 accesses the destination base station 14-2, it sends a MAC address authentication frame transmission request frame (8)Mn1a3a2() (n1 is the wireless MAC address of the base station 14-1) of the mobile terminal (user equipment UE) 13-2 to the source base station 14-1, and the source base station 14-1 checks the MAC address a3a2 of the mobile terminal (user equipment UE) 13-2 in the MAC address table of the base station 14-1 (not shown) and sends a MAC address authentication IP packet (9), (10), (11)MB2B1(a3a2) (B2 is the NIC MAC address of the destination base station 14-2, and a3a2 is stored in the option field of the IP header) or a MAC address authentication frame MB2a3a2 of the mobile terminal (user equipment UE) 13-2 to the destination base station 14-2. If an FBU packet is sent when moving between rings, the packet is wrapped with MAC address B2a3a2 in CoA (the IPv6 prefix of the router in the new ring and the MAC address of the new base station) and sent as a MAC packet addressed to the NICMAC address of the router in the old ring. During movement within the ring, if the MAC address of terminal 13-1 with MAC address a1a2, which is the same lower address as the lower address a2 of mobile terminal 13-2, is stored in the MAC address table (not shown) of base station 14-1, then just as in the case where the lower address (e.g., from the least significant bit to the 22nd bit) of the MAC address of said mobile terminal in the frame add, drop and pass through device connected to the source base station or an intermediate base station is stored in the overlapping use lower address memory (10), the lower address a2 (e.g., from the least significant bit to the 22nd bit) of the MAC address a3a2 of said mobile terminal 13-2 is stored in the overlapping use lower address memory (10) of frame add, drop and pass through device 6-2 connected to the destination base station; however, at this point, the frame from mobile terminal 13-1 has not yet reached frame add, drop and pass through device 6-1, so the above operation is not performed. When the MAC address authentication IP packet arrives at frame add, drop and pass device 6-2, the frame's destination MAC address B2 is stored together with the destination port number in a MAC address table (not shown in the figure) that stores only base station NIC MAC addresses, so the frame is sent to the destination base station 14-2. When the MAC address authentication frame arrives at the destination base station 14-2, the MAC address of the mobile terminal (user equipment UE) 13-2 is stored in a MAC address table (not shown), a channel is set to the mobile terminal (user equipment UE) 13-2, and the frame Ma3a2n2() is sent to the mobile terminal (user equipment UE) 13-2.

[0052] When a frame (12)Mn2a3a2(I0) (n2 indicates the wireless MAC address of the base station 14-2, and a3a2 indicates the MAC address of the mobile terminal (user equipment) 13-2) from the mobile terminal (user equipment UE) 13-2 arrives at the base station 14-2, the frame is sent to the frame adding, dropping and passing device 6-2 as (13)Mr1r2a3a2(I0) immediately after the destination base station is changed when the frame adding, dropping and passing device 6-2 connected to the destination base station is a device that connects to a base station approaching the router 22 on the counterclockwise ring 1. When the frame from the mobile terminal (user equipment) 13-2 reaches the frame add, drop and pass device 6-2, the frame is a frame immediately after the destination base station has been changed, but the frame is not a location registration frame, so if the lower address of the source MAC address of the frame is not stored in the duplicated use lower address memory (10) and the lower address of the source MAC address of the frame is not stored in the lower address memory (7) that specifies frame transmission outside the ring, the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies frame transmission outside the ring, and an unnecessary lower address deletion bit is attached to the frame, and the frame is sent to the counterclockwise ring. The frame (14) Mn2a3a2 (I0) is sent via the counterclockwise ring working transmission line 1 to the vertex device 5 having the address table 12 in which the NICMAC address of the ring network interface of the router 22 is stored.

[0053] When the frame being forwarded on counterclockwise ring 1 arrives at vertex device 5, the frame's destination MAC address r1r2 is stored in address table 12 for the router, so the frame is dropped from the ring as (16)Mr1r2a3a2(I0) and headed to router 22, destined for server 20 outside the ring.

[0054] When the frame arrives at router 22, the source MAC address (a3a2) and IP address (I3) of the frame are stored in an ARP table (not shown), or the source MAC address (a3a2) is placed in the option field of the IP header, and the IP frame is forwarded as shown in the figure by (17)IPI3I0 (IP indicates an IP address, I3 indicates the IP address of the terminal connected to terminal device 13-2, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0055] Next, when the mobile terminal (tablet user equipment UE) 13-1 receiving the UDP one-way download service sends frame (19) Mr1r2a1a2(I0) (M indicates an Ethernet frame, r1r2 indicates the NIC MAC address of the ring network interface of the router 22, a1a2 indicates the upper MAC address a1 and the lower MAC address a2 which are the MAC addresses of the terminal equipment 13-1, and I0 indicates the IP address of the destination server) to the frame add, drop and pass-through device 6-1 via the base station 14-1, at this point, the lower address a2 of the MAC address of the mobile terminal 13-2 has been deleted from the lower address memory (7) which specifies frame transmission outside the ring, so the lower address of the source MAC address of the frame is not stored in the duplicated use lower address memory (10). ), and the lower address of the source MAC address of the frame is not stored in the lower address memory (7) that specifies sending the frame outside the ring, so the lower address of the source MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, and an unnecessary lower address deletion bit is attached to the frame, and the frame is sent to the vertex device 5 that has the address table 12 that stores the NICMAC address of the ring network interface of the router 22 that is connected to the server 20 via the current transmission line 1 of the counterclockwise ring.

[0056] When the frame is transferred by (20) Mr1r2a1a2 (I0) through counterclockwise ring 1 as shown in the figure and arrives at frame add, drop, and pass-through device 6-2, the lower address of the source MAC address of the frame is stored in lower address memory (7) that specifies frame transmission outside the ring, and the unnecessary lower address erase bit is attached to the frame, so the lower address a2 in lower address memory (7) is erased, the frame is copied, and the copied frame is sent to base station 14-2 outside the ring, and the original copy frame is sent to the counterclockwise ring. Since the lower address a3a2, which is the same lower address as the lower address a2 of the source MAC address of the frame with the unnecessary lower address erase bit that arrived at base station 14-2, is stored in a MAC address table (not shown), the frame with the stored MAC address or the frame with the unnecessary lower address erase bit is sent to frame add, drop, and pass-through device 6-2, and the lower address a2 of the MAC address is stored in the duplicated use lower address memory. In the figure, a horizontal line is drawn through the lower address a2 in the lower address memory (7) to indicate that it has been erased, and the lower address a2 is stored in the overlapping lower address memory (10). The frame (20) Mr1r2a1a2 (I0) is sent to the counterclockwise ring. When the frame arrives at router 22, the source MAC address (a1a2) and IP address (I2) of the frame are stored in an ARP table (not shown), or the source MAC address (a1a2) is entered into the options field of the IP header, and the IP frame is forwarded as shown in the figure by (24) IPI2I0 (IP indicates an IP address, I2 indicates the IP address of mobile terminal (user equipment) 13-1, and I0 indicates the IP address of the destination server 20), until it reaches server 20.

[0057] Next, when an IP packet (25) IPI0I2 (IP indicates an IP address, I2 is the IPv6 address or IPv4 address of mobile terminal 13-1, and I0 is the IP address of server 20) from server 20 arrives at router 22, if the IP packet is an IPv6 address, the destination MAC address paired with the destination IPv6 address I2 of the packet is copied from the MAC address portion of the destination IPv6 address, and a MAC frame (26) Ma1a2r1r2 (I2) using this as the MAC header address of the MAC frame is sent to vertex 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 is used as the destination MAC header address of the MAC frame, or the MAC address a1a2 in the option field of the IP header is used as the destination MAC address, and a MAC frame (26)Ma1a2r1r2(I2) using the NIC MAC address r1r2 of the ring network interface of the router 22 as the source MAC address is sent to the vertex device 5 of the ring network.

[0058] When the MAC frame (26) Ma1a2r1r2 (I2) arrives at the vertex device 5, the frame is sent to the clockwise ring 2 because the source MAC address of the frame is stored in the address table 12 for router connection.

[0059] When frame (28)Ma1a2r1r2(I2) is transferred along clockwise ring 2 and arrives at frame add, drop, and pass-through device 6-2, the lower address a2 (e.g., the least significant bit through the 22nd bit) of the frame's destination MAC address a1a2 is stored in duplicate-usage lower address memory 10, so the frame is copied and the copy is sent to the clockwise ring as (29)Ma1a2r1r2(I2), and the original copy is sent to base station 14-2 outside the ring as (30)Ma1a2r1r2(I2). Since the destination MAC address a1a2 of the frame arriving at base station 14-2 is not stored in the MAC address table (not shown), the frame is discarded.

[0060] When the frame (29) Ma1a2r1r2 (I2) is transferred through the clockwise ring (2) and arrives at the frame add, drop and pass-through device 6-1, if the lower address of the frame's destination MAC address is stored in the duplicated use lower address memory (10), the frame is copied and the copy frame is sent to the front of the clockwise ring, and the original copy frame is sent out of the ring. On the other hand, if the lower address of the frame's destination MAC address is not stored in the duplicated use lower address memory (10) and the lower address of the frame's destination MAC address is not stored in the lower address memory (7-1) that specifies frame sending out of the ring, the frame is sent to the front of the clockwise ring. However, in the figure, the lower address of the frame's destination MAC address is stored in the lower address memory that specifies frame sending out of the ring, so the frame is sent out of the ring as (31) Ma1a2r1r2 (I2). Since the destination MAC address a1a2 of the frame sent to the base station 14-1 outside the ring is stored in a MAC address table (not shown), the frame (32)Ma1a2n1(I2) reaches the mobile terminal (user equipment UE) 13-1. It is assumed that the MAC address a3a2 in the MAC address table (not shown) of the base station 14-1 has already been deleted.

[0061] In Figures 1 and 2, when a mobile terminal moves to a destination base station on the left-handed ring that is away from the router, the lower addresses (e.g., the least significant bit to the 22nd bit) of the MAC address of the mobile terminal in the device that adds, drops, and passes frames connected to the source base station are erased from the lower address memory (7) that specifies sending frames outside the ring, but when a mobile terminal moves to a destination base station on the left-handed ring that is closer to the router, the lower addresses (e.g., the least significant bit to the 22nd bit) of the MAC address of the mobile terminal in the device that adds, drops, and passes frames connected to the source base station are not erased from the lower address memory (7) that specifies sending frames outside the ring, but remain as they are, but this is not a problem because they are erased by a frame that has an unnecessary lower address erasure bit.

[0062] When a location registration frame from the mobile terminal arrives at a device for adding, dropping, or passing through a frame, the lower address of the source MAC address of the frame is stored in a location registration lower address memory, and the frame is sent through the counterclockwise ring to the apex device; when an incoming frame or communication initiation frame from the clockwise ring arrives at a device for adding, dropping, or passing through a frame, if the lower address of the destination MAC address of the frame is stored in the location registration lower address memory, the frame is copied, the copied frame is sent to the clockwise ring, and the original frame of the copied frame is sent out of the ring; or when a location registration frame from the mobile terminal arrives at a device for adding, dropping, or passing through a frame, the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame out of the ring, and the frame is sent to the apex device in the same way as other frames, and incoming frames from the clockwise ring are also forwarded in the same way as other frames.

[0063] Next, the flow operations of frame add, drop and pass devices 6-1, 6-2, 6-3 will be explained using the operation flow diagrams of Figures 3A, 3B, and 3C1. Figure 3C2 shows the operation of claim 11. In Figures 3A, 3B, 3C1, and 3C2, the lower address memory (7) that specifies frame transmission outside the ring is described as frame drop lower address memory. (b1), (b2), (b3), (c1), (c2), (c3), etc. within the flow symbols that describe the operation of the flow diagram, and B1, B2, B3, C1, C2, etc. written outside the flow symbols, are entered in a sequencer using JK flip-flops as shown in Figure 4, and (b1), (b2), (b3), (c1), (c2), (c3), etc. indicate the positions within the sequencer that perform the corresponding operations described in Figure 3 in sequence diagram 4, and B1, B2, B3, C1, C2, etc. are written in correspondence with Figure 3 as input signals to the AND gates in sequence diagram 4.

[0064] 3A, 100 determines whether a frame has been received from the clockwise ring (2) (b1), and if YES (B1), 101 determines whether the destination MAC lower address of the received frame is stored in the duplicated use lower address memory (10) (b2), and if YES (B2), 102 copies the received frame, sends the copied frame to the clockwise ring (2), and drops the original frame of the copied frame from the ring and sends it toward the base station (b3). If NO (F1) at 100, the process transitions to (F1) at 106. If NO (C1) at 101, 103 determines whether the destination MAC lower address of the received frame is stored in the lower address memory (7) that specifies frame transmission outside the ring (c2), and if YES (C2), 104 drops the received frame from the ring and sends it toward the base station (c3). If the answer is NO in 103 (D1), the received frame in 105 is sent to the clockwise ring (2) (d2). The time-out in 130 written under the above operations (b3), (c3), and (d2) causes a transition to 100 (a). This time-out is the time-out of the counter that generates the reset signal (a) for the sequencer operation written in Figure 5.

[0065] 3B, it is determined (f2) whether the frame 106 has been received from the ADD line (base station), and if the result is YES (F2), it is determined (f3) whether the source MAC lower address of the received frame 107 is not stored in the lower address memory (7) that specifies frame transmission outside the ring, and whether the source MAC lower address of the received frame is not stored in the duplicated use lower address memory (10), and if the result is YES (F3), it stores the source MAC lower address of the received frame 108 in the lower address memory (7) that specifies frame transmission outside the ring, and attaches an unnecessary lower address deletion bit to the received frame (f4), and the output is (F4), and the received frame 109 is sent to the counterclockwise ring (1) (f5). If the result is NO at 106 (I1), it transitions to (I1) at 115. If the answer is NO at 107 (G1), it is determined whether the source lower MAC address of the received frame at 110 is stored in the duplicated use lower address memory (10) (g2), and if the answer is YES (H3), the source lower MAC address of the received frame at 113 is stored in the duplicated use lower address memory (10) (h3), the output is (H4), the received frame at 114 is sent to the counterclockwise ring (1) (h4), and the process returns to 100(a) at 130. If the answer is NO at 110 (G2), the source lower MAC address of the received frame at 111 is stored in the lower address memory (7) that specifies frame sending outside the ring (g3), the output is (G3), the received frame at 112 is sent to the counterclockwise ring (1) (g5), and the process returns to 100(a) at 130.

[0066] Next, in 115 of Figure 3C1, it is determined whether a frame has been received from the counterclockwise ring (1) (i2), and if the answer is YES (I2), it is determined whether the source MAC lower address of the received frame (116) is stored in the lower address (7) that specifies frame transmission outside the ring, and / or whether the source MAC lower address of the received frame is stored in the duplicated use lower address memory (10) and whether an unnecessary lower address deletion bit is attached to the received frame (i3), and if the answer is YES (I3), it erases the source MAC lower address of the received frame (117) from the lower address (7) that specifies frame transmission outside the ring and from the duplicated use lower address memory (10) (i4), copies the received frame (118), drops the copied frame from the ring, and sends the original frame of the copied frame to the counterclockwise ring (1) (i5), and returns to (a) of 130. If the answer is NO (a) at 115, it transitions to (a) of 100. If the answer is NO at 116 (J1), it is determined whether the source lower MAC address of the received frame at 119 is stored in the lower address memory (7) that specifies sending the frame outside the ring, and whether an unnecessary lower address deletion bit is attached to the received frame (j2), and if the answer is YES (J2), the source lower MAC address of the received frame at 120 is deleted from the lower address memory (7) that specifies sending the frame outside the ring and stored in the overlapping use lower address memory (10) (j3), and the received frame at 121 is sent to the counterclockwise ring (1) (j4), and at 130, the process returns to (a) of 100. If the answer is NO at 119 (K1), the process transitions to 121.

[0067] 3C2, at 115, it is determined whether a frame has been received from the counterclockwise ring (1) (i2), and if YES (I2), it is determined whether the source MAC lower address of the received frame at 116 is stored in the lower address (7) that specifies frame transmission outside the ring, and / or the source MAC lower address of the received frame is stored in the duplicated use lower address memory (10), and whether an unnecessary lower address deletion bit is attached to the received frame (i3), and if YES (I3), the source MAC lower address of the received frame at 217 is deleted from the lower address (7) that specifies frame transmission outside the ring and from the duplicated use lower address memory (10) (i4), and the received frame at 218 is sent to the counterclockwise ring (1) (i5), and at 130, it returns to 100(a). If NO (a) at 115, it transitions to 100(a). If the answer is NO at 116 (J1), it is determined whether the source lower MAC address of the received frame at 119 is stored in the lower address memory (7) that specifies sending the frame outside the ring, and whether an unnecessary lower address deletion bit is attached to the received frame (j2), and if the answer is YES (J2), the source lower MAC address of the received frame at 120 is deleted from the lower address memory (7) that specifies sending the frame outside the ring and stored in the overlapping use lower address memory (10) (j3), and the received frame at 121 is sent to the counterclockwise ring (1) (j4), and at 130, the process returns to (a) of 100. If the answer is NO at 119 (K1), the process transitions to 121. FIG. 3C2, in combination with FIGS. 3A and 3B, can be applied to the case of UDP transmission using TCP or one-way path setting frames to perform the methods of claims 10 and 11.

[0068] Next, the operation of part of the sequence diagram in Figure 3A will be explained using Figure 4. 450 is a JKFF, 451 is an AND circuit, and 400 is a delay circuit. All JKFFs are reset by the timeout signal (a) of 130. When a timer-out signal (a) is input to JKFFs 450-1 and 400, the Q bars of JKFFs 450-1, 450-2, and 450-3 become 1, the output of 451-1 becomes 1, and with the J input of 450-1 at 1 and the K input at 0, a system clock c is input, so the output of JKFF 450-1 becomes 1. After that, both the J and K inputs of JKFF 450-1 become 0, so the output remains at 1. The output 1 of this causes the operation (b1) of 452-2 to be performed, its YES output signal B1 being input to AND circuit 451-2, and output 1 being input to J of JKFF 450-2, so the output of JKFF 450-2 becomes 1, the output 1 of this causes the operation (b2) of 452-3 to be performed, its output signal B2 being input to AND circuit 451-3, and output 1 being input to J of JKFF 450-3, so the output of JKFF 450-3 becomes 1, and the output 1 of this causes the operation (b3) to be performed. F1 is the negated output of (b1), and C1 is the negated output of (b2). The AND circuit 451-4 receives the Q-bar output 1 of JKFF 450-5 and the 1 of C1, so the output of JKFF 450-4 becomes 1, and the operation of (c2) of 453-2 is performed with the output 1, the output signal C2 is input to AND circuit 451-5, and the output 1 is input to J of JKFF 450-5, and the operation of (c3) is performed with the output 1. D1 is the negated output of (c2). Although other branch sequencer diagrams are not shown in Figure 4, they will have the same form as above.

[0069] Next, a sequencer driver circuit for a device that adds, drops, and passes packets when loopback is performed on both sides of a ring network failure without steering when a failure occurs is described with reference to Figure 5. A clockwise ring receive packet is input to input FIFO 500. FIFO 500 outputs 8-bit parallel data 520, packet start bit 521, and packet end bit 522. FIFO 500 operates on an 8-bit parallel clock, and signal 522, which indicates the end bit of the packet read from FIFO 500, serves as a stop signal for the read clock of FIFO 500. Signal 521 of the first bit of the packet in FIFO 500 serves as start signals 510 and 511 for the 550-byte timer and the 1512-byte timer. Signal 521 of the first bit of the packet in FIFO 500 also serves as a set signal for latch circuits 503-1 and 503-3. If the end-of-packet bit signal 522 is input to AND circuit 504-1 before the 550-byte timer times out and latch circuit 503-2 is set at the output, the timeout signal of the 550-byte timer resets latch circuits 503-1 and 503-3 via AND circuit 504-2, and the timeout signal of the 1512-byte timer stops at AND circuit 504-3. On the other hand, if the end-of-packet bit signal 522 does not set latch circuit 503-2 before the 550-byte timer times out, the timeout signal of the 550-byte timer is stopped at AND circuit 504-2 and does not reset latch circuit 503-2, so the timeout signal 412 of the 1512-byte timer passes through AND circuit 504-3 and is input to 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 becomes a reset signal (a) for all JKFFs in the sequencer circuit, and also becomes a read restart signal for the FIFO 500. If the frame storage capacity of the FIFO exceeds a certain value, approximately 550 bytes of frames are discarded on the input side of the FIFO.

[0070] The configuration method of the lower address memory that specifies the frame add, drop, and pass device's frame transmission outside the ring in the first and second embodiments is disclosed in Chapter 3, "Address Memory Method Using Data Storage Area as Address," on page 44 of "Proposal of a MAC-Operated Tree-Shaped Ring Network for Bidirectionally Forwarding Packets Having Only the Source Terminal Address," in the IEICE Technical Report CS2013-28-CS2013-40, Communication Methods, Vol. 113, No. 207, September 12-13, 2013, and in Chapter 3, "Packet's Add, Drop, and Pass Equipment," in Session 10, Part 5, of ICETC2022, available at https: / / www.ieice.org / publications / proceedings. It is also disclosed in JP 2019-097045 (Address Memory Method). The overlapping lower address memory has a similar configuration. This method can also be configured as shown in the principle diagram in Figure 6. In Figure 6, the output of 32 bits of SRAM output data (70) is latched by a latch circuit (55), and the latch output signal, a bit 0 write signal (59), and the output (60) of the lower 5 bits of the lower MAC address (58) decoded by a decoder (53) are input to a logic circuit (54), which sends the signal to the outside and writes it to the SRAM from the CPU.

[0071] Although the present invention has been described using an example in which SRAM is used, it can also be realized using MRAM. [Explanation of symbols]

[0072] 1 Counterclockwise ring transmission line 2 Clockwise ring transmission line 5 Vertex device 6-1, 6-2, 6-3 Frame Add, Drop and Pass Devices 7 Lower address memory that specifies packet transmission outside the ring 10 Duplicate use lower address memory (erase lower address memory) 13-1, 13-2, 13-3 Mobile terminals 14-1,14-2,14-3 Base station (eNB / BS) 15 Mobile Device Movement 20 servers 22 Router

Claims

1. A communication system in which a plurality of frame add, drop and pass devices are inserted into a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1, base stations are connected to the frame add, drop and pass devices, and a mobile terminal under the control of the base station communicates with a destination server or exchange via the router connected to the apex device on the ring network, the router having the function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and the function of blocking the passage of packets having the NIC MAC address of the ring network interface of the router as a source MAC address, and in which packets from the mobile terminal travel between the router and the server or exchange across the ring network as Ethernet (registered trademark) frames, and between the router and the server or exchange as IP packets, When a frame from the mobile terminal arrives at a device for adding, dropping, and passing frames in a ring network, regardless of whether the frame is a frame immediately after a change of the destination base station or not, or whether the frame is a communication initiation frame or not, means for storing the lower address of the source MAC address of the frame in a lower address memory specifying frame transmission outside the ring when the lower address of the source MAC address of the frame is not stored in a deletion lower address memory (hereinafter referred to as a duplicated use lower address memory) and when the lower address of the source MAC address of the frame is not stored in a lower address memory specifying frame transmission outside the ring, and attaching an unnecessary lower address deletion bit to the frame, and sending the frame with the unnecessary lower address deletion bit attached to the counterclockwise ring; means for storing the lower address of the source MAC address of the frame in a duplicated use lower address memory when the lower address of the source MAC address of the frame is stored in a lower address memory specifying frame transmission outside the ring, and sending the frame to the counterclockwise ring without attaching an unnecessary lower address deletion bit to the frame; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, or / and if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and if an unnecessary lower address deletion bit is attached to the frame, delete the lower address from the lower address memory, delete the lower address from the duplicated use lower address memory, copy the frame, drop the copy frame from the ring and send it to the base station, and send the original frame of the copy frame to the counterclockwise ring, On the other hand, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, delete the lower address from the lower address memory that specifies sending the frame outside the ring, and store the lower address in a duplicated use lower address memory, means for transferring the frame on the counterclockwise ring as is, other than the above, and directing the frame to the router via the vertex device; When a frame arrives at the apex device from the server via the router and is sent to the clockwise ring, and arrives at the frame add, drop, and pass-through device, means for copying the frame and sending the copy frame forward in a clockwise direction on the ring when the lower address of the destination MAC address of the frame is stored in a duplicated use lower address memory, and sending the original frame of the copy frame out of the ring; means for sending the frame forward in a clockwise direction on the ring when the lower address of the destination MAC address of the frame is not stored in the duplicated use lower address memory and when the lower address of the destination MAC address of the frame is not stored in a lower address memory that specifies frame sending out of the ring; and means for sending the frame out of the ring when the lower address of the destination MAC address of the frame is stored in a lower address memory that specifies frame sending out of the ring; A communication system characterized in that the base station is provided with means for returning a frame to the device for adding, dropping and passing frames connected to the base station when the base station receives a frame with an unnecessary lower address elimination bit attached thereto, and if a MAC address with the same lower address as the lower address of the source MAC address of the frame is stored in the MAC address table, returning the frame to the device for adding, dropping and passing frames connected to the base station, and storing the lower address of the source MAC address of the frame with the unnecessary lower address elimination bit attached thereto in a duplicate use lower address memory.

2. Immediately before the mobile terminal accesses a destination base station approaching the router on the counterclockwise ring, it sends a MAC address authentication packet transmission request frame to the source base station of the mobile terminal, and the source base station checks the MAC address of the mobile terminal in a MAC address table and sends the MAC address authentication packet of the mobile terminal to the destination base station. When the MAC address authentication packet arrives at a device for adding, dropping, and passing frames connected to the destination base station, if the lower address of the MAC address of the mobile terminal is stored in a duplicated use lower address memory, or / and, 2. The communication system according to claim 1, further comprising means for storing the lower address of the MAC address of the mobile terminal in the duplicated use lower address memory when the lower address of the MAC address of the mobile terminal is stored in the duplicated use lower address memory of a frame adding, dropping and passing device, and / or when another MAC address with the same lower address as the lower address of the MAC address of the mobile terminal is stored in the MAC address table of the source base station, and when the MAC address authentication packet arrives at a frame adding, dropping and passing device connected to the destination base station.

3. 2. The communication system according to claim 1, further comprising means for, when a location registration frame from the mobile terminal arrives at a device for adding, dropping, or passing frames, storing a lower address of the source MAC address of the frame in a location registration lower address memory, and directing the frame to a vertex device via a through-hole on the counterclockwise ring, and when an incoming frame or a communication initiation frame from the clockwise ring arrives at a device for adding, dropping, or passing frames, if the lower address of the destination MAC address of the frame is stored in the location registration lower address memory, copying the frame, sending the copy frame to the clockwise ring, and sending the original frame of the copy frame out of the ring.

4. 2. The communication system according to claim 1, wherein said frame adding, dropping and passing device does not have a timer function for storing addresses in memory.

5. 2. The communication system of claim 1, wherein the frames are Ethernet frames carrying TCP packets or download unidirectional UDP packets.

6. A frame add, drop and pass device, comprising: When a frame from a mobile terminal arrives at the add, drop, or pass-through device of the frame, means for storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring when the lower address of the source MAC address of the frame is not stored in a duplicate use lower address memory and when the lower address of the source MAC address of the frame is not stored in a lower address memory that specifies sending the frame outside the ring, and attaching an unnecessary lower address erasure bit to the frame and sending the frame with the unnecessary lower address erasure bit attached to the counterclockwise ring; means for storing the lower address of the source MAC address of the frame in a duplicate use lower address memory when the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and sending the frame to the counterclockwise ring without attaching an unnecessary lower address erasure bit to the frame; means for storing the lower address of the source MAC address of a frame in a duplicated use lower address memory and discarding the frame when the frame to which an unnecessary lower address deletion bit is added from a base station arrives at an add, drop or pass-through device of the frame; When a frame from the counterclockwise ring arrives at the add, drop, or pass-through device for that frame, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, or / and if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and if an unnecessary lower address deletion bit is attached to the frame, delete the lower address from the lower address memory, delete the lower address from the duplicated use lower address memory, copy the frame, drop the copy frame from the ring and send it to the base station, and send the original frame of the copy frame to the counterclockwise ring, On the other hand, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, delete the lower address from the lower address memory that specifies sending the frame outside the ring, and store the lower address in a duplicated use lower address memory, means for transmitting the frame to the counterclockwise ring as is, except for the above; When a frame from the clockwise ring arrives at the add, drop, or pass-through device for that frame, means for copying the frame and sending the copy frame forward in a clockwise direction on the ring if the lower address of the destination MAC address of the frame is stored in a duplicated use lower address memory, and sending the original frame of the copy frame out of the ring; means for sending the frame forward in a clockwise direction on the ring if the lower address of the destination MAC address of the frame is not stored in the duplicated use lower address memory and if the lower address of the destination MAC address of the frame is not stored in a lower address memory that specifies frame sending out of the ring; and means for sending the frame out of the ring if the lower address of the destination MAC address of the frame is stored in a lower address memory that specifies frame sending out of the ring.

7. The frame add, drop and pass device inputs 8-bit parallel data of a frame arriving from the clockwise ring and 10 bits of the frame's start bit and end bit into the input FIFO, and when the sequencer circuit reads the frame's start bit from the FIFO, it starts the 550 byte timer and the 1500 byte timer, and when the frame's end bit is read before the 550 byte timer times out, it stops reading from the FIFO, resets the 1500 byte timer with the timeout pulse of the 550 byte timer, and the sequence of the sequencer circuit ends. and means for resetting all JKFFs in the sequencer circuit and restarting reading of the FIFO regardless of the end of the sequence of the sequencer circuit, while stopping operation of the 550-byte timer if the end-of-frame bit is not read before the 550-byte timer times out, and stopping reading from the FIFO if the end-of-frame bit is read before the 1500-byte timer times out, and resetting all JKFFs in the sequencer circuit and restarting reading of the FIFO regardless of the end of the sequence of the sequencer circuit.

8. 2. A method for configuring a lower address memory for specifying frame sending out of a ring of a frame adding, dropping and passing device used in a communication system according to claim 1, wherein when storing the lower address of a source MAC address of a frame, the method comprises storing parallel data of the logical sum of latch output signals of each bit of parallel data read from a plurality of cells at a position addressed by the lower part of the lower address of the source MAC address of a frame and each bit of parallel data obtained by decoding the upper part of the lower address of the source MAC address at the address specified position in the SRAM, thereby inserting and storing the upper part of the lower address of the source MAC address at the position of bit 1 of the decoding as bit 1, which means lower address storage; When outputting a signal indicating whether the lower address of the source MAC address of the frame is stored or not, a logical sum output of all bits of parallel data obtained by logically multiplying the latch output signal of each bit of parallel data read from a plurality of cells at a position addressed by the lower part of the lower address of the source MAC address of the frame and the latch output signal of each bit of parallel data obtained by decoding the upper part of the lower address of the source MAC address is sent, and when the output is bit 1, it is determined that the lower address of the source MAC address of the frame is stored, and when the output is bit 0, it is determined that the lower address of the source MAC address of the packet is not stored, When deleting the lower address of the source MAC address of the frame, a method for configuring a lower address memory that specifies sending of a frame outside the ring of a frame add, drop, and pass device, in which a latch signal of parallel data that is the logical product of each bit of parallel data read from a plurality of cells at a position addressed by the lower part of the lower address of the source MAC address of the frame and the bit inversion bits of each bit of parallel data obtained by decoding the upper part of the lower address of the source MAC address is stored at the address specified position in the SRAM, thereby inserting and storing bit 0, which means no lower address storage, at the position of bit 1 of the decoded lower part of the lower address of the source MAC address.

9. A method for transmitting packets from a mobile terminal to a destination server or exchange via a router connected to a vertex device on the ring network, the router having a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and a function of blocking the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router, the method comprising: inserting a plurality of frame add, drop and pass devices into a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; connecting a base station to the frame add, drop and pass devices; and transmitting packets from a mobile terminal to a vertex device on the ring network via the ring network, the vertex device having a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and a function of blocking the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router, the method comprising: transmitting packets from the mobile terminal to the router via the ring network as Ethernet (registered trademark) frames and between the router and the server or exchange as IP packets; When a frame from the mobile terminal arrives at a device for adding, dropping, and passing frames in a ring network, regardless of whether the frame is a frame immediately after a change of the destination base station or not, or whether the frame is a communication initiation frame or not, a step of storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring when the lower address of the source MAC address of the frame is not stored in a duplicate use lower address memory and when the lower address of the source MAC address of the frame is not stored in a lower address memory that specifies sending the frame outside the ring, and attaching an unnecessary lower address erasure bit to the frame, and sending the frame with the unnecessary lower address erasure bit attached to the counterclockwise ring; otherwise, when the lower address of the source MAC address of the frame is stored in a duplicate use lower address memory, storing the lower address of the source MAC address of the frame in a duplicate use lower address memory; and when the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring, and sending the frame to the counterclockwise ring without attaching an unnecessary lower address erasure bit to the frame; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, or / and if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and an unnecessary lower address deletion bit is attached to the frame, delete the lower address from the lower address memory, delete the lower address from the duplicated use lower address memory, copy the frame, drop the copy frame from the ring and send it to the base station, and send the original frame of the copy frame to the counterclockwise ring, On the other hand, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, delete the lower address from the lower address memory that specifies sending the frame outside the ring, and store the lower address in a duplicated use lower address memory, otherwise, forwarding the frame on the counterclockwise ring as is, and directing it to the router via the vertex device; When a frame arrives at the apex device from the server via the router and is sent to the clockwise ring, and arrives at the frame add, drop, and pass-through device, a step of copying the frame and sending the copy frame forward in a clockwise direction on the ring if the lower address of the destination MAC address of the frame is stored in a duplicated use lower address memory, and sending the original frame of the copy frame out of the ring, sending the frame forward in a clockwise direction on the ring if the lower address of the destination MAC address of the frame is not stored in the duplicated use lower address memory and if the lower address of the destination MAC address of the frame is not stored in a lower address memory that specifies frame sending out of the ring, and sending the frame out of the ring if the lower address of the destination MAC address of the frame is stored in a lower address memory that specifies frame sending out of the ring; A method characterized by comprising the steps of, when a frame with an unnecessary lower address erasure bit attached arrives from a frame add, drop and pass-through device connected to the base station, and if a MAC address with the same lower address as the lower address of the source MAC address of the frame is stored in the MAC address table, returning the frame to the frame add, drop and pass-through device connected to the base station, and storing the lower address of the source MAC address of the frame with the unnecessary lower address erasure bit attached in a duplicate use lower address memory.

10. A method for transmitting packets from a mobile terminal to a destination server or exchange via a router connected to a vertex device on the ring network, the router having a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and a function of blocking the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router, the method comprising: inserting a plurality of frame add, drop and pass devices into a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; connecting a base station to the frame add, drop and pass devices; and transmitting packets from a mobile terminal to a vertex device on the ring network via the ring network, the vertex device having a function of receiving packets arriving from the counterclockwise ring of the ring network and forwarding them to a router and a function of blocking the passage of packets having a source MAC address that is the NIC MAC address of the ring network interface of the router, the method comprising: transmitting packets from the mobile terminal to the router via the ring network as Ethernet (registered trademark) frames and between the router and the server or exchange as IP packets; When a frame from the mobile terminal arrives at a device for adding, dropping, and passing frames in a ring network, regardless of whether the frame is a frame immediately after a change of the destination base station or not, or whether the frame is a communication initiation frame or not, a step of storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring when the lower address of the source MAC address of the frame is not stored in a duplicate use lower address memory and when the lower address of the source MAC address of the frame is not stored in a lower address memory that specifies sending the frame outside the ring, and attaching an unnecessary lower address erasure bit to the frame, and sending the frame with the unnecessary lower address erasure bit attached to the counterclockwise ring; otherwise, when the lower address of the source MAC address of the frame is stored in a duplicate use lower address memory, storing the lower address of the source MAC address of the frame in a duplicate use lower address memory; and when the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, storing the lower address of the source MAC address of the frame in a lower address memory that specifies sending the frame outside the ring, and sending the frame to the counterclockwise ring without attaching an unnecessary lower address erasure bit to the frame; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, or / and if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and an unnecessary lower address deletion bit is attached to the frame, delete the lower address from the lower address memory and the duplicated use lower address memory, and send the frame to the counterclockwise ring; On the other hand, if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, delete the lower address from the lower address memory that specifies sending the frame outside the ring, and store the lower address in a duplicated use lower address memory, otherwise, forwarding the frame on the counterclockwise ring as is, and directing it to the router via the vertex device; When a frame arrives at the apex device from the server via the router and is sent to the clockwise ring, and arrives at the frame add, drop, and pass-through device, if the lower address of the destination MAC address of the frame is stored in a duplicate-use lower address memory, copying the frame and sending the copy frame forward in a clockwise direction on the ring and sending the original frame of the copy frame out of the ring; if the lower address of the destination MAC address of the frame is not stored in the duplicate-use lower address memory and the lower address of the destination MAC address of the frame is not stored in a lower address memory that specifies frame sending out of the ring, sending the frame forward in a clockwise direction on the ring; and if the lower address of the destination MAC address of the frame is stored in a lower address memory that specifies frame sending out of the ring, sending the frame out of the ring.

11. a step in which the communicating mobile terminal or a base station to which the communicating mobile terminal belongs sends a one-way route setting frame having the MAC address of the mobile terminal as a source MAC address to a frame add, drop and pass-through device connected to the base station at a long period, and when the frame arrives at the frame add, drop and pass-through device, if the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, the lower address of the source MAC address of the frame is stored in a duplicated use lower address memory, and if the lower address of the source MAC address of the frame is stored in a lower address memory that specifies frame transmission outside the ring, the lower address of the source MAC address of the frame is stored in a lower address memory that specifies frame transmission outside the ring, and the frame is sent to the counterclockwise ring without adding an unnecessary lower address deletion bit to the frame; When the frame arrives at a frame add, drop, or pass-through device, If the lower address of the source MAC address of the frame is stored in a lower address memory that specifies sending the frame outside the ring, and if an unnecessary lower address deletion bit is not attached to the frame, delete the lower address of the source MAC address of the frame from the lower address memory that specifies sending the frame outside the ring, and store the lower address in a duplicated use lower address memory, 11. The method of claim 10, further comprising the step of otherwise forwarding the frame on the counterclockwise ring via a vertex device to a router.

12. 11. A method according to claim 9 or 10, further comprising the steps of: when a location registration frame from the mobile terminal arrives at a device for adding, dropping and passing frames, storing the lower address of the source MAC address of the frame in a location registration lower address memory, and directing the frame through the counterclockwise ring to the apex device; and when an incoming frame or communication initiation frame from the clockwise ring arrives at a device for adding, dropping and passing frames, if the lower address of the destination MAC address of the frame is stored in the location registration lower address memory, copying the frame, sending the copy frame to the clockwise ring, and sending the original frame of the copy frame out of the ring.

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