Mobile terminal handover, frame add, drop and pass device, and communication device in ring communication system

Abstract

To provide a communication device that easily realizes a mobile terminal handover by using a ring network that transfers an Ethernet frame.SOLUTION: When a frame from a mobile terminal arrives at a device for adding, dropping, and passing a frame of a ring network, if a transmission source MAC address of the frame is stored in a frame drop address table, a lower address of the transmission source MAC address of the frame is included in data stored in a data storage area of the frame drop address table. When a bit 1 of a negative bit is stored at an end of the data storage area, the transmission source MAC address of the frame is stored in the frame drop address table, the negative bit is erased, and except for the above, the lower address of the transmission source MAC address of the frame is stored in a lower address memory that specifies a frame transmission to the outside of the ring, and the frame is transmitted to a counterclockwise ring.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a mobile terminal handover method in a ring communication system, a device for adding, dropping and passing frames, and a communication device, and in particular to a method for handing over a mobile terminal in a network that makes use of the characteristics of a ring network in which SRAM that stores lower addresses of MAC addresses is used in the device for adding, dropping and passing frames in the ring network, and that mainly searches for a drop connection destination from the ring network using the lower address of the destination MAC address of an Ethernet (registered trademark) frame. The present invention uses an Ethernet frame and a frame that uses the MAC address portion of the IPv6 address as the MAC address of the frame.

[0002] A conventional example of an address storage method is the one disclosed in Patent Document 1, Japanese Patent Application Laid-Open No. 2000-151617, entitled "Table This conventional example is related to the memory circuit of MAC addresses, It consists of a first table consisting of RAM or the like having column addresses, MAC address data areas, and index areas, and a second table consisting of RAM or the like having row and column addresses, MAC address data areas, and index areas. 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 the lower bit string (for example, 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 stored in the index area of ​​address location A of the first table. This is a method of specifying recording areas by nesting.

[0003] Furthermore, as a conventional technique for storing addresses, Patent Document 2, Japanese Patent Application Laid-Open No. 2004-15592 "MAC Address Pointer Structure, MAC Address Rearrangement Method." This conventional example is a method 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 space, 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 pass frames. 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 master switch receives a failure notification frame 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 by nesting, which causes a problem that it takes a long time to trace the stored address destination.

[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 vacant entry table position for the MAC address specified by the column, the MAC address will be stored in the entry table position of a different lower bit column. In this case, however, when selecting the position to store the MAC address, it is necessary to search the entry table positions specified by the two lower bit columns, and since there are multiple stored addresses at the same address position in the same entry table, it is necessary to compare these multiple addresses, which results in a problem that the search takes a long time.

[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 800 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.

[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 without using the conventional MAC address table by using a ring network in which SRAM that stores lower addresses and intermediate addresses of MAC addresses is used in the ring node devices, in order to expand Layer 2 handover within a subnet by enlarging one MAC domain using an Ethernet ring network and 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 above-mentioned problems in the prior art, and the means for solving the problems are the first to ninth aspects of the present invention as 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 server or exchange as Ethernet frames across the ring network 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 source MAC address of the frame in the frame drop address table (11) if the source MAC address of the frame is stored in the frame drop address table (11); for storing the source MAC address of the frame in the frame drop address table (11) if a lower address (for example, the 22nd bit from the least significant bit) of the source MAC address of the frame is included in data stored in a data storage area of ​​the frame drop address table (11) and a negation bit 1 is stored at the end of the data storage area; and for erasing the negation bit; and for storing the lower address of the source MAC address of the frame in a lower address memory that specifies frame transmission outside the ring otherwise, and for transmitting the frame to the counterclockwise ring; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the frame is a frame that has just moved to a base station away from the router on a counterclockwise ring, and if a lower address of the source MAC address of the frame is stored in a lower address memory that specifies frame transmission outside the ring, erase the lower address from the lower address memory; On the other hand, if the frame is not a frame that has just moved to a base station away from the router on the counterclockwise ring, 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, the lower address is erased from the lower address memory, the source MAC address of the frame is stored in a data storage area of ​​a frame drop address table (11), and a negation bit 1 is stored at the end of the data storage area; means for erasing the MAC address from the frame drop address table (11) if the source MAC address of the frame is stored in a frame drop address table and the frame has just moved to a destination base station away from the router on a counterclockwise ring, and for other cases, transferring the frame as is on the counterclockwise ring and sending it to the router via a 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, or pass-through device, a means for dropping the frame from the ring if the destination MAC address of the frame is stored in a frame drop address table (11); for sending the frame out of the ring if the destination MAC address of the frame is not stored in the frame drop address table (11) and a 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; and for sending the frame clockwise to the front of the ring if the destination MAC address of the frame is not stored in the frame drop address table (11) and a 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.

[0020] A second aspect of the present invention is a communication system according to the first aspect of the present invention, When a mobile terminal (user equipment UE) moves from a source base station to a destination base station on the side of a vertex device on a counterclockwise ring, the mobile terminal sends a MAC address authentication packet transmission request frame for the mobile terminal to the source base station, the source base station checks the MAC address of the mobile terminal in a MAC address table, and sends a MAC address authentication packet to the destination base station on the counterclockwise ring, and if the lower addresses (e.g., the least significant bit to the 22nd bit) of the MAC address of the mobile terminal of a frame adding, dropping and passing device connected to the source base station or an intermediate base station are included in the 48-bit MAC address read from the frame drop address table (11), the communication system further comprises means for storing the MAC address of the mobile terminal in the frame drop address table (11) of the frame adding, dropping and passing device connected to the destination base station.

[0021] A third aspect of the present invention provides a communication system according to the first aspect of the present invention, When a mobile terminal (user equipment UE) moves from a source base station to a destination base station on the side of a vertex device on a counterclockwise ring, the mobile terminal sends a MAC address authentication packet transmission request frame for the mobile terminal to the source base station, the source base station checks the MAC address of the mobile terminal in a MAC address table, and sends a MAC address authentication packet to the destination base station on the counterclockwise ring, and if the lower address (e.g., the least significant bit to the 22nd bit) of the MAC address of the mobile terminal of a frame add, drop and pass device connected to the source base station or an intermediate base station is included in the 48-bit MAC address read from the frame drop address table (11), the communication system further comprises means for storing the MAC address of the mobile terminal paired with a reserved bit in the frame drop address table (11) of the frame add, drop and pass device connected to the destination base station.

[0022] A fourth aspect of the present invention provides a communication system according to the third aspect of the present invention, 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, If the source MAC address of the frame is stored in the frame drop address table (11) as a reserved bit pair, the source MAC address of the frame is stored in the frame drop address table (11) and the reserved bit is cleared. When the frame from the clockwise ring arrives at the frame add, drop and pass-through device, The communication system further comprises means for not dropping the frame from the ring if the destination MAC address of the frame is stored as a reserved bit in the frame drop address table (11).

[0023] A fifth aspect of the present invention provides a communication system according to the first aspect of the present invention, The communication system further comprises means for transmitting a frame to the clockwise ring when the destination MAC address of the frame arriving at the frame adding, dropping and passing device from the clockwise ring is stored in a frame drop address table in a pair with a negation bit.

[0024] A sixth aspect of the present invention provides 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.

[0025] A seventh aspect of the present invention is a communication system according to the first aspect of the present invention, The frame is a communication system that is a frame carrying TCP packets or bidirectional UDP packets.

[0026] An eighth aspect of the present invention is a communication system according to the second aspect of the present invention, The frame is a communication system that carries TCP packets or UDP packets.

[0027] A ninth aspect of the present invention is a communication device, When a frame from a 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 source MAC address of the frame in the frame drop address table (11) if the source MAC address of the frame is stored in the frame drop address table (11); for storing the source MAC address of the frame in the frame drop address table (11) if a lower address (for example, the 22nd bit from the least significant bit) of the source MAC address of the frame is included in data stored in a data storage area of ​​the frame drop address table (11) and a negation bit 1 is stored at the end of the data storage area; and for erasing the negation bit; and for storing the lower address of the source MAC address of the frame in a lower address memory that specifies frame transmission outside the ring otherwise, and for transmitting the frame to the counterclockwise ring; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the frame is a frame that has just moved to a base station away from the router on a counterclockwise ring, and if a lower address of the source MAC address of the frame is stored in a lower address memory that specifies frame transmission outside the ring, erase the lower address from the lower address memory; On the other hand, if the frame is not a frame that has just moved to a base station away from the router on the counterclockwise ring, 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, the lower address is erased from the lower address memory, the source MAC address of the frame is stored in a data storage area of ​​a frame drop address table (11), and a negation bit 1 is stored at the end of the data storage area; means for erasing the MAC address from the frame drop address table (11) if the source MAC address of the frame is stored in a frame drop address table and the frame has just moved to a destination base station away from the router on a counterclockwise ring, and for other cases, transferring the frame as is on the counterclockwise ring and sending it to the router via a 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, or pass-through device, The communication device comprises means for dropping the frame from the ring if the destination MAC address of the frame is stored in a frame drop address table (11), for sending the frame out of the ring if the destination MAC address of the frame is not stored in the frame drop address table (11) and 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, and for sending the frame clockwise to the front of the ring if the destination MAC address of the frame is not stored in the frame drop address table (11) 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.

[0028] A tenth aspect of the present invention is a frame adding, dropping and passing device used in the communication system according to the first aspect of the present invention, wherein a configuration method of a lower address memory for specifying packet transmission outside the ring of the own frame adding, dropping and passing device is a method of storing, when storing the lower address of the source MAC address of a frame, 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 upper part of the lower address of the source MAC address of a frame and each bit of parallel data obtained by decoding the lower part of the lower address of the source MAC address, by storing, at the address specified position of the SRAM, bit 1 of the lower part of the lower address of the source MAC address 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, the method sends out 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 upper 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 lower part of the lower address of the source MAC address, and when the output is bit 1, it is determined that the lower address of the source MAC address of the packet 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, the device for adding, dropping and passing packets stores 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 upper 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 lower part of the lower address of the source MAC address at the addressed 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. [Effects of the Invention]

[0029] As explained above, the present invention uses, instead of a MAC address table, a lower address memory and a frame drop address table 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 moved to a base station away from the router on the counterclockwise ring, the lower address is simply erased from the lower address memory. On the other hand, if the frame is not a frame that has just moved to a base station away from the router on the counterclockwise ring, the lower address is erased from the lower address memory, and the source MAC address of the frame is stored in the frame drop address table together with bit 1, which is the negation bit. If the lower address of the source MAC address of a frame to be added to the ring is included in the stored data in the frame drop address table, the 48-bit source MAC address is stored. 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, which has the effect of reducing 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]

[0030] [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 frame drop address table and a lower address memory that specifies 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 multiple devices are connected in a ring shape by an optical transmission line. [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 frame drop address table and a lower address memory that specifies 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 3] FIG. 1 is a diagram showing an example of the configuration of a frame adding, dropping and passing device according to a first embodiment and a second embodiment of the present invention. [Figure 4] FIG. 10 is a diagram showing another example of the configuration of the frame adding, dropping and passing device according to the first and second embodiments of the present invention. [Figure 5] FIG. 10 is a diagram for explaining a method of configuring a lower address memory that specifies sending a frame 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

[0031] 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 frame add, drop, and pass-through devices in a dual ring network, each connected by optical transmission paths, and each having a lower address memory for specifying frame transmission outside the ring and a frame drop address table. 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.

[0032] In Figure 1, 1 is the transmission path of the counterclockwise ring, 2 is the transmission path of the clockwise ring, 5 is the 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, 11 is a frame drop address table, 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 the 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 (32) 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), which specifies frame transmission outside the ring, has 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.

[0033] The operation of Figure 1 will be explained below. An example is shown in which a mobile terminal (user device UE) 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 (user device UE) 13-2, and I0 indicates the IP address of the destination server 20) to the base station 14-2. Here, a2 is not ASCII code. When the Ethernet frame (2) Mr1r2a3a2 (I0) (r1r2 indicates the NIC MAC address of the ring network interface of the router 22) arrives at the frame add, drop and pass-through device 6-2 from the terminal 13-2, if the source MAC address of the frame is stored in the frame drop address table (11), the source MAC address of the frame is stored in the frame drop address table (11), and if the lower address (the 22nd bit from the least significant bit) of the source MAC address of the frame is included in the data stored in the data storage area of ​​the frame drop address table (11) and bit 1 of the negation bit is stored at the end of the data storage area, the source MAC address of the frame is stored in the frame drop address table (11) and the negation bit is erased. However, in the figure, in cases other than those mentioned above, the lower address (for example, the 22nd bit from the least significant bit) of the source MAC address of the frame is stored in the lower address memory (7) which specifies the sending of the frame outside the 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.

[0034] 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, I3 indicates the IP address of mobile terminal (user equipment) 13-2, and I0 indicates the IP address of destination server 20), until it reaches server 20.

[0035] Next, an example will be shown in which the mobile terminal (user equipment UE) 13-2 moves from the base station 14-2 to the base station 14-1. Just before the mobile terminal (user equipment UE) 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 (user equipment UE) 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 (user equipment UE) 13-2 in the MAC address table of the base station 14-2 (not shown) and sends MAC address authentication IP packets (8), (9), and (10)MB1B2(a3a2) of the mobile terminal (user equipment UE) 13-2 (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 stored in the option field of the IP header) to the destination base station 14-1. When the MAC address authentication IP packet arrives at the frame add, drop and pass device 6-1, the frame's destination MAC address B1 is stored together with the destination port number in a MAC address table (not shown in the figure) that stores only the base station NIC MAC address, 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.

[0036] 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 (user equipment UE) 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, if 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-through device (ring node device) 6-1, if the source MAC address of the frame is stored in the frame drop address table (11), the source MAC address of the frame is stored in the frame drop address table (11), and if the lower address (the 22nd bit from the least significant bit) of the source MAC address of the frame is included in the data stored in the data storage area of ​​the frame drop address table (11) and bit 1 of the negation bit is stored at the end of the data storage area, the source MAC address of the frame is stored in the frame drop address table (11) and bit 1 of the negation bit is erased. However, in the figure, in cases other than those mentioned above, the lower address of the source MAC address of the frame (for example, the 22nd bit from the least significant bit) is stored in the lower address memory (7) that specifies the frame transmission outside the 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.

[0037] When the frame is transferred by (13) Mr1r2a3a2 (I0) along the counterclockwise ring 1 as shown in the figure and arrives at the frame add, drop, and pass-through device 6-2, the frame is a frame immediately after the destination base station has been changed, and the lower addresses (e.g., the least significant bit through the 22nd bit) of the source MAC address of the frame are stored in the lower address memory (7) that specifies sending the frame out of the ring. Therefore, the lower addresses (e.g., the least significant bit through the 22nd bit) of the source MAC address of the frame are deleted from the lower address memory (7) that specifies sending the frame out of the ring. If the source MAC address of the frame is stored in the frame drop address table (11) and the frame is a frame immediately after moving to a destination base station on the counterclockwise ring away from the router, the MAC address is deleted from the frame drop address table (11). Furthermore, if the frame is not a frame immediately after a change of the destination base station, and the lower address α (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, the lower address (for example, 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 sending the frame outside the ring, and the source MAC address of the frame is stored in the data storage area of ​​the frame drop address table (11), and bit 1, a negation bit, is stored at the end of the data storage area. In the figure, a horizontal line is drawn through the lower address a2 of the lower address memory (7) that specifies sending a frame outside the ring, indicating that it has been erased. 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.

[0038] 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.

[0039] Next, when a mobile terminal (user equipment UE) 13-1 receiving a UDP download service sends a 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, if the source MAC address of the frame is stored in the frame drop address table (11) when the frame from the mobile terminal arrives at the frame add, drop and pass-through device 6-1 of the ring network, the source MAC address of the frame is stored in the frame drop address table (11). If the lower address (the least significant bit to the 22nd bit) of the source MAC address of the frame is included in the data stored in the data storage area of ​​the frame drop address table (11) and if the negation bit 1 is stored at the end of the data storage area, the source MAC address of the frame is stored in the frame drop address table (11) and the negation bit 1 is erased. However, in the figure, in cases other than the above, the lower address (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 the sending of the frame outside the ring. 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 .

[0040] 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.

[0041] 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.

[0042] When frame (28) Ma1a2r1r2 (I2) is transferred through clockwise ring 2 and arrives at frame add, drop and pass device 6-2, if the frame's destination MAC address is stored in frame drop address table (11), the frame is dropped from the ring. However, in the figure, the frame's destination MAC address is not stored in frame drop address table (11), and the lower addresses (for example, the least significant bit to the 22nd bit) of the frame's destination MAC address are not stored in lower address memory (7) that specifies sending the frame outside the ring, so the frame is sent forward on the clockwise ring.

[0043] When the frame (29) Ma1a2r1r2 (I2) is transferred through the clockwise ring 2 and arrives at the frame add, drop and pass device 6-1, if the destination MAC address of the frame is stored in the frame drop address table (11), the frame is dropped from the ring. However, in the figure, the destination MAC address of the frame is not stored in the frame drop address table (11), and the lower addresses (for example, the least significant bit to the 22nd bit) of the destination MAC address of the frame are stored in the lower address memory (7) that specifies sending the frame outside the ring, so the frame is sent outside 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 in the figure, the frame (32)Ma1a2n1(I2) (n1 is the wireless MAC address of the base station 14-1) reaches the mobile terminal (user equipment UE) 13-1.

[0044] 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, each having a lower address memory that specifies frame transmission outside the ring and a frame drop address table. 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.

[0045] In FIG. 2, the devices with the numbers indicated in the figure operate in the same way as in FIG.

[0046] The operation of Figure 2 will be explained below. An example is shown in which a mobile terminal (user device UE) 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 device 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. When the Ethernet frame (2) Mr1r2a3a2 (I0) (r1r2 indicates the NIC MAC address of the ring network interface of the router 22) arrives at the frame add, drop and pass-through device 6-1 from the terminal 13-2, if the source MAC address of the frame is stored in the frame drop address table (11), the source MAC address of the frame is stored in the frame drop address table (11), and if the lower address (the 22nd bit from the least significant bit) of the source MAC address of the frame is included in the data stored in the data storage area of ​​the frame drop address table (11) and a negation bit is stored at the end of the data storage area, the source MAC address of the frame is stored in the frame drop address table (11) and the negation bit is erased. However, in the figure, in cases other than the above, the lower address a2 (for example, the 22nd bit from the least significant bit) of the source MAC address of the frame is stored in the lower address memory (7) which specifies the sending of the frame outside the ring.

[0047] 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.

[0048] Next, when a mobile terminal (user equipment UE) 13-1 receiving a UDP download service sends a frame (9) 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 equipment 6-1 via the base station 14-1, if the source MAC address of the frame is stored in the frame drop address table (11), the source MAC address of the frame is stored in the frame drop address table (11), and the frame If the lower address (the least significant bit to the 22nd bit) of the source MAC address of the frame is included in the data stored in the data storage area of ​​the frame drop address table (11) and if a negation bit, bit 1, is stored at the end of the data storage area, the source MAC address of the frame is stored in the frame drop address table and the negation bit is erased. In the figure, the lower address (for example, the least significant bit to the 22nd bit) of the source MAC address of the frame is stored in a lower address memory (7) that specifies the sending of the frame outside the ring. 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 current transmission line 1 of the counterclockwise ring.

[0049] When the frame is forwarded by (10) Mr1r2a1a2 (I0) on the counterclockwise ring 1 as shown in the figure and arrives at the frame add, drop and pass device 6-2, the lower addresses (e.g., the least significant bit to the 22nd bit) of the frame's source MAC address are not stored in the lower address memory (7) that specifies sending the frame outside the ring, so the frame is sent directly to the counterclockwise ring. When the frame arrives at the vertex device 5 where the frame's destination MAC address r1r2 is stored in the address table 12 for router connection, the frame is dropped from the ring as (13) Mr1r2a1a2 (I0) toward the 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 (14)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.

[0050] 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 (15)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 MAC address authentication IP packets (16), (17), and (18)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) of the mobile terminal (user equipment UE) 13-2 to the destination base station 14-2. In this case, since 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 a MAC address table (not shown) of base station 14-1, the 48-bit source MAC address (a3a2) of the MAC address of the mobile terminal is stored in the address location memory area of ​​SRAM (11) for the frame drop address table accessed with the second short lower address (e.g., the least significant bit to the 16th bit) of the MAC address of the mobile terminal of the frame adding, dropping and passing device connected to the destination base station, just as in the case where the lower address (the least significant bit to the 22nd bit) of the MAC address of the mobile terminal is included in the 48-bit MAC address data read from the data memory area of ​​SRAM (11) for the frame drop address table accessed with the second short lower address (e.g., the least significant bit to the 16th bit) of the MAC address of the mobile terminal of the frame adding, dropping and passing device connected to the destination base station. When the MAC address authentication IP packet arrives at the frame add, drop and pass device 6-2, after the above operations are performed, the frame is sent to the destination base station 14-2 because the destination MAC address B2 of the frame is stored together with the destination port number in a MAC address table (not shown in the figure) that stores only the base station NIC MAC address. 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.

[0051] When a frame (19)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) 13-2 arrives at the base station 14-2, the frame is sent to the frame adding, dropping and passing device 6-2 as (20)Mr1r2a3a2(I0) immediately after the destination base station is changed, if 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 the frame immediately after the destination base station has been changed, and the 48-bit source MAC address (a3a2) of the frame is stored in the frame drop address table (11), which is accessed by the second short lower address (for example, the least significant bit to the 16th bit) of the source MAC address of the frame, so the 48-bit source MAC address is stored. 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 current transmission line 1 of the counterclockwise ring.

[0052] 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 (23)Mr1r2a3a2(I0) and headed for router 22 outside the ring.

[0053] 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 (24)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.

[0054] 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.

[0055] 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.

[0056] When frame (28) Ma1a2r1r2 (I2) is transferred through clockwise ring 2 and arrives at frame add, drop, and pass-through device 6-2, the destination MAC address a1a2 of the frame is not stored in the memory area of ​​the address location of frame drop address table (11), which is accessed by the second lower address (e.g., the least significant bit to the 16th bit) of the destination MAC address a1a2 of the frame, and the lower address (e.g., the least significant bit to the 22nd bit) of the destination MAC address of the frame is not stored in lower address memory (7), which specifies sending the frame outside the ring, so the frame is sent forward on the clockwise ring.

[0057] When the frame (29) Ma1a2r1r2 (I2) is transferred along the clockwise ring 2 and arrives at the frame add, drop and pass-through device 6-1, the MAC address a1a2 of the mobile terminal 13-1 is not stored in the memory area of ​​the address position of the frame drop address table (11) that is accessed by the second lower address (e.g., the least significant bit to the 16th bit) of the MAC address a1a2 of the mobile terminal 13-1, and the lower address (e.g., the least significant bit to the 22nd bit) of the destination MAC address of the frame is stored in the lower address memory (7) that specifies sending the frame outside the ring, so the frame is sent outside the ring as frame (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.

[0058] Next, an example of the configuration of a device for adding, dropping and passing frames according to the first and second embodiments of the present invention is shown in FIG.

[0059] In Figure 3, 100 is a CPU, 101 is a header of a frame arriving from a base station, 102 is a header of a frame arriving from the counterclockwise ring, 103 is a header of a frame arriving from the clockwise ring, 104 is an SRAM for a lower address memory that specifies sending a frame outside the ring, 105 is a decoder or decoder memory for the lower 5 bits of the 22-bit lower address of the MAC address, 107 is an SRAM for a frame drop address table, 108 is the upper part of the lower address (the 5th to 21st bits counting from the lowest address bit), 109 and 111 are the lower 5 address bits of the lower MAC address, 110-1 is a 32-bit data bus, 110-2 is a 64-bit data bus, 112 is an address for the frame drop address table, and 113 is a signal that specifies whether the frame is to be passed or dropped.

[0060] Next, the operation of Fig. 3 will be explained. The lower 48 bits of the source MAC address and 2 bytes of the packet length field (for example, the lower 3 bits of the lower byte contain a control bit) of the header 101 of a packet arriving from a base station are taken into register D of CPU 100 via 64-bit data bus 110-2, and the 49 bits of the MAC address read out via bus 110-2 from the frame drop address table (107) accessed using the lower 16 bits (112) of the 48 bits of the source MAC address taken into register E is input into register E, and if the contents of register D and the contents of register E match, the data is left as is, but if the lower 22 bits of register D and the lower 22 bits of register E match and the 49th bit of register E is bit 1 indicating a negation bit, the data of the lower 48 bits of register D and the 49th bit is bit 0 is sent to the frame drop address table (107) via bus 110-2. The data is written to drop address table 107, and other than the above, the upper 17 bits A5-21 of the 22-bit source lower MAC address are used on address line 107 to access lower address memory 104, which specifies packet transmission outside the ring selected by CS and OE. The 32-bit parallel data from the data storage area read out to 32-bit data bus 110 by WE is input to register A of the CPU. On the other hand, the lower addresses A0-4 of the 22-bit source lower MAC address are taken into register B of the CPU by data bus 110-1 from a decoder for the lower 5 bits of the 22-bit lower address of the MAC address, or decoder memory 105. The contents of register A and register B are ORed, and the result remains in register A. The result of this operation is written by WE to the data storage area of ​​lower address memory 104, which specifies packet transmission outside the ring.

[0061] Also, the 48 lower address bits of the source MAC address and the 2-byte packet length field (for example, the lower 3 bits of the lower byte contain a control bit) of the header 102 of the packet arriving from the counterclockwise ring are taken into register D of the CPU 100 via the 64-bit data bus 110-2, and the upper 17 bits A5-21 of the 22-bit source lower MAC address are accessed via address line 107 to the lower address memory 104 which specifies packet transmission outside the ring selected by CS and OE, and the 32-bit parallel data of the data storage area read out to the 32-bit data bus 110 by WE is input to register A of the CPU, and on the other hand, the decoder or decoder memory 105 for the lower 5 bits of the 22-bit lower address of the MAC address accessed by the lower address A0-4 (109) of the 22-bit source lower MAC address is decoded. The loaded data is taken into register B of the CPU via data bus 110-1, the contents of register A and register B are ANDed and the result is left in register C, the contents of register C and the contents of register B are compared bit by bit, and if the comparison result is true and the control bit contains a signal for the frame immediately after the base station has moved in a direction away from router 22 on the counterclockwise ring, the lower address is erased from lower address memory 104 which specifies packet transmission outside the ring, since the data decoded by the decoder for the lower 5 bits of the lower 22 bits of the MAC address or decoder memory 105 has been taken into register B of the CPU, the inverted bit of that data and the data read from address memory 104 are taken in, and the parallel data ANDed with the contents of register A is written to lower address memory 104.On the other hand, if the comparison result is true and the control bits do not include a signal indicating that the frame was sent immediately after a base station moved away from router 22 on the counterclockwise ring, the lower address is erased from lower address memory 104, which specifies sending the packet outside the ring, by taking the data decoded by decoder memory 105 for the lower 5 bits of the 22 bits of the lower address of the MAC address and loading it into register B of the CPU, and loading the inverted bit of that data and the data read from address memory 104, and then writing the parallel data ANDed with the contents of register A into lower address memory 104, and storing the 48 bits of the source MAC address and negation bit of the frame, which are the contents of register D, in frame drop address table 107. On the other hand, if the comparison result is false, nothing is done.

[0062] In addition, the 48-bit destination MAC address and 16-bit all-0 data of the packet header 103 from the clockwise ring are taken into register D of the CPU 100 via the 64-bit data bus 110-2, and the 49-bit data read onto the data bus 110-2 from the frame drop address table (107) accessed by the lower 16-bit address (112) of the register D is taken into register E, and if the contents of register D and register E match, a packet drop signal is sent to packet pass or drop signal 113 to send the frame out of the ring. Other than the above, 32-bit parallel data read from a memory area of ​​lower address memory 104 specifying packet transmission outside the ring, accessed by the upper address 17 bits A5-21 (108) of the lower 22 bits of the destination MAC address in register D, is taken into register A of the CPU via 32-bit data bus 110-1. Meanwhile, data decoded by decoder or decoder memory 105 for the lower 5 bits of the lower 22 bits of the MAC address, accessed by the lower address A0-4 (108) of the lower 22 bits of the destination MAC address, is taken into register B of the CPU via data bus 110-1. The bit-by-bit AND results of each bit of register A and each bit of register B are input into register C, and each bit of register C is compared with each bit of register B. If the comparison result is true, that is, a match, a frame drop signal is sent to frame pass or drop signal 113. If the comparison result is false, that is, a mismatch, a packet pass signal is sent to packet pass or drop signal 113. The lower address can be deleted from the lower address memory 104, which specifies packet transmission outside the ring, by loading the data decoded by the decoder for the lower 5 bits of the 22 bits of the lower address of the MAC address, or the decoder memory 105, into register B of the CPU, and then writing the parallel data obtained by ANDing the inverted bit of the decoded data with the contents of register A, which has loaded the data read from the address memory 104, into the lower address memory 104.

[0063] Next, another example of the configuration of the frame adding, dropping and passing device according to the first and second embodiments of the present invention is shown in FIG.

[0064] 4 has the same configuration as FIG. 3 except that there is no decoder or decoder memory 105 for the lower 5 bits of the lower 22 bits of the MAC address.

[0065] Next, the operation of Fig. 4 will be explained. The lower 48 bits of the source MAC address and the 2 bytes of the packet length field of the header 101 of a packet arriving from the base station are taken into register D of CPU 100 via 64-bit data bus 110-2, and the 49 bits of the MAC address read out via bus 110-2 from the frame drop address table (107) accessed using the lower 16 bits (112) of the 48 bits of the source MAC address taken into register E is input into register E. If the contents of register D and register E match, the data is left as is, but if the lower 22 bits of register D and the lower 22 bits of register E match and the 49th bit of register E is bit 1 indicating a negation bit, the data of the lower 48 bits of register D and the 49th bit is bit 0 is inputted via bus 110-2. The data is written to the frame drop address table 107, and other than the above, the upper 17 bits A5-21 of the 22-bit source lower MAC address are accessed by address line 107 from lower address memory 104, which specifies packet transmission outside the ring selected by CS and OE, and the 32-bit parallel data from the data storage area read out to the 32-bit data bus 110 by WE is input to register A of the CPU, while the lower addresses A0-4 of the 22-bit source lower MAC address are decoded by shifting in a shift register and taken into register B of the CPU, the contents of register A and register B are ORed and the result remains in register A, and the result of this operation is written by WE to the data storage area of ​​lower address memory 104, which specifies packet transmission outside the ring.

[0066] In addition, the 48 lower address bits of the source MAC address and the 2-byte packet length field (a control bit is added to the lower 4 bits of the lower byte) of the header 102 of the packet arriving from the counterclockwise ring are taken into register D of the CPU 100 via the 64-bit data bus 110-2, and the upper 17 bits A5-21 of the 22-bit source lower MAC address are accessed via address line 107 to access lower address memory 104 which specifies packet transmission outside the ring selected by CS and OE. The 32-bit parallel data of the data storage area read out to the 32-bit data bus 110 by WE is input to register A of the CPU, while the data decoded by shifting the lower address A0-4 of the 22-bit source lower MAC address in the shift register is input to register A of the CPU. The contents of register A and register B are taken into register B, and the result of an AND operation on the contents of register A and register B remains in register C. The contents of register C and the contents of register B are compared bit by bit. If the comparison result is true and the control bit contains a signal for the frame immediately after the base station has moved in a direction away from router 22 on the counterclockwise ring, the lower address is erased from lower address memory 104, which specifies packet transmission outside the ring, by shifting the lower 5 bits of the 22 bits of the lower address of the MAC address in a shift register, and the inverted bits of the decoded data are taken into register B of the CPU and the data read out from lower address memory 104, and the parallel data obtained by ANDing this with the contents of register A is written to lower address memory 104.On the other hand, if the comparison result is true and the control bit does not include a signal for the frame immediately after a base station has moved away from router 22 on the counterclockwise ring, the lower address is erased from lower address memory 104, which specifies packet transmission outside the ring, by shifting the lowest 5 bits of the 22 bits of the lower address of the MAC address in a shift register, decoded, and the inverted bits of the decoded data are taken into register B of the CPU and the data read from lower address memory 104, and the parallel data obtained by ANDing this with the contents of register A is written to lower address memory 104, and the 48th bit of the source MAC address of the frame and the 49th bit, negation bit 1, of the contents of register D are stored in frame drop address table 107. On the other hand, if the comparison result is false, nothing is done.

[0067] In addition, the 48-bit destination MAC address and 16-bit all-0 data of the packet header 103 from the clockwise ring are taken into register D of the CPU 100 via the 64-bit data bus 110-2, and the 49-bit data read onto the data bus 110-2 from the frame drop address table (107) accessed by the lower 16-bit address (112) of the register D is taken into register E, and if the contents of register D and register E match, a packet drop signal is sent to packet pass or drop signal 113 to send the frame out of the ring. Other than the above, 32-bit parallel data read from a memory area of ​​lower address memory 104 that specifies packet transmission outside the ring and is accessed by the upper address 17 bits A5-21 of the lower 22 bits of the destination MAC address in register D is taken into register A of the CPU via 32-bit data bus 110-1, while the lower address A0-4 of the lower 22 bits of the destination MAC address is shifted in a shift register and decoded data is taken into register B of the CPU, the AND results of each bit of register A and each bit of register B are input into register C, and each bit of register C is compared with each bit of register B, and if the comparison result is true (match), a frame drop signal is sent to frame pass or drop signal 113. If the comparison result is false (mismatch), a packet pass signal is sent to packet pass or drop signal 113. In addition, the deletion of the lower address from the lower address memory 104 that specifies packet transmission outside the ring can be performed by taking the inverted bit of the data decoded by shifting in the shift register into register B of the CPU, and writing the parallel data ANDed with the contents of register A into the lower address memory 104.

[0068] 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 deleted 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 deleted from the lower address memory (7) that specifies sending frames outside the ring, but remain as they are, which is not a problem.

[0069] The configuration method of the lower address memory that specifies packet transmission outside the ring of the frame add, drop, and pass devices 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 Bidirectional Transfer of Packets Having Only the Source Terminal Address," in the Communication Methods section of the Institute of Electronics, Information and Communication Engineers (IEICE) Technical Report CS2013-28-CS2013-40, 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). This method can also be configured as shown in Figure 5, which is a principle diagram. In FIG. 5, the output of the 32-bit (70) SRAM output data for lower addresses is latched by a latch circuit (55), and the output (60) of the latch output signal, a bit 0 write signal (59), and the output of the decoder (53) that decodes the lower 5 bits (58) of the lower MAC address are input to a logic circuit (54), which outputs the output, which is sent to the outside of the ASIC, small LSI, or FPGA and rewritten to the SRAM for lower address memory.

[0070] In the first embodiment, ring failures can be handled without flooding by steering or double-ring loopback. When double-ring loopback is used, in the event of a ring network failure, frames are looped back to the backup transmission path at the frame add, drop, and pass-through devices on both sides of the failure point, and a loopback bit is added when the loopback occurs. The frame with the loopback bit added passes through all devices up to the second loopback point, and the loopback bit is removed during the second loopback. 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]

[0071] 1 Counterclockwise ring transmission line 2 Clockwise ring transmission line 5 Vertex device 6-1, 6-2, 6-3 Frame add, drop and pass equipment (ring node equipment) 7 Lower address memory that specifies frame transmission outside the ring 11 Frame Drop Address Table 12 Address table for router connections 13-1, 13-2, 13-3 Mobile terminal (user equipment UE) 14-1, 14-2, 14-3 Base station (BS) 15 Mobile Device Movement 20 servers 22 Router 26 Switchboard 27 Home Memory 100 CPU 101 Header of frame arriving from base station 102 Header of a frame arriving from the counterclockwise ring 103 Header of a frame arriving from the clockwise ring 104 SRAM for lower address memory that specifies frame transmission outside the ring 105 Decoder or decoder memory for the lower 5 bits of the lower 22 bits of the MAC address 107 SRAM for frame drop address table 108 The upper part of the lower address of the MAC address (bits 5 to 21 counting from the least significant address bit) 109, 111 Lower 5 bits of the MAC address 110-1 32-bit data bus 110-2 64-bit data bus 112 Address for frame drop address table 113 Frame pass or drop signal

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 source MAC address of the frame in the frame drop address table (11) if the source MAC address of the frame is stored in the frame drop address table (11); for storing the source MAC address of the frame in the frame drop address table (11) if a lower address (e.g., the 22nd bit from the least significant bit) of the source MAC address of the frame is included in data stored in a data storage area of ​​the frame drop address table (11) and a negation bit 1 is stored at the end of the data storage area; and for erasing the negation bit; and for storing the lower address of the source MAC address of the frame in a lower address memory that specifies frame transmission outside the ring and transmitting the frame to the counterclockwise ring otherwise; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the frame is a frame that has just moved to a base station away from the router on a counterclockwise ring, and if a lower address of the source MAC address of the frame is stored in a lower address memory that specifies frame transmission outside the ring, erase the lower address from the lower address memory; On the other hand, if the frame is not a frame that has just moved to a base station on the counterclockwise ring in a direction away from the router, 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 in the lower address memory is erased, the source MAC address of the frame is stored in a data storage area of ​​a frame drop address table (11), and a negation bit 1 is stored at the end of the data storage area; means for erasing the MAC address in the frame drop address table (11) when the source MAC address of the frame is stored in a frame drop address table and the frame has just moved to a destination base station away from the router on a counterclockwise ring, and for other cases, transferring the frame as is on the counterclockwise ring and sending it to the router via a 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, or pass-through device, a means for dropping the frame from the ring if the destination MAC address of the frame is stored in a frame drop address table (11); for sending the frame out of the ring if the destination MAC address of the frame is not stored in the frame drop address table (11) and a 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; and for sending the frame clockwise towards the front of the ring if the destination MAC address of the frame is not stored in the frame drop address table (11) and a 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.

2. 2. The communication system according to claim 1, further comprising means for, when a mobile terminal (user equipment UE) moves from a source base station to a destination base station on the side of a vertex device on a counterclockwise ring, the mobile terminal sends a frame requesting transmission of a MAC address authentication packet of the mobile terminal to the source base station, the source base station checks the MAC address of the mobile terminal in a MAC address table, and sends a MAC address authentication packet to the destination base station on the counterclockwise ring, and if a lower address (e.g., from the least significant bit to the 22nd bit) of the MAC address of the mobile terminal of a frame add, drop and pass device connected to the source base station or an intermediate base station is included in the 48-bit MAC address read from the frame drop address table (11), storing the MAC address of the mobile terminal in the frame drop address table (11) of the frame add, drop and pass device connected to the destination base station.

3. 2. The communication system according to claim 1, further comprising means for storing the MAC address of the mobile terminal in pairs with a reserved bit in the frame drop address table (11) of a frame drop address table (11) of a frame adding, dropping and passing device connected to the destination base station when the mobile terminal (user equipment UE) moves from a source base station to a destination base station on the side of the apex device on a counterclockwise ring, the mobile terminal sends a MAC address authentication packet transmission request frame of the mobile terminal to the source base station, the source base station checks the MAC address of the mobile terminal in a MAC address table and sends a MAC address authentication packet to the destination base station on the counterclockwise ring, and if a lower address (e.g., from the least significant bit to the 22nd bit) of the MAC address of the mobile terminal of a frame adding, dropping and passing device connected to the source base station or an intermediate base station is included in the 48-bit MAC address read from the frame drop address table (11),

4. 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, If the source MAC address of the frame is stored in the frame drop address table (11) with a reserved bit pair, store the source MAC address of the frame in the frame drop address table (11) and clear the reserved bit, and when the frame from the clockwise ring arrives at the frame add, drop and pass-through device, 4. The communication system according to claim 3, further comprising means for not dropping the frame from the ring if the destination MAC address of the frame is stored as a reserved bit in a frame drop address table (11).

5. 2. The communication system according to claim 1, further comprising means for transmitting a frame to the clockwise ring when the destination MAC address of the frame arriving at the frame add, drop and pass-through device from the clockwise ring is stored in a frame drop address table in a pair with a negation bit.

6. 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.

7. 2. The communication system of claim 1, wherein the frames are frames carrying TCP packets or bidirectional UDP packets.

8. 3. The communication system according to claim 2, wherein the frame is a frame carrying a TCP packet or a UDP packet.

9. A communication device, When a frame from a 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 source MAC address of the frame in the frame drop address table (11) if the source MAC address of the frame is stored in the frame drop address table (11); for storing the source MAC address of the frame in the frame drop address table (11) if a lower address (e.g., the 22nd bit from the least significant bit) of the source MAC address of the frame is included in data stored in a data storage area of ​​the frame drop address table (11) and a negation bit 1 is stored at the end of the data storage area; and for erasing the negation bit; and for storing the lower address of the source MAC address of the frame in a lower address memory that specifies frame transmission outside the ring and transmitting the frame to the counterclockwise ring otherwise; When a frame from the counterclockwise ring arrives at a frame add, drop, or pass-through device, If the frame is a frame that has just moved to a base station away from the router on a counterclockwise ring, and if a lower address of the source MAC address of the frame is stored in a lower address memory that specifies frame transmission outside the ring, erase the lower address from the lower address memory; On the other hand, if the frame is not a frame that has just moved to a base station on the counterclockwise ring in a direction away from the router, 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 in the lower address memory is erased, the source MAC address of the frame is stored in a data storage area of ​​a frame drop address table (11), and a negation bit 1 is stored at the end of the data storage area; means for erasing the MAC address in the frame drop address table (11) when the source MAC address of the frame is stored in a frame drop address table and the frame has just moved to a destination base station away from the router on a counterclockwise ring, and for other cases, transferring the frame as is on the counterclockwise ring and sending it to the router via a 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, or pass-through device, a frame drop address table (11) for dropping the frame from the ring if the destination MAC address of the frame is stored in the frame drop address table (11); a frame drop address table (11) for sending the frame out of the ring if the destination MAC address of the frame is not stored in the frame drop address table (11) and a 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; and a frame drop address table (11) for sending the frame clockwise to the front of the ring if the destination MAC address of the frame is not stored in the frame drop address table (11) and a 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.

10. In a frame adding, dropping and passing device used in a communication system according to claim 1, a method for configuring a lower address memory for specifying packet transmission outside the ring of the frame adding, dropping and passing device is as follows: 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 upper part of the lower address of the source MAC address of a frame and each bit of parallel data obtained by decoding the lower part of the lower address of the source MAC address is stored at the address specified position in the SRAM, and bit 1 of the decoding bit 1 position of the lower address of the source MAC address is inserted and stored 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 upper 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 lower 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 packet 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 latch signal of parallel data of the logical product of each bit of parallel data read from a plurality of cells at a position addressed by the upper part of the lower address of the source MAC address of the frame and the bit inversion bit of each bit of parallel data obtained by decoding the lower part of the lower address of the source MAC address is stored at the address specified position of 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, in a device for adding, dropping and passing packets.

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