Handover method using ring network for retrieving drop connection destination of packet from ring network with low-order address of destination mac address of ethernet frame

Abstract

To implement handover by transferring an Ethernet frame via a ring network.SOLUTION: When a packet from a terminal 13 arrives at a device 6 of a ring network, 1 is stored in first and second bits of a storage region at an address position of an SRAM which is accessed by a low-order address of a source MAC address, 1 is stored in third and fourth bits of a storage region at an address position of the SRAM which is accessed by an intermediate address of the source MAC address, and the packet is sent out to a counterclockwise ring. When the packet arrives at the device 6, in the case where 1 is stored in the first and second bits of the storage region at the address position of the SRAM which is accessed by the low-order address of the source MAC address and 1 is stored in the third and fourth bits of the storage region at the address position of the SRAM which is accessed by the intermediate address of the source MAC address, the source MAC address is stored in an address table and the packet is directed toward a server via the counterclockwise ring.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A conventional example of an address storage method is disclosed in Japanese Patent Application Laid-Open No. 2000-151617, "Table This conventional example is related to the storage circuit of MAC addresses, It consists of a first table consisting of a RAM or the like having a column address, a MAC address data area, and an index area, and a second table consisting of a RAM or the like having a row and column address, a MAC address data area, and an index area. In this conventional example, the entire 48 bits of a MAC address are stored at position A, which is specified in the memory of the first table by the lower bit string (for example, 16 bits). If another MAC address is already stored at position A, it is recorded at an empty address position B in the memory of the second table, and the recorded address position B is stored in the index area of ​​address position A of the first table. This is a method of specifying a recording area by nesting.

[0003] As a conventional technique for storing addresses, Patent Document 2, Japanese Patent Application Laid-Open No. 2004-15592, "MAC address pointer structure, MAC address rearrangement method." This conventional example is a method of storing multiple MAC addresses at the same address position in an entry table specified by a low-order bit string. If there is no free area, the MAC address is stored in an entry table specified by a low-order bit string different from the low-order bit string of the MAC address.

[0004] A typical conventional example of a ring network is a ring network using a master switch and a slave switch, as described in Patent Document 3. If one of the ring ports on the switch is a blocked port that does not pass frames, This prevents congestion caused by cluttering. If a fault occurs in the ring network, the monitoring frames sent from the master switch to the master switch will not arrive, and instead The master switch receives a failure notification frame from the slave switch at the failure point. The master switch unblocks the blocked port of the master switch to allow the frame to pass. Also, a blocked port is set on the failed transmission line side of one of the slave switches of the failure point, and the link The ring network continues to operate even after the ring network has recovered from a failure. Generally, in a conventional ring network, a MAC address table is used in the ring node device, so that in the event of a transmission line failure, the FDBs of all ring node devices in the ring are cleared and the FDBs are reconstructed by flooding.

[0005] An example of a handover method is Patent Document 4. This prior art is a method that has an IPv6 connection via a base station before switching via a gateway and a base station between a mobile terminal and an access router, and an IPv6 connection via a destination base station, and reduces the interruption time of packets via the connections when switching connections. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-151617 A [Patent Document 2] JP 2004-15592 A [Patent Document 3] Retable No. 2008-068813 [Patent Document 4] Re-tabled publication No. 2017-195497 [Non-patent literature]

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

[0008] The conventional address storage method disclosed in Japanese Patent Application Laid-Open No. 2000-151617 stores MAC addresses by nesting, which causes a problem that it takes a long time to trace the stored address destination.

[0009] In addition, in the conventional address storage method disclosed in Japanese Patent Application Laid-Open No. 2004-15592, the lower bits It is described that if there is no vacancy in the entry table position of the MAC address specified by the string, the MAC address will be stored in the entry table position of a different lower bit string. In that case, however, when selecting the position to store the MAC address, it is necessary to search the entry table positions specified by the two lower bit strings, and since there are multiple stored addresses at the same address position in the same entry table, it is necessary to compare these multiple addresses, which results in a problem of long search times.

[0010] Conventional ring networks, such as Non-Patent Document 1 and Patent Document 3, store the destination MAC addresses of packets bound for the left-handed ring, the destination MAC addresses of packets bound for the right-handed ring, and the destination MAC addresses of packets sent outside the ring using MAC addresses and port numbers, which results in a large number of MAC addresses to be stored.When the MAC address table stores the entire 48 bits of the MAC address at the address position accessed by the memory using the lower address of the MAC address, or when the upper address is stored, if the MAC address cannot be stored, a drawback is that when the destination MAC address of a packet to be forwarded is not stored in the MAC address table, the packet is flooded.

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

[0012] Furthermore, in a conventional ring network, when searching for a connection destination, the entire destination MAC address is required, and searching using the lower address of the destination MAC address is not possible. Also, in a ring network, even if it is desired to store the source MAC address of a packet in an address table that specifies the passage of the packet so that a reverse packet can pass through a node device that stores a lower address equal to the lower address of the source MAC address, the storage process is not possible because the lower address of the destination MAC address does not indicate when the packet arrived at the destination. When the destination address is fixed, such as a server, it can be reached using the destination MAC address, but this is not possible for a terminal with many destinations.

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

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

[0015] The present invention has been made in consideration of the above problems in the conventional art, and the means for solving the problems are as follows: first to fourth aspects of the present invention. A first aspect of the present invention is a system in which a plurality of devices for adding, dropping and passing packets are inserted into a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1, an L2 switch and a base station are connected to the devices for adding, dropping and passing packets, and a terminal and a mobile terminal under each of the L2 switch and the base station have a function of receiving a packet arriving from the counterclockwise ring of the ring network and transferring it to a router, and a function of blocking the passage of a packet having a NIC MAC address of a ring network interface of the router as a source MAC address when the source MAC address of the packet is stored in a MAC address table of the device itself, in order to communicate with a destination server via the router for a video lecture, a video conference involving a call signal or content distribution, packets from the terminal and the mobile terminal travel between the router and a destination server via the router connected to the router as TCP, UDP Ethernet (registered trademark) frames for TCP and call signals, etc., and between the router and the server and between the router and the server or exchange as IP packets, When the ring network is not in a faulty state, When a packet from the terminal or mobile terminal arrives at an add, drop, or pass-through device of the packet in the ring network, regardless of whether the packet is a packet immediately after a change of the destination base station or whether the packet is a communication start packet, storing a bit 1 in the first and second bit positions of a storage area of ​​an address location of an SRAM for a lower address and intermediate address designation memory accessed by the lower address of the source MAC address of the packet, and storing a bit 1 in the third and fourth bit positions of a storage area of ​​an address location of the SRAM accessed by the intermediate address of the source MAC address of the packet, and sending the packet onto a counterclockwise ring; When the packet arrives at a packet add, drop, or pass-through device, means for storing the source MAC address of the packet in an SRAM for an address table designating a packet's passage when a bit 1 is stored in the first and second bit positions of a storage area of ​​an address position of the SRAM for a lower address and intermediate address designation memory accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in the third and fourth bit positions of a storage area of ​​an address position of the SRAM accessed by an intermediate address of the source MAC address of the packet, and directing the packet on a counterclockwise ring to a ring node device in which a ring network interface NIC MAC address of a router to which a server is connected via a router is stored as a destination MAC address of the packet; When a packet from a server is sent to a clockwise ring from a ring node device in which the NIC MAC address of the router is stored as the source MAC address of the packet via a router, and the packet arrives at an add, drop, or pass-through device of the packet, means for sending the packet forward on the clockwise ring if the destination MAC address of the packet is stored in an SRAM for an address table specifying the passage of the packet, sending the packet out of the ring if the destination MAC address of the packet is not stored in the SRAM for the address table specifying the passage of the packet and bit 1 is stored in the first and second bit positions of a storage area of ​​an address position of the SRAM for a lower address and intermediate address specification memory accessed with a lower address of the destination MAC address of the packet and bit 1 is stored in the third and fourth bit positions of a storage area of ​​an address position of the SRAM accessed with an intermediate address of the destination MAC address of the packet, and means for sending the packet forward on the clockwise ring in other cases.

[0016] A second aspect of the present invention is a system according to the first aspect of the present invention, characterized in that when the bit strings of the lower address and intermediate address of the source MAC address of a packet are the same, the bit string of the intermediate address is changed to a bit string in which the upper and lower bits are swapped, and the system stores and reads the lower address and intermediate address in an SRAM for use as a memory for specifying the lower address and intermediate address.

[0017] A third aspect of the present invention provides a system according to the first aspect of the present invention, This system is characterized in that when the bit string of the lower address of the source MAC address of a packet is the same as the bit string of the intermediate address, one bit of the NIC address maker bit string of the intermediate address is changed, and the lower address and intermediate address are stored in and read from the SRAM for the designation memory.

[0018] A fourth aspect of the present invention is a method for transmitting packets from a mobile terminal to a destination server via a ring node device connected to the ring network, the method comprising: inserting a plurality of packet add, drop and pass devices in a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; connecting a base station to the packet add, drop and pass devices; and blocking the passage of a packet having a source MAC address that is the NIC MAC address of a ring network interface of the router when the source MAC address of the packet is stored in a MAC address table of the device itself, the method comprising the steps of: transmitting packets from the mobile terminal to the ring node device via the ring network as Ethernet frames of TCP and UDP for call signals, etc., and transmitting packets between the router and the server or exchange as IP packets, the method comprising the steps of: inserting a plurality of packet add, drop and pass devices in a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; connecting a base station to the packet add, drop and pass devices; When the ring network is not in a faulty state, When a packet from the mobile terminal arrives at an add, drop and pass device of the packet of the ring network, regardless of whether the packet is a packet immediately after changing the destination base station or not, storing a bit 1 in the first and second bit positions of a storage area of ​​an address location of an SRAM for a lower address and intermediate address designation memory accessed by the lower address of the source MAC address of the packet, and storing a bit 1 in the third and fourth bit positions of a storage area of ​​an address location of the SRAM accessed by the intermediate address of the source MAC address of the packet, and sending the packet onto a counterclockwise ring; When the packet arrives at a packet add, drop, or pass-through device, when a bit 1 is stored in the first and second bit positions of a storage area of ​​an address location of the SRAM for a lower address and intermediate address designation memory accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in the third and fourth bit positions of a storage area of ​​an address location of the SRAM accessed by an intermediate address of the source MAC address of the packet, storing the source MAC address of the packet in an SRAM for an address table designating the passage of the packet, and directing the packet on a counterclockwise ring to a ring node device in which a ring network interface NIC MAC address of a router to which a server is connected via a router is stored as a destination MAC address of the packet; When a packet from a server is sent to a clockwise ring from a ring node device in which the NIC MAC address of the router is stored as the source MAC address of the packet via a router, and the packet arrives at an add, drop, or pass-through device of the packet, if the destination MAC address of the packet is stored in the SRAM for the address table specifying the passage of the packet, sending the packet forward on the clockwise ring; if the destination MAC address of the packet is not stored in the SRAM for the address table specifying the passage of the packet and bit 1 is stored in the first and second bit positions of the memory area of ​​the address position of the SRAM for the lower address and intermediate address specification memory accessed with the lower address of the destination MAC address of the packet, and bit 1 is stored in the third and fourth bit positions of the memory area of ​​the address position of the SRAM accessed with the intermediate address of the destination MAC address of the packet;

[0019] A fifth aspect of the present invention is a method according to the fourth aspect of the present invention, characterized in that the mobile terminal further comprises a step of accessing a receiving mail server and, if a response packet cannot be received from the receiving mail server, sending a retransmission packet to the receiving mail server. Effect of the Invention

[0020] As described above, the present invention uses SRAM for lower address and intermediate address designation memory for designating packet transmission outside the ring instead of a MAC address table, which makes operation simple and fast, and the ring node device (device for adding, dropping and passing packets) can be realized with two SRAMs, which has the effect of reducing system costs. Also, the present invention is a method for realizing handover of a mobile terminal within one domain by a ring network using the above memory, which has the effect of reducing power consumption and system costs and enabling high-speed communication. [Brief description of the drawings]

[0021] [Figure 1]FIG. 1 is a diagram for explaining an example of handover operation of a packet forwarding system between a mobile terminal that forwards MAC packets through a base station connected to the packet add, drop and pass device in a dual ring network in which multiple devices are connected by an optical ring, and a server connected to the ring network via a router, the packet add, drop and pass device having an SRAM for lower address and intermediate address designation memory that designates packet transmission outside the ring in the first embodiment of the present invention and an address table that designates packet passing; [Figure 2A] An example of an operation flow diagram of a packet adding, dropping and passing device according to a first embodiment of the present invention. [Figure 2B] An example of an operation flow diagram of a packet adding, dropping and passing device according to a first embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0023] In Fig. 1, 1 is an optical transmission line of a counterclockwise ring, 2 is an optical transmission line of a clockwise ring, 6-1, 6-2, 6-3, and 6-4 are devices (ring node devices) for adding, dropping, and passing packets, 8 is an address table that specifies the passing of packets, 11 is an SRAM for lower addresses and intermediate addresses that specify packet transmission outside the ring, 13-1, 13-2, and 13-3 are mobile terminals, 14-1, 14-2, and 14-3 are base stations (BS), 20 is a server, and 22 is a router. In addition, (1) to (39) indicate the transfer order of packets, which are abbreviated as MAC addresses in letter symbols to be transferred on the ring indicated by the dotted lead line, and I0, I1, I2, and I3 are global IPv4 addresses that are dynamically set as IP addresses in the terminals, or domestic IPv4 addresses of service providers. Or they are IPv6 addresses. The OE conversion circuit, EO conversion circuit, input buffer, and output buffer are not shown in the figure.

[0024] The operation of Fig. 1 will be explained below. An example is shown in which the mobile terminal 13-2 for sending mail sends packet (1) Mn1γβα(I0) (M indicates an Ethernet packet, n1 indicates the wireless MAC address of the base station 14-1, r1r2 indicates the NIC MAC address of the ring network interface of the router 22, γβα indicates the upper MAC address γ, the intermediate MAC address β, and the lower MAC address α, which are the MAC addresses of the mobile terminal 13-2, and I0 indicates the IP address of the destination server) to the base station 14-1. When a packet arrives at the add, drop and pass device 6-1 from the terminal 13-2, the lower address α (for example, the 1st bit to the 17th bit) of the source MAC address of the packet is accessed, and a bit 1 is stored in the 1st bit of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory for designating packet transmission outside the ring, and the intermediate address β (for example, the 18th bit to the 34th bit) of the source MAC address of the packet is accessed, and a bit 1 is stored in the 2nd bit as the even parity of the 1st bit. A bit 1 is stored in the third bit of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by the address 17 (bits 1 to 17), and a bit 1 is stored in the fourth bit as the even parity of the third bit. When α and β have the same bit string, one bit of the NIC manufacturer of β is changed and stored, and the packet is sent to the address table 12 of the packet add, drop and pass-through device 6-4 in which the NIC MAC address of the upper ring network interface of the router 22 connected to the server 20 is stored via the currently used optical transmission line 1 of the counterclockwise ring.

[0025] When the packet is transferred by (3) Mr1r2γβα(I0) through counterclockwise ring 1 as shown in the figure and arrives at packet add, drop and pass-through device 6-2, a bit 1 is stored in the first and second bits of the address location storage area of ​​SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed with lower address α (e.g., the 1st bit to the 17th bit) of the source MAC address of the packet, and a bit 1 is stored in the first and second bits of the address location storage area of ​​SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed with intermediate address β (e.g., the 18th bit to the 34th bit as the 1st bit to the 17th bit of the memory) of the source MAC address of the packet. If bit 1 is stored in the third and fourth bits of the memory area of ​​the address location of the SRAM (11) for α, if α and β have the same bit string, and if the NIC manufacturer of β is stored with one bit changed, the source MAC address of the packet is stored in the address table that specifies the passage of the packet, but since it is not stored, the packet is sent directly to the vertex device 5 on the counterclockwise ring 1, and when the packet arrives at the packet add, drop and passage device 6-4 (vertex device), since the destination MAC address r1r2 of the packet is stored in the address table 12 for the router, the packet is dropped from the ring as (6)Mr1r2γβα(I0) toward the router 22 outside the ring. When the packet arrives at router 22, the source MAC address (γβα) and IP address (I3) of the packet are stored in an ARP table not shown in the figure, or the source MAC address (γβα) is placed in the options field of the IP header, and the IP packet is forwarded as shown in the figure by (7) IPI3I0 (IP indicates an IP address, I3 indicates the IP address of mobile terminal 13-2, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0026] Next, when a mobile terminal 13-1 receiving a telework service transmits a packet (9) Mr1r2δβα(I0) (M indicates an Ethernet packet, r1r2 indicates the NIC MAC address of the ring network interface of the router 22, δβα indicates the upper MAC address δ, the intermediate MAC address β, and the lower MAC address α, which are the MAC addresses of the terminal device 13-1, and I0 indicates the IP address of the destination server) to the device 6-1 for adding, dropping, and passing the packet via the base station 14-1, a bit 1 is stored in the first bit of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring, which is accessed by the lower address α of the source MAC address of the packet, and a bit 0 is stored in the second bit as the even parity of the first bit. A bit 1 is stored in the third bit of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address specification memory that specifies packet transmission outside the ring accessed by the intermediate address β of the source MAC address of the packet, a bit 1 is stored in the fourth bit as the even parity of the third bit, and if α and β have the same bit string, one bit of the NIC manufacturer of β is changed and stored, or the bit order of β is swapped up and down, and the packet is sent to the address table 12 in which the NIC MAC address of the ring network interface of the router 22 that is connected to the server 20 via the current optical transmission line 1 of the counterclockwise ring is stored.

[0027] When the packet is forwarded on the counterclockwise ring 1 by (10) Mr1 r2 δ β α (I0) as shown in the figure and arrives at the packet add, drop and pass device 6-2, the packet passes through the device 6-2 and arrives at the packet add, drop and pass device 6-4 (vertex device) where the destination MAC address r1 r2 of the packet is stored in the address table 12 for the router, the packet is dropped from the ring as (13) Mr1 r2 δ β α (I0) toward the router 22 outside the ring. When the packet arrives at the router 22, the source MAC address (δ β α) and IP address (I2) of the packet are stored in an ARP table (not shown) or the source MAC address (δ β α) is put in the option field of the IP header, and the IP packet is forwarded by (14) IPI2 I0 (IP indicates an IP address, I2 indicates the IP address of the mobile terminal 13-1, and I0 indicates the IP address of the destination server 20) as shown in the figure, and reaches the server 20.

[0028] Next, an example will be shown in which mobile terminal 13-2 moves from base station 14-1 to base station 14-2. When a packet (15)Mn2γβα(I0) (n2 indicates the wireless NIC MAC address of base station 14-2, and γβα indicates the MAC address of mobile terminal 13-2 (upper address γ, middle address β, lower address α)) from mobile terminal 13-2 arrives at base station 14-2, there is a packet immediately after the destination base station is changed when packet add, drop and pass through device 6-2 connected to the destination base station is a device that connects to a base station approaching server 20 on counterclockwise ring 1, and this packet is sent to packet add, drop and pass through device 6-2 as (16)Mr1r2γβα(I0). When the packet from the mobile terminal 13-2 reaches the add, drop and pass-through device 6-2, a bit 1 is stored in the first bit of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the lower address α of the source MAC address of the packet, and a bit 1 is stored in the second bit as the even parity of the first bit, and a bit 1 is stored in the third bit of the memory area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring and is accessed by the intermediate address β of the source MAC address of the packet, and a bit 1 is stored in the fourth bit as the even parity of the third bit, and the packet is sent to the address table 12 in which the NICMAC address of the upper ring network interface of the router 22 that connects to the server 20 via the working optical transmission line 1 of the counterclockwise ring is stored.

[0029] When the packet arrives at packet add, drop, and pass-through device 6-4 (vertex device) on counterclockwise ring 1 as is, since the packet's destination MAC address r1r2 is stored in address table 12 for the router, the packet is dropped from the ring as (19)Mr1r2γβα(I0) and headed for router 22 outside the ring.

[0030] When the packet arrives at router 22, the source MAC address (γβα) and IP address (I3) of the packet are stored in an ARP table not shown in the figure, or the source MAC address (γβα) is placed in the option field of the IP header, and the IP packet is forwarded as shown in the figure by (20)IPI3I0 (IP indicates an IP address, I3 indicates the IP address of the terminal connected to terminal device 13-2, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0031] Next, when a response packet (21) IPI0I2 (IP indicates an IP address, I2 is the IPv6 address or IPv4 address of terminal device 13-1, and I0 is the IP address of server 20) for the upload packet from server 20 arrives at router 22, if the packet is an IPv6 address, the destination MAC address of the packet's destination IPv6 address I2 is copied from the MAC address portion of the destination IPv6 address, and a MAC packet (22) Mδβαr1r2 (I2) used as the MAC header address of the MAC packet is sent to packet add, drop, and pass-through device 6-4 (apex device) of the ring network. If the packet is an IPv4 address, the destination MAC address δβα paired with the destination IP address I2 of the packet is obtained from an ARP table (not shown in the figure), and a MAC packet (22)Mδβαr1r2(I2) using the MAC address in the optional field of the IP header as the destination MAC address and the NIC MAC address r1r2 of the ring network interface of router 22 as the source MAC address is sent to device 6-4 (vertex device) for adding, dropping, and passing packets in the ring network.

[0032] When the MAC packet (22) Mδβαr1r2 (I2) arrives at packet add, drop and pass-through device 6-4 (vertex device), the source MAC address of the packet is stored in address table 12 for router connection, so the packet is sent to clockwise ring 2.

[0033] When a packet (23)Mδβαr1r2 (I2) is transferred through clockwise ring 2 and arrives at packet add, drop, and pass-through device 6-2, the destination MAC address δβα of the packet is not stored in address table 8 specifying the passage of the packet, and bit 1 is stored in the first bit of the storage area of ​​the address location of SRAM (11) for the lower address memory specifying packet transmission outside the ring accessed by the lower address α of the destination MAC address of the packet, and bit 1 is stored in the second bit as the even parity of the first bit, and bit 1 is stored in the third bit of the storage area of ​​the address location of SRAM (11) for the lower address memory specifying packet transmission outside the ring accessed by the intermediate address β of the destination MAC address of the packet, and bit 1 is stored in the fourth bit as the even parity of the third bit, so that the packet is sent outside the ring as (25)Mδβαr1r2 (I2). When the packet arrives at base station 14-2, the packet is discarded because the destination MAC address of the packet is not stored in a MAC address table (not shown).

[0034] Next, when the mobile terminal 13-1 transmits a retransmission packet (26) Mn1δβα(I0) (M indicates an Ethernet packet, n1 indicates the MAC address of the base station 14-1, δβα indicates the upper MAC address δ, the middle MAC address β, and the lower MAC address α which are the MAC addresses of the terminal device 13-1, and I0 indicates the IP address of the destination server) to the packet add, drop, and pass-through device 6-1 via the base station 14-1, a bit 1 is stored in the first bit of the memory area of ​​the address position of the SRAM (11) for the lower address and middle address designation memory which designates packet transmission outside the ring and is accessed by the lower address α of the source MAC address of the packet, and a bit 1 is stored in the second bit as the even parity of the first bit, and the packet A bit 1 is stored in the third bit of the storage area of ​​the address position of the SRAM (11) for the lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by the intermediate address β of the source MAC address of the packet, and a bit 1 is stored in the fourth bit as the even parity of the third bit. If α and β have the same bit string, one bit of the NIC manufacturer of β is changed and stored, or the bit order of β is swapped up and down, and the packet is sent to the address table 12 in which the NIC MAC address of the ring network interface of the router 22 that is connected to the server 20 via the current optical transmission line 1 of the counterclockwise ring is stored.

[0035] When the packet is transferred by (28) Mr1r2δβα(I0) through counterclockwise ring 1 as shown in the figure and arrives at device 6-2 for adding, dropping, and passing packets, bit 1 is stored in the first and second bits of the storage area of ​​the address location of SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by lower address α (e.g., bits 1 to 17) of the source MAC address of the packet, and bit 1 is stored in the first and second bits of the storage area of ​​the address location of SRAM (11) for lower address and intermediate address designation memory that designates packet transmission outside the ring accessed by intermediate address β (e.g., bits 18 to 34 are set as bits 1 to 17 of the memory) of the source MAC address of the packet. When bit 1 is stored in the third and fourth bits of the memory area of ​​the address location of the SRAM (11) for the specified lower address and intermediate address specification memory, and when α and β are the same bit string, and β is stored with one bit of the NIC manufacturer changed, the source MAC address δβα of the packet is stored in the address table that specifies the passage of the packet, and when the destination MAC address r1r2 of the packet arrives at the packet add, drop and passage device 6-4 (vertex device) where the packet's destination MAC address r1r2 is stored in the address table 12 for the router, the packet is dropped from the ring as (31)Mr1r2δβα(I0) toward the router 22 outside the ring. When the packet arrives at router 22, the source MAC address (δβα) and IP address (I2) of the packet are stored in an ARP table (not shown), or the source MAC address (δβα) is placed in the options field of the IP header, and the IP packet is forwarded as shown in the figure by (32)IPI2I0 (IP indicates an IP address, I2 indicates the IP address of mobile terminal 13-1, and I0 indicates the IP address of the destination server 20), and reaches server 20.

[0036] Next, when a response packet (33) IPI0I2 (IP indicates an IP address, I2 is the IPv6 address or IPv4 address of terminal device 13-1, and I0 is the IP address of server 20) of the retransmitted packet (32) from server 20 arrives at router 22, if the packet is an IPv6 address, the destination MAC address of the packet's destination IPv6 address I2 is copied from the MAC address portion of the destination IPv6 address, and a MAC packet (34) Mδβαr1r2 (I2) used as the MAC header address of the MAC packet is sent to packet add, drop, and pass-through device 6-4 (apex device) of the ring network. If the packet is an IPv4 address, the destination MAC address δβα paired with the destination IP address I2 of the packet is obtained from an ARP table (not shown in the figure), and a MAC packet (34)Mδβαr1r2(I2) using the MAC address in the optional field of the IP header as the destination MAC address and the NIC MAC address r1r2 of the ring network interface of router 22 as the source MAC address is sent to device 6-4 (apex device) for adding, dropping, and passing packets in the ring network.

[0037] When the MAC packet (34) Mδβαr1r2 (I2) arrives at packet add, drop and pass-through device 6-4 (vertex device), the source MAC address of the packet is stored in address table 12 for router connection, so the packet is sent to clockwise ring 2.

[0038] When packet (35)Mδβαr1r2(I2) is forwarded through clockwise ring 2 and arrives at packet add, drop, and pass-through device 6-2, the packet is sent to clockwise ring 2 because the destination MAC address δβα of the packet is stored in address table 8, which specifies the pass-through of the packet. When the packet (37) Mδβαr1r2 (I2) is transferred through clockwise ring 2 and arrives at packet add, drop, and pass device 6-1, the destination MAC address δβα of the packet is not stored in address table 8 specifying the pass of the packet, and bit 1 is stored in the first bit of the storage area of ​​the address position of SRAM (11) for the lower address and intermediate address designation memory specifying packet transmission outside the ring, which is accessed by the lower address α of the destination MAC address of the packet, and bit 1 is stored in the second bit as the even parity of the first bit, and bit 1 is stored in the third bit of the storage area of ​​the address position of SRAM (11) for the lower address and intermediate address designation memory specifying packet transmission outside the ring, which is accessed by the intermediate address β of the destination MAC address of the packet, and bit 1 is stored in the fourth bit as the even parity of the third bit, so that the packet is sent outside the ring. When the packet arrives at base station 14-1, the destination MAC address of the packet is stored in a MAC address table (not shown), so the packet is headed for destination mobile terminal 13-1.

[0039] Next, Fig. 2A and Fig. 2B show an example of an operation flow diagram of the device for adding, dropping and passing packets in the first embodiment. In Fig. 2A, 100 judges whether a packet has arrived from the clockwise ring, and if YES, 101 judges whether the destination MAC address of the received packet is stored in the address table that specifies the passing of the packet, and if NO, 102 judges whether bit 1 is stored in the first and second bits of the data storage area of ​​the address position of the memory for packet dropping (SRAM for the lower address and intermediate address specification memory that specifies the packet sending out of the ring) accessed by the lower address of the destination MAC address of the received packet, and whether bit 1 is stored in the third and fourth bits of the data storage area of ​​the address position of the memory for packet dropping accessed by the intermediate address of the destination MAC address of the received packet, and if YES, 103 sends the received packet out of the ring and returns to (a). If NO, 104 sends the received packet forward to the clockwise ring and returns to (a). If NO at 100, transition to (b). If the answer is YES at 101, the process transitions to 104. In FIG. 2B, 105 judges whether a packet has arrived from the ADD line, and if Yes, stores bit 1 in the first and second bits of the data storage area of ​​the address position of the memory for packet dropping (SRAM for the lower address memory and intermediate address specification memory for specifying packet transmission outside the ring) accessed by the lower address of the source MAC address of the received packet of 106, stores bit 1 in the third and fourth bits of the data storage area of ​​the address position of the memory for packet dropping accessed by the intermediate address of the source MAC address of the received packet, sends the received packet of 107 to the front of the ring in a counterclockwise direction, and returns to (a). If NO in 105, it is determined whether a packet has arrived from the counterclockwise ring in 108, and if YES, it is determined whether bit 1 is stored in the first and second bits of the data storage area of ​​the address position of the memory for packet drop (SRAM for the lower address memory and the intermediate address designation memory for specifying packet transmission outside the ring) accessed by the lower address of the source MAC address of the received packet in 109, and whether bit 1 is stored in the third and fourth bits of the data storage area of ​​the address position of the memory for packet drop accessed by the intermediate address of the source MAC address of the received packet, and if YES, it is determined whether the source MAC address of the received packet in 110 is stored in the address table for specifying the passage of the packet, and the received packet in 111 is sent forward to the counterclockwise ring, and transition is made to (a). If NO in 108, it returns to (a). If NO in 109, it transitions to 111.

[0040] In the first embodiment, bit 1 is stored in the first and second bits of the storage area of ​​the address position of the SRAM accessed by the lower address of the destination MAC address of the packet in the ring node device, and bit 1 is stored in the third and fourth bits of the storage area of ​​the address position of the SRAM accessed by the intermediate address of the destination MAC address of the packet in the ring node device, and the problem is the number of stored MAC addresses in the address table that specifies the passage of the packet. Incidentally, if the number of packet terminals to be added to the ring is 10,000, the number of terminals to be transferred on the ring is 100,000, and the number of address designation bits of the SRAM is 17 bits, then 10,000*100,000*10,000 / EXP(17ln2) / EXP(17ln2)=580, and there is no problem in realizing the first embodiment. In addition, the method of using 24-bit lower address memory may cause problems with skew and hazards in the logic circuit of the decoder ASIC. If a decoder memory is used to avoid this, it will become a ROM, which will slow down the operation. In addition, since the first embodiment can be configured using only existing memory, it is easy to introduce into a LAN.

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

[0042] In the case of a ring fault in the first embodiment, it can be handled without flooding by steering or both-ring loopback. In the case of both-ring loopback, when a ring network fault occurs, the add, drop and pass devices of the packet on both sides of the fault point loop back, and when the loopback occurs, a loopback bit is added, and the packet with the loopback bit added passes through all the devices up to the second loopback point, and the loopback bit is removed at the second loopback. [Explanation of symbols]

[0043] 1. Counterclockwise ring optical transmission line 2. Clockwise ring optical transmission line 5 Vertex device 6-1, 6-2, 6-3 Packet Add, Drop and Pass Devices 8 Address table that specifies the passage of packets 11 SRAM for lower address and intermediate addressing memory for packet sending out of the ring 12 Address table for router connections 13-1, 13-2, 13-3, 13-4 Terminal equipment 14-1, 14-2, 14-3 Base station (BS) 20 Servers 22 Router

Claims

1. a ring node device on a ring network having a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1, a plurality of devices for adding, dropping and passing packets are inserted into the ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1, an L2 switch and a base station are connected to the devices for adding, dropping and passing packets, and a terminal and a mobile terminal under each of the L2 switch and the base station have a function of receiving a packet arriving from the counterclockwise ring of the ring network and transferring it to a router, and a function of blocking the passage of a packet having a NIC MAC address of a ring network interface of the router as a source MAC address when the source MAC address of the packet is stored in a MAC address table of the device itself, the system allowing packets from the terminal and the mobile terminal to travel between the router and a destination server via the router connected to the router as TCP, TCP and UDP Ethernet frames for call signals, etc., across the ring network, and IP packets between the router and the server, and between the router and the server or the switch, When the ring network is not in a faulty state, When a packet from the terminal or mobile terminal arrives at an add, drop, or pass-through device of the packet of the ring network, regardless of whether the packet is a packet immediately after a change of a destination base station or whether the packet is a communication start packet, storing a bit 1 in the first and second bit positions of a storage area of ​​an address location of an SRAM for a lower address and intermediate address designation memory accessed by the lower address of the source MAC address of the packet, and storing a bit 1 in the third and fourth bit positions of a storage area of ​​an address location of the SRAM accessed by the intermediate address of the source MAC address of the packet, and sending the packet onto a counterclockwise ring; When the packet arrives at a packet add, drop, or pass-through device, means for storing the source MAC address of the packet in an SRAM for an address table designating a packet's passage when a bit 1 is stored in the first and second bit positions of a storage area of ​​an address position of the SRAM for a lower address and intermediate address designation memory accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in the third and fourth bit positions of a storage area of ​​an address position of the SRAM accessed by an intermediate address of the source MAC address of the packet, and directing the packet on a counterclockwise ring to a ring node device in which a ring network interface NIC MAC address of a router to which a server is connected via a router is stored as a destination MAC address of the packet; When a packet from a server is sent to a clockwise ring from a ring node device in which the NIC MAC address of the router is stored as the source MAC address of the packet via a router, and the packet arrives at an add, drop, or pass-through device of the packet, means for transmitting the packet to the front of the clockwise ring when the destination MAC address of the packet is stored in an SRAM for an address table specifying the passage of the packet, transmitting the packet to the outside of the ring when the destination MAC address of the packet is not stored in the SRAM for the address table specifying the passage of the packet and bit 1 is stored in the first and second bit positions of a storage area of ​​an address position of an SRAM for a lower address and intermediate address specification memory accessed by a lower address of the destination MAC address of the packet and bit 1 is stored in the third and fourth bit positions of a storage area of ​​an address position of the SRAM accessed by an intermediate address of the destination MAC address of the packet, and transmitting the packet to the front of the clockwise ring in other cases.

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

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

4. a ring node device on a ring network connected to the ring node device on the ring network, the ring node device having a function of receiving a packet arriving from the left-handed ring of the ring network and transferring the packet to a router and a function of blocking the passage of a packet having a NIC MAC address of a ring network interface of the router as a source MAC address of the packet when the source MAC address of the packet is stored in a MAC address table of the ring node device, the method comprising: inserting a plurality of packet add, drop and pass devices in a ring network of a clockwise ring transmission path 2 and a counterclockwise ring transmission path 1; and passing packets from the mobile terminal to and from the ring node device on the ring network as TCP and UDP Ethernet frames for call signals or the like across the ring network and as IP packets between the router and the server or exchange, in order to communicate with a destination server via the ring node device connected to the router for email communication, video conference involving call signals or content distribution, the method comprising: When the ring network is not in a faulty state, When a packet from the mobile terminal arrives at an add, drop and pass device of the packet of the ring network, regardless of whether the packet is a packet immediately after changing the destination base station or not, storing a bit 1 in the first and second bit positions of a storage area of ​​an address location of an SRAM for a lower address and intermediate address designation memory accessed by the lower address of the source MAC address of the packet, and storing a bit 1 in the third and fourth bit positions of a storage area of ​​an address location of the SRAM accessed by the intermediate address of the source MAC address of the packet, and sending the packet onto a counterclockwise ring; When the packet arrives at a packet add, drop, or pass-through device, when a bit 1 is stored in the first and second bit positions of a storage area of ​​an address position of the SRAM for a lower address and intermediate address designation memory accessed by a lower address of the source MAC address of the packet, and a bit 1 is stored in the third and fourth bit positions of a storage area of ​​an address position of the SRAM accessed by an intermediate address of the source MAC address of the packet, storing the source MAC address of the packet in an SRAM for an address table designating a packet passage, and directing the packet on a counterclockwise ring to a ring node device in which a ring network interface NIC MAC address of a router to which a server is connected via a router is stored as a destination MAC address of the packet; When a packet from a server is sent to a clockwise ring from a ring node device in which the NIC MAC address of the router is stored as the source MAC address of the packet via a router, and the packet arrives at an add, drop, or pass-through device of the packet, sending the packet forward on the clockwise ring if the destination MAC address of the packet is stored in an SRAM for an address table specifying the passage of the packet, sending the packet out of the ring if the destination MAC address of the packet is not stored in the SRAM for the address table specifying the passage of the packet and if a bit 1 is stored in the first and second bit positions of a storage area of ​​an address location of an SRAM for a lower address and intermediate address specification memory accessed with a lower address of the destination MAC address of the packet and a bit 1 is stored in the third and fourth bit positions of a storage area of ​​an address location of the SRAM accessed with an intermediate address of the destination MAC address of the packet, and sending the packet forward on the clockwise ring otherwise.

5. 5. The method according to claim 4, further comprising the step of: said mobile terminal accessing a receiving mail server, and sending a retransmission packet to the receiving mail server if the mobile terminal is unable to receive a response packet from the receiving mail server.

Images