JP2023123314A - Packet transfer system that performs handover by using ring network using low-order address storage method - Google Patents

Abstract

To provide a packet transfer system that realizes a handover of a radio system at low cost at high speed.SOLUTION: A packet transfer system is configured to: in the case with an initial packet from a mobile terminal through a mobile destination base station, having reached a packet-added device, a packet-dropped device, and a packet-passed device (node devices), and with a deleted-low-order address storage memory having stored the low-order address of a transmission source MAC address of the packet. leave it as it is, or otherwise, with the deleted-low-order address storage memory having not stored the low-order address of the transmission source MAC address of the packet, store the low-order address of the transmission source MAC address of the packet into a low-order address memory for designating packet transmission to the outside of a ring, and transmit the packet to a front side of a counterclockwise ring, and then, when the packet reaches the node device, with the low-order address memory for designating packet transmission to the outside of the ring, having stored the low-order address of the transmission source MAC address of the packet, delete the low-order address.SELECTED DRAWING: Figure 1

Description

The present invention relates to a packet transfer system that performs handover using a ring network that transfers Ethernet packets using a MAC address lower order address storage method.

As a conventional example of the address storage method, there is Japanese Unexamined Patent Application Publication No. 2000-151617 entitled "Table Creation and Search Apparatus". This conventional example relates to a MAC address storage circuit, and includes a first table composed of a RAM having a matrix address, a MAC address data area, and an index area, a RAM having a matrix address, a MAC address data area, and an index area. and so on. In this conventional example, the entire 48-bit MAC address is stored in the location A, which designates the memory of the first table with the low-order bit string (for example, 16 bits). If another MAC address is already stored in the position A, it is recorded in the free address position B of the memory of the second table, and the recorded address position B is stored in the address position A of the first table. Store in the index area. This is a method of specifying recording areas by nesting.

Further, as a conventional technique of the address storage method, there is Japanese Unexamined Patent Application Publication No. 2004-15592 of Patent Document 2, "MAC Address Pointer Structure, MAC Address Rearrangement Method". This conventional example is a method of storing a plurality of MAC addresses in the same address position of the entry table specified by the low-order bit string. If there is no free area, the MAC address is stored in an entry table designated by a lower bit string different from the lower bit string of the MAC address.

As a conventional example of a ring network, a ring network using a master switch and a slave switch as in Patent Document 3 is common. In this ring network, one ring port of the master switch is a block port that does not allow frames to pass through, preventing congestion due to flooding. If a failure occurs in the ring network, the monitoring frame sent from the master switch and returned to the master switch will not be delivered. Instead, the failure notification frame will be delivered to the master switch from the slave switch at the failure point. unblock the blocked port of the to pass the frame. Also, a block port is set on the failed transmission line side of one of the slave switches at the failure point, and the operation of the ring network is maintained even after the failure of the ring network is recovered.

Further, as a conventional example of handover in a wireless network, there is Patent Document 4. In this prior art, the handover of a network that communicates with a mobile terminal via a base station from a control station that transfers ATM cells is performed by delay D1 from the control station to the mobile terminal via the source base station and When the difference in delay D2 from the base station to the mobile terminal is (D1-D2>0), the ATM cell is delayed by the control station when the base station of the ATM cell sent from the control station to the mobile terminal is switched, This is a method that is executed by switching to prevent order reversal of ATM cells.

Moreover, there is Patent Document 5 as an example of another handover method. This prior art has a connection via a base station and a gateway between a mobile terminal and a server via a base station before switching and a connection via a switching destination base station, and packets via the connection reduce the disconnection time when the connection is switched. The method.

Japanese Patent Application Laid-Open No. 2000-151617 Japanese Patent Application Laid-Open No. 2004-15592 Retable 2008-068813 Japanese Patent Application Laid-Open No. 2001-128212 Retable 2017-195497

Conventional example of conventional address storage method JP-A-2000-151617 stores MAC addresses by nesting, so there is a problem that it takes a long time to trace the storage addresses. Also, since the entire 48 bits of the essential MAC address are stored, there is a problem that the storage area becomes large.

Further, Japanese Patent Laid-Open No. 2004-15592, which is a conventional example of a conventional address storage method, describes that if there is no space in the entry table position of the MAC address specified by the lower bit string, the MAC address is stored in the entry table position of a different lower bit string. However, in that case, when selecting a location to store the MAC address, it is necessary to search the entry table location specified by the two low-order bit strings, and at the same address location of the same entry table, Since there are multiple storage addresses, multiple address comparisons need to be made, and the problem is that retrieval is time consuming.
Searching for the MAC address by the low-order bit string is fast, but the method of basically storing the entire MAC address in the low-order bit string position is accurate storage. I have a few problems.
Patent Document 3, which is a conventional ring network, uses a MAC address table that uses 48-bit MAC addresses, so it has the drawback that the number of MAC addresses that can be stored is small.

In Patent Document 4 of the conventional handover, it is necessary to find the difference between the delay between the path before switching and the path after switching from the control station to the mobile terminal. Since it can only be measured as half of the round-trip time from the terminal to the mobile terminal, there is a problem of lack of accuracy in measuring the delay time.

Further, in Patent Document 5 of the conventional handover, since two connections are provided between the server and the mobile terminal for switching, it is necessary to identify the two connections, which has the drawback of complicating the handover control.

An object of the present invention is to present an address storage method that does not use a conventional MAC address table, and to present a method for realizing easy handover and short-distance movement of a mobile terminal using a ring network.

The present invention has been made in view of the above-mentioned problems of the prior art, and the means for solving the problems is as follows.
One base station is accommodated in a device for adding, dropping, and passing packets of a ring network, and mobile terminals under the base station block passage of MAC packets other than OAM packets arriving from the clockwise ring of the ring network. A packet transfer system that enables movement between base stations of a mobile terminal of a network that communicates mainly by MAC packets between a vertex device of the ring network and a server connected via a gateway or a router,
When a packet from the server direction arrives at the router, if the destination MAC address of the packet is stored in the duplicated lower address address table, the packet has a duplicated lower address bit and the duplicated lower address. A copy packet of that packet is sent with an identification bit, and the copy packet waits until the response packet of the copy packet arrives. When a packet is sent from a device to a clockwise ring and arrives at a device that adds, drops, or passes a packet, the packet is given a bit indicating a duplicate lower address, and the copy packet bit is given. and the lower address of the destination MAC address of the packet is stored in the erased lower address storage memory, the blocking bit is stored at that address location together with the identification bit of the duplicate lower address, and the packet is is copied, the copy packet is sent forward in a clockwise direction, the original packet is sent out of the ring, and when the response packet for that packet arrives, only the blocking bit is deleted, and the packet is sent to the router. In addition to the above, when a bit indicating a duplicate lower address is added to the packet, and the lower address of the destination MAC address of the packet is stored in a lower address memory that designates packet transmission outside the ring if so, erasing the lower address in the lower address memory, storing the lower address in the erased lower address memory, storing a blocking bit and a duplicate lower address identification bit in the lower address location; Copy the packet, send the copy packet to the front of the ring in a clockwise direction, send the original packet out of the ring, and when a response packet for that packet arrives, delete only the blocking bit, and send the packet. When a packet sent to a router and arriving from a clockwise ring is assigned a bit indicating a duplicated lower address and the bit of a copy packet is not assigned, the lower address of the destination MAC address of the packet is A duplicate low address stored in an erased low address memory, and no blockage bit is stored in that low address location, and the duplicate low address identification bit for the packet is stored in that low address location. Send the packet out of the ring if it matches the identification bit, otherwise send it forward in the clockwise ring,
In cases other than the above, when a bit indicating a duplicate lower address is not added to the packet, and the lower address of the destination MAC address of the packet is stored in the lower address memory that specifies packet transmission outside the ring. If so, the packet is sent out of the ring, and if the lower address of the destination MAC address of the packet is not stored in the lower address memory that specifies packet sending out of the ring, the packet is rotated clockwise. means for delivering forward of the ring;
When a MAC packet from the mobile terminal via the base station arrives at the ring network packet add, drop and pass device,
Regardless of whether said packet is the first packet via the target base station or not the first packet,
If the lower address of the source MAC address of the packet is not stored in the erased lower address storage memory, the lower address of the source MAC address of the packet is stored in the lower address memory designating transmission of the packet out of the ring. If the lower address of the source MAC address of the packet is stored in the erased lower address storage memory, a bit indicating duplicate lower address is added to the packet, and the packet is sent to the top of the counterclockwise ring. directed to the server through the device,
When the packet arrives at a device for adding, dropping, and passing packets, if the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet transmission out of the ring, the lower address The lower address of the memory is erased, the lower address of the transmission source MAC address of the packet is stored in the erased lower address storage memory, a bit indicating a duplicate lower address is added to the packet, and the packet is transferred to the left. directed to the server through a vertex device on a rotating ring;
When the packet arrives at the router, if the packet has a duplicated lower address bit, the source MAC address of the packet is added to the duplicated lower address address table and the duplicated lower address identification bit and means for storing together.

As described above, the present invention replaces the conventional MAC address table with a lower address memory designating packet transmission outside the ring applied to a 1-bit storage method that means lower address storage in a lower address memory. and erase lower address storage memory are used in the node device of the ring network, and the node device is used to perform handover of the mobile station, so handover can be performed easily, power consumption and system cost can be suppressed, and high speed can be achieved. It has the effect of being able to communicate with

A device for adding, dropping, and passing a plurality of packets having a lower address memory for designating packet transmission out of the ring and an erase lower address storage memory for transferring Ethernet packets according to the first embodiment of the present invention is an optical transmission line. FIG. 4 is a diagram for explaining network handover operation in which a ring network connected by 1 is used for communication between a mobile terminal and a server; Out-of-ring device for adding, dropping and passing packets having low-order address memory and erasing low-order address storage memory for transferring Ethernet packets according to the first embodiment of the present invention. FIG. 4 is an explanatory diagram of a configuration example of a lower address memory that specifies packet transmission;

A first embodiment of the present invention will be described with reference to FIG. In this embodiment, a counterclockwise ring and a vertex device in which a plurality of packet add, drop, and pass devices having an erasing lower address storage memory and a lower address memory specifying packet transmission outside the ring, and a server are connected to each other are connected. A base station belonging to a server connected via a router to said vertex device of a double ring network connected by a clockwise ring optical transmission line whose transmission direction is opposite to that of the ring, and a device for adding, dropping and passing said packet. This is an example of handover operation using a ring network in which subordinate mobile terminals transfer Ethernet packets. Said server is an Internet connection server or a content server.

In FIG. 1, 1 is a subscriber system counterclockwise ring, 2 is a subscriber system clockwise ring, 6-1, 6-2, 6-3 are packet add, drop and pass devices, and 7 is an outside ring. 9 is an erased lower address memory, 11 is an auxiliary address table in which base station MAC addresses are stored, 22 is a router, 12-1, 12-2 and 12-3 are base stations. Station, 13-1, 13-2, 13-3 are mobile terminals receiving TCP or UDP packets, 14 is mobile terminal movement, 20 is a server, 30-1 is a first memory, 30-2 is a duplicate. An address table of lower addresses, 32 is a mobile control station. Also, (1) to (44) are packets, and I0, I1, I2, I3, and I4 are domestic or regional IP addresses of service providers. or an IPv6 address. Packet add, drop and pass devices are devices that operate at the layer 2 level. Dotted lines in the figure are lead lines for explanation.
A base station may also have a relay TCP circuit for TCP packet communication. A mobile terminal that receives a UDP packet sends a response packet to the server when it receives a packet with a copy bit added.

The operation of FIG. 1 will be described below. First, it is assumed that the IP address I1 of the router 22 and the MAC address r1r2 of the ring transmission interface are already stored in the ARP tables of the TCP mobile terminals 13-1, 13-2, and 13-3. The TCP mobile terminal 13-3 sends packet (1) Mr1r2a4a2 (I0) (M indicates an Ethernet packet, r1 indicates the upper MAC address of the interface of the router 22, r2 indicates the lower MAC address, a4a2 indicates the TCP mobile terminal 13-3 and I0 indicates the IP address of the destination server 20) is sent to the packet add, drop and pass device 6-3. When the packet reaches the add, drop, and pass device 6-3 from the TCP mobile terminal 13-3, the lower address a2 of the source MAC address of the packet is set to the lower address that designates the transmission of the packet out of the ring. It is stored in the address memory 7. The packet is forwarded by (2) Mr1r2a4a2 (I0) on counterclockwise optical ring 1 and arrives at vertex device 5 as shown in the figure. The packet is sent out of the ring and reaches router 22 .

When the packet (3) Mr1r2a4a2 (I0) arrives at the router 22, the IP packet IPI4I0 (IP indicates the IP packet, I4 indicates the IP address of the source mobile station 13-3, I0 indicates the IP address of the source mobile station 13-3, and I0 is the server 20 ) is sent to the server 20 .

Next, the TCP mobile terminal 13-2 sends a packet (5) Mr1r2a3a2 (I0) (M indicates an Ethernet packet, r1 indicates the upper MAC address of the interface of the router 22, r2 indicates the lower MAC address, a3a2 indicates the TCP mobile terminal 13-3, and I0 indicates the IP address of the destination server 20) is sent to the packet add, drop, and pass device 6-2. indicates When the packet reaches the add, drop, and pass device 6-2 from the TCP mobile terminal 13-2, the lower address a2 of the source MAC address of the packet is set to the lower address that designates the transmission of the packet out of the ring. It is stored in the address memory 7. The packet is forwarded by (6) Mr1r2a3a2 (I0) on counterclockwise optical ring 1, and arrives at packet add, drop and pass device 6-3.

When the packet (6) Mr1r2a3a2 (I0) arrives at the packet add/drop/pass device 6-3, the lower address a2 of the packet transmission source MAC address is the lower address designating the packet transmission out of the ring. Since it is stored in the memory 7, the lower address a2 is erased, the lower address a2 is stored in the erased lower address storage memory 9, and a bit indicating duplicate lower address is added to the packet. A horizontal line indicates that the lower address a2 is erased. The packet is forwarded by (7) Mr1r2a3a2 (I0) on anticlockwise ring 1 and arrives at vertex device 5 as shown. The packet is sent out of the ring and reaches router 22 .

When the packet (8) Mr1r2a3a2 (I0) arrives at the router 22, the source MAC address a3a2 and the source IP address I3 of the packet are stored in the first memory 30-1, and the overlapping lower address is stored in the packet. Since the bit indicating that is given, the source MAC address a3a2 of the packet is stored in the duplicated lower address table 30-2, and the IP packet (9) IPI3I0 (IP indicates an IP packet, IP3 indicates indicates the IP address of the source mobile station 13-2, and I0 is the destination IP address of the server 20).

Next, the TCP mobile station 13-1 sends a packet (10) Mr1r2a1a2 (I0) (M indicates an Ethernet packet, r1 is the upper address of the destination MAC address of the router 22, and r2 is the lower address. a1a2 indicates the upper MAC address a1 and the lower MAC address a2 which are the MAC addresses of the TCP mobile terminal 13-1, and I0 indicates the IP address of the destination server 20). 1 is shown. When the packet reaches the add, drop and pass device 6-1 from the TCP mobile station 13-1, the lower address memory 7 designates transmission of the packet out of the ring with the lower address a2 of the source MAC address of the packet. memorize to The packet is forwarded by (11) Mr1r2a1a2 (I0) on counterclockwise ring 1 as shown in the figure and arrives at packet add, drop and pass device 6-2.

When the packet (11) Mr1r2a1a2 (I0) arrives at the packet add/drop/pass device 6-2, the lower address a2 of the packet transmission source MAC address is the lower address designating the packet transmission out of the ring. Since it is stored in the memory 7, the lower address a2 is erased, the lower address a2 is stored in the erased lower address storage memory 9, and a bit indicating duplicate lower address is added to the packet. The packet is forwarded by (12) Mr1r2a1a2 (I0) on counterclockwise ring 1, and arrives at packet add, drop and pass device 6-3. The fact that the lower address a2 is erased is shown by drawing a horizontal line through the letter a2, which is the label of the lower address, in the drawing.

When the packet (12) Mr1r2a1a2 (I0) arrives at the packet add, drop and pass device 6-3, the lower address a2 of the source MAC address of the packet is stored in the erased lower address storage memory 9. Therefore, a bit indicating a duplicate lower address is given to the packet, and the packet is forwarded by (13) Mr1r2a1a2 (I0) in counterclockwise ring 1 as shown in the figure, via vertex device 5, router 22 (14) as Mr1r2a1a2 (I0).

When the packet (14) Mr1r2a1a2 (I0) arrives at the router 22, the source MAC address a1a2 and the source IP address I2 of the packet are stored in the first memory 30-1, and the overlapping lower address is stored in the packet. Since the bit indicating that is given, the source MAC address a1a2 of the packet is stored in the address table 30-2 of duplicated lower addresses, the output port corresponding to the destination IP address I0 of the packet is read, and Send out. The packet is shown by (15) IPI2I0 (IP indicates an IP address, I2 indicates the IP address of the source terminal 13-1, and I0 indicates the IP address of the destination server 20). to reach the server 20 .

Next, when the TCP mobile station 13-2 moves from passing through the base station 12-2 to under the control of the base station 12-1, before that, the MAC of the base station 12-1 is transmitted from the mobile control station 32 that controls the base station. Since a control packet containing information on the movement of the mobile station 13-2 whose destination MAC address is the address B1 has arrived at the base station 12-1, the movement of the mobile station 13-2 is permitted by the destination base station 12-1. A request packet is sent to the server 20 . When the packet (16) Mr1r2a3a2 (I0) arrives at the router 22 as (19) Mr1r2a3a2 (I0), the source MAC address a3a2 and source IP address I3 of the packet are stored in the first memory 30-1. , since a bit indicating a duplicated lower address is added to the packet, the source MAC address a3a2 of the packet is stored in the duplicated lower address address table 30-2, and is associated with the destination IP address I0 of the packet. Read an output port and send to that port. The packet is shown by (20) IPI3I0 (IP indicates an IP address, I3 indicates the IP address of the source terminal 13-2, and I0 indicates the IP address of the destination server 20). is sent to the server 20 at . The server 20 authenticates the movement of the mobile terminal 13-2 to the destination base station 12-1 by the packet.

Packet (21) IPI0I3 (IP indicates an IP packet, I0 indicates the source IP address of the server 20, and I3 indicates the destination IP address to the mobile terminal 13-2) from the server 20. ) arrives at the router 22, the destination IP address I3 of the packet is stored in the first memory 30-1, so the MAC address a3a2 paired with the IP address I3 is read, and the IP packet and the interface MAC address r1r2 of the router 22 as the source MAC address. , the packet (22) Ma3a2r1r2 (I3) is sent from the vertex device 5 to the right Send to the rotating ring 2 .

Next, the procedure for transferring the packet (22) Ma3a2r1r2 (I3) arriving at the vertex device 5 through the clockwise optical ring 2 will be described. Packet (23) Ma3a2r1r2 (I3) is transferred as shown in the figure and arrives at packet add, drop and pass device 6-3. Packet (23) Ma3a2r1r2 (I3) is not a communication start packet, but the lower address a2 of the destination MAC address of the packet is stored in the erased lower address storage memory 9, and the bit indicating the duplicate lower address is duplicated in the packet. Since bit 1 of the lower address identification bit is added, the packet is sent out of the ring as (24) Ma3a2r1r2 (I3). At this time, a blocking bit (indicated by symbol B in the figure) is stored in the lower address position of the erase lower address memory 9 . Bit 1 of the duplicate lower address identification bit is also stored but not shown in the figure. Bit 1 of the duplicated lower address identification bits is used to identify which lower address of the duplicated lower addresses the packet that arrives later is, and this bit is also given by the router to the packet that arrives later. When the packet (24) Ma3a2r1r2c (I3) is sent out of the ring, a copy packet of that packet is sent to the clockwise ring as (25) Ma3a2r1r2c (I3).

When the packet (25) Ma3a2r1r2c (I3) arrives at the packet add/drop/pass device 6-2, the packet is not a communication start packet, and the lower address a2 of the destination MAC address of the packet is erased from the lower address storage. Since the packet is stored in the memory 9 and has a duplicated lower address bit and a duplicated lower address identification bit bit 1, the packet is sent out of the ring as (26) Ma3a2r1r2c (I3). . At this time, a blocking bit (indicated by B in the figure) is stored in the lower address position of the erase lower address memory 9 . When the packet (26) Ma3a2r1r2c (I3) is sent out of the ring, a copy packet of that packet is sent to the clockwise ring as (27) Ma3a2r1r2c (I3). When the packet add, drop and pass device 6-2 sends out (26) Ma3a2r1r2c (I3) outside the ring, it temporarily stores the destination MAC address of the packet in a memory (not shown), and generates a response packet for that packet. does not arrive from outside the ring within a fixed time, the lower address of the destination MAC address of the copy packet is deleted from the erase lower address storage memory 9.

When the packet (27) Ma3a2r1r2c (I3) reaches the packet add/drop/pass device 6-1, the packet is not a communication start packet and the lower address a2 of the destination MAC address of the packet is The packet is not stored in the erased lower address storage memory 9, the bit indicating the duplicated lower address and the bit 1 of the duplicated lower address identification bit are added to the packet, and the lower address a2 of the destination MAC address of the packet is in the ring. Since it is stored in the lower address memory 7 that designates packet transmission to the outside, the lower address in the lower address memory is erased, the lower address is stored in the erase lower address storage memory 9, and the packet is stored in the ring. Send out (28) Ma3a2r1r2c (I3).

When the packet (28) Ma3a2r1r2c (I3) reaches the mobile terminal 13-2, it is a movement permission packet, so the mobile terminal 13-2 sends the packet (30) Mr1r2a3a2 (I0) to the base station 12-1. do. When the packet arrives at the base station 12-1, the base station 12-1 determines that the packet is a packet immediately after the destination base station is changed, adds a signal g to that effect, and converts the packet into a packet. to the add, drop and pass device 6-1. When the packet from the TCP mobile station 13-2 reaches the add, drop and pass device 6-1, the lower address a2 of the transmission source MAC address of the packet is stored in the erased lower address storage memory 9, Since the blockage bit is stored at that position, the blockage bit is deleted and the packet is forwarded by (31) Mr1r2a3a2g (I0) on counterclockwise optical ring 1 as shown in the figure, adding the packet, Head to the drop and pass device 6-2.

When the packet (31) Mr1r2a3a2g (I0) arrives at the packet add/drop/pass device 6-2, the packet is the packet immediately after the destination base station is changed, and the lower address of the source MAC address of the packet. If a2 is stored in the lower address memory 7 designating packet transmission to the outside of the ring, the stored lower address a2 is erased and the lower address a2 is stored in the erased lower address memory 9. Since the lower address a2 of the transmission source MAC address of the packet is stored in the erased lower address memory 9, the packet is given a bit indicating a duplicate lower address, and the packet is sent to the counterclockwise optical ring 1. (32) is forwarded by Mr1r2a3a2g (I0) as shown in the figure and arrives at the packet add, drop and pass device 6-3.

When the packet (32) Mr1r2a3a2g (I0) arrives at the packet add/drop/pass device 6-3, the packet is a packet immediately after the destination base station is changed, and the lower address of the source MAC address of the packet is If a2 is stored in the lower address memory 7 designating packet transmission to the outside of the ring, the stored lower address a2 is erased and the lower address a2 is stored in the erased lower address memory 9. Since the lower address a2 of the transmission source MAC address of the packet is stored in the erased lower address memory 9, the packet is given a bit indicating a duplicate lower address, and the packet is sent to the counterclockwise optical ring 1. (33) is transferred by Mr1r2a3a2g (I0) as shown in the figure, and reaches the router 22 via the vertex device 5. FIG.
If the packet arriving at the router from the server is converted into a MAC packet and the destination MAC address of the packet is stored in the address table 30-2 of duplicated lower addresses, the response packet of the copy packet of the packet stream is placed at that position. If there is no sign indicating that the packet has been received (indicated by r in the figure), the packet is delayed by packet waiting means not shown in the figure, a copy packet of that packet is sent to the ring side, and the copy packet is responded to. When a packet is received, the packet is sent from the packet waiting means. At that time, the symbol r, which signifies the end of packet waiting, is written in the address table of duplicate lower addresses. In the figure, the symbol r is stored by packet (33) Mr1r2a3a2g (I0).
The copy packet is sent to open the gate for one packet stream to be sent out of the ring, and the destination MAC of the packet when it arrives at the packet add, drop and pass device from the clockwise ring. If the lower address of the address is stored in the erased lower address memory, then the packet is sent out of the ring whether or not the blocking bit is stored at that lower address location.

Next, a packet (35) IPI0I3 (IP indicates an IP packet, I0 indicates the source IP address of the server 20, and I3 indicates the destination IP address to the mobile terminal 13-2) from the server 20 to the router 22. When the packet arrives, the destination MAC address a3a2 of the packet is stored in the duplicated lower address address table 30-2, and the packet waiting end symbol r is stored at that position. A bit to that effect is stored, and a MAC packet (36) Ma3a2r1r2 (I3) is sent from the vertex device 5 to the clockwise ring 2.

The procedure for transferring the packet (36) Ma3a2r1r2 (I6) arriving at the vertex device 5 through the clockwise optical ring 2 will now be described. Packet (37) Ma3a2r1r2 (I3) is transferred as shown and arrives at packet add, drop and pass device 6-3. Packet (37) Ma3a2r1r2 (I3) is not a communication start packet, but the lower address a2 of the destination MAC address of the packet is stored in the erase lower address memory 9, and the blocking bit is stored at that location. Send the packet clockwise to the front of the ring (38) as Ma3a2r1r2 (I3).

When the packet (38) Ma3a2r1r2 (I3) arrives at the packet add, drop and pass device 6-2, the lower address a2 of the destination MAC address of the packet is stored in the erased lower address storage memory 9, and the Since the blockage bit is stored in the lower address position, the packet is sent to the front of the clockwise ring as (39) Ma3a2r1r2 (I3).

When the packet (39) Ma3a2r1r2 (I3) sent to the clockwise ring 2 reaches the packet add, drop and pass device 6-1, the lower address a2 of the destination MAC address of the packet is erased from the lower address memory. 9, and the blocking bit is stored in the lower address position thereof, the packet is sent out of the ring and sent to the mobile station 13-2 as packet (40) Ma3a2r1r2 (I3).

Embodiment 1 does not use an address table for designating packet passage, but uses an erased lower address storage memory. There is an advantage that the number of stored MAC addresses in the address table does not increase even if the one-way setting packet with the source MAC address of the terminal is sent up to the apex device in front of the server.

Embodiment 1 shows an example in which the lower address of the source MAC address of an Ethernet packet (MAC packet) is stored in the lower address memory. A system may be used in which the lower address of the address part is stored in the lower address memory and the MAC address part of the lower address of the source IPv6 address is stored in the address table.

In the first embodiment described above, an example is shown in which the lower address of the source MAC address is stored in the lower address memory that designates packet transmission to the outside of the ring. This is a long low-order address storage on the premise that there is no case where all the bits in the low-order address bit string are bit 0.
Storing the lower address of the transmission source MAC address of the packet in the first embodiment in the lower address memory that designates packet transmission outside the ring is performed when at least one bit of bit 1 is included in the bit string of the lower address. Alternatively, bit 1, which means lower address storage, may be stored at a position addressed by a lower address of the source MAC address in a lower address memory that specifies packet transmission to the outside of the ring.
Alternatively, storing the lower address of the transmission source MAC address of the packet in a lower address memory that specifies packet transmission outside the ring is performed when at least one bit of bit 1 is included in the bit string of the lower address. , decode each bit of the parallel data read from the location addressed by the high-order part of the low-order address of the source MAC address and the low-order part of the low-order address of the source MAC address in the low-order address memory that specifies packet transmission out of the ring By storing the latch signal of the parallel data which is the logical sum of each bit of the parallel data and the address specified position of the lower address memory designating packet transmission out of the ring, the lower part of the lower address of the transmission source MAC address is stored. It is also possible to insert and store the bit 1 at the position of the bit 1 of the decode as the bit 1 meaning lower address storage.

The configuration method of the above lower address memory is based on the IEICE Technical Report (IEICE Technical Report CS2013-28-CS2013-40), Communication method vol 113 No, 207, September 12-13, 2013, "Having only the originating terminal address Proposal of MAC-operated tree-like ring network for forwarding packets in both directions", page 44, chapter 3 "Address storage method using data storage area as address". It is also disclosed in Japanese Unexamined Patent Application Publication No. 2019-097045 (address storage method). The method can also be configured as shown in FIG.
In FIG. 2, the storage of the lower address and the erasing of the lower address are switched under the control of the bit 0 write signal (H), which is the erase signal of the stored lower address. For storing/erasing the lower address, the 32-bit parallel data of the position addressed by the upper part (17 bits) of the lower address of the MAC address is taken into the logic circuit, and the lower part (5 bits) of the lower address of the MAC address is read into the logic circuit. The 32-bit parallel data resulting from the operation with the decoded signal is written again to the SRAM. The logic circuit consists of a small LSI, FPGA, or ASIC, and uses an external SRAM.
Since the erased lower address storage memory (erased lower address storage memory) only needs to store duplicated lower addresses, it may have a small capacity. It's okay.

1 Subscriber's counterclockwise ring
2 Subscriber system clockwise ring 5 Vertex devices 6-1, 6-2, 6-3 Packet add, drop and pass device 7 Lower address memory for designating packet transmission out of the ring 9 Erase lower address storage memory 12-1, 12-2, 12-3 Base stations 13-1, 13-2, 13-3 Mobile stations (mobile terminals)
14 Movement of mobile station 20 Server 22 Router

Claims (1)

One base station is accommodated in a device for adding, dropping, and passing packets of a ring network, and mobile terminals under the base station block passage of MAC packets other than OAM packets arriving from the clockwise ring of the ring network. A packet transfer system that enables movement between base stations of a mobile terminal of a network that communicates mainly by MAC packets between a vertex device of the ring network and a server connected via a gateway or a router,
When a packet from the server direction arrives at the router, if the destination MAC address of the packet is stored in the duplicated lower address address table, the packet has a duplicated lower address bit and the duplicated lower address. A copy packet of the packet is sent with an identification bit, and the copy packet waits until the response packet of the copy packet arrives. is sent from the vertex device to the clockwise ring and arrives at the packet add, drop and pass devices, if the packet is given a bit indicating a duplicate lower address and the copy packet bit is given and if the lower address of the destination MAC address of the packet is stored in the erased lower address storage memory, storing the blocking bit together with the identification bit of the duplicated lower address at that address location, The packet is copied, the copied packet is forwarded in a clockwise direction to the front of the ring, the original packet is transmitted out of the ring, and only the blocking bit is transmitted when the response packet of the packet transmitted out of the ring arrives. If the packet is deleted and the packet is sent to the router, and if the packet is given a bit indicating a duplicated lower address other than the above, and the lower address of the destination MAC address of the packet is sent out of the ring is stored in the lower address memory specifying store the address identification bit, copy the packet, send the copy packet to the front of the ring in a clockwise direction, send the original packet out of the ring, and when the response packet of that packet arrives, the blocking bit is deleted, and the packet is directed to the router, and if the packet arriving from the clockwise ring is given a bit indicating a duplicate lower address and the bit of the copy packet is not given, the packet If the lower address of the destination MAC address of the packet is stored in the erased lower address memory and no blockage bit is stored in that lower address location, and the duplicate lower address identification bit of the packet is in that lower address location sends the packet out of the ring if it matches the duplicate lower address identification bit stored in
In cases other than the above, when a bit indicating a duplicate lower address is not added to the packet, and the lower address of the destination MAC address of the packet is stored in the lower address memory that specifies packet transmission outside the ring. If so, the packet is sent out of the ring, and if the lower address of the destination MAC address of the packet is not stored in the lower address memory that specifies packet sending out of the ring, the packet is rotated clockwise. means for delivering forward of the ring;
When a MAC packet from the mobile terminal via the base station arrives at the ring network packet add, drop and pass device,
Regardless of whether said packet is the first packet via the target base station or not the first packet,
If the lower address of the source MAC address of the packet is not stored in the erased lower address storage memory, the lower address of the source MAC address of the packet is stored in the lower address memory designating transmission of the packet out of the ring. If the lower address of the source MAC address of the packet is stored in the erased lower address storage memory, a bit indicating duplicate lower address is added to the packet, and the packet is sent to the top of the counterclockwise ring. directed to the server through the device,
When the packet arrives at a device for adding, dropping, and passing packets, if the lower address of the source MAC address of the packet is stored in a lower address memory that specifies packet transmission out of the ring, the lower address The lower address of the memory is erased, the lower address of the transmission source MAC address of the packet is stored in the erased lower address storage memory, a bit indicating a duplicate lower address is added to the packet, and the packet is transferred to the left. directed to the server through a vertex device on a rotating ring;
When the packet arrives at the router, if the packet has a duplicated lower address bit, the source MAC address of the packet is added to the duplicated lower address address table and the duplicated lower address identification bit and means for storing together.