JP2023086138A - Handover Using Ring Network Using Lower Address Storage Method - Google Patents

Abstract

To provide a packet transfer system that achieves handover in a wireless system at low cost and at high speed.SOLUTION: When a packet from a TCP mobile terminal via a base station arrives at a packet add, drop and pass device of a ring network or tree-like ring network, if a signal indicating that the packet is a packet immediately after moving to the base station is given by the base station, the lower address of the packet's source MAC address is deleted from a lower address memory that designates the passage of the packet in the packet add, drop, and pass device, and the packet is directed to a server via a vertex device on a counterclockwise ring. When the packet arrives at the packet add, drop and pass device, the lower address of the source MAC address of the packet is stored in the lower address memory that designates passage of the packet, and the packet is directed to the server via the vertex device on the counterclockwise ring.SELECTED DRAWING: Figure 1

Description

The present invention relates to handover using a ring network for transferring 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 control station to the mobile terminal is D2 (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 times of the route before switching and the route 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 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 handover control.

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

The present invention has been made in view of the problems of the prior art described above. A first aspect of the present invention is to accommodate a base station in the lowest ring of a ring network or a tree-like ring network, and mobile terminal communicates with a server or relay station using MAC packets via a gateway or router connected to a vertex device of the ring network or tree-like ring network. A packet forwarding system,
The MAC packet from the mobile terminal via the base station passes through the ring network or the lower ring network of the tree-like ring network to the own add, drop, and pass device of the packet. If the lower address of the source MAC address of the packet is stored in the lower address memory that specifies the passage of the packet of the device for adding, dropping and passing the packet when arriving from, erasing the address, forwarding the packet forward in a counterclockwise ring;
when said packet arrives at a packet add, drop and pass device,
If the source MAC address of the packet is stored in the address table that specifies packet transmission to the outside of the ring, that address is erased, and the lower address of the source MAC address of the packet is specified to pass the packet. means for storing the packet in a low-order address memory and sending the packet forward in a counterclockwise ring;
The MAC packet from the mobile terminal via the base station passes through the ring network or the lower ring network of the tree-like ring network to the device for adding, dropping, and passing the packet itself. If you arrive from
When the lower address of the source MAC address of the packet is stored in the lower address memory designating passage of the packet, the source MAC address of the packet is stored in the address table designating transmission of the packet out of the ring. and, other than the above, the packet is sent to the front of the counterclockwise ring as it is,
when said packet arrives at a packet add, drop and pass device,
means for storing a lower address of the source MAC address of the packet in a lower address memory for designating passage of the packet, and transmitting the packet forward in a counterclockwise ring;
When a packet other than the communication start packet from the server arrives at the device for adding, dropping, and passing the own packet in the clockwise ring,
When the destination MAC address of the packet is stored in an address table that specifies packet transmission outside the ring, the packet is transmitted out of the ring, and the destination MAC address of the packet specifies the packet transmission out of the ring. If it is not stored in the specified address table and if the lower address of the destination MAC address of the packet is stored in the lower address memory that specifies the passage of the packet, the packet is forwarded in the clockwise ring. and means for sending the packet out of the ring except for the above.

A second aspect of the present invention is packet waiting means applied to a packet transfer system that enables the mobile terminal to move between base stations,
receive a packet from the mobile terminal via the base station and further from the upper ring network via the lower ring network of the tree-like ring network to the server; store in memory and send the packet to the server, or put the source MAC address of the packet in the option area of the IP header of the IP packet and send it to the server;
When the own packet waiting means receives a packet having a signal indicating that it is a packet immediately after changing the passing base station,
When a MAC address different from the MAC address having the lower address of the source MAC address of the received packet as a lower address is stored in the first memory of the own packet waiting means, the MAC address is stored in the first memory. storing the MAC address in the second memory of its own packet waiting means;
Alternatively, when the first memory of the self-packet waiting means is not used, the lower address is still stored in the lower address memory for designating the addition, drop, and transmission of the packet to the outside of the ring of the device of the ring network. storing, in a second memory of the own packet waiting means, the source MAC address of the received packet received by the own packet waiting means, the packet having a signal indicating that the low order address is stored;
In the method that does not use the first memory of the own packet waiting means, the same lower address as the MAC address stored in the second memory of the own packet waiting means is assigned to the IP packet of the packet arriving from the server. If the lower address of the MAC address written in the option area of the IP header of is different from the MAC address written in the memory 2, the MAC address is stored in the third memory, and The packet is sent to the mobile terminal side after causing the own packet waiting means to wait until the source MAC address of the packet arriving from the mobile terminal side is stored in the third memory of the own packet waiting means. After that, the MAC address stored in the third memory of the self-standby means is erased, and the MAC address stored in the second memory of the self-standby means is erased after a predetermined time from the storage of the address. or
In the method using the first memory of the packet waiting means, when the destination IP address of the IP packet arriving from the server to the own packet waiting means is stored in the second memory of the own packet waiting means , causing the packet to wait until a retransmission request packet or a retransmission packet arrives from the mobile terminal whose source MAC address is the MAC address corresponding to the destination IP address stored in the second memory; when a packet or a retransmission packet arrives, erasing the source MAC address and the source IP address of the retransmission request packet or the retransmission packet from the second memory of the self-packet waiting means;
This packet waiting means is characterized by:

A third aspect of the present invention is a memory system of a lower address memory for designating passage of packets in a device for adding, dropping and passing packets of the ring network or tree-like ring network of the packet transfer system, wherein: 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 each bit of the parallel data obtained by decoding the low-order part of the low-order address of the source MAC address. bit 1 of the bit 1 position of decoding the lower part of the lower address of the source MAC address by storing the parallel data latch signal of the logical sum of is inserted and stored as bit 1, which means lower address storage,
When deleting the lower address of the source MAC address from the lower address memory that specifies the passage of the packet, the lower address memory that specifies the passage of the packet is read from the location addressed by the upper part of the lower address of the source MAC address. The parallel data latch signal of the AND of each bit of the parallel data obtained by decoding the lower part of the lower address of the source MAC address and the bit-inverted bit of each bit of the parallel data obtained by decoding the lower part of the lower address memory of the lower address memory that specifies the passage of the packet. A packet transfer characterized by inserting and storing the lower part of the lower address of the source MAC address into the position of bit 1 of decoding as bit 0 meaning no lower address storage by storing in the addressing position. It is a memory system of low-order address memory that designates packet add, drop and passage of packets in the ring network or tree-like ring network of the system.

As described above, according to the present invention, the memory bit length is reduced to only the lower address of the MAC address, and the number of addresses stored in the memory is increased. A ring network in which the address storage method is applied to a 1-bit storage method that means lower address storage in a lower address memory that designates the passage of packets in devices for adding, dropping and passing packets in the ring network for transferring Ethernet frames. Since this is a method of realizing handover of a mobile terminal by means of the method, power consumption and system cost can be suppressed, and high-speed communication can be performed.

A device for adding, dropping, and passing a plurality of packets having a lower address memory for designating passage of packets and an address table for designating transmission of packets outside the ring, for transferring Ethernet packets according to the first embodiment of the present invention. A handover operation of a mobile terminal in a packet transfer system that communicates between a mobile terminal under the control of a base station and a server connected to the lowest ring network of a tree-like ring network in which ring networks connected by optical transmission lines are connected in a tree form. A figure explaining.

A first embodiment of the present invention will be described with reference to FIG. This embodiment optically transmits a plurality of packet add, drop, and pass devices having a lower address memory that designates the passage of packets and an address table that designates the transmission of packets outside the ring. 1 is an example of handover operation of a mobile terminal in a packet transfer system in which communication is performed between a mobile terminal under a base station connected to the lowest ring network of a tree-like ring network in which ring networks connected by paths are connected in a tree form and a server; . Said server is an Internet connection server.

In FIG. 1, 1 is a subscriber system counterclockwise optical ring, 2 is a subscriber system clockwise optical ring, 3 is a subscriber system ring network, 4 is an upper ring network, 5 is a vertex device, 6-1, 6-2 and 6-3 are packet add, drop and pass devices, 8 is a lower address memory that specifies the passage of packets, 11 is an address table that specifies transmission of packets outside the ring, 22 is a router, and 12-. 1, 12-2, 12-3, 12-4 and 12-5 are base stations, 13-1, 13-2 and 13-3 are TCP mobile terminals, 14 is mobile terminals, and 20 is a server. Also, (1) to (29) are packets, and I0, I1, I2, I3, and I4 are domestic or regional IP addresses of service providers. or an IPv6 address.
Note that the address table 11 for designating packet transmission to the outside of the ring is an address table that does not store port numbers and stores a small number of MAC addresses, unlike conventional MAC address tables.

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 13-1 sends packet (1) Mr1r2a1a2 (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 of the interface of the router 22, a1a2 indicates the upper MAC address a1 and the lower MAC address a2, which are the MAC addresses of the TCP mobile terminal 19-1, and I0 indicates the IP address of the destination server 20) to the packet add, drop, and pass device 6-1. Here is an example sent. When the packet reaches the add, drop, and pass device 6-1 from the TCP mobile terminal 19-1, the packet is sent to the counterclockwise optical ring 1 as it is (2) indicated by Mr1r2a1a2 (I0) in the figure. and arrives at the packet add, drop and pass device 6-2.

When the packet (2) Mr1r2a1a2 (I0) arrives at the packet add/drop/pass device 6-2, the lower address a2 of the packet transmission source MAC address is stored in the lower address memory 8 for designating the passage of the packet. Remember. The packet is forwarded by (3) Mr1r2a1a2 (I0) in counterclockwise optical ring 1, and arrives at packet add, drop and pass device 6-3.

When the packet (3) Mr1r2a1a2 (I0) arrives at the packet add/drop/pass device 6-3, the lower address a2 of the packet transmission source MAC address is stored in the lower address memory 8 for designating the passage of the packet. Remember. The packet is forwarded by (4) Mr1r2a1a2 (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 the router 22 via the upper ring network 4 and the vertex device of the upper ring network 4 . The upper ring network 4 includes a wireless subscriber intra-station ring including a base station consisting of a left-handed ring 1 and a right-handed ring 2, and a packet add, drop, and pass device of the subscriber system ring network 3 of the same form. Adds, drops, and configures with equipment.

When the packet (5) Mr1r2a1a2 (I0) arrives at the router 22, the source MAC address a1a2 and the source IP address I2 of the packet are stored in a first memory (not shown). The output port corresponding to the destination of the destination IP address I0 of the packet is found and sent to that port. The packet is shown by (6) 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). , and reaches the server 20 .

Next, the TCP portable terminal 13-2 sends packet (7) Mr1r2a3a2 (I0) (M indicates an Ethernet packet, r1 indicates the upper MAC address of the interface of the router 22, and r2 indicates the lower MAC address of the interface of the router 22). , a3a2 indicate the upper MAC address a3 and the lower MAC address a2, which are the MAC addresses of the terminal 19-2, and I0 indicates the IP address of the server 20, which is the destination. send to When the packet reaches the add, drop, and pass device 6-1 from the TCP mobile terminal 13-2, the packet is directly sent to the counterclockwise optical ring 1 by (8) Mr1r2a3a2 (I0) as shown in the figure. It is transferred as shown and arrives at the packet add, drop and pass device 6-2.

When the packet (8) Mr1r2a3a2 (I0) arrives at the packet add/drop/pass device 6-2, the lower address a2 of the packet transmission source MAC address is stored in the lower address memory 8 for designating packet passage. Remember. The packet is forwarded by (9) Mr1r2a3a2 (I0) on counterclockwise optical ring 1, and reaches vertex device 5 via packet add, drop and pass device 6-3.

The packet arriving at the vertex device 5 is sent out of the ring and reaches the router 22 via the upper ring network 4 and the vertex device of the upper ring network 4 .

When the packet (11) Mr1r2a3a2 (I0) arrives at the router 22, after storing the source MAC address a3a2 and the source IP address I3 of the packet in a first memory (not shown), the destination IP address of the packet Read the output port corresponding to I0 and send to that port. The packet is shown by (12) 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). , and reaches the server 20 .

Next, the TCP portable terminal 13-3 sends the packet (13) Mr1r2a4a2 (I0) 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 portable terminal 13-3, the lower address a2 of the source MAC address of the packet designates passage of the packet. , the source MAC address a4a2 of the packet is stored in the address table 11 that designates packet transmission to the outside of the ring, and the packet is sent to the counterclockwise optical ring 1 (14) Mr1r2a4a2 (I0) , and reaches the vertex device 5 as shown in the figure.

The packet arriving at the vertex device 5 is sent out of the ring and reaches the router 22 via the upper ring network 4 and the vertex device of the upper ring network 4 .

When the packet (15) Mr1r2a4a2 (I0) arrives at the router 22, the source MAC address a4a2 and the source IP address I4 of the packet are stored in a first memory (not shown), and then the destination IP address of the packet is stored. Read the output port corresponding to I0 and send to that port. The packet is shown by (16) IPI4I0 (IP indicates an IP address, I4 indicates the IP address of the source terminal 13-3, and I0 indicates the IP address of the destination server 20). , and reaches the server 20 .

Next, when the TCP mobile terminal 13-2 moves from being used by the base station 12-1 to being under the control of the base station 13-2, and the packet (19) Mr1r2a3a2 (I0) arrives at the base station 12-2, the base station 12- 2 sends a signal g to the effect that the movement of the base station used by the mobile terminal used by the mobile terminal that is the source of the packet is movement to the server side on the counterclockwise ring, based on the information on the base station passed before the movement that is attached to the packet. and sends the packet to the packet add, drop and pass device 6-2. When the packet from the TCP portable terminal 13-2 reaches the add, drop and pass device 6-2, the packet is a packet immediately after being moved, and the lower address a2 of the source MAC address of the packet is Since the address is stored in the lower address memory 8 that designates passage, the address is erased, and the packet is transferred by (20) Mr1r2a3a2g (I0) on the counterclockwise optical ring 1 as shown in the figure, and the packet is added. , drop and pass device 6-3. Erasure of the lower address a2 in the lower address memory 8, which designates passage of the packet, is shown by drawing a horizontal line through the symbol a2.

When the packet (20) Mr1r2a3a2g (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 transferred to the lower address memory 8 for designating passage of the packet. Remember. The packet is forwarded by (21) Mr1r2a3a2g (I0) on counterclockwise optical ring 1 and reaches vertex device 5 as shown in the figure.

The packet arriving at the vertex device 5 is sent out of the ring and reaches the router 22 via the upper ring network 4 and the vertex device of the upper ring network 4 .

When the packet (22) Mr1r2a3a2g (I0) arrives at the router 22, after storing the source MAC address and the source IP address of the packet in the first memory (not shown), the destination IP address I0 of the packet is stored. The corresponding output port is read from an IP routing table (not shown) and the packet is sent to the server 20 from that port. Since the packet (22) Mr1r2a3a2g is provided with the signal g indicating that it is the first packet after the change of the passing base station, the MAC address of the same lower address as the lower address a2 of the transmission source MAC address of the packet is The MAC address a4a2, which is a MAC address different from the packet source MAC address a3a2, and the corresponding IP address I4 are read from the first memory (not shown) and stored in the second memory (not shown). When the destination IP address of the IP packet arriving from the server 20 is the IP address I4 stored in the second memory, the packet from the server 20 with the IP address I4 is transferred from the TCP mobile terminal side to the source of the packet arriving from the TCP mobile terminal side. A buffer (not shown) is made to wait until the retransmission packet (26) Mr1r2a4a2 (I0) of MAC address a4a2 stored in the second memory (not shown) is received. This is done to prevent the packet of the destination MAC address of the lower address a2 from being erroneously sent out of the ring during clockwise optical ring transfer. When the packet (26) Mr1r2a4a2 (I0) is received, the waiting packet from the server with the destination IP address I4 is sent to the vertex device 5 as shown by (27) Ma4a2r1r2 (I2). Send out.

Regarding the packet (26) Mr1r2a4a2(I0), the retransmission packet from the terminal 13-3 is transferred to the packet add, drop and pass device 6-3 as illustrated by the packet (24) Mr1r2a4a2(I0). arrive at When the packet 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 lower address memory 8 for designating passage of the packet. The source MAC address a4a2 of the packet is stored in the address table 11 for designating packet transmission outside the ring. The packet is forwarded by (25) Mr1r2a4a2 (I0) on counterclockwise optical ring 1 as shown in the figure, via vertex device 5, upper ring network 4, via the vertex device of the upper ring network, router Arrive at 22.

Next, the procedure for forwarding the packet (27) Ma4a2r1r2(I4) arriving at the device 5 connected to the upper ring is forwarded through the clockwise optical ring 2 will be described. Packet (28) Ma4a2r1r2 (I4) is transferred as shown in the figure and arrives at packet add, drop and pass device 6-3. Since the destination MAC address a4a2 is stored in the address table 11, which designates packet transmission outside the ring, the packet is transmitted outside the ring, and (29) Ma4a2r1r2 (I4) directs the mobile terminal 13 as shown in the figure. -3 is reached.

In the first embodiment, an example is shown in which the lower address of the source MAC address is stored in the lower address memory that designates passage of the packet. is a long low-order address store assuming that there is no case where all bits of are bit 0.
Storing the lower address of the source MAC address of the packet in the first embodiment in the lower address memory that specifies the passage of the packet means that if the bit string of the lower address contains at least one bit of bit 1, the packet It is also possible to store bit 1, which means lower address storage, at a position addressed by the lower address of the source MAC address in the lower address memory that specifies the passage of the MAC address.
Alternatively, storing the lower address of the source MAC address of the packet in a lower address memory that specifies passage of the packet means that when the bit string of the lower address contains at least one bit of bit 1, the 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 each bit of the parallel data obtained by decoding the low-order part of the low-order address of the source MAC address. By storing the parallel data latch signal of the logical sum of and at the address specified position of the lower address memory that specifies the passage of the packet, the bit at the position of the decode bit 1 of the lower part of the lower address of the source MAC address 1 may be inserted and stored as bit 1, which means lower address storage.

1 Subscriber system counterclockwise optical ring
2 Subscriber system clockwise optical ring 3 Subscriber system ring 4 Upper ring 5 Vertex devices 6-1, 6-2, 6-3 Packet add, drop and pass device 8 Lower address memory for specifying packet pass 11 Address tables 12-1, 12-2, 12-3, 12-4, 12-5 for designating packet transmission outside the ring 13-1, 13-2, 13-3 Mobile terminal 14 Mobile terminal Mobile 20 Server 22 Router

Claims (3)

A base station is accommodated in the lowest ring of a ring network or a tree-like ring network, and a mobile terminal under the base station is a server or a relay through a gateway or a router connected to a top device of the ring network or tree-like ring network. A packet transfer system that enables a mobile terminal of a network that communicates with a station using MAC packets to move between base stations,
The MAC packet from the mobile terminal via the base station passes through the ring network or the lower ring network of the tree-like ring network to the own add, drop, and pass device of the packet. If the lower address of the source MAC address of the packet is stored in the lower address memory that specifies the passage of the packet of the device for adding, dropping and passing the packet when arriving from, erasing the address, forwarding the packet forward in a counterclockwise ring;
when said packet arrives at a packet add, drop and pass device,
If the source MAC address of the packet is stored in the address table that specifies packet transmission to the outside of the ring, that address is erased, and the lower address of the source MAC address of the packet is specified to pass the packet. means for storing the packet in a low-order address memory and sending the packet forward in a counterclockwise ring;
The MAC packet from the mobile terminal via the base station passes through the ring network or the lower ring network of the tree-like ring network to the device for adding, dropping, and passing the packet itself. If you arrive from
When the lower address of the source MAC address of the packet is stored in the lower address memory designating passage of the packet, the source MAC address of the packet is stored in the address table designating transmission of the packet out of the ring. and, other than the above, the packet is sent to the front of the counterclockwise ring as it is,
when said packet arrives at a packet add, drop and pass device,
means for storing a lower address of the source MAC address of the packet in a lower address memory for designating passage of the packet, and transmitting the packet forward in a counterclockwise ring;
When a packet other than the communication start packet from the server arrives at the device for adding, dropping, and passing the own packet in the clockwise ring,
When the destination MAC address of the packet is stored in an address table that specifies packet transmission outside the ring, the packet is transmitted out of the ring, and the destination MAC address of the packet specifies the packet transmission out of the ring. If it is not stored in the specified address table and if the lower address of the destination MAC address of the packet is stored in the lower address memory that specifies the passage of the packet, the packet is forwarded in the clockwise ring. A packet transfer system that enables a mobile terminal to move between base stations, further comprising means for sending the packet out of the ring.
A packet waiting means applied to a packet transfer system that enables movement of the mobile terminal between base stations according to claim 1,
receive a packet from the mobile terminal via the base station and further from the upper ring network via the lower ring network of the tree-like ring network to the server; store in memory and send the packet to the server, or put the source MAC address of the packet in the option area of the IP header of the IP packet and send it to the server;
When the own packet waiting means receives a packet having a signal indicating that it is a packet immediately after changing the passing base station,
When a MAC address different from the MAC address having the lower address of the source MAC address of the received packet as a lower address is stored in the first memory of the own packet waiting means, the MAC address is stored in the first memory. storing the MAC address in the second memory of its own packet waiting means;
Alternatively, when the first memory of the self-packet waiting means is not used, the lower address is still stored in the lower address memory for designating the addition, drop, and transmission of the packet to the outside of the ring of the device of the ring network. storing, in a second memory of the own packet waiting means, the source MAC address of the received packet received by the own packet waiting means, the packet having a signal indicating that the low order address is stored;
In the method that does not use the first memory of the own packet waiting means, the same lower address as the MAC address stored in the second memory of the own packet waiting means is assigned to the IP packet of the packet arriving from the server. If the lower address of the MAC address written in the option area of the IP header of is different from the MAC address written in the memory 2, the MAC address is stored in the third memory, and The packet is sent to the mobile terminal side after causing the own packet waiting means to wait until the source MAC address of the packet arriving from the mobile terminal side is stored in the third memory of the own packet waiting means. After that, the MAC address stored in the third memory of the self-standby means is erased, and the MAC address stored in the second memory of the self-standby means is erased after a predetermined time from the storage of the address. or
In the method using the first memory of the packet waiting means, when the destination IP address of the IP packet arriving from the server to the own packet waiting means is stored in the second memory of the own packet waiting means , causing the packet to wait until a retransmission request packet or a retransmission packet arrives from the mobile terminal whose source MAC address is the MAC address corresponding to the destination IP address stored in the second memory; when a packet or a retransmission packet arrives, erasing the source MAC address and the source IP address of the retransmission request packet or the retransmission packet from the second memory of the self-packet waiting means;
Packet waiting means characterized by:
2. A memory system of a lower address memory for designating passage of packets in the device for adding, dropping and passing packets of the ring network or tree-like ring network of the packet transfer system according to claim 1, wherein the passage of packets is designated. Logical sum of each bit of parallel data read from a lower address memory address-addressed by the upper part of the lower address of the source MAC address and each bit of parallel data obtained by decoding the lower part of the lower address of the source MAC address bit 1 of the bit 1 position of the source MAC address is decoded by storing the latch signal of the parallel data in the address specifying position of the lower address memory that designates passage of the packet. In a memory system that inserts and stores as bit 1, which means
When deleting the lower address of the source MAC address from the lower address memory that specifies the passage of the packet, the lower address memory that specifies the passage of the packet is read from the location addressed by the upper part of the lower address of the source MAC address. The parallel data latch signal of the AND of each bit of the parallel data obtained by decoding the lower part of the lower address of the source MAC address and the bit-inverted bit of each bit of the parallel data obtained by decoding the lower part of the lower address memory of the lower address memory that specifies the passage of the packet. A packet transfer characterized by inserting and storing the lower part of the lower address of the source MAC address into the position of bit 1 of decoding as bit 0 meaning no lower address storage by storing in the addressing position. A memory system of low-order address memories for designating packet add, drop and pass through devices in the system's ring network or tree-like ring network.

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