JP2023063033A - Handover Using Ring Network Using Lower Address Storage Method - Google Patents

Abstract

To provide a packet transfer system, packet waiting means, a packet transfer method, a lower address memory, and a communication method that achieve handover of a wireless system at low cost and at high speed.SOLUTION: In the case where a mobile terminal and a server communicate via ring network, when a packet from the server arrives at a forwarding device, it is determined whether a destination MAC address or source MAC address of the packet is stored in a packet passage bridging address table, a passage prohibition lower address memory, or a lower address memory designating packet transmission outside the ring, and the packet is added, dropped, and passed.SELECTED DRAWING: Figure 2

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

A conventional example of a conventional address storage method Japanese Patent Laid-Open No. 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 Application 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 An object of the present invention is to provide a method for realizing easy handover and short-distance movement of a mobile terminal using a ring network using a conventional address storage method that does not use a MAC address table.

The present invention has been made in view of the problems of the prior art described above. When a packet to be forwarded arrives at a packet add, drop and pass device, the destination MAC address of the packet is not stored in the packet pass bridging address table, and the destination MAC address of the packet is lower than the If the address is not stored in the packet passage prohibited lower address memory 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, the packet The lower address of the destination MAC address of is stored in the bridging address table for passing the packet, the packet is sent out of the ring, the packet arrives at the device for adding, dropping and passing the packet from the counterclockwise ring, and the packet If the lower address of the source MAC address of is stored in the lower address memory that designates packet transmission out of the ring, the source MAC address of the packet is stored in the packet passage bridging address table, Packets are sent out to the front of the counterclockwise ring, packets arrive from outside the ring to the device for adding, dropping, and passing packets, and the lower address of the source MAC address of the packet is stored in the lower address memory that designates the packet to be sent out of the ring. If it is stored, and if the source MAC address of the packet is stored in the bridging address table for passing the packet, that address is erased, and the lower address of the source MAC address of the packet is transferred to the packet. In this method, the data is stored in the pass-prohibited low-order address memory and transmitted to the front of the counterclockwise ring.

Moreover, the second aspect of the present invention is
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 communicates with a server through a router connected to a vertex device of the ring network or the tree-like ring. , a packet transfer system that enables mobile terminals to move between base stations,
When a packet arrives at a device for adding, dropping, and passing packets in a ring network from a clockwise ring, if the destination MAC address of the packet is stored in the bridging address table for passing the packet, the packet is forwarding the packet to the front of the clockwise ring, and if the lower address of the destination MAC address of the packet is not stored in the lower address memory designating the packet to be sent out of the ring, sending the packet to the front of the clockwise ring; Other than the above, if the lower address of the destination MAC address of the packet is stored in the packet passage prohibited lower address memory, the packet is sent out of the ring, and other than the above, the destination MAC address of the packet is stored. When the lower address is stored in the lower address memory that designates packet transmission to the outside of the ring, the destination MAC address of the packet is stored in the packet passing bridging address table, and the packet is transmitted out of the ring. means and
When a packet arrives at a ring network packet add, drop, and pass device from a counterclockwise ring, the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring. means for storing the source MAC address of the packet in a packet passage bridging address table if the packet is present, and transmitting the packet to the front of the counterclockwise ring as it is except for the above;
When a packet from outside the ring arrives at the ring network packet add, drop and pass device,
If the packet is not a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
When the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, and the source MAC address of the packet is stored in the packet transit bridging address table , erasing the stored address, storing the lower address of the transmission source MAC address of the packet in a packet pass-prohibited lower address memory, and sending the packet forward in the counterclockwise ring;
When a packet from outside the ring arrives at the ring network packet add, drop and pass device,
If the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
When the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, and the source MAC address of the packet is stored in the packet transit bridging address table and means for erasing the stored address, storing the lower address of the transmission source MAC address of the packet in a packet pass-prohibited lower address memory, and transmitting the packet forward in the counterclockwise ring. and

A third aspect of the present invention is the packet transfer system according to the second aspect of the present invention,
When a packet arrives from a left-handed ring,
If the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
If the lower address of the source MAC address of the packet is stored in the lower address memory that designates the transmission of the packet out of the ring, delete the lower address, and otherwise rotate the packet counterclockwise. The packet forwarding system further includes means for forwarding on the ring.

A fourth aspect of the present invention is the packet transfer system according to the second or third aspect of the present invention,
The mobile terminal further comprises means for sending a retransmission packet or a retransmission request packet to the server when no packet arrives from the server for a predetermined time or longer during communication.

A fifth aspect of the present invention is the packet transfer system according to the second aspect of the present invention,
The mobile terminal simply transmits a location registration packet or a one-way setup packet having a source MAC address at a constant period or at a period equal to or less than the timer value of the memory of the device for adding, dropping, and passing packets. It further comprises means for transmitting packets from the base station through which the packets are to pass to the ring network or the tree-like ring network.

A sixth aspect of the present invention is packet waiting means applied to the packet transfer system according to the second to fourth aspects of the present invention,
The source MAC address and the source IP address of a packet directed from a mobile terminal to a server via a base station, a ring network or a tree-like ring network are stored in the first memory of the own packet waiting means of the router or gateway, and are addressed to the server. or put the source MAC address of the original IP packet destined for the server into the option area of the IP header of the IP packet and send it to the server;
When a packet having a signal indicating that the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing the packet of the ring network to be added arrives at the self-packet waiting means,
If a MAC address different from the source MAC address of the packet is stored in the first memory of the packet waiting means, the lower address of the source MAC address of the packet is stored as a lower address. storing the MAC address and the IP address corresponding to the MAC address in the second memory of the own packet waiting means;
Alternatively, if the first memory of the own packet waiting means is not used, storing the source MAC address of the packet as a seed MAC address in the second memory of the own packet waiting means,
In the method that does not use the first memory of the self-packet waiting means, the same lower address as the seed MAC address stored in the second memory of the self-packet waiting means is added to the IP header of the IP packet arriving from the server. and if the MAC address is different from the seed MAC address stored in the second memory, the MAC address of the option area of the IP header of the IP packet is stored in the second memory. Then, the packet is waited until a retransmission packet from the mobile terminal whose source MAC address is the MAC address of the packet arrives, and when the retransmission packet arrives, the source MAC address of the retransmission packet is changed to the self. Erasing from the second memory of the packet waiting means, and erasing the seed MAC address whose lower address is the lower address of the source MAC address after a certain period of time from when the seed MAC address is stored in the second memory;
On the other hand, in the method of using the first memory of the own packet waiting means, when a packet having the destination IP address of the IP address stored in the second memory of the own packet waiting means arrives from the server, TCP packets wait until reception of a retransmission packet from a TCP mobile terminal, with the source MAC address being the MAC address stored in the second memory corresponding to the destination IP address of the packet, and the UDP packet Wait until receiving a one-way setup packet with a source MAC address, and when the ACK packet, retransmission packet, or one-way setup packet arrives, the source MAC address of the ACK packet, retransmission packet, or one-way setup packet erasing the source IP address from the second memory of the own packet waiting means;
It is characterized by

A seventh aspect of the present invention is a wireless communication system including a handover between a base station and a mobile terminal, which is used in the inter-base-station moving method of the mobile terminal in the packet transfer system according to the second to fourth aspects of the present invention. A section communication method,
When the mobile terminal moves between base stations, if the radio waves from the destination base station become stronger than the radio waves from the base station currently receiving packets, the mobile terminal is sent to the destination base station by CSMA/CA. Secure the specified time slot position of the specified frequency used by the terminal, or secure the CDMA code or OFDM symbol code, and move to the destination base with the secured time slot of the specified frequency or CDMA of that code or OFDM of that code It is characterized by starting communication with a station. .

The eighth aspect of the present invention specifies the addition, drop, and passing of packets in the ring network or tree-like ring network of the packet transfer system according to the second aspect of the present invention, and the transmission of the packets to the outside of the ring. Each bit of parallel data read from a lower address memory that designates packet transmission to the outside of the ring with the upper part of the lower address of the source MAC address and the address of the source MAC address addressing of a lower address memory designating packet transmission out of the ring or a lower address memory designating passage of a packet with a latch signal of parallel data obtained by ORing each bit of parallel data obtained by decoding the lower part of the lower address; a memory that inserts and stores the lower part of the lower address of the source MAC address by storing the lower part of the lower address of the source MAC address as bit 1 at the position of bit 1 of decoding as bit 1 that means lower address storage,
When deleting the lower address of the source MAC address from the lower address memory that specifies packet transmission outside the ring, the lower address memory that specifies packet transmission outside the ring is replaced with the upper part of the lower address of the source MAC address. Each bit of the parallel data read from the addressed position and the bit-inverted bit of each bit of the parallel data decoded from the lower part of the lower address of the transmission source MAC address are logically ANDed to the outside of the ring. By storing the lower address portion of the lower address of the transmission source MAC address in the address specifying position of the lower address memory designating packet transmission, bit 0 is inserted into the position of decode bit 1 as bit 0 meaning no lower address storage. It is a lower address memory for designating packet add, drop and passing devices for packet transmission outside the ring of a ring network or tree-like ring network of a packet transfer system.

Also, a ninth aspect of the present invention is
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 communicates with a server through a router connected to a vertex device of the ring network or the tree-like ring. , a packet transfer method that enables a mobile terminal to move between base stations,
When a packet arrives at a device for adding, dropping, and passing packets in a ring network from a clockwise ring, if the destination MAC address of the packet is stored in the bridging address table for passing the packet, the packet is forwarding the packet to the front of the clockwise ring, and if the lower address of the destination MAC address of the packet is not stored in the lower address memory designating the packet to be sent out of the ring, sending the packet to the front of the clockwise ring; Other than the above, if the lower address of the destination MAC address of the packet is stored in the packet passage prohibited lower address memory, the packet is sent out of the ring, and other than the above, the destination MAC address of the packet is stored. When the lower address is stored in the lower address memory that designates packet transmission to the outside of the ring, the destination MAC address of the packet is stored in the packet passing bridging address table, and the packet is transmitted out of the ring. a step;
When a packet arrives at a ring network packet add, drop, and pass device from a counterclockwise ring, the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring. If it is, the source MAC address of the packet is stored in the packet passing bridging address table, and other than the above, the packet is sent to the front of the counterclockwise ring as it is,
When a packet arrives from a left-handed ring,
If the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
If the lower address of the source MAC address of the packet is stored in the lower address memory that designates the transmission of the packet out of the ring, delete the lower address, and otherwise rotate the packet counterclockwise. When a packet arrives at the ring network packet add, drop, and pass device from outside the ring,
If the packet is not a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
When the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, and the source MAC address of the packet is stored in the packet transit bridging address table , erasing the stored address, storing the lower address of the transmission source MAC address of the packet in a packet pass-prohibited lower address memory, and sending the packet forward in the counterclockwise ring;
When a packet arrives at the ring network packet add, drop and pass device from outside the ring,
If the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
When the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, and the source MAC address of the packet is stored in the packet transit bridging address table and a step of erasing the stored address, storing the lower address of the transmission source MAC address of the packet in a packet pass-prohibited lower address memory, and transmitting the packet forward in a counterclockwise ring. It is a way to

As described above, in the present invention, instead of using a 48-bit MAC address, the memory bit length is shortened to increase the number of memory addresses. Since memory is used in a ring network that transfers Ethernet packets, and handover and short-distance terminal movement are realized by the ring network, it is similar to the conventional flooding of unknown packets by using a MAC address table with missing memory addresses. Since there is no problem and the conventional block port is no longer required, power consumption and system cost can be suppressed, and high-speed communication is possible.

Addition of a plurality of packets having a lower address memory for designating packet transmission outside the ring, a bridge address table for packet passage, and a lower address memory for prohibiting packet passage in the first embodiment of the present invention. 1 is a diagram for explaining handover operation of a network using a tree-like ring network in which devices for , drop and pass are connected by optical transmission lines for communication between a mobile terminal and a server; Addition of a plurality of packets having a lower address memory for designating packet transmission outside the ring, a bridge address table for packet passage, and a lower address memory for prohibiting packet passage in the second embodiment of the present invention. 1 is a diagram for explaining handover operation of a network using a tree-like ring network in which devices for , drop and pass are connected by optical transmission lines for communication between a mobile terminal and a server;

A first embodiment of the present invention will be described with reference to FIG. In this embodiment, a plurality of packet add, drop, and pass devices having a lower address memory for designating packet transmission to the outside of the ring, a bridging address table for packet passage, and a lower address memory for prohibiting packet passage, and a server are routers. This is an example of handover operation using a tree-like ring network that transfers Ethernet packets composed of vertex devices connected via. The server is a content server.

In FIG. 1, 1 is a left-handed optical ring, 2 is a right-handed optical ring, 3 is a subscriber system ring, 4 is an upper ring, 5 is a vertex device, and 6-1, 6-2, and 6-3 add packets. , a drop and pass device, 7 a lower address memory for designating packet transmission outside the ring, 9-1 a packet pass prohibition lower address memory, 9-2 a bridging address table for packet pass, 12-1, 12-2, 12-3, 12-4, 12-5 are base stations, 13-1, 13-2, 13-3 are mobile terminals, 14 is the moving direction of mobile terminals, 20 is a server, and 22 is a router. be. Also, (1) to (39) are packets, and I0, I1, I2, I3, I4, and I6 are domestic or regional IP addresses of service providers. or an IPv6 address.
The packet passing bridging address table 9-2 differs from the conventional MAC address table in that it does not store port numbers and stores a small number of MAC addresses.

The operation of FIG. 1 will be described below. First, when the TCP mobile terminals 13-1, 13-2, and 13-3 move under the server 20 or when a communication start packet directed to the server 20 arrives at the router in front of the server 20, terminal authentication is performed. , the IP address and MAC address of the terminal are stored in the ARP table of the router 22, and the IP address I1 of the router 22 and the MAC address r1r2 of the ring transmission line interface are already stored in the ARP table of the terminal. . 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 13-1, 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 portable terminal 13-1, the source MAC address a1a2 of the packet is stored in the packet pass bridging address table 9-2. Therefore, the lower address a2 of the source MAC address of the packet is stored in the lower address memory 7 for designating packet transmission out of the ring. The packet is forwarded by (2) Mr1r2a1a2 (I0) on counterclockwise optical ring 1, and arrives at packet add, drop and pass device 6-2.

When the packet (2) Mr1r2a1a2 (I0) arrives at the packet add, drop and 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 not stored in the memory 7 at this point, the packet is forwarded by (3) Mr1r2a1a2 (I0) on the counterclockwise optical ring 1 to the packet add, drop and pass device 6-3. arrive.

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 the lower address designating the packet transmission out of the ring. Since it is not stored in memory 7 , the packet is forwarded by ( 4 ) Mr 1 r 2 a 1 a 2 (I 0 ) on counterclockwise optical ring 1 and reaches vertex device 5 . The packet is sent outside the ring and reaches the router 22 via the upper ring 4 . The upper ring 4 has the same structure as the subscriber system ring, which is a double ring of the left-handed ring 1 and the right-handed ring 2, and the subscriber system ring 3, and operates in the same manner.

When the packet (5) Mr1r2a1a2 (I0) arrives at the router 22, 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 . The source MAC address of the original packet is entered in the option field of the IP header of that packet.

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 13-2, and I0 indicates the IP address of the destination server 20) to the packet add, drop and pass device 6-2. send to When the packet reaches the add, drop and pass device 6-2 from the TCP portable terminal 13-2, the source MAC address a3a2 of the packet is stored in the packet pass bridging address table 9-2. Therefore, the lower address a2 of the source MAC address of the packet is stored in the lower address memory 7 for designating packet transmission out of the ring. The packet is forwarded by (8) Mr1r2a3a2 (I0) on counterclockwise optical ring 1 and arrives at packet add, drop and pass device 6-3.

When the packet (8) Mr1r2a3a2 (I0) arrives at the packet add, drop and 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 not stored in memory 7, the packet is forwarded by (9) Mr1r2a3a2 (I0) on counterclockwise optical ring 1 and reaches vertex device 5 as shown.

Said packet arriving at the vertex device 5 is sent out of the ring and reaches the router 22 via the upper ring 4 as indicated by (10) Mr1r2a3a2 (I0).

When the packet (10) Mr1r2a3a2 (I0) arrives at the router 22, the output port corresponding to the destination domain of the destination IP address I0 of the packet is read and sent to that port. The packet is shown by (11) 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 . The source MAC address of the original packet is entered in the option field of the IP header of that packet.

When the packet (11) IPI3I0 of the download request or the like arrives, the server 20 sends to the router 22 the response packet (12) IPI0I2 of the packet that previously arrived from the terminal 13-1. The source MAC address of the original packet is entered in the option field of the IP header of that packet. The router 22 sets the MAC address a1a2 written in the option area of the IP header of the packet as the destination MAC address and the MAC address r1r2 of the interface of the router 22 as the source MAC address, and attaches the packet (13) to the IP packet. Transfer Ma1a2r1r2 (I2) to clockwise ring 2 as shown. The packet arrives at the packet add, drop and pass device 6-2, the destination MAC address a1a2 of the packet is not stored in the packet pass bridging address table 9-2 at this time, and the Since the lower address a2 of the destination MAC address of the packet is stored in the lower address memory 7 for designating packet transmission out of the ring, the destination MAC address a1a2 of the packet is stored in the packet transit bridge address table 9-2. store and send the packet out of the ring to base station 12-2 as shown by (16) Ma1a2r1r2 (I2). Since the destination mobile terminal of the packet is not under the control of the base station 12-2, the response packet of the packet does not reach the packet add, drop and pass device 6-2.

Since the ACK packet of the packet (12) IPI0I2 does not arrive, the server 20 sends the retransmission packet (17) IPI0I2 to the router 22 . The source MAC address of the original packet is entered in the option field of the IP header of that packet. The router 22 attached the MAC address a1a2 written in the option area of the IP header of the packet as the destination MAC address and the MAC address r1r2 of the interface of the router 22 as the source MAC address to the IP packet. 22 obtains the destination MAC address a1a2 from the destination IP address I2 of the packet by means of an ARP table not shown in the figure, and transfers the packet (18) Ma1a2r1r2 (I2) to the clockwise ring 2 as shown in the figure. When the packet arrives at the packet add/drop/pass device 6-2 as (20) Ma1a2r1r2 (I2), the destination MAC address a1a2 of the packet is stored in the packet pass bridge address table 9-2. Therefore, the packet is sent to the front of clockwise ring 2 by (21) Ma1a2r1r2 (I2) as shown in the figure.

The packet is forwarded by (21) Ma1a2r1r2 (I2) through clockwise ring 2 as shown in the figure and arrives at packet add, drop and pass device 6-1. The packet add, drop, and pass device 6-1 stores the destination MAC address a1a2 of the packet in the packet pass bridging address table 9-2 in the same manner as described above, and sends the packet out of the ring. , arrives at terminal 13-1 as indicated by (22) Ma1a2r1r2 (I2).

When the packet (22) Ma1a2r1r2 (I2) arrives at the terminal 13-1, an ACK packet (23) Mr1r2a1a2 (I0) is sent to the packet add/drop/pass device 6-1.
When the packet arrives at the packet add/drop/pass device 6-1, the lower address a2 of the source MAC address of the packet is stored in the lower address memory 7 for designating packet transmission outside the ring. In addition, since the packet transmission source MAC address a1a2 is stored in the packet passing bridging address table 9-2, the address a1a2 is erased, and the packet is stored in the packet passage prohibited lower address memory 9-1. The lower address a2 of the source MAC address is stored, and the packet is sent by (24) Mr1r2a1a2 (I0) toward the device 6-2 for adding, dropping and passing packets through counterclockwise ring 1 as shown in the figure. . The erasure of the address a1a2 is indicated by a horizontal line above a1a2 in the figure.

When the packet (24) Mr1r2a1a2 (I0) arrives at the packet add/drop/pass device 6-2, the lower address of the packet transmission source MAC address is stored in the lower address memory 7 for designating packet transmission outside the ring. Since the address a2 is stored at this time, the source MAC address a1a2 of the packet is stored in the packet passage bridging address table 9-2, and the packet is transmitted by the counterclockwise ring 1 (25) Mr1r2a1a2 (I0 ) as shown in the figure.

When the packet arrives at the router 22 as shown by (27) Mr1r2a1a2 (I0), the lower address a2 of the packet's source MAC address is stored in memory, and the MAC address stored in that memory is stored in memory. If the IP packet arriving from the server contains the subordinate address a2 of the MAC address (a3a2) described in the option area of the IP header as the subordinate address of the MAC address (a3a2), the MAC packet with the MAC address attached to the IP packet is sent. , waits until the retransmission packet (32) Mr1r2a3a2 (I0) from the mobile terminal having that MAC address as the source MAC address arrives.

The retransmission packet (32) Mr1r2a3a2(I0) is sent from the TCP mobile terminal 13-2 as packet (29) Mr1r2a3a2(I0) to the packet add, drop and pass device 6-2. In the passing device 6-2, the lower address a2 of the source MAC address of the packet is stored in the lower address memory 7 that designates packet transmission outside the ring, and the source MAC address a3a2 of the packet is stored at this point. Since it is not stored in the bridging address table for packet passage, it is a packet that has arrived at the router 22 as it is.

When the retransmission packet (32) Mr1r2a3a2 (I0) arrives at the router 22, the waiting packet (33) Ma3a2r1r2 (I3) is sent to the clockwise ring 2 via the upper ring 4 and the vertex device 5 of the subscriber ring. Send out. The packet is forwarded by (35) Ma3a2r1r2 (I3) as shown in the figure and arrives at the packet add, drop and pass device 6-2. The lower address a2 of the destination MAC address of the packet arriving at the packet add, drop and pass device 6-2 is stored in the lower address memory 7 designating the packet transmission outside the ring, and the destination of the packet. Since the lower address a2 of the MAC address is not stored in the packet passage prohibited lower address memory 9-1, and the destination MAC address a3a2 of the packet is not stored in the packet passage bridge address table 9-2 at this time, , the destination MAC address a3a2 of the packet is stored in the packet transit bridge address table 9-2, and the packet is sent out of the ring by (36) Ma3a2r1r2 (I3) as shown in the figure.

Next, when the TCP mobile terminal 13-2 moves from under the control of the base station 12-2 to under the control of the base station 12-1 and the packet (37) Mr1r2a3a2 (I0) arrives at the base station 12-1, the packet is , packet add, drop and pass device 6-1. When the packet from the TCP mobile terminal 13-2 reaches the add, drop and pass device 6-1, a lower address memory for designating transmission of the packet out of the ring with the lower address a2 of the source MAC address of the packet. Store in 7. When the packet reaches the add, drop, and pass device 6-2, the packet is the packet immediately after the base station has moved, and the lower address a2 of the source MAC address of the packet designates packet transmission out of the ring. Since it is stored in the lower address memory 7, the lower address is erased. The packet is forwarded by (39) Mr1r2a3a2g (I0) on counterclockwise optical ring 1 to router 22 as shown in the figure.

When the packet arrives at the router 22, after storing the source MAC address and the source IP address of the packet in a memory (not shown), the output port corresponding to the destination domain of the destination IP address I0 of the packet is read. , is sent to the port, and the IP address corresponding to the MAC address of the same lower address as the lower address a2 of the source MAC address of the packet is read from a storage address of the memory not shown in the above figure, and the destination of the IP address is read. When a packet with an IP address arrives from the server 20, the packet from the server with the IP address is put on standby in the same manner as described above.

In the first embodiment described above, the TCP portable terminal 13-2 is an example of transit base station movement in the direction away from the server in the ring network. By the packet immediately after moving the base station via the base station 12-2, the transmission source MAC address of the packet is stored in the lower address memory 7 which designates the packet transmission outside the ring of the device 6-2 for adding, dropping and passing the packet. If the transmission source MAC address a3a2 of the packet is stored in the packet passing bridging address table 9-2, the address a3a2 is erased and the packet passage prohibited subordinate address is stored. The lower address a2 of the source MAC address of the packet is stored in the address memory 9-1. When the packet from the TCP mobile terminal 13-2 immediately after moving the base station arrives at the router 22, when the router 22 performs the same operation as in the first embodiment, the TCP mobile terminal under the control of the base station 12-1 retransmits the packet. When a packet arrives at the packet add, drop, and pass device 6-2 from the counterclockwise ring, the lower address a2 of the packet transmission source MAC address is stored in the lower address memory 7 for designating packet transmission outside the ring. If stored, the source MAC address of the packet is stored in the packet passing bridging address table 9-2.

In the above embodiment 1, since the MAC address of the source terminal is put in the option area of the IP header heading from the router to the server and sent, the session layer of the router stores the source terminal information and the server side waits for the packet. measures may be carried out. Note that the conversion from the IP address of the router 22 to the destination mobile terminal MAC address may be performed by the SSD. Alternatively, the destination mobile terminal MAC address may be generated from the lower address of IPv6.

In the first embodiment, when a communication start packet arrives from the mobile terminal to the server 20, the server 20 stores the IP address of the router 22 in the home memory using the home IP address of the mobile terminal as a key. access and do. Therefore, the care-of address is not used until the server.

A second embodiment of the present invention will now be described with reference to FIG. In this embodiment, a plurality of packet add, drop, and pass devices having a lower address memory for designating packet transmission to the outside of the ring, a bridging address table for packet passage, and a lower address memory for prohibiting packet passage, and a server are routers. This is an example of handover operation using a tree-like ring network that transfers Ethernet packets composed of vertex devices connected via. The server is a content server. This embodiment operates the packet waiting means of the router only when the router 22 receives a packet from the portable terminal including a signal g indicating that the packet is a packet immediately after moving the passing base station.

The operation of FIG. 2 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, 13-3, and 13-4. 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 13-1, 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 portable terminal 13-1, the source MAC address a1a2 of the packet is stored in the packet pass bridging address table 9-2. Therefore, the lower address a2 of the source MAC address of the packet is stored in the lower address memory 7 for designating packet transmission out of the ring. The packet is forwarded by (2) Mr1r2a1a2 (I0) on counterclockwise optical ring 1, and arrives at packet add, drop and pass device 6-2.

When the packet (2) Mr1r2a1a2 (I0) arrives at the packet add, drop and 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 not stored in the memory 7 at this point, the packet is forwarded by (3) Mr1r2a1a2 (I0) on the counterclockwise optical ring 1 to the packet add, drop and pass device 6-3. arrive.

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 the lower address designating the packet transmission out of the ring. Since it is not stored in memory 7 , the packet is forwarded by ( 4 ) Mr 1 r 2 a 1 a 2 (I 0 ) on counterclockwise optical ring 1 and reaches vertex device 5 . The packet is sent outside the ring and reaches the router 22 via the upper ring 4 . The upper ring 4 has the same structure as the subscriber system ring, which is a double ring of the left-handed ring 1 and the right-handed ring 2, and the subscriber system ring 3, and operates in the same manner.

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 the memory 1 (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 13-2, and I0 indicates the IP address of the destination server 20) to the packet add, drop and pass device 6-2. send to
When the packet reaches the add, drop and pass device 6-2 from the TCP portable terminal 13-2, the source MAC address a3a2 of the packet is stored in the packet pass bridging address table 9-2 at this time. Therefore, the lower address a2 of the transmission source MAC address of the packet is stored in the lower address memory 7 for designating packet transmission outside the ring. The packet is forwarded by (8) Mr1r2a3a2 (I0) on counterclockwise optical ring 1 and arrives at packet add, drop and pass device 6-3.

When the packet (8) Mr1r2a3a2 (I0) arrives at the packet add, drop and 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 not stored in memory 7, the packet is forwarded by (9) Mr1r2a3a2 (I0) on counterclockwise optical ring 1 and reaches vertex device 5 as shown.

Said packet arriving at the vertex device 5 is sent out of the ring and reaches the router 22 via the upper ring 4 as indicated by (10) Mr1r2a3a2 (I0).

When the packet (10) Mr1r2a3a2 (I0) arrives at the router 22, after storing the source MAC address a3a2 and the source IP address I3 of the packet in the memory 1 (not shown), the destination IP address I0 of the packet is stored. , read the output port corresponding to the destination domain of the , and send it to that port. The packet is shown by (11) 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 .

When the packet (11) IPI3I0 of the download request or the like arrives, the server 20 sends to the router 22 the response packet (12) IPI0I2 of the packet that previously arrived from the terminal 13-1. The router 22 obtains the destination MAC address a1a2 from the destination IP address I2 of the packet from the memory 1 or the ARP table (not shown in the figure). (14) Transfer as illustrated by Ma1a2r1r2 (I2). The packet arrives at the packet add/drop/pass device 6-2 as (15) Ma1a2r1r2 (I2), and the destination MAC address a1a2 of the packet is stored in the packet pass bridge address table 9-2 at this time. and the lower address a2 of the packet's destination MAC address is stored in the lower address memory 7 for designating packet transmission outside the ring. store it in the bridge address table 9-2 and send the packet out of the ring as indicated by (16) Ma1a2r1r2 (I2).

Since the ACK packet of the packet (12) IPI0I2 does not arrive, the server 20 sends the retransmission packet (17) IPI0I2 to the router 22 . The router 22 obtains the destination MAC address a1a2 from the destination IP address I2 of the packet from the memory 1 or the ARP table (not shown in the figure), and sends the packet (18) Ma1a2r1r2 (I2) to the clockwise ring 2 as shown in the figure. Forward.
The packet arrives at the packet add/drop/pass device 6-2 as (20) Ma1a2r1r2 (I2), and the destination MAC address a1a2 of the packet is stored in the packet pass bridge address table 9-2. Therefore, the packet is sent to the front of clockwise ring 2 by (21) Ma1a2r1r2 (I2) as shown in the figure.

The packet is forwarded by (21) Ma1a2r1r2 (I2) through clockwise ring 2 as shown in the figure and arrives at packet add, drop and pass device 6-1. When the packet arrives, the packet add, drop, and pass device 6-1 stores the destination MAC address a1a2 of the packet in the packet pass bridging address table 9-2 in the same manner as described above. Send the packet out of the ring and have it arrive at terminal 13-1 as shown by (22) Ma1a2r1r2 (I2).

When the packet (22) Ma1a2r1r2 (I2) arrives at the mobile terminal 13-1, an ACK packet (23) Mr1r2a1a2 (I0) is sent to the packet add, drop and pass device 6-1.
When the packet arrives at the packet add/drop/pass device 6-1, the lower address a2 of the source MAC address of the packet is stored in the lower address memory 7 for designating packet transmission outside the ring. In addition, since the packet transmission source MAC address a1a2 is stored in the packet passing bridging address table 9-2, the address a1a2 is erased, and the packet is stored in the packet passage prohibited lower address memory 9-1. The lower address a2 of the source MAC address is stored, and the packet is sent by (24) Mr1r2a1a2 (I0) toward the device 6-2 for adding, dropping and passing packets through counterclockwise ring 1 as shown in the figure. . The erasure of the address a1a2 is indicated by a horizontal line above a1a2 in the figure.

When the packet (24) Mr1r2a1a2 (I0) arrives at the packet add/drop/pass device 6-2, the lower address of the packet transmission source MAC address is stored in the lower address memory 7 for designating packet transmission outside the ring. Since the address a2 is stored, the source MAC address of the packet is stored in the packet passage bridging address table 9-2, and the packet is sent to the counterclockwise ring 1 by (25) Mr1r2a1a2 (I0). Transfer as indicated.

When the packet arrives at the router 22 as shown by (27) Mr1r2a1a2 (I0), the IP address corresponding to the source MAC address a3a2 of the same lower address as the lower address a2 of the source MAC address of the packet is The IP packet (28) IPI0I3 from the server having the destination IP address is not waited as it is because the packet (27) Mr1r2a1a2 (I0) does not have the signal g indicating that it is a packet immediately after the base station has moved. send to

The retransmission packet (32) Mr1r2a3a2(I0) is sent from the TCP portable terminal 13-2 as packet (29) Mr1r2a3a2(I0) to the packet add, drop and pass device 6-2, and the packet is added, dropped and passed. In the device 6-2, the lower address a2 of the source MAC address of the packet is stored in the lower address memory 7 that designates packet transmission outside the ring, and the source MAC address a3a2 of the packet is stored in the device 6-2. Since it is not stored in the passing bridging address table 9-2 at this time, it is a packet that has arrived at the router 22 as it is.

Next, the destination MAC address a3a2 corresponding to the destination IP address I2 of the packet (28) IPI0I3 from the server is read from the memory 1 (not shown), and the packet (33) Ma3a2r1r2 (I3) added to the IP packet is transferred to the upper An example of sending to clockwise ring 2 via ring 4 and vertex device 5 of the subscriber ring is shown. The packet is forwarded by (35) Ma3a2r1r2 (I3) as shown in the figure and arrives at the packet add, drop and pass device 6-2. The lower address a2 of the destination MAC address of the packet that has arrived at the packet add, drop, and pass device 6-2 is not stored in the packet passage prohibited lower address memory 9-1, and the destination MAC address of the packet is stored in the lower address memory 7 for designating packet transmission outside the ring, and the destination MAC address a3a2 of the packet is not stored in the packet passing bridge address table 9-2 at this time. , the destination MAC address a3a2 of the packet is stored in the packet transit bridge address table 9-2, and the packet is sent out of the ring by (36) Ma3a2r1r2 (I3) as shown in the figure.
The packet (36) Ma3a2r1r2 (I3) reaches the TCP mobile terminal 13-2.

When the packet (36) Ma3a2r1r2 (I3) reaches the TCP mobile terminal 13-2, the TCP mobile terminal 13-2 adds an ACK packet (37) Mr1r2a3a2 (I0) via the base station 12-2, It is sent to the drop and pass device 6-2. When the packet arrives at the packet add/drop/pass device 6-2, the packet transmission source MAC address a3a2 is stored in the packet pass bridge address table 9-2. The lower address a2 of the original MAC address is stored in the packet passage prohibited lower address memory 9-1. The packet is forwarded by counterclockwise ring 1 and arrives at router 22 as shown by (40) Mr1r2a3a2 (I0).

Next, when the TCP mobile terminal 13-2 moves from under the control of the base station 12-2 to under the control of the base station 12-1 and the packet (41) Mr1r2a3a2 (I0) arrives at the base station 12-1, the packet A signal g indicating the movement of the base station is put in the option area of the IP header, and sent to the packet add, drop and pass device 6-1. When the packet from the TCP mobile terminal 13-2 reaches the add, drop, and pass device 6-1, the source MAC address a3a2 of the packet is not stored in the packet passing bridging address table 9-2. Therefore, the lower address a2 of the transmission source MAC address of the packet is stored in the lower address memory 7 for designating packet transmission outside the ring. When the packet reaches the add, drop, and pass device 6-2, the packet is the packet immediately after the base station has moved, and the lower address a2 of the source MAC address of the packet designates packet transmission out of the ring. Since it is stored in the lower address memory 7, the lower address is erased. The packet is forwarded by (43) Mr1r2a3a2g (I0) on counterclockwise optical ring 1 to router 22 as shown in the figure.

When the packet arrives at the router 22, after storing the source MAC address and the source IP address of the packet in the memory 1 (not shown), the output port corresponding to the destination domain of the destination IP address I0 of the packet is selected. Since the packet is read out and sent to the port, and the indication g indicating that the packet is a packet immediately after moving the base station, the packet has the same lower address as the lower address a2 of the source MAC address of the packet. If the MAC address is stored in memory 1 (not shown in the figure), the MAC address and its corresponding IP address are stored in memory 2 (not shown in the figure). When the destination IP address of a packet arriving from the server 20 is stored in the memory 2 not shown in the figure, the MAC address corresponding to the destination IP address of the packet is read from the memory 2, and Wait in a buffer (not shown) until a retransmission packet arrives from the mobile terminal whose source MAC address is the MAC address. The figure shows a memory state in which the same lower address as the lower address of the source MAC address of the packet is not stored in the lower address memory 7 that designates packet transmission outside the ring of the packet add, drop and pass device 6-2. A retransmission packet from the terminal 13-4 is required to store the lower address to the terminal 13-4.

In the second embodiment described above, the TCP portable terminal 13-2 is an example of transit base station movement in the direction away from the server in the ring network. When a packet immediately after movement arrives at the packet add/drop/pass device 6-2 from outside the ring, the lower address of the source MAC address of the packet is stored in the lower address memory 7 for designating packet transmission to the outside of the ring. If the packet transmission source MAC address a3a2 is stored in the packet passage bridging address table 9-2, the address a3a2 is erased and the packet passage prohibited lower address is stored. The lower address a2 of the source MAC address of the packet is stored in the memory 9-1. When a packet from the TCP mobile terminal 13-2 immediately after moving to the base station arrives at the router 22, when the router 22 performs the same packet waiting operation as in the second embodiment, the TCP mobile terminal under the control of the base station 12-1 When a retransmitted packet arrives at the packet add, drop and pass device 6-2 from the counterclockwise ring, the lower address a2 of the source MAC address of the packet designates transmission of the packet out of the ring. 7, the source MAC address of the packet is stored in the bridging address table for passing the packet.

It should be noted that a lower address memory for designating packet passage may be added to the packet add, drop, and passage device 6 of the second embodiment.
As for the operation in this case, in Embodiment 2, when a packet transferred through counterclockwise ring 1 arrives at packet add, drop, and pass device 6, it is always stored in the lower address memory designating the pass of the packet. The lower address of the source MAC address of the packet is stored, and furthermore, when the packet transferred in the clockwise ring from the server 20 reaches the packet add, drop and pass device 6, the destination MAC address of the packet is stored. When the lower address is not stored in the lower address memory that specifies packet transmission outside the ring and the lower address of the destination MAC address of the packet is not stored in the lower address memory that specifies packet passage adds the operation of discarding the packet.

In the above operation, the terminal packet directed to the server does not store the lower address of the source MAC address of the packet in the lower address memory, Since a 1-bit storage low-order address memory is used, there is no memory leakage of low-order addresses, and there is no problem of flooding of unknown packets.

In the above first and second embodiments, an example of a packet from a server directed to a TCP portable terminal is shown, but the present invention can also be applied to UDP video packets. In the case of a UDP terminal, if no packet arrives from the server for a certain period of time, the UDP mobile terminal needs to send out a communication partner confirmation packet such as a ping packet. However, as in the present invention, the packet immediately after moving the base station arrives at the packet add, drop, and passing device from the counterclockwise ring, and the lower address of the source MAC address of the packet is the packet to the outside of the ring. If the packet is stored in the low-order address memory for which transmission is designated, there will be no opportunity to require transmission of the communication partner confirmation packet unless the operation of erasing the low-order address is executed.

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 Add, drop, and pass devices for packets 7 Specify packet transmission outside the ring Lower address memory 9-1 Packet passage prohibition Lower address memory 9-2 Packet passage bridge address tables 12-1, 12-2, 12-3, 12-4, 12-5 Base stations 13-1, 13- 2, 13-3, 13-4 TCP mobile terminal 14 Movement of mobile terminal 20 Server 22 Router

Claims (8)

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 communicates with a server through a router connected to a vertex device of the ring network or the tree-like ring. , a packet transfer system that enables mobile terminals to move between base stations,
When a packet arrives at a device for adding, dropping, and passing packets in a ring network from a clockwise ring, if the destination MAC address of the packet is stored in the bridging address table for passing the packet, the packet is forwarding the packet to the front of the clockwise ring, and if the lower address of the destination MAC address of the packet is not stored in the lower address memory designating the packet to be sent out of the ring, sending the packet to the front of the clockwise ring; Other than the above, if the lower address of the destination MAC address of the packet is stored in the packet passage prohibited lower address memory, the packet is sent out of the ring, and other than the above, the destination MAC address of the packet is stored. When the lower address is stored in the lower address memory that designates packet transmission to the outside of the ring, the destination MAC address of the packet is stored in the packet passing bridging address table, and the packet is transmitted out of the ring. means and
When a packet arrives at a ring network packet add, drop, and pass device from a counterclockwise ring, the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring. means for storing the source MAC address of the packet in a packet passage bridging address table if the packet is present, and transmitting the packet to the front of the counterclockwise ring as it is except for the above;
When a packet from outside the ring arrives at the ring network packet add, drop and pass device,
If the packet is not a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
When the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, and the source MAC address of the packet is stored in the packet transit bridging address table , erasing the stored address, storing the lower address of the transmission source MAC address of the packet in a packet pass-prohibited lower address memory, and sending the packet forward in the counterclockwise ring;
When a packet from outside the ring arrives at the ring network packet add, drop and pass device,
If the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
When the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, and the source MAC address of the packet is stored in the packet transit bridging address table and means for erasing the stored address, storing the lower address of the transmission source MAC address of the packet in a packet pass-prohibited lower address memory, and transmitting the packet forward in the counterclockwise ring. A packet transfer system that enables mobile terminals to move between base stations.
When a packet arrives from a left-handed ring,
If the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
If the lower address of the source MAC address of the packet is stored in the lower address memory that designates the transmission of the packet out of the ring, delete the lower address, and otherwise rotate the packet counterclockwise. 2. The packet transfer system according to claim 1, further comprising means for transmitting to the front of the ring, allowing mobile terminals to move between base stations.
3. The mobile terminal according to claim 1, further comprising means for sending a resend packet or a resend request packet to the server when no packet arrives from the server for a predetermined time or longer during communication. A packet transfer system that enables mobile terminals to move between base stations.
The mobile terminal simply transmits a location registration packet or a one-way setup packet having a source MAC address at a constant period or at a period equal to or less than the timer value of the memory of the device for adding, dropping, and passing packets. 2. The packet transfer system according to claim 1, further comprising means for sending packets from base stations through which the packets pass to said ring network or tree-like ring network.
A packet waiting means applied to the packet transfer system according to any one of claims 1 to 4,
The source MAC address and the source IP address of a packet directed from a mobile terminal to a server via a base station, a ring network or a tree-like ring network are stored in the first memory of the own packet waiting means of the router or gateway, and are addressed to the server. or put the source MAC address of the original IP packet destined for the server into the option area of the IP header of the IP packet and send it to the server;
When a packet having a signal indicating that the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing the packet of the ring network to be added arrives at the self-packet waiting means,
If a MAC address different from the source MAC address of the packet is stored in the first memory of the packet waiting means, the lower address of the source MAC address of the packet is stored as a lower address. storing the MAC address and the IP address corresponding to the MAC address in the second memory of the own packet waiting means;
Alternatively, if the first memory of the own packet waiting means is not used, storing the source MAC address of the packet as a seed MAC address in the second memory of the own packet waiting means,
In the method that does not use the first memory of the self-packet waiting means, the same lower address as the seed MAC address stored in the second memory of the self-packet waiting means is added to the IP header of the IP packet arriving from the server. and if the MAC address is different from the seed MAC address stored in the second memory, the MAC address of the option area of the IP header of the IP packet is stored in the second memory. Then, the packet is waited until a retransmission packet from the mobile terminal whose source MAC address is the MAC address of the packet arrives, and when the retransmission packet arrives, the source MAC address of the retransmission packet is changed to the self. Erasing from the second memory of the packet waiting means, and erasing the seed MAC address whose lower address is the lower address of the source MAC address after a certain period of time from when the seed MAC address is stored in the second memory;
On the other hand, in the method of using the first memory of the own packet waiting means, when a packet having the destination IP address of the IP address stored in the second memory of the own packet waiting means arrives from the server, TCP packets wait until reception of a retransmission packet from a TCP mobile terminal, with the source MAC address being the MAC address stored in the second memory corresponding to the destination IP address of the packet, and the UDP packet Wait until receiving a one-way setup packet with a source MAC address, and when the ACK packet, retransmission packet, or one-way setup packet arrives, the source MAC address of the ACK packet, retransmission packet, or one-way setup packet erasing the source IP address from the second memory of the own packet waiting means;
Packet waiting means characterized by:
A communication method in a wireless section including handover between a base station and a mobile terminal used in the method of moving a mobile terminal between base stations in the packet transfer system according to any one of claims 1 to 4,
When the mobile terminal moves between base stations, if the radio waves from the destination base station become stronger than the radio waves from the base station currently receiving packets, the mobile terminal is sent to the destination base station by CSMA/CA. Secure the specified time slot position of the specified frequency used by the terminal, or secure the CDMA code or OFDM symbol code, and move to the destination base with the secured time slot of the specified frequency or CDMA of that code or OFDM of that code A radio section communication method including handover between a base station and a mobile terminal, characterized by starting communication with a base station.
2. A low-order address memory for designating out-ring packet transmission of a 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 packet is transmitted out of the ring. 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 and By storing the parallel data latch signal of the logical sum of A memory for inserting and storing the lower part as bit 1 at the position of bit 1 of decoding as bit 1 meaning lower address storage,
When deleting the lower address of the source MAC address from the lower address memory that specifies packet transmission outside the ring, the lower address memory that specifies packet transmission outside the ring is replaced with the upper part of the lower address of the source MAC address. Each bit of the parallel data read from the addressed position and the bit-inverted bit of each bit of the parallel data decoded from the lower part of the lower address of the transmission source MAC address are logically ANDed to the outside of the ring. By storing the lower address portion of the lower address of the transmission source MAC address in the address specifying position of the lower address memory designating packet transmission, bit 0 is inserted into the position of decode bit 1 as bit 0 meaning no lower address storage. A low-order address memory for designating packet add, drop, and transmission out of the ring of passing devices of a ring network or a tree-like ring network of a packet transfer system, characterized by storing.
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 communicates with a server through a router connected to a vertex device of the ring network or the tree-like ring. , a packet transfer method that enables a mobile terminal to move between base stations,
When a packet arrives at a device for adding, dropping, and passing packets in a ring network from a clockwise ring, if the destination MAC address of the packet is stored in the bridging address table for passing the packet, the packet is forwarding the packet to the front of the clockwise ring, and if the lower address of the destination MAC address of the packet is not stored in the lower address memory designating the packet to be sent out of the ring, sending the packet to the front of the clockwise ring; Other than the above, if the lower address of the destination MAC address of the packet is stored in the packet passage prohibited lower address memory, the packet is sent out of the ring, and other than the above, the destination MAC address of the packet is stored. When the lower address is stored in the lower address memory that designates packet transmission to the outside of the ring, the destination MAC address of the packet is stored in the packet passing bridging address table, and the packet is transmitted out of the ring. a step;
When a packet arrives at a ring network packet add, drop, and pass device from a counterclockwise ring, the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring. If it is, the source MAC address of the packet is stored in the packet passing bridging address table, and other than the above, the packet is sent to the front of the counterclockwise ring as it is,
When a packet arrives from a left-handed ring,
If the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
If the lower address of the source MAC address of the packet is stored in the lower address memory that designates the transmission of the packet out of the ring, delete the lower address, and otherwise rotate the packet counterclockwise. When a packet arrives at the ring network packet add, drop, and pass device from outside the ring,
If the packet is not a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
When the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, and the source MAC address of the packet is stored in the packet transit bridging address table , erasing the stored address, storing the lower address of the transmission source MAC address of the packet in a packet pass-prohibited lower address memory, and sending the packet forward in the counterclockwise ring;
When a packet from outside the ring arrives at the ring network packet add, drop and pass device,
If the packet is a packet immediately after changing the base station through which the mobile terminal passes and changing the device for adding, dropping, and passing packets added from outside the ring,
When the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, and the source MAC address of the packet is stored in the packet transit bridging address table and a step of erasing the stored address, storing the lower address of the transmission source MAC address of the packet in a packet pass-prohibited lower address memory, and transmitting the packet forward in a counterclockwise ring. A packet transfer method that enables a mobile terminal to move between base stations.

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