JP2023047452A - Address storage method, ring network using the same, and handover using ring network - Google Patents

Abstract

To provide a device and a packet transfer method for achieving handover of a wireless system at low cost and at high speed.SOLUTION: In the case where a TCP mobile terminal and a server communicate via a ring network, when a packet forwarded in a clockwise ring from the server arrives at a packet add, drop, and pass device, if a lower address of a destination MAC address of the packet is stored in a lower address memory that specifies transmitting the packet out of the ring, the destination MAC address of the packet is stored in a bridging address table for packet passage and the packet is transmitted out of the ring. When a packet arrives at the packet add, drop, and pass device from outside the ring, and if a source MAC address of the packet is stored in the bridging address table for packet passage, the address is deleted, and a lower address of the source MAC address of the packet is stored in a packet passage prohibition lower address memory.SELECTED DRAWING: Figure 1

Description

The present invention relates to an address storage method such as a MAC address, a ring network for transferring Ethernet packets using the method, and a handover using the ring network.

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

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

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

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

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

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

An object of the present invention is to provide a conventional address storage method that does not use a MAC address table, and to realize a ring network using the same, handover using the ring network, and short-distance movement of mobile terminals.

The present invention has been made in view of the problems of the prior art described above. When a packet transferred through the ring arrives at a packet add, drop, and pass device, when the lower address of the destination MAC address of said packet is stored in a lower address memory designating packet transmission out of the ring stores the destination MAC address of the packet in a packet passing bridging address table, sends the packet out of the ring, and arrives at a packet add, drop, and pass device from outside the ring; is stored in the packet passage bridging address table, the address is deleted, and the lower address of the packet source MAC address is stored in the packet passage prohibited lower address memory. is.

A second aspect of the present invention is to transmit packets in a ring network when a terminal and a server communicate via a double ring network consisting of a left-handed ring and a right-handed ring in which the direction of transmission is opposite to that of the ring. An add, drop and pass device,
When a packet arrives from the clockwise ring, and the destination MAC address of the packet is stored in the packet passing bridging address table, the packet is sent to the front of the clockwise ring, and the destination MAC of the packet is sent. If the address is stored in the address table that specifies packet transmission outside the ring, the packet is transmitted outside the ring, and the lower address of the destination MAC address of the packet specifies packet transmission outside the ring. If the packet is not stored in the lower address memory, the packet is sent to the front of the clockwise ring; otherwise, if the lower address of the destination MAC address of the packet is stored in the packet passage prohibited lower address memory means for sending the packet out of the ring, storing the destination MAC address of the packet in a bridging lower address table for packet passage, and sending the packet out of the ring;
When a packet arrives from outside the ring, the lower address of the source MAC address of the packet is stored in a lower address memory for designating packet transmission to the outside of the ring, and the source MAC address of the packet is the bridging address for passing the packet. If it is stored in the table, erase the stored address, store the lower address of the source MAC address of the packet in the pass-prohibited lower address memory of the packet, and lower the source MAC address of the packet If the address is stored in the packet's pass-barred lower address memory, and if the pass-barred operation stop bit is stored in that low-order address storage location, then the source MAC address of said packet is stored in the out-of-ring packet. The packet is stored in an address table that designates transmission, and if the passage prohibition operation stop bit is not stored at that position, the packet is directly transmitted to the front of the counterclockwise ring.

Also, a third aspect of the present invention provides the apparatus for adding, dropping, and passing packets according to the second aspect of the present invention,
When a packet arrives from the counterclockwise ring, if the lower address of the transmission source MAC address of the packet is stored in the pass prohibition lower address of the packet, the pass prohibition operation stop bit is stored in the lower address storage location. Other than the above, it is characterized by further comprising means for sending the packet to the front of the counterclockwise ring as it is.

A fourth aspect of the present invention is packet transfer in a ring network when a terminal and a server communicate via a double ring network consisting of a left-handed ring and a right-handed ring opposite to the ring. a method,
When a packet arrives at a packet add, drop and pass device from the clockwise ring, the packet is sent to the clockwise ring if the destination MAC address of the packet is stored in the packet pass bridging address table. If the destination MAC address of the packet is stored in the address table that designates packet transmission outside the ring, the packet is transmitted out of the ring, and the lower address of the destination MAC address of the packet is sent forward. is not stored in the lower address memory that designates the packet to be sent out of the ring, the packet is sent to the front of the ring in a clockwise direction, and other than the above, the lower address of the destination MAC address of the packet If the packet is stored in the prohibited lower address memory, the packet is sent out of the ring; otherwise, the destination MAC address of the packet is stored in the packet passage bridging lower address table, and the packet is transferred to the ring. sending out;
When a packet arrives at a device for adding, dropping, and passing packets from outside the ring, the lower address of the source MAC address of the packet is stored in a lower address memory designating packet transmission to the outside of the ring, and the packet is transmitted. If the original MAC address is stored in the packet passage bridging address table, the stored address is erased and the lower address of the packet transmission source MAC address is stored in the packet passage prohibited lower address memory. , when the lower address of the transmission source MAC address of the packet is stored in the packet passage prohibition lower address memory, and when the pass prohibition operation stop bit is stored in the lower address storage location, the packet A step of storing the source MAC address in an address table for designating packet transmission to the outside of the ring, and transmitting the packet to the front of the counterclockwise ring as it is when the passage prohibition operation stop bit is not stored at that position. and

A fifth aspect of the present invention is the packet transfer method according to the fourth aspect of the present invention,
When a packet arrives at a packet add, drop, and pass device from a counterclockwise ring, if the lower address of the source MAC address of the packet is stored in the pass-prohibited lower address of the packet, the lower address is stored. It is characterized by further comprising the step of storing a pass prohibition operation stop bit in a position and transmitting the packet to the front of the counterclockwise ring as it is except for the above.

As described above, the present invention applies a low-order address storage method with a short storage bit length, a large number of storage addresses, and no omission of storage addresses to a ring network for transferring Ethernet packets. Since it is a method that realizes handover and short-range terminal movement by network and ring network, there is no problem such as flooding of unknown packets due to the use of the conventional MAC address table with memory address omission, and the conventional block port is unnecessary. , power consumption and system cost are reduced, and high-speed communication is possible.

A lower address memory for designating packet transmission to the outside of the ring, a bridging address table for packet passage, a lower address memory for prohibiting packet passage, and packet transmission to the outside of the ring for transferring Ethernet packets in the first embodiment of the present invention. A diagram for explaining the operation of using a ring network in which a plurality of packet add, drop, and pass devices having an address table that designates is connected by an optical transmission line for communication between a terminal and a server Lower address memory for designating packet transmission to outside the ring, packet passage bridging address table, packet passage prohibition lower address memory, and packet transmission to outside the ring according to the third embodiment of the present invention A diagram for explaining the handover operation of a network that uses a ring network in which multiple packet add, drop, and pass devices that have an address table that specifies are connected by optical transmission lines for communication between a mobile terminal and a server Lower address memory for designating packet transmission to outside the ring, packet passage bridging address table, packet passage prohibition lower address memory and packet transmission to outside the ring for transferring Ethernet packets in the fourth embodiment of the present invention A diagram for explaining the handover operation of a network that uses a ring network in which multiple packet add, drop, and pass devices that have an address table that specifies 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. This embodiment comprises a lower address memory for transferring Ethernet packets in the first embodiment and designating packet transmission to the outside of the ring, a bridge address table for packet passage, a lower address memory for prohibiting packet passage, and a memory for outside the ring. This is an operation example of a ring network that transfers Ethernet packets, which consists of a vertex device in which a plurality of packet add, drop, and pass devices having an address table specifying packet transmission and a server are connected via a router. Packets transferred in this ring network include UDP packets and YouTube packets that use TCP only at the start of communication, in addition to TCP packets.

In FIG. 1, 1 is a counterclockwise optical ring, 2 is a clockwise optical ring, 5 is a vertex device, 6-1, 6-2, 6-3 are packet add, drop and pass devices, and 7 is out of the ring. 9-1 is a lower address memory for packet passage prohibition; 9-2 is a bridging address table for packet passage; 11 is an address table for designating packet transmission outside the ring; Routers, 13-1, 13-2 and 13-3 are terminals, and 20 is a server. Also, (1) to (31) are packets, and I0, I1, I2, I4, and I5 are domestic or regional IP addresses of service providers. or an IPv6 address.

The bridge address table 9-2 for passing packets and the address table 11 for designating packet transmission to the outside of the ring are address tables that do not store port numbers and have a small number of stored MAC addresses, unlike conventional MAC address tables. .

The operation of FIG. 1 will be described below. First, it is assumed that the IP address I2 of the router 22 and the MAC address r1r2 of the ring transmission interface are already stored in the ARP tables of the terminals 13-1, 13-2 and 13-3. The terminal 13-3 sends a packet (1) Mr1r2a3a2 (I0) (M indicates an Ethernet packet, r1 indicates the upper MAC address of the interface of the router 22, r2 indicates the lower MAC address of the interface of the router 22, a3a2 indicates the terminal 13 -3, which are the upper MAC address a3 and the lower MAC address a2, and I0 indicates the IP address of the destination server 20) is sent to the packet add, drop, and pass device 6-3. show. When the packet reaches the add, drop, and pass device 6-3 from the terminal 13-3, the lower address memory designates the packet transmission out of the ring with the lower address a2 of the source MAC address of the packet. Store in 7. The packet is forwarded by (2) Mr1r2a3a2 (I0) on counterclockwise optical ring 1 and arrives at vertex device 5 as shown in the figure.
The packet is sent out of the ring and reaches router 22 .

When the packet (3) 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 (4) IPI5I0 (IP indicates an IP address, I5 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 . Packet (4) IPI5I0 response packet (5) IPI0I5, which arrives at the server 20 for the download request, etc., is sent to the router 22 . When the reply packet (5) IPI0I5 arrives, the router 22 obtains the destination MAC address a3a2 from the ARP table from the destination IP address I5 of the packet, and forwards the packet (6) Ma3a2r1r2 (I5) to the vertex device 5 as shown in the figure. to the clockwise ring 2 via .

Said packet arrives at the packet add, drop and pass unit 6-3 as shown in the figure by (7) Ma3a2r1r2 (I5). The destination MAC address a3a2 of the packet arriving at the device 6-3 for adding, dropping, and passing the packet is not stored in the address table 11 that designates packet transmission outside the ring at this time, and the destination of the packet is While the MAC address a3a2 is not stored in the packet passing bridging address table 9-2 at this time, the lower address a2 of the destination MAC address of the packet is stored in the lower address memory 7 for designating packet transmission outside the ring. Since it is stored, the destination MAC address a3a2 of the packet is stored in the packet passing bridging address table 9-2, the packet is sent out of the ring, and (8) Ma3a2r1r2 (I5) is shown in the figure. to reach the terminal 13-3.

When the ACK packet (9) Mr1r2a3a2 (I0) of the packet (8) Ma3a2r1r2 (I5) arrives at the packet add, drop and pass device 6-3 from the terminal 13-3, the source MAC address of the packet is Since the lower address is stored in the lower address memory 7 for designating packet transmission to the outside of the ring, and the source MAC address a3a2 of the packet is stored in the packet passing bridging lower address table 9-2, a3a2 is erased, and the lower address of the source MAC address of the packet is stored in the packet passage prohibited lower address memory 9-1. The packet is forwarded by left-handed ring 1, through vertex device 5, and reaches router 22 as shown by (11) Mr1r2a3a2 (I0).

Next, the terminal 13-1 sends a packet (12) 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 terminal 13-1, and I0 indicates the IP address of the destination server 20) to the packet add, drop, and pass device 6-1. do. When the packet reaches the add, drop, and pass device 6-1 from the TCP mobile terminal 13-1, the lower address a2 of the source MAC address of the packet is set to the lower address that designates the transmission of the packet out of the ring. It is stored in the address memory 7. The packet is forwarded by (14) Mr1r2a1a2 (I0) on counterclockwise optical ring 1, and arrives at packet add, drop and pass device 6-3.

When the packet (14) 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 packet passage prohibited lower address memory 9-1. Since it is stored, the pass inhibit operation stop bit is stored at the lower address location. The pass inhibit operation stop bit is marked as the letter S (meaning STOP) in the figure.
The packet is forwarded by ( 16 ) Mr 1 r 2 a 1 a 2 (I 0 ) on counterclockwise optical ring 1 and reaches router 22 via vertex device 5 .

When the packet (16) Mr1r2a1a2 (I0) arrives at the router 22, the output port corresponding to the destination IP address I0 of the packet is read and sent to that port. The packet is shown by (17) IPI4I0 (IP indicates an IP address, I4 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 server 20 sends to the router 22 a packet (17) IPI4I0 response packet (18) IPI0I4 for the download request or the like. Router 22 refers to the ARP table and sends packet (19) Ma1a2r1r2 (I4) to clockwise ring 2 via vertex device 5 .

The packet is forwarded by (20) Ma1a2r1r2 (I4) through clockwise ring 2 as shown in the figure and arrives at packet add, drop and pass device 6-3, where the packet's destination MAC address a1a2 is The destination MAC address a1a2 of the packet is not stored in the address table 11 that designates packet transmission to the outside, and the destination MAC address a1a2 of the packet is not stored in the packet passing bridging lower address table 9-2. is stored in the pass-prohibited lower-order address memory 9-1, and the pass-prohibited operation stop bit (S) is stored in the storage lower address position. It is sent to the front of the ring 2.

The packet is forwarded by (21) Ma1a2r1r2 (I4) through clockwise ring 2 as shown in the figure, arrives at the packet add, drop and pass device 6-1, and is processed in the same manner as above. The destination MAC address a1a2 of the packet is stored in the bridge address table 9-2, the packet is sent outside the ring, and arrives at the terminal 13-1 as shown by (23) Ma1a2r1r2 (I4). .

Next, an example in which the terminal 13-3 sends the packet (24) Mr1r2a3a2(I0) to the packet add/drop/pass device 6-3 is shown. When the packet 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 packet passage prohibited lower address memory 9-1, and the lower address Since the pass prohibition operation stop bit (S) is stored in the address storage position, the source MAC address a3a2 of the packet is stored in the address table 11 for designating packet transmission out of the ring. The packet is sent to the server 20 side, and the response packet arrives at the packet add, drop and pass device 6-3 as indicated by (30) Ma3a2r1r2 (I5) from the clockwise ring. Since the destination MAC address a3a2 of the packet is stored in the address table 11 that specifies the packet transmission outside the ring of the packet add, drop and pass device 6-3, the packet is transmitted outside the ring ( 31) Arrive at terminal 13-3 as illustrated by Ma3a2r1r2 (I5).

In addition, in the first embodiment described above, an example is shown in which the lower address of the source MAC address is stored in the lower address memory that designates packet transmission to the outside of the ring. bit 1, which means lower address storage, is stored in the lower address memory designating packet transmission out of the ring at the location addressed by the lower address of the source MAC address. It may be to remember.
Alternatively, storing the lower address of the transmission source MAC address of the packet in a lower address memory designating packet transmission to the outside of the ring means that the lower address memory designating packet transmission to the outside of the ring is stored in the lower address memory of the transmission source MAC address. Parallel data latch signal of logical sum of each bit of parallel data read from the position addressed by the upper part of the address and each bit of parallel data decoded from the lower part of the lower address of the transmission source MAC address is output to the outside of the ring. By storing at the address specifying position of the lower address memory which designates the packet transmission of the source MAC address, the bit 1 at the position of the decoding bit 1 of the lower part of the lower address of the source MAC address is used as the bit 1 indicating lower address storage. Insertion storage may also be used.

In Embodiment 1 described above, multi-round packets are discarded by the multi-round bit adding device.

Although the first embodiment described above can operate as a LAN, it can also operate as a MAN via an edge node. In that case, an address table of a dedicated ring node device that stores MAC addresses directed to the head office server is used. Use a ring.

A lower address memory for designating packet passage may be added to the packet add, drop, and passage device 6 of the first embodiment.
As for the operation in this case, in Embodiment 1, 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 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.

A second embodiment of the present invention will now be described with reference to FIG. This embodiment comprises a plurality of packets having an address table for designating packet transmission to the outside of the ring, a lower address memory for designating packet transmission to the outside of the ring, a bridge address table for packet passage, and a lower address memory for prohibiting packet passage. This is an example of handover operation using a ring network that transfers Ethernet packets composed of a vertex device in which add, drop, and pass devices and a server are connected via a router. The server is a content server.

In FIG. 2, 3 is a subscriber system ring, 4 is an upper ring, 12-1, 12-2, 12-3, 12-4 and 12-5 are base stations, 13-1, 13-2 and 13-4. is the mobile terminal, 14 is the moving direction of the mobile terminal, and the rest is the same as in FIG. Also, (1) to (39) are packets, and I0, I1, I2, I3, I4, and I6 are domestic or regional IP addresses of service providers.

The operation of FIG. 2 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. . 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 router 22, r2 indicates the lower MAC address of the interface of 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 mobile 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/pass device 6-2, the lower address a2 of the packet source MAC address is stored in the packet passage prohibited lower address memory 9-1. Since it is not stored at this point, the packet is forwarded by (3) Mr1r2a1a2 (I0) on 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 packet passage prohibited lower address memory 9-1. Since it is not stored, the packet is forwarded by (4) Mr1r2a1a2 (I0) on left-handed optical ring 1 and arrives at vertex device 5 as shown. 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 .

Next, the TCP mobile terminal 13-2 sends a 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 mobile 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/pass device 6-3, the lower address a2 of the packet source MAC address is stored in the packet passage prohibited lower address memory 9-1. Since it is not stored, 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 .

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 transfers the packet (13) Ma1a2r1r2 (I2) obtained from the destination IP address I2 of the packet to the destination MAC address a1a2 from the ARP table (not shown) to the clockwise ring 2 as shown in the drawing. 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 address table 11 specifying packet transmission outside the ring, and the destination of the packet A lower address memory 7 in which the MAC address a1a2 is not stored in the packet passing bridging address table 9-2 at this time, and the lower address a2 of the destination MAC address of the packet designates packet transmission outside the ring. , the destination MAC address a1a2 of the packet is stored in the packet passing bridging address table 9-2, and the packet is sent out of the ring (16) as indicated by Ma1a2r1r2 (I2) in the figure. send as

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 transfers the packet (18) Ma1a2r1r2 (I2) whose destination MAC address a1a2 is obtained from the destination IP address I2 of the packet by the ARP table not shown in the figure to the clockwise ring 2 as shown in the figure. 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. 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 a2 of the source MAC address of the packet is stored in the packet pass prohibited lower address memory 9-1. Since it is not stored, the packet is forwarded by 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 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 put on standby until the retransmission packet (32) Mr1r2a3a2 (I0) from the corresponding mobile terminal 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 resent packet (32) Mr1r2a3a2 (I0) arrives at the router 22, the waiting packet (28)) packet (33) Ma3a2r1r2 (I3) with the destination MAC address corresponding to the destination IP address I2 of IPI0I3 is added. It is sent to the clockwise ring 2 via the upper ring 4 and the vertex device 5 of the subscriber ring. 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 destination MAC address a3a2 of the packet arriving at the packet add, drop, and pass device 6-2 is not stored in the address table 11 specifying packet transmission outside the ring, and is lower than the destination MAC address of the packet. Since the address a2 is stored in the lower address memory 7 that designates packet transmission to the outside of 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 above 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, if the lower address a2 of the transmission source MAC address of the packet is stored in the pass-prohibited lower address memory of the packet, the lower address is stored. The pass prohibition operation stop bit (S) is stored in the position, but since the lower address a2 is not stored at this time, the packet is left as it is in the counterclockwise optical ring 1 (39) Mr1r2a3a2g (I0) shown in the figure. and is directed to the router 22.

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 second embodiment described above, the TCP mobile 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 lower address of 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 packet add, drop and pass device 6-2. 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 memory 9-1 stores that address. The lower address a2 of the transmission source MAC address of the packet is stored, and the lower address a2 of the transmission source MAC address of the packet is stored in the packet passage prohibition lower address memory 9-1, and the passage is prohibited at the lower address storage location. When the operation stop bit is stored, the source MAC address a3a2 of the packet is stored in the address table 11 for designating packet transmission out of the ring. 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 second embodiment, an ACK from the TCP mobile terminal under the control of the base station 12-1 is received. When a packet arrives at the packet add/drop/pass device 6-2 from the counterclockwise ring, the lower address of the transmission source MAC address of the packet is stored in the packet passage prohibited lower address memory 9-1. If so, the pass inhibit operation stop bit is stored in the lower address storage location.

In the above embodiment 2, the MAC address of the source terminal is put in the option area of the IP header directed from the router to the server and sent, and the session layer of the router stores the source terminal information, and the packet waiting means on the server side may be executed. Note that the conversion from the IP address of the router 22 to the MAC address may be performed by an SSD. Alternatively, a MAC address may be generated from an IPv6 lower address.

In the second embodiment, when a communication start packet arrives at the server 20 from the mobile terminal, 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. Since the TCP3 way (syn) contains the information necessary for starting data communication, authentication is also performed therein.

A third embodiment of the present invention will now be described with reference to FIG. This embodiment comprises a plurality of packets having an address table for designating packet transmission to the outside of the ring, a lower address memory for designating packet transmission to the outside of the ring, a bridge address table for packet passage, and a lower address memory for prohibiting packet passage. This is an example of handover operation using a ring network that transfers Ethernet packets composed of a vertex device in which add, drop, and pass devices and a server are connected via a router. The server is a content server. In this embodiment, a signal g from the mobile terminal side indicating that the packet has just moved through the base station to be passed through, a packet add/drop on the ring, and a packet pass prohibition stop in the lower address memory of the pass device. The point is that the packet waiting means of the router is operated only when the router receives the signal g indicating that the bit has been stored.

In FIG. 3, the symbols are all the same as in FIG. 2 except for the additional signal g to the packet.

The operation of FIG. 3 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 line interface are already stored in the ARP tables of the TCP mobile terminals 13-1, 13-2, 13-3, and 13-4. 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 router 22, r2 indicates the lower MAC address of the interface of 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 mobile 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/pass device 6-2, the lower address a2 of the packet source MAC address is stored in the packet passage prohibited lower address memory 9-1. Since it is not stored at this point, the packet is forwarded by (3) Mr1r2a1a2 (I0) on 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 packet passage prohibited lower address memory 9-1. Since it is not stored, the packet is forwarded by (4) Mr1r2a1a2 (I0) on left-handed optical ring 1 and arrives at vertex device 5 as shown. 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 a 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 mobile terminal 13-2 sends a 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 mobile 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/pass device 6-3, the lower address a2 of the packet source MAC address is stored in the packet passage prohibited lower address memory 9-1. Since it is not stored, 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 a memory (not shown), the destination IP address I0 of the packet is stored. Read the output port corresponding to the destination domain and send 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 sends the packet (13) Ma1a2r1r2 (I2) obtained by obtaining the destination MAC address a1a2 from the destination IP address I2 of the packet from the memory or ARP table (not shown in the figure) to the clockwise ring 2 as 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 address table 11 that specifies packet transmission outside the ring. , the destination MAC address a1a2 of the packet is not stored in the packet passing bridging address table 9-2 at this time, and the lower address a2 of the destination MAC address of the packet is Since the destination MAC address a1a2 of the packet is stored in the low-order address memory 7 that designates transmission, it is stored in the packet passing bridging address table 9-2, and the packet is sent out of the ring (16) Ma1a2r1r2. Send as shown in the figure by (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 transfers the packet (18) Ma1a2r1r2 (I2) obtained by obtaining the destination MAC address a1a2 from the destination IP address I2 of the packet from the memory or ARP table (not shown in the figure) to the clockwise ring 2 as shown in the figure. do.
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 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 a2 of the source MAC address of the packet is stored in the packet pass prohibited lower address memory 9-1. Since it is not stored, the packet is forwarded by 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 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 put on standby until the retransmission packet (32) Mr1r2a3a2 (I0) from the corresponding mobile terminal 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 packet's source MAC address is stored in the lower address memory 7 that specifies packet transmission outside the ring, and the packet's source MAC address a3a2 is stored in the packet This packet arrives at the router 22 as it is because it is not stored in the bridging bridge address table 9-2 for passing through at this time.

When the resent packet (32) Mr1r2a3a2 (I0) arrives at the router 22, the waiting packet (28)) packet (33) Ma3a2r1r2 (I3) with the destination MAC address corresponding to the destination IP address I2 of IPI0I3 is added. It is sent to the clockwise ring 2 via the upper ring 4 and the vertex device 5 of the subscriber ring. 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 destination MAC address a3a2 of the packet arriving at the packet add, drop and pass device 6-2 is not stored in the address table 11 specifying packet transmission outside the ring at this time, and the destination MAC address of the packet The lower address a2 of the address is stored in the lower address memory 7 that designates 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 point. Therefore, 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 lower address a2 of the transmission source MAC address of the packet is stored in the pass-prohibited lower address memory 9-1. Store the pass inhibit operation stop bit S (meaning STOP) in the storage location. 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 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 that port, and since the packet is given the indication g indicating that it is a packet immediately after moving the base station, the MAC with the same lower address as the lower address a2 of the source MAC address of the packet An IP address corresponding to the address is read from a memory address not shown in the above figure, and when a packet with the destination IP address of that IP address arrives from the server 20, the packet from the server with the IP address is processed in the same manner as described above. 2 is made to wait by the packet waiting means of the buffer not shown in the figure.

In the third embodiment described above, the TCP mobile 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 memory 9-1 stores the lower address a2 of the packet source MAC address, and the packet pass-prohibited lower address memory 9-1 stores the lower address a2 of the packet source MAC address. If the pass prohibition operation stop bit is stored in the address storage location, the source MAC address a3a2 of the packet is stored in the address table 11 that designates packet transmission out of the ring. When a 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 third embodiment, an ACK is received from the TCP mobile terminal under the control of the base station 12-1. When a packet arrives at the packet add/drop/pass device 6-2 from the counterclockwise ring, the lower address of the transmission source MAC address of the packet is stored in the packet passage prohibited lower address memory 9-1. If so, the pass inhibit operation stop bit is stored in the lower address storage location.

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 third embodiment.
As for the operation in this case, in the third embodiment, when a packet transferred through counterclockwise ring 1 arrives at the 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.

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 table 11 Address tables 12-1, 12-2, 12-3, 12-4 for designating packet transmission outside the ring , 12-5 base stations 13-1, 13-2, 13-3, 13-4 TCP mobile terminal 14 movement of mobile terminal 20 server 22 router

A lower address memory for designating packet transmission to the outside of the ring, a bridging address table for packet passage, a lower address memory for prohibiting packet passage, and packet transmission to the outside of the ring for transferring Ethernet packets in the first embodiment of the present invention. A diagram for explaining the operation of using a ring network in which a plurality of packet add, drop, and pass devices having an address table that designates is connected by an optical transmission line for communication between a terminal and a server A second embodiment of the present invention: a lower address memory for designating packet transmission to the outside of the ring, a bridging address table for packet passage, a lower address memory for prohibiting packet passage, and packet transmission to the outside of the ring. A diagram for explaining the handover operation of a network that uses a ring network in which multiple packet add, drop, and pass devices that have an address table that specifies are connected by optical transmission lines for communication between a mobile terminal and a server Lower address memory for designating packet transmission to outside the ring, packet passage bridging address table, packet passage prohibition lower address memory, and packet transmission to outside the ring according to the third embodiment of the present invention A diagram for explaining the handover operation of a network that uses a ring network in which multiple packet add, drop, and pass devices that have an address table that specifies are connected by optical transmission lines for communication between a mobile terminal and a server

Claims (4)

A device for adding, dropping, and passing packets of a ring network when a terminal and a server communicate via a double ring network consisting of a left-handed ring and a right-handed ring with a transmission direction opposite to that of the ring,
When a packet arrives from the clockwise ring, and the destination MAC address of the packet is stored in the packet passing bridging address table, the packet is sent to the front of the clockwise ring, and the destination MAC of the packet is sent. If the address is stored in the address table that specifies packet transmission outside the ring, the packet is transmitted outside the ring, and the lower address of the destination MAC address of the packet specifies packet transmission outside the ring. If the packet is not stored in the lower address memory, the packet is sent to the front of the clockwise ring; otherwise, if the lower address of the destination MAC address of the packet is stored in the packet passage prohibited lower address memory means for sending the packet out of the ring, storing the destination MAC address of the packet in a bridging lower address table for packet passage, and sending the packet out of the ring;
When a packet arrives from outside the ring, the lower address of the source MAC address of the packet is stored in a lower address memory for designating packet transmission to the outside of the ring, and the source MAC address of the packet is the bridging address for passing the packet. If it is stored in the table, erase the stored address, store the lower address of the source MAC address of the packet in the pass-prohibited lower address memory of the packet, and lower the source MAC address of the packet If the address is stored in the packet's pass-barred lower address memory, and if the pass-barred operation stop bit is stored in that low-order address storage location, then the source MAC address of said packet is stored in the out-of-ring packet. and means for storing the packet in an address table designating transmission, and transmitting the packet to the front of the counterclockwise ring as it is when the passage prohibition operation stop bit is not stored at that position. Add, drop and pass devices.
When a packet arrives from the counterclockwise ring, if the lower address of the transmission source MAC address of the packet is stored in the pass prohibition lower address of the packet, the pass prohibition operation stop bit is stored in the lower address storage location. 2. The apparatus for adding, dropping, and passing packets according to claim 1, further comprising means for sending the packet to the front of the counterclockwise ring as it is except for the above.
A packet transfer method for a ring network when a terminal and a server communicate via a double ring network consisting of a left-handed ring and a right-handed ring opposite in transmission direction to the ring, comprising:
When a packet arrives at a packet add, drop and pass device from the clockwise ring, the packet is sent to the clockwise ring if the destination MAC address of the packet is stored in the packet pass bridging address table. If the destination MAC address of the packet is stored in the address table that designates packet transmission outside the ring, the packet is transmitted out of the ring, and the lower address of the destination MAC address of the packet is sent forward. is not stored in the lower address memory that designates the packet to be sent out of the ring, the packet is sent to the front of the ring in a clockwise direction, and other than the above, the lower address of the destination MAC address of the packet If the packet is stored in the prohibited lower address memory, the packet is sent out of the ring; otherwise, the destination MAC address of the packet is stored in the packet passage bridging lower address table, and the packet is transferred to the ring. sending out;
When a packet arrives at a device for adding, dropping, and passing packets from outside the ring, the lower address of the source MAC address of the packet is stored in a lower address memory designating packet transmission to the outside of the ring, and the packet is transmitted. If the original MAC address is stored in the packet passage bridging address table, the stored address is erased and the lower address of the packet transmission source MAC address is stored in the packet passage prohibited lower address memory. , when the lower address of the transmission source MAC address of the packet is stored in the packet passage prohibition lower address memory, and when the pass prohibition operation stop bit is stored in the lower address storage location, the packet A step of storing the source MAC address in an address table for designating packet transmission to the outside of the ring, and transmitting the packet to the front of the counterclockwise ring as it is when the passage prohibition operation stop bit is not stored at that position. and a packet transfer method.
When a packet arrives at a packet add, drop, and pass device from a counterclockwise ring, if the lower address of the source MAC address of the packet is stored in the pass-prohibited lower address of the packet, the lower address is stored. 2. The packet forwarding method according to claim 1, further comprising the step of storing a pass prohibition operation stop bit in a position and transmitting said packet to the counterclockwise ring front side as it is except for the above.

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