JP2023047359A - 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 packet forwarded in a clockwise ring from a server arrives at a packet add, drop, and pass device, when 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 lower address of the destination MAC address of the packet is stored in a bridging lower address memory for packet passage and the packet is transmitted out of the ring. In the case where a packet arrives from outside the ring, if a lower address of a source MAC address of the packet is stored in the lower address memory that specifies transmitting the packet out of the ring, when the lower address of the source MAC address of the packet is stored in the bridging lower address memory for packet passage, a pass prohibition bit is stored at the address position of the packet of the bridging lower address memory for packet passage.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.

Further, regarding movement of a mobile terminal, Patent Document 5 discloses an example of using IPv6 as a care-of address.

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 Japanese Patent Application Laid-Open No. 4491980

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.

Also, the method of using IPv6 as the care-of address of Patent Document 5 uses multiple routers in the mobile provider network from the mobile provider network to the server that connects to the Internet, and has the problem of high cost and large delay.

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 lower address of the destination MAC address of the packet in the bridging lower address memory for packet passage, sends the packet out of the ring, and the packet arrives at the device for adding, dropping, and passing the packet from outside the ring. and the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission outside the ring, and the lower address of the source MAC address of the packet is the lower address of the packet passing bridge. When stored in the address memory, a method of storing the pass prohibition bit in the address position of the pass bridging lower address memory for the packet.

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 a clockwise ring, if the destination MAC address of the packet is stored in an address table that specifies packet transmission outside the ring, the packet is transmitted out of the ring and If the lower address of the destination MAC address is not stored in the lower address memory that designates packet transmission outside the ring, the packet is sent to the node device in front of the clockwise ring, and the lower address of the destination MAC address of the packet is sent. If the address is stored in the low-order address memory that designates packet transmission outside the ring, and if the low-order address of the destination MAC address of the packet is stored in the bridging low-order address memory for packet passage, its position If the pass prohibition bit is stored in the ring, the packet is sent out of the ring. means for transmitting the packet to a device, storing the lower address of the destination MAC address of the packet in a packet passing bridge lower address memory, and transmitting the packet out of the ring;
When a packet arrives from a counterclockwise ring, the lower address of the source MAC address of the packet is stored in the bridging lower address memory for packet passage, and the lower address of the source MAC address of the packet is stored in the low-order address memory that designates packet transmission outside the ring, the low-order address of the source MAC address of the packet is stored in the bridging low-order address memory for packet passage. deleting the lower address of the source MAC address of the packet from the lower address memory designating packet transmission outside the ring, regardless of whether or not the passage prohibition bit is stored, and deleting the lower address of the source MAC address of the packet If a pass prohibition bit is stored at that location where the lower address is stored in the packet pass bridge lower address memory, delete the pass prohibition bit at that location; otherwise, pass the packet as is. means for delivering forward of the counterclockwise ring;
When a packet arrives from outside the ring, the lower address of the source MAC address of the packet is not stored in the bridging lower address memory for packet passage, and the lower address of the source MAC address of the packet is When stored in the bridging lower address memory for packet passage, the source MAC address of the packet is stored in an address table for designating packet passage outside the ring, and the lower address of the source MAC address of the packet is stored. is not stored in the bridging lower address memory for passing the packet, the lower address of the source MAC address of the packet is stored in the lower address memory for designating packet transmission outside the ring, and the source of the packet When the lower address of the MAC address is stored in the lower address memory that designates the transmission of the packet out of the ring, and the lower address of the source MAC address of the packet is stored in the bridging lower address memory for passing the packet. and means for storing a pass prohibition bit in the lower address storage location of the bridging lower address memory for passing packets.

A third aspect of the present invention is that when the packet arrives from the counterclockwise ring and the packet is a packet immediately after changing the device for adding, dropping, and passing the packet, It further comprises means for deleting the lower address of the source MAC address of the packet from the lower address memory designating transmission of the packet out of the ring.

A fourth aspect of the present invention is that, when a packet arrives from outside the ring, if the packet to be added is changed by a device for adding, dropping, or passing the packet, It further comprises means for storing a lower address of the source MAC address in a lower address memory designating transmission of the packet out of the ring.

A fifth 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 in transmission direction to the ring. a method,
When a packet arrives at a packet add, drop, and pass device from a clockwise ring, and the destination MAC address of the packet is stored in an address table that specifies packet transmission out of the ring, the packet is sent out of the ring, and if the lower address of the destination MAC address of the packet is not stored in the lower address memory that designates the packet to be sent out of the ring, the packet is sent clockwise to the node device ahead of the ring. and when the lower address of the destination MAC address of the packet is stored in a lower address memory for designating packet transmission out of the ring, the lower address of the destination MAC address of the packet is stored in the bridging lower address memory for passing the packet. , and if a no-passage bit is stored at that location, send the packet out of the ring; Forward packet add, drop and pass device, other than the above, the lower address of the destination MAC address of the packet is stored in the bridging lower address memory for passing the packet, and the packet is sent out of the ring. a sending step;
When a packet arrives at a packet add, drop, and pass device from a counterclockwise ring, the lower address of the source MAC address of the packet is stored in the packet pass bridging lower address memory, and When the lower address of the source MAC address of the packet is stored in a lower address memory that designates transmission of the packet out of the ring, the lower address of the source MAC address of the packet is the bridging lower address for passing the packet. deleting the lower address of the source MAC address of the packet from the lower address memory designating transmission of the packet out of the ring, regardless of whether or not a passage prohibition bit is stored at that location stored in the memory; , if the pass prohibition bit is stored at the position where the lower address of the source MAC address of the packet is stored in the packet transit bridge lower address memory, delete the pass prohibition bit at that position; Otherwise, sending the packet to the front of the counterclockwise ring as it is;
When a packet arrives at the packet add, drop and pass device from outside the ring,
When the lower address of the source MAC address of the packet is not stored in the bridging lower address memory for packet passage, and the lower address of the source MAC address of the packet is stored in the bridging lower address memory for packet passage. If so, the source MAC address of the packet is stored in an address table for designating packet passage outside the ring, and the lower address of the source MAC address of the packet is stored in the bridging lower address memory for packet passage. If not stored, and if the lower address of the source MAC address of the packet is not stored in the bridging lower address memory for packet passage, the lower address of the source MAC address of the packet is stored outside the ring. When the lower address of the source MAC address of the packet is stored in the lower address memory for passing the packet, a pass prohibition bit is stored in that position. a packet forwarding method comprising:

A sixth aspect of the present invention is that when the packet arrives from the counterclockwise ring and the packet is a packet immediately after changing the device for adding, dropping, and passing the packet, The method further comprises the step of deleting the lower address of the source MAC address from the lower address memory designating packet transmission out of the ring.

In a seventh aspect of the present invention, when a packet arrives from outside the ring, the source of the packet immediately after changing the device for adding, dropping, and passing the packet to which the packet is added is The method further comprises the step of storing a lower address of the MAC address in a lower address memory designating packet transmission out of the ring.

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-distance terminal movement by network and ring network, there is no problem of unknown packet flooding due to the use of the conventional MAC address table with missing memory addresses, and the conventional block port is unnecessary, so consumption is reduced. Power and system costs can be suppressed, and high-speed communication is possible.

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

A first embodiment of the present invention will be described with reference to FIG. This embodiment transfers the Ethernet packet of the first embodiment, and has a lower address memory for designating packet transmission outside the ring and a pass prohibition bit addition area. This is an operation example of a ring network that transfers Ethernet packets, which consists of a plurality of packet add, drop, and pass devices having an address table that specifies packet transmission, and a top device to which a server is 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, 6-1, 6-2, 6-3 are packet add, drop and pass devices, 6-4 is a vertex device, and 7 is a ring. 9 is a bridging bridge lower address memory for packet passage having a passage prohibition bit addition area; 11 is an address table for designating packet transmission to the outside of the ring; 22 is a router; -1, 13-2, 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.
Note that the address table 11 for designating packet transmission to the outside of the ring is an address table that does not store port numbers and stores a small number of MAC addresses, unlike conventional MAC address tables.

The operation of FIG. 1 will be described below. First, it is assumed that the IP address 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). While the destination MAC address of the packet arriving at the packet add, drop and pass device 6-3 is not currently stored in the address table 11 for designating packet transmission out of the ring, the destination MAC of the packet In a state where the lower address a2 of the address is not stored in the bridging lower address memory 9 for passing the packet at this point, the lower address memory 7 in which the lower address a2 of the destination MAC address of the packet designates the transmission of the packet out of the ring. , the lower address a2 of the destination MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet, the packet is sent out of the ring, and (8) Ma3a2r1r2 (I5) reaches terminal 13-3 as shown in FIG.

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 in the packet passing bridge lower address memory 9, the packet passing bridge lower address memory 9 stores the packet. A passage prohibition bit is stored in the address position where the lower address of the source MAC address of is stored. The no-pass bit is represented in the figure as the letter N (NOT). This may be stored in the pass-through lower address memory for other packets of 1-bit storage. 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 the lower address designating the packet transmission out of the ring. Since the lower address a2 of the transmission source MAC address of the packet is stored in the memory 7, the lower address a2 of the packet passing bridge lower address memory 9, and the passage prohibition bit is stored at the address position, the packet is transmitted. The lower address a2 of the original MAC address is deleted from the lower address memory 7 for designating packet transmission to the outside of the ring, the lower address a2 of the transmission source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet, Delete the no-pass bit stored at that address location. Deletion of the lower address a2 of the source MAC address of the packet from the lower address memory 7 that designates packet transmission outside the ring is indicated by placing a horizontal line - on a2 in the figure, and The lower address a2 is stored in the packet pass bridge lower address memory 9, and the pass prohibition bit stored at that address position can be deleted by drawing a horizontal line over N (NOT), which means the pass prohibition bit. shown 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) clockwise ring 2 as shown in the figure, and arrives at the packet add, drop and pass device 6-3, where the packet's destination MAC address is outside the ring. The lower address a2 of the destination MAC address of the packet is not stored in the address table 11 that designates the packet to be sent to, but is stored in the bridging lower address memory 9 for passing the packet, which has a passage prohibition bit addition area. , the packet is forwarded to the front of the clockwise ring 2 of that device because no pass prohibition bit is stored at that position.

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 lower address a2 of the destination MAC address of the packet is stored in the bridge lower address memory 9, sent outside the ring, and arrives at the terminal 13-1 (23) Ma1a2r1r2 (I4) as shown in the figure.

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 source MAC address of the packet is not stored in the lower address memory 7 designating packet transmission outside the ring. , and the lower address a2 of the source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet. It is stored in the address table 11 that designates transmission. 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 the first embodiment described above, an example is shown in which the lower address of the source MAC address is stored in the bridging lower address memory for packet passage or in the lower address memory for designating packet transmission outside the ring. Storing the lower address of the bridging lower address memory or the source MAC address of the packet in the lower address memory that designates sending the packet out of the ring designates sending out of the packet through the bridging lower address memory or out of the ring. It is also possible to store bit 1, which means lower address storage, at a position addressed by the lower address memory of the transmission source MAC address.
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 second embodiment of the present invention will now be described with reference to FIG. This embodiment designates a bridge lower address memory for passing packets and a packet transmission outside the ring, which has a lower address memory for specifying packet transmission outside the ring and a pass prohibition bit addition area for transferring Ethernet packets. Operation of an Ethernet packet forwarding ring network consisting of a plurality of packet add, drop and pass devices having an address table and a subordinate address memory specifying the passage of packets and apex devices to which servers are connected via routers. For example. 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.

This embodiment differs only in that a lower address memory 10 for designating packet passage is added to the packet add, drop, and passage device 6 of the first embodiment.
In the operation of this embodiment, when a packet transferred through counterclockwise ring 1 arrives at packet add, drop, and pass unit 6, it is always sent to the lower address memory that specifies the pass of the packet. Stores the lower address of the source MAC address of the packet, 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 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 Further, when the lower address of the destination MAC address of the packet is not stored in the bridging lower address memory for passing the packet, an operation of discarding the packet is added.

In the second embodiment, the terminal packet directed to the server designates the passage of all packets in the ring, the device for adding, dropping, and passing packets. 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, so a multi-round bit assignment device can be made unnecessary.

A third embodiment of the present invention will now be described with reference to FIG. This embodiment has a plurality of bridging lower address memories for packet passage, which have 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, and a pass prohibition bit addition area. This is an example of handover operation using a ring network that transfers Ethernet packets consisting of a vertex device in which a packet add, drop and pass device and a server are connected via a router. The server is a content server.

In FIG. 3, 3 is a subscriber system ring, 4 is a core network ring, 12-1, 12-2, 12-3, 12-4, 12-5 are base stations, 13-1, 13-2, 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. 3 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 lower address a2 of the source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet. Since it is not stored, 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 (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 transmission source MAC address is stored in the packet pass bridge lower address memory 9. Since it is not stored at this time, 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 and pass device 6-3, the lower address a2 of the source MAC address of the packet is stored in the packet passing bridging lower address memory 9. Since it is not, the packet is forwarded on counterclockwise optical ring 1 by (4) Mr1r2a1a2 (I0) and arrives at vertex device 5 as shown. The packet is sent out of the ring and reaches the router 22 via the upper ring 4, which is the core network. 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 lower address a2 of the source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet. Since it is not stored, 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 source MAC address of the packet is stored in the packet passing bridging lower address memory 9. Since it is not, 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 The lower address a2 of the MAC address is not stored in the bridging lower address memory 9 for passing the packet, which has the passage prohibited bit addition area, at this time, and the lower address a2 of the destination MAC address of the packet is out of the ring. is stored in the lower address memory 7 that designates the transmission of the packet, the lower address a2 of the destination MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet, and the packet is sent out of the ring, (16) Send as indicated by Ma1a2r1r2 (I2).

The server 20 sends to the router 22 a retransmission packet (17) IPI0I2 of the packet (12) IPI0I2. 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 address table 11 specifying packet transmission outside the ring. and the lower address a2 of the destination MAC address of the packet is stored in the packet pass-through lower address memory 9 having a pass-prohibited bit addition area, and the pass-prohibited bit is not stored at that location. , sends the packet 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 lower address a2 of the destination MAC address of the packet in the packet pass bridging lower address memory 9 in the same manner as described above, and transfers the packet to the outside of the ring. and 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 lower address a2 of the source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet, the pass prohibition bit is stored in that position, and the packet is sent to the counterclockwise ring 1. (24) Mr1r2a1a2 (I0) as shown in FIG. The description of the pass inhibit bit is indicated by the letter N (meaning NOT) 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 and the lower address a2 of the source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet, the lower address specifying the transmission of the packet out of the ring The lower address a2 of the source MAC address of the packet is deleted from the address memory 7. In the figure, a2 is shown deleted by a horizontal line. The packet is forwarded by (25) Mr1r2a1a2 (I0) over left-handed ring 1 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 not stored in the lower address memory 7 for designating packet transmission outside the ring, and the lower address a2 of the source MAC address of the packet is not stored. is stored in the bridging lower address memory for packet passage, the source MAC address a3a2 of the packet is stored in the address table designating the packet transmission out of the ring, and the packet arrives at the router 22.

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 source MAC address of the packet is stored in the bridging lower address memory for passing the packet, the packet deletes the lower address a2 of the source MAC address of , from the lower address memory that specifies packet transmission outside the ring. 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 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. 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. When the lower address a2 of the transmission source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet, the passage prohibition bit is stored in that position. 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 anti-clockwise ring, the packet passing bridging lower address memory 9 stores the lower address a2 of the source MAC address of the packet. In addition, when 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, the bridging lower address memory 9 for passing the packet stores the address of the packet. Delete the lower address of the lower address memory that designates packet transmission to the outside of the ring, regardless of whether or not the pass prohibition bit is stored at that position where the lower address a2 of the source MAC address is stored.

In the above embodiment 3, 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 third 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 TCP3way (syn) contains the information necessary for starting data communication, authentication is also performed therein.

A fourth embodiment of the present invention will now be described with reference to FIG. This embodiment has a plurality of bridging lower address memories for packet passage, which have 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, and a pass prohibition bit addition area. This is an example of handover operation using a ring network that transfers Ethernet packets consisting of a vertex device in which a packet add, drop and pass device and a server are connected via a router. The server is a content server. In this embodiment, when the router receives a signal to the effect that the lower address stored in the lower address memory that designates packet transmission from the mobile terminal to the outside of the ring has been deleted, and the pass prohibition bit is stored in the bridge lower address memory for packet passage. is to operate the packet waiting means of the router only when the router receives a signal indicating that the packet has been stored.

All symbols in FIG. 4 are the same as in FIG.

The operation of FIG. 4 will be described below. First, it is assumed that the IP address I1 of the router 22 and the MAC address r1r2 of the ring transmission interface are already stored in the ARP tables of the TCP mobile terminals 13-1, 13-2, and 13-3. 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 lower address a2 of the source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet. Since it is not stored, 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 (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 transmission source MAC address is stored in the packet pass bridge lower address memory 9. Since it is not stored at this time, 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 and pass device 6-3, the lower address a2 of the source MAC address of the packet is stored in the packet passing bridging lower address memory 9. Since it is not, the packet is forwarded on counterclockwise optical ring 1 by (4) Mr1r2a1a2 (I0) and arrives at vertex device 5 as shown. The packet is sent out of the ring and reaches the router 22 via the upper ring 4, which is the core network. 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 lower address a2 of the source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet. Since it is not stored, 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 source MAC address of the packet is stored in the packet passing bridging lower address memory 9. Since it is not, 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 transfers the packet (13) Ma1a2r1r2 (I2) obtained by obtaining the destination MAC address a1a2 from the destination IP address I2 of the packet by means of a 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, 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 The lower address a2 of the MAC address is not stored in the bridging lower address memory 9 for passing the packet, which has the passage prohibited bit addition area, at this time, and the lower address a2 of the destination MAC address of the packet is out of the ring. Therefore, the lower address a2 of the destination MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet, and the packet is sent out of the ring ( 16) Send as illustrated by Ma1a2r1r2 (I2).

The server 20 sends to the router 22 a retransmission packet (17) IPI0I2 of the packet (12) IPI0I2. 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 address table 11 specifying packet transmission outside the ring. Since the lower address a2 of the destination MAC address of the packet is stored in the packet pass bridge lower address memory 9 having a passage prohibited bit addition area, the packet is transferred to the front of the clockwise ring 2 ( 21) Send by Ma1a2r1r2 (I2) as shown.

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 lower address a2 of the destination MAC address of the packet in the packet pass bridging lower address memory 9 in the same manner as described above, and transfers the packet to the outside of the ring. and 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, and 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 out of the ring. and the lower address a2 of the source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet. (24) Mr1r2a1a2g (I0) sends the packet including the signal g to the counterclockwise ring toward the packet add, drop and pass device 6-2 as shown in the figure. The storage of the pass-through bits in memory is indicated in the figure by the letter N (NOT).

When the packet (24) Mr1r2a1a2g (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 and the lower address a2 of the source MAC address of the packet is stored in the packet passing bridging lower address memory 9, the packet is designated to be sent out of the ring. The lower address a2 of the source MAC address of the packet is deleted from the lower address memory 7. In the figure, a2 is shown deleted by a horizontal line. A signal g indicating that the lower address of the transmission source MAC address of the packet has been deleted from the lower address memory 7 for designating packet transmission to the outside of the ring is added to the packet, and the packet is sent to the counterclockwise ring 1 (25). Transfer as illustrated by Mr1r2a1a2g (I0).

When the packet arrives at the router 22 as shown by (27) Mr1r2a1a2g (I0), the lower address of the source MAC address of the packet is sent from the lower address memory 7 that designates the packet to be sent out of the ring. is given, the IP packet from the server whose destination IP address is the IP address corresponding to the source MAC address a3a2, which is the same as the lower address a2 of the source MAC address of the packet. (28) Make IPI0I3 wait until the retransmission packet (32) Mr1r2a3a2 (I0) from the mobile terminal corresponding to that packet 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 not stored in the lower address memory 7 for designating packet transmission outside the ring, and the lower address of the source MAC address of the packet is not stored. Since the address a2 is stored in the bridging lower address memory for packet passage, the source MAC address a3a2 of the packet is stored in the address table for designating packet transmission outside the ring, and the packet arrives at the router 22. .

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 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, 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 a packet that has just moved from the base station, so the lower address a2 of the source MAC address of the packet is sent out of the ring. The packet is deleted from the designated lower address memory, and the packet is forwarded by (39) Mr1r2a3a2g (I0) on counterclockwise optical ring 1 to the 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 fourth 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. When the lower address a2 of the transmission source MAC address of the packet is stored in the bridging lower address memory 9 for passing the packet, the passage prohibition bit is stored in that position. 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 packet waiting operation as in the second embodiment, the TCP mobile terminal under the control of the base station 12-1 When an ACK packet arrives at the packet add/drop/pass device 6-2 from the anti-clockwise ring, the packet pass bridging lower address memory 9 stores the lower address a2 of the source MAC address of the packet. In addition, when 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, the bridging lower address memory 9 for passing the packet stores the address of the packet. Delete the lower address of the lower address memory that designates packet transmission to the outside of the ring, regardless of whether or not the pass prohibition bit is stored at that position where the lower address a2 of the source MAC address is stored.

A fifth embodiment of the present invention will now be described with reference to FIG. This embodiment has 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, and a passage prohibition bit addition area. This is an example of handover operation using a ring network that transfers Ethernet packets consisting of a vertex device in which multiple packet add, drop and pass devices and a server are connected via a router with a lower address memory that specifies be. The server is a content server.
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.

This embodiment differs only in that a lower address memory 10 for designating packet passage is added to the packet add, drop, and passage device 6 of the fourth embodiment.
In the operation of this embodiment, when a packet transferred through counterclockwise ring 1 arrives at the packet add, drop and pass device 6 in the fourth embodiment, it is always sent to the lower address memory that specifies the pass of the packet. Stores the lower address of the source MAC address of the packet, 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 not stored in the low-order address memory that specifies packet transmission outside the ring, and the low-order address of the destination MAC address of the packet is not stored in the bridging low-order address memory for packet passage, In addition, when the lower address of the destination MAC address of the packet is not stored in the lower address memory that designates passage of the packet, an operation of discarding the packet is added.

It should be noted that the lower address memory for designating the passage of packets can also operate in addition to the apparatus for adding, dropping, and passing packets in the third embodiment.

In the present embodiment 5, the terminal packet directed to the server designates the passage of the packet of the device for adding, dropping, and passing all packets of the ring. 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, so a multi-round bit assignment device can be made unnecessary.

In Embodiments 1 to 5, instead of the lower address memory 9 that designates the packet passage bridge having the passage prohibition bit addition area, an address that designates the packet passage bridge having the passage prohibition bit addition area is used. A table can also be used.

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: Lower address memory 10 that designates a bridge for packet passage having passage prohibited bit addition area: Lower address memory 11 that designates packet passage Address tables 12-1, 12- that designate packet transmission outside the ring 2, 12-3, 12-4, 12-5 Base station 13-1, 13-2, 13-3, 13-4 TCP mobile terminal 14 Movement of mobile terminal 20 Server 22 Router

Claims (6)

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 a clockwise ring, if the destination MAC address of the packet is stored in an address table that specifies packet transmission outside the ring, the packet is transmitted out of the ring and If the lower address of the destination MAC address is not stored in the lower address memory that designates packet transmission outside the ring, the packet is sent to the node device in front of the clockwise ring, and the lower address of the destination MAC address of the packet is sent. If the address is stored in the low-order address memory that designates packet transmission outside the ring, and if the low-order address of the destination MAC address of the packet is stored in the bridging low-order address memory for packet passage, its position If the pass prohibition bit is stored in the ring, the packet is sent out of the ring. means for transmitting the packet to a device, storing the lower address of the destination MAC address of the packet in a packet passing bridge lower address memory, and transmitting the packet out of the ring;
When a packet arrives from a counterclockwise ring, the lower address of the source MAC address of the packet is stored in the bridging lower address memory for packet passage, and the lower address of the source MAC address of the packet is stored in the low-order address memory that designates packet transmission outside the ring, the low-order address of the source MAC address of the packet is stored in the bridging low-order address memory for packet passage. deleting the lower address of the source MAC address of the packet from the lower address memory designating packet transmission outside the ring, regardless of whether or not the passage prohibition bit is stored, and deleting the lower address of the source MAC address of the packet If a pass prohibition bit is stored at that location where the lower address is stored in the packet pass bridge lower address memory, delete the pass prohibition bit at that location; otherwise, pass the packet as is. means for delivering forward of the counterclockwise ring;
When a packet arrives from outside the ring, the lower address of the source MAC address of the packet is not stored in the bridging lower address memory for packet passage, and the lower address of the source MAC address of the packet is When stored in the bridging lower address memory for packet passage, the source MAC address of the packet is stored in an address table for designating packet passage outside the ring, and the lower address of the source MAC address of the packet is stored. is not stored in the bridging lower address memory for passing the packet, the lower address of the source MAC address of the packet is stored in the lower address memory for designating packet transmission outside the ring, and the source of the packet When the lower address of the MAC address is stored in the lower address memory that designates the transmission of the packet out of the ring, and the lower address of the source MAC address of the packet is stored in the bridging lower address memory for passing the packet. and means for storing a pass inhibit bit in said lower address storage location of a bridge lower address memory for passing packets, if any.
When the packet arrives from the counterclockwise ring, if the packet is a packet immediately after changing the device for adding, dropping, and passing the packet to be added, the lower address of the source MAC address of the packet is sent to the ring. 2. Apparatus for adding, dropping and passing packets according to claim 1, further comprising means for deleting from a lower address memory designating outgoing packets.
When a packet arrives from outside the ring, in the case of a packet immediately after changing the device for adding, dropping, and passing the packet to be added, the lower address of the source MAC address of the packet is transferred outside the ring. 3. An apparatus for adding, dropping and passing packets according to claim 1 or 2, further comprising means for storing in a lower address memory designating the sending of packets of.
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 a clockwise ring, and the destination MAC address of the packet is stored in an address table that specifies packet transmission out of the ring, the packet is sent out of the ring, and if the lower address of the destination MAC address of the packet is not stored in the lower address memory that designates the packet to be sent out of the ring, the packet is sent clockwise to the node device ahead of the ring. and when the lower address of the destination MAC address of the packet is stored in a lower address memory for designating packet transmission out of the ring, the lower address of the destination MAC address of the packet is stored in the bridging lower address memory for passing the packet. , and if a no-passage bit is stored at that location, send the packet out of the ring; Forward packet add, drop and pass device, other than the above, the lower address of the destination MAC address of the packet is stored in the bridging lower address memory for passing the packet, and the packet is sent out of the ring. a sending step;
When a packet arrives at a packet add, drop, and pass device from a counterclockwise ring, the lower address of the source MAC address of the packet is stored in the packet pass bridging lower address memory, and When the lower address of the source MAC address of the packet is stored in a lower address memory that designates transmission of the packet out of the ring, the lower address of the source MAC address of the packet is the bridging lower address for passing the packet. deleting the lower address of the source MAC address of the packet from the lower address memory designating transmission of the packet out of the ring, regardless of whether or not a passage prohibition bit is stored at that location stored in the memory; , if the pass prohibition bit is stored at the position where the lower address of the source MAC address of the packet is stored in the packet transit bridge lower address memory, delete the pass prohibition bit at that position; Otherwise, sending the packet to the front of the counterclockwise ring as it is;
When a packet arrives at the packet add, drop and pass device from outside the ring,
When the lower address of the source MAC address of the packet is not stored in the bridging lower address memory for packet passage, and the lower address of the source MAC address of the packet is stored in the bridging lower address memory for packet passage. If so, the source MAC address of the packet is stored in an address table for designating packet passage outside the ring, and the lower address of the source MAC address of the packet is stored in the bridging lower address memory for packet passage. If not stored, and if the lower address of the source MAC address of the packet is not stored in the bridging lower address memory for packet passage, the lower address of the source MAC address of the packet is stored outside the ring. When the lower address of the source MAC address of the packet is stored in the lower address memory for passing the packet, a pass prohibition bit is stored in that position. and a packet forwarding method.
When the packet arrives from a counterclockwise ring, if the packet is a packet immediately after changing the device for adding, dropping, and passing the packet to be added, the lower address of the source MAC address of the packet is removed from the ring. 2. The packet transfer method according to claim 1, further comprising the step of deleting from the lower address memory designating the transmission of the packet.
When a packet arrives from outside the ring, in the case of a packet immediately after changing the device for adding, dropping, and passing the packet to which the packet is added, the lower address of the source MAC address of the packet is sent to the packet outside the ring. 3. A packet transfer method according to claim 1, further comprising the step of storing in a lower address memory designating transmission.

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