JP2023070687A - Address storage method and packet transfer system enabling movement between base stations such as handover in ring network using the same - Google Patents

Abstract

To realize handover of a radio system at a low cost and at high speed.SOLUTION: A packet transfer system stores a low-order address of a transmission source MAC address to a low-order address memory that designates transmission to the outside of a ring when a packet of a ring network or tree-like ring network arrives at an adding, dropping and passing device, stores the transmission source MAC address in an address table that designates transmission to the outside of the ring and makes it head toward a server via a top device with a counterclockwise ring when the low-order address of the transmission source MAC address is stored in the low-order address memory that prohibits transmission to the outside of the ring, and stores the low-order address of the transmission source MAC address of the packet in the low-order address memory that prohibits packet transmission to the outside of the ring and makes it head toward the server via the top device with the counterclockwise ring when the low-order address of the transmission source MAC address is stored in the low-order address memory that designates transmission to the outside of the ring in a case where the packet arrives at the adding, dropping and passing device.SELECTED DRAWING: Figure 1

Description

The present invention relates to an address storage method such as a MAC address, and a packet transfer system using the same that enables movement between base stations such as handover in a ring network for transferring Ethernet (registered trademark) packets.

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), in the case of switching the base station of the ATM cell sent from the control station to the mobile terminal, the ATM cell is delayed by the control station, This is a method that is executed by switching to prevent order reversal of ATM cells.

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

Further, regarding movement of a mobile terminal, Patent Document 6 discloses an example of using IPv6 as a care-of address.

Further, as an example of a ring network using the low-order address storage method, there is Patent Document 7. This disclosed example consists of two ring transmission lines consisting of an outer ring and an inner ring whose transmission direction is opposite to that of the ring, vertex nodes on the two ring transmission lines, and packets sent from the nodes to the outer ring being transmitted from the vertex. A double ring network is arranged in the form of a tree having an end point node which is a node requiring the longest distance to reach a node, and a plurality of nodes between the end point node and the vertex node, and each lower ring All packets dropped from the outer ring of the apex node are connected to the outer ring of the upper ring, and packets dropped from the inner ring of the upper ring are connected to the inner ring of the apex node of each lower ring. , one switch is connected to the top node of the topmost ring network of the tree-like ring network, and the packet transferred on the outer ring passes through the ring without dropping the node up to the top node. In the packet forwarding system of the configuration, when a packet was added to the ring, one memory, the fuzzy storage address memory for packet drops for the inner ring of the added node, was addressed with the lower address of the source address of the packet. 1 is stored in a position and one memory, which is an ambiguous storage bit string combined value memory for packet passage for the inner ring, is taken from the transmission source address of the packet, and the taken upper address is obtained. If 1 is not stored in the position addressed by the bit string of the exclusive OR of each bit of the bit string of the lower address and each bit of the bit string of the lower address, the packet is directed to the exchange on the outer ring as it is, and 1 is stored, the entire source address of the packet is stored in the packet drop address table for the inner ring, the packet is directed to the exchange on the outer ring, and the node on the way to the exchange If the entire source address of the packet is stored in the packet drop address table for the inner ring, the address is erased and the ambiguous storage address memory for packet drop for the inner ring is stored. If a 1 is not read when one memory is addressed with a lower address than the source address of the packet, the packet is passed through the node, and if a 1 is read, the node's packet passing One memory, which is an ambiguous storage bit string composite value memory, is used to extract upper and lower addresses from the source address of the packet, and to extract each bit of the extracted upper address bit string and each bit of the lower address bit string exclusively By storing 1 in the position addressed by the logical sum bit string and directing the packet to the exchange, the packet from the exchange to the node where the packet from the terminal direction was added to the ring. switching function means including a function of sending packets arriving from the outer ring of the vertex node to the inner ring to the switch; If one memory, the fuzzy store address memory for the drop, is addressed with the lower address of the destination address of the packet and no 1 is read, let the packet pass through the node, and if a 1 is read and one memory, which is an ambiguous storage bit string combined value memory for packet passing, is sampled from the destination address of the packet to obtain the upper and lower addresses, and each bit of the sampled upper address bit string and the lower address bit string If a 1 is not stored in the location addressed by the exclusive OR bit string of each bit of , the packet is dropped at that node, while the fuzzy storage bit string composite value memory for packet passage, 1 One memory is sampled from the destination address of the packet, the upper address and the lower address, and 1 is specified by the bit string of the exclusive OR of each bit of the sampled upper address bit string and each bit of the lower address bit string. is stored, and if the entire destination address of the packet is in the address table for packet drop, drop it at that node, and if not, let it pass through that node. A packet transfer system characterized by comprising means for judging whether a packet transferred on an inner ring is dropped or passed.

Japanese Patent Application Laid-Open No. 2000-151617 Japanese Patent Application Laid-Open No. 2004-15592 Retable 2008-068813 Japanese Patent Application Laid-Open No. 2001-128212 Retable 2017-195497 Japanese Patent Application Laid-Open No. 4491980 JP 2017-192118 A

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

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

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

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

Also, the method of using IPv6 as the care-of address of Patent Document 6 uses multiple routers in the mobile provider network from the mobile subscriber network to the server that connects to the Internet, and has the problem of high cost and large delay. .
Patent Document 7 discloses a fuzzy storage address memory for packet drop that stores bit 1 at a location addressed by a lower address of the source MAC address of the packet, and a fuzzy storage address memory for packet drop that stores the source MAC address of the packet. The address table and the high-order address and low-order address are sampled from the source address of the packet, and the bit at the position specified by the bit string of the exclusive OR of the bit string of the high-order address and the bit string of the low-order address. It is an example of using one hash memory, which is an ambiguous storage bit string composite value memory for packet passing, which stores 1, and is used in a mobile network, but does not show a method for avoiding malfunction of the ring network.

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

The present invention has been made in view of the above-mentioned problems of the prior art, and a first aspect of the present invention is to:
A base station is accommodated in the lowest ring of a ring network or a tree-like ring network, and a TCP mobile terminal under the base station communicates with a server via a router connected to a vertex device of the ring network or the tree-like ring. A packet waiting means applied to a packet transfer system that enables mobile terminals of a network to move between base stations,
The transmission source MAC address of a packet from a mobile terminal to a server or a relay station via a base station, a ring network or a tree-like ring network is set as the own packet of the gateway or router connected to the top device of the ring network or the tree-like ring network. Store the packet in a first memory of the standby means and send the packet to the server or the relay station, or store the source MAC address of the packet directed to the server or the relay station in the optional area of the IP header of the IP packet and send it to the server or relay station,
When the own packet waiting means receives a packet having a signal indicating that the base station through which the packet from the mobile terminal passes has been changed and the device for adding, dropping and passing the packet to be added has been changed,
When a MAC address having a lower address of the source MAC address of the received packet is stored in the first memory of the packet waiting means, the MAC address stored in the first memory is automatically retrieved. stored in a second memory of the packet waiting means;
Alternatively, if the first memory of the self-packet waiting means is not used, the source MAC address of the received packet is stored in the second memory of the self-packet waiting means,
In the method that does not use the first memory of the own packet waiting means, the same lower address as the MAC address stored in the second memory of the own packet waiting means is assigned to the IP packet of the packet arriving from the server. If the lower address of the MAC address written in the option area of the IP header has a lower address, the MAC address is stored in the memory 2, and the packet is sent to the own packet waiting means as the source MAC of the packet arriving from the terminal side. After waiting until the address is stored in the second memory of the own packet waiting means, after sending to the terminal side, the MAC address and its lower address stored in the second memory of the own waiting means Clear the MAC address with the same lower address as
In the method using the first memory of the packet waiting means, when the destination IP address of the IP packet arriving from the server to the own packet waiting means is stored in the second memory of the own packet waiting means , causing the packet to wait until a retransmission request packet or a retransmission packet arrives from the mobile terminal whose source MAC address is the MAC address corresponding to the destination IP address stored in the second memory; when a packet or a retransmission packet arrives, erasing the source MAC address and the source IP address of the retransmission request packet or the retransmission packet from the second memory of the self-packet waiting means;
It is packet waiting means.

A second aspect of the present invention is that the packet waiting means of the present invention is accommodated in a base station in the lowest ring of a ring network or a tree-like ring network, and TCP mobile terminals under the base station are connected to the ring network or the tree-like ring network. Packet forwarding to enable inter-base station movement of mobile terminals of the network, with or without, in routers or gateways connected to apex devices of a similar ring to communicate with servers a system,
When a TCP packet from the mobile terminal via the base station arrives at a device for adding, dropping, and passing packets of the ring network or tree-like ring network,
Regardless of whether or not the packet is a packet immediately after moving the base station,
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 of the device for adding, dropping and passing the packet, and the lower address memory prohibits packet transmission outside the ring. When the lower address of the source MAC address of the packet is stored, or when the hash of the source MAC address of the packet is stored in a hash memory that prohibits packet transmission outside the ring, The source MAC address of the packet is stored in an address table that specifies packet transmission outside the ring, and the packet is directed to the server via the vertex device in the counterclockwise ring, and the packet is added, dropped, and If the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, the lower address of the source MAC address of the packet when it reaches a passing device. is stored in a lower address memory that prohibits packet transmission outside the ring or the hash of the source MAC address of the packet is stored in a hash memory that prohibits packet transmission outside the ring, and the packet is rotated counterclockwise without changing the above. means for directing through a vertex device in a ring to said server;
When a TCP packet from said server arrives at a packet add, drop and pass device on a clockwise ring,
When the destination MAC address of the packet is stored in an address table that specifies packet transmission outside the ring, the packet is transmitted out of the ring, and the destination MAC address of the packet specifies the packet transmission out of the ring. If it is not stored in the specified address table, and if the lower address of the destination MAC address of the packet is stored in the lower address memory that prohibits packet transmission outside the ring, the packet is rotated clockwise. in the ring downward direction of the ring, or when the destination MAC address of the packet is not stored in an address table specifying packet transmission outside the ring, and the hash of the destination MAC address of the packet is outside the ring If the packet is stored in the hash memory that prohibits sending the packet to the outside of the ring, the packet is sent in the downward direction of the clockwise ring. means for sending the packet out of the ring if it is stored in a lower address memory designating packet sending,
In addition, when the TCP mobile terminal does not receive a packet from the server for a certain period of time or longer during communication, the TCP mobile terminal either sends a resend packet, a resend request packet, or a communication partner confirmation packet to the server, or It is characterized by comprising means for periodically sending a one-way path setting packet having a MAC address.

A third aspect of the present invention is the packet transfer system according to the second aspect of the present invention,
The TCP mobile terminal further comprises means for sending a one-way path setting packet having a source MAC address to a device for adding, dropping, and passing packets belonging to the base station immediately after changing the base station to be used. It is characterized by

A fourth aspect of the present invention is the packet transfer system according to the second aspect of the present invention,
Immediately after changing the base station to be used, the TCP mobile terminal sends a one-way path setting packet having a source MAC address to the add, drop, and passing devices of packets belonging to the base station, and Immediately after changing the station, if there is a mobile terminal with a source MAC address of the same lower address as the lower address of the source MAC address, a one-way setting packet having the source MAC address of the mobile terminal is sent to the base station. It is characterized by further comprising means for sending packets belonging to the base station to add, drop and pass devices.

A fifth aspect of the present invention is the packet waiting means according to the first aspect of the present invention,
Source of the received packet when its own packet waiting means receives a packet having a signal to the effect that the base station through which the packet from the mobile terminal passes has been changed and the apparatus for adding, dropping and passing the packet to be added has been changed. The packet waiting means is characterized in that only the MAC address obtained by removing the source MAC address of the received packet from the MAC address having the lower address of the MAC address as the lower address is used as the MAC address of the waiting packet of the packet waiting means. .

A sixth aspect of the present invention is an apparatus for adding, dropping, and passing packets in the ring network or tree-like ring network of the packet transfer system according to the second aspect of the present invention, wherein the add, drop, and Storing the lower address of the source MAC address in the lower address memory for designating packet transmission to the outside of the ring of the passing device stores the lower address of the source MAC address for designating packet transmission to the outside of the ring. is to store bit 1, which means lower address storage, at the location addressed by
Deleting the lower address of the source MAC address from the lower address memory that specifies packet transmission out of the ring means that the lower address memory that specifies packet transmission out of the ring is addressed with the lower address of the source MAC address. A device for adding, dropping and passing packets in a ring network or tree-like ring network of a packet transfer system characterized by writing bit 0 meaning no lower address storage in a location.

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

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

A lower address memory that specifies packet transmission outside the ring, a lower address memory that specifies prohibition of packet transmission outside the ring, and a packet transmission outside the ring that transfers the Ethernet packet of the first embodiment of the present invention. A diagram for explaining handover operation of a network that uses a tree-like ring network in which a plurality of packet add, drop, and pass devices with address tables connected by optical transmission lines is used for communication between a TCP mobile terminal and a server. . A lower address memory that specifies packet transmission outside the ring, a lower address memory that specifies prohibition of packet transmission outside the ring, and a packet transmission outside the ring that transfers Ethernet packets in the second embodiment of the present invention. FIG. 4 is 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 for packet transmission are connected by optical transmission lines for communication between a TCP mobile terminal and a server;

A first embodiment of the present invention will be described with reference to FIG. In this embodiment, a lower address memory for designating packet transmission to the outside of the ring, a low address memory for designating packet transmission to the outside of the ring, and an address table for designating packet transmission to the outside of the ring. This is an example of handover operation using a tree-like ring network in which a plurality of packet add, drop, and pass devices are connected by optical transmission lines. The server is a content server.

In FIG. 1, 1-1 is a subscriber system counterclockwise optical ring 1-1 is a subscriber system clockwise optical ring, 2 and 3 are subscriber system rings, 4 is an upper ring, 5 is a vertex device, 6- 1, 6-2, 6-3 are packet add, drop and pass devices; 7 is a lower address memory for designating packet transmission outside the ring; 11 is an address table for designating packet transmission outside the ring; 12-1, 12-2, 12-3, 12-4, 12-5 are base stations; 13-1, 13-2, 13-3 are A TCP mobile terminal, 15 is a mobile terminal, 20 is a server, 22 is a router, and 27 is a home memory. Also, (1) to (33) are packets, and I0, I1, I2, I3, and I4 are domestic or regional IP addresses of service providers. or an IPv6 address.
Note that the address table 11 for designating packet transmission to the outside of the ring is an address table that does not store port numbers and stores a small number of MAC addresses, unlike conventional MAC address tables.

The operation of FIG. 1 will be described below. First, it is assumed that the IP address I1 of the router 22 and the MAC address r1r2 of the ring transmission interface are already stored in the ARP tables of the TCP mobile terminals 13-1, 13-2, and 13-3. 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 of the transmission source MAC address of the packet specifies prohibition of packet transmission outside the ring. If it is stored in the address memory 14, the source MAC address of that packet is stored in the address table 11 that designates packet transmission outside the ring. The address a2 is stored in the lower address memory 7 which designates packet transmission to the outside of the ring. The packet is forwarded by (2) Mr1r2a1a2 (I0) on counterclockwise optical ring 1-1, and arrives at packet add, drop and pass device 6-2.

When the packet (2) Mr1r2a1a2 (I0) arrives at the packet add, drop and pass device 6-2, the lower address a2 of the packet transmission source MAC address is the lower address designating the packet transmission out of the ring. If it is stored in the memory 7, the lower address of the source MAC address of the packet is stored in the lower address memory 14 that designates prohibition of packet transmission outside the ring. It is transferred by (3) Mr1r2a1a2 (I0) on the optical ring 1-1 as shown in the figure, and arrives at the 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 the lower address designating the packet transmission out of the ring. If it is stored in the memory 7, the lower address of the source MAC address of the packet is stored in the lower address memory 14 that designates prohibition of packet transmission outside the ring. It is transferred by (4) Mr1r2a1a2 (I0) on the optical ring 1-1 and reaches the vertex device 5 as shown in the figure. The packet is sent outside the ring and reaches the router 22 via the upper ring 4 . The upper ring 4 has the same configuration as the subscriber ring 3 and the subscriber system ring composed of the left-handed optical ring 1-1 and the right-handed optical ring 2, and operates in the same manner.

When the packet (5) Mr1r2a1a2 (I0) arrives at the router 22, the source MAC address a1a2 and the source IP address I2 of the packet are stored in the memory 1 (not shown). The output port corresponding to the destination of the destination IP address I0 of the packet is obtained from the IP routing table 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 server 20, which is the destination. send to When the packet reaches the add, drop and pass device 6-1 from the TCP mobile terminal 13-2, the lower address a2 of the source MAC address of the packet specifies prohibition of packet transmission outside the ring. If it is stored in the lower address memory 14, the source MAC address of the packet is stored in the address table 11 for designating packet transmission outside the ring. The lower address a2 is stored in the lower address memory 7 which designates packet transmission to the outside of the ring. The packet is forwarded by (8) Mr1r2a3a2 (I0) on the counterclockwise optical ring 1-1, and arrives at the packet add, drop and pass device 6-2.

When the packet (8) Mr1r2a3a2 (I0) arrives at the packet add/drop/pass device 6-2, the lower address a2 of the packet transmission source MAC address is the lower address designating the packet transmission out of the ring. If it is stored in the memory 7, the lower address of the source MAC address of the packet is stored in the lower address memory 14 that designates prohibition of packet transmission outside the ring. It is forwarded by (9) Mr1r2a3a2 (I0) on the optical ring 1-1 as shown in the figure, and reaches the vertex device 5 via the packet add, drop and pass device 6-3.

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

When the packet (11) Mr1r2a3a2 (I0) arrives at the router 22, after storing the source MAC address a3a2 and the source IP address I3 of the packet in the memory 1 (not shown), the destination IP address I0 of the packet is stored. Reads the output port corresponding to , and sends it to that port. The packet is illustrated by (12) IPI3I0 (IP indicates an IP address, I3 indicates the IP address of the source terminal 13-2, and I0 indicates the IP address of the destination relay station 20). , and reaches the relay station 20 .

Next, when the TCP mobile terminal 13-2 moves under the control of the base station 12-2 and the packet (13) Mr1r2a3a2 (I0) arrives at the base station 12-2, base A signal g to the effect that the station is moved is entered, and sent to the packet add, drop and pass device 6-2. When the packet from the TCP mobile terminal 13-2 reaches the add, drop and pass device 6-2, the packet is sent out of the ring regardless of whether it is a packet immediately after changing the passing base station. Since the lower address of the source MAC address of the packet is not stored in the lower address memory 14, the lower address a2 of the source MAC address of the packet is specified to be sent out of the ring. It is stored in the lower address memory 7 . The packet is forwarded by (14) Mr1r2a3a2g (I0) on the counterclockwise optical ring 1-1 to the packet add, drop and pass device 6-3.

When the packet (14) Mr1r2a3a2gp (I0) arrives at the packet add/drop/pass device 6-3, the packet is a packet immediately after moving from the base station, but the lower order of the source MAC address of the packet is If the address a2 is stored in the lower address memory 7 that designates packet transmission to outside the ring, the lower address a2 of the source MAC address of the packet is transferred to the outside of the ring without erasing the stored lower address a2. The packet is stored in the lower address memory 14 that specifies transmission prohibition, but since it is not stored, the packet is forwarded by (15) Mr1r2a3a2gp (I0) in the counterclockwise optical ring 1-1 as shown in the figure, and the vertex Device 5 is reached.

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

When the packet (16) Mr1r2a3a2g (I0) arrives at the router 22, after storing the source MAC address and source IP address of the packet in a memory (not shown), Read an output port and send to that port. Since the packet (16) Mr1r2a3a2g is given the indication g indicating that it is a packet immediately after moving the base station, the MAC address a1a2 of the same lower address as the lower address a2 of the source MAC address of the packet and its MAC The IP address I2 corresponding to the address is read from the storage address of the memory 1 (not shown) and stored in the memory 2 (not shown). When the destination IP address of the IP packet arriving from the server 20 is the IP address I2 stored in the memory 2, the packet from the server 20 with the IP address I2 is transferred from the TCP mobile terminal side to the source IP address I2. Wait in a buffer (not shown) until the retransmission packet (24) Mr1r2a1a2 (I0) is received. When the packet (24) Mr1r2a1a2 (I0) is received, the packet from the relay station with the IP address I2 waiting in the buffer (25) Ma3a2r1r2 (I3), (26) Ma1a2r1r2 (26) I2) sends it to the vertex device 5 via the upper ring 4, as shown in the figure.

Regarding the packet (24) Mr1r2a1a2(I0), the retransmission packet from the terminal 13-1 passes through the packet add, drop and pass device 6-1 as illustrated by the packet (20) Mr1r2a1a2(I0). via (21) Mr 1 r 2 a 1 a 2 (I 0 ) is forwarded to the packet add, drop and pass device 6-2 on the counterclockwise optical ring 1-1. When the packet arrives at the packet add, drop, and pass device 6-2, 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. Therefore, the source MAC address a1a2 of the packet is stored in the lower address memory 14 packet designating prohibition of packet transmission outside the ring. The packet is forwarded by (22) Mr1r2a1a2 (I0) through counterclockwise optical ring 1-1 as shown in FIG.

Next, the procedure for transferring the packets (25) Ma3a2r1r2(I3) and (26) Ma1a2r1r2(I2) arriving at the vertex device 5 through the clockwise optical ring 2 will be described. Packets (27) Ma3a2r1r2(I3) and (28) Ma1a2r1r2(I2) are transferred as shown in the figure and arrive at packet add, drop and pass device 6-3. The two packets pass through the packet add, drop and pass device 6-3 because the lower address of the destination MAC address is not stored in the lower address memory 7 that designates packet transmission out of the ring.

The two packets are transferred by (29) Ma3a2r1r2 (I3) and (30) Ma1a2r1r2 (I2) as shown in the figure and arrive at the packet add, drop and pass device 6-2. The destination MAC addresses of the two packets are not stored in the address table 11 that specifies packet transmission outside the ring, and the lower address a2 of the destination MAC address specifies prohibition of packet transmission outside the ring. 14, both packets pass through that device 6-2. Packet (29) Ma3a2r1r2 (I3) is a packet that does not need to be waited by the packet waiting means, but when the packet waiting means decides whether the packet is waiting, the passing base station is changed, and the packet to be added is added or dropped. and when the packet waiting means of the router receives a packet having a signal g indicating that the passing device has been changed, a packet directed to the source mobile terminal of the MAC address having the lower address of the source MAC address of the packet as the lower address. This is a packet that has been queued because it targets . However, at this point, the destination MAC address a3a2 of the packet specifies the transmission of the packet out of the ring by the one-way setting packet having the transmission source MAC address a3a2 by the self-help efforts of the portable terminal 13-2 that has moved to the passing base station. Since the packet is not set in the address table 11 to be used, the packet passes through the device 6-2. This problem can be solved by periodically transmitting the one-way path setting packet for a certain period of time when the portable terminal moves between base stations that it passes through. It is also possible to rely only on the terminal's retransmission function without waiting for packets directed to a mobile terminal that has changed the base station to pass through.
On the other hand, the packet (30) Ma1a2r1r2 (I2) is sent out of the ring by the packet add/drop/pass device 6-1 and reaches the terminal 13-1.

In the first embodiment described above, the TCP mobile terminal 13-2 is an example of transit base station movement in the direction toward the server in the ring network. When a packet immediately after the station moves passes through the packet add, drop, and pass device 6-1 and arrives at the packet add, drop, and pass device 6-2, the packet is designated to be sent out of the ring. If the lower address a2 of the source MAC address of the packet is stored in the address memory 7, the lower address memory 14, which specifies prohibition of packet transmission outside the ring, stores the lower address a2 of the source MAC address of the packet. If the packet is stored but not stored, the packet is passed through the device 6-2 and sent to the anticlockwise ring 1-1. In the above stored state, when a packet whose lower address of the source MAC address is a2 arrives from outside the ring to the device 6-2 for adding, dropping and passing that packet, that packet causes the packet to be sent outside the ring. If the lower address a2 is stored in the lower address memory 14 that specifies prohibition of transmission of the packet, the source MAC address of the packet is stored in the address table 11 that specifies packet transmission outside the ring. Even if the lower address a2 is stored in the lower address memory 14, which specifies prohibition of packet transmission outside the ring, and the number of addresses stored in the memory increases, the portable terminal causing the packet cannot add, drop, or pass the packet. device 6-2, the number of addresses stored in the address table 11 specifying packet transmission to the outside of the ring does not increase.

Further, in the first embodiment described above, an example was 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.
Storing the lower address of the source MAC address of the packet in the lower address memory designating packet transmission outside the ring means that the lower address memory designating packet transmission out of the ring is addressed with the lower address of the source MAC address. It is also possible to store bit 1, which means lower address storage, at a designated position.
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 the first embodiment, when a communication start packet arrives at the server 20 from the mobile terminal, the server 20 accesses the home memory with the IP address of the router 22 using the home IP address of the mobile terminal as a key. 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.

In the first embodiment described above, the telephone relay station is connected to the router 22, and the router 22 and the telephone relay station remove the MAC address from the voice MAC packet arriving at the router 22 from the mobile terminal. , the transmission source MAC address of the voice MAC packet can be written in the forwarding network configuration.

A second embodiment of the present invention will now be described with reference to FIG. In this embodiment, a lower address memory for designating packet transmission to the outside of the ring, a low address memory for designating packet transmission to the outside of the ring, and an address table for designating packet transmission to the outside of the ring. This is an example of network handover operation in which a tree-like ring network in which a plurality of packet add, drop, and pass devices are connected by optical transmission lines is used for communication between a TCP mobile terminal and a server. Said server is an Internet connection server. This embodiment does not have the subscriber system rings 2 and 3 and the upper ring 4 of the first embodiment. Since the subscriber system ring composed of the left-handed ring 1-1 and the right-handed ring 1-2 and the router 22 operate in the same manner as in the first embodiment, the explanation of the operation will be omitted.

The ambiguous storage address memory for packet drop, which stores bit 1 at the position addressed by the lower address of the source MAC address of the packet in Patent Document 7, designates the transmission of the packet out of the ring in the first embodiment. The address table for packet drop, which corresponds to the lower address memory and stores the source MAC address of the packet, corresponds to the address table for specifying the packet transmission outside the ring in the first embodiment. Ambiguity for packet passing by sampling high-order and low-order addresses and storing bit 1 at a location addressed by a bit sequence of exclusive OR of each bit of the high-order address bit sequence and each bit of the low-order address bit sequence One hash memory, which is a storage bit string composite value memory, is a lower address memory that specifies prohibition of packet transmission out of the ring in the first embodiment or a hash memory that specifies prohibition of packet transmission out of the ring of the present invention. Applicable.

1-1 Subscriber system anticlockwise optical ring
1-2 Subscriber system clockwise optical rings 2, 3 Subscriber system ring 4 Upper ring 5 Vertex devices 6-1, 6-2, 6-3 Packet add, drop and pass devices 7 Packets out of ring Lower address memory 11 for designating transmission Address table 14 for designating packet transmission out of the ring Low address memory 12-1, 12-2, 12-3, 12-4, 12-5 Base stations 13-1, 13-2, 13-3, 13-4 TCP mobile terminal 15 Movement of mobile terminal 20 Relay station 22 Router 27 Home memory

Claims (6)

A base station is accommodated in the lowest ring of a ring network or a tree-like ring network, and a TCP mobile terminal under the base station communicates with a server via a router connected to a vertex device of the ring network or the tree-like ring. A packet waiting means applied to a packet transfer system that enables mobile terminals of a network to move between base stations,
The transmission source MAC address of a packet from a mobile terminal to a server or a relay station via a base station, a ring network or a tree-like ring network is set as the own packet of the gateway or router connected to the top device of the ring network or the tree-like ring network. Store the packet in a first memory of the standby means and send the packet to the server or the relay station, or store the source MAC address of the packet directed to the server or the relay station in the optional area of the IP header of the IP packet and send it to the server or relay station,
When the own packet waiting means receives a packet having a signal indicating that the base station through which the packet from the mobile terminal passes has been changed and the device for adding, dropping and passing the packet to be added has been changed,
When a MAC address having a lower address of the source MAC address of the received packet is stored in the first memory of the packet waiting means, the MAC address stored in the first memory is automatically retrieved. stored in a second memory of the packet waiting means;
Alternatively, if the first memory of the self-packet waiting means is not used, the source MAC address of the received packet is stored in the second memory of the self-packet waiting means,
In the method that does not use the first memory of the own packet waiting means, the same lower address as the MAC address stored in the second memory of the own packet waiting means is assigned to the IP packet of the packet arriving from the server. If the lower address of the MAC address written in the option area of the IP header has a lower address, the MAC address is stored in the memory 2, and the packet is sent to the own packet waiting means as the source MAC of the packet arriving from the terminal side. After waiting until the address is stored in the second memory of the own packet waiting means, after sending to the terminal side, the MAC address and its lower address stored in the second memory of the own waiting means Clear the MAC address with the same lower address as
In the method using the first memory of the packet waiting means, when the destination IP address of the IP packet arriving from the server to the own packet waiting means is stored in the second memory of the own packet waiting means , causing the packet to wait until a retransmission request packet or a retransmission packet arrives from the mobile terminal whose source MAC address is the MAC address corresponding to the destination IP address stored in the second memory; when a packet or a retransmission packet arrives, erasing the source MAC address and the source IP address of the retransmission request packet or the retransmission packet from the second memory of the self-packet waiting means;
A packet waiting means is accommodated in the lowest ring of a ring network or a tree-like ring network, and a TCP mobile terminal under the base station is connected to a top device of the ring network or the tree-like ring via a router. A packet forwarding system that enables inter-base station movement of a mobile terminal of a network, with or without said router, in communication with a server, comprising:
When a TCP packet from the mobile terminal via the base station arrives at a device for adding, dropping, and passing packets of the ring network or tree-like ring network,
Regardless of whether or not the packet is a packet immediately after moving the base station,
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 of the device for adding, dropping and passing the packet, and the lower address memory prohibits packet transmission outside the ring. When the lower address of the source MAC address of the packet is stored, or when the hash of the source MAC address of the packet is stored in a hash memory that prohibits packet transmission outside the ring, The source MAC address of the packet is stored in an address table that specifies packet transmission outside the ring, and the packet is directed to the server via the vertex device in the counterclockwise ring, and the packet is added, dropped, and If the lower address of the source MAC address of the packet is stored in a lower address memory that designates packet transmission out of the ring, the lower address of the source MAC address of the packet when it reaches a passing device. is stored in a lower address memory that prohibits packet transmission outside the ring or the hash of the source MAC address of the packet is stored in a hash memory that prohibits packet transmission outside the ring, and the packet is rotated counterclockwise without changing the above. means for directing through a vertex device in a ring to said server;
When a TCP packet from said server arrives at a packet add, drop and pass device on a clockwise ring,
When the destination MAC address of the packet is stored in an address table that specifies packet transmission outside the ring, the packet is transmitted out of the ring, and the destination MAC address of the packet specifies the packet transmission out of the ring. If it is not stored in the specified address table, and if the lower address of the destination MAC address of the packet is stored in the lower address memory that prohibits packet transmission outside the ring, the packet is rotated clockwise. in the ring downward direction of the ring, or when the destination MAC address of the packet is not stored in an address table specifying packet transmission outside the ring, and the hash of the destination MAC address of the packet is outside the ring If the packet is stored in the hash memory that prohibits sending the packet to the outside of the ring, the packet is sent in the downward direction of the clockwise ring. means for sending the packet out of the ring if it is stored in a lower address memory designating packet sending,
In addition, when the TCP mobile terminal does not receive a packet from the server for a certain period of time or longer during communication, the TCP mobile terminal either sends a resend packet, a resend request packet, or a communication partner confirmation packet to the server, or A packet transfer system that enables a mobile terminal to move between base stations, characterized by comprising means for periodically sending a one-way setting packet having a MAC address.
The TCP mobile terminal further comprises means for sending a one-way path setting packet having a source MAC address to a device for adding, dropping, and passing packets belonging to the base station immediately after changing the base station to be used. 2. The packet transfer system according to claim 1, which enables a mobile terminal to move between base stations.
Immediately after changing the base station to be used, the TCP mobile terminal sends a one-way path setting packet having a source MAC address to the add, drop, and passing devices of packets belonging to the base station, and Immediately after changing the station, if there is a mobile terminal with a source MAC address of the same lower address as the lower address of the source MAC address, a one-way setting packet having the source MAC address of the mobile terminal is sent to the base station. 2. The packet transfer system according to claim 1, further comprising means for sending a packet belonging to a base station to an add, drop, and pass device.
Source of the received packet when its own packet waiting means receives a packet having a signal to the effect that the base station through which the packet from the mobile terminal passes has been changed and the apparatus for adding, dropping and passing the packet to be added has been changed. 2. The MAC address of the waiting packet of the packet waiting means is only the MAC address obtained by removing the source MAC address of the received packet from the MAC address having the lower address of the MAC address as the lower address. A packet transfer system that enables mobile terminals to move between base stations.
2. A packet add, drop, and pass device of a ring network or a tree-like ring network of a packet transfer system according to claim 1, wherein said add, drop, and pass device designates packet transmission out of the ring. Storing the lower address of the source MAC address in the address memory means storing the lower address in the location where the lower address memory for specifying packet transmission to outside the ring is addressed by the lower address of the source MAC address. is to remember
Deleting the lower address of the source MAC address from the lower address memory that specifies packet transmission out of the ring means that the lower address memory that specifies packet transmission out of the ring is addressed with the lower address of the source MAC address. A device for adding, dropping and passing packets in a ring network or tree-like ring network of a packet transfer system characterized by writing bit 0 meaning no lower address storage in a location.
2. A low-order address memory for designating out-ring packet transmission of a device for adding, dropping, and passing packets of the ring network or tree-like ring network of the packet transfer system according to claim 1, wherein the packet is transmitted out of the ring. Each bit of the parallel data read from the location addressed by the high-order part of the low-order address of the source MAC address and each bit of the parallel data obtained by decoding the low-order part of the low-order address of the source MAC address and By storing the latch signal of the parallel data of the logical sum of the above-mentioned address designation position of the lower address memory designating packet transmission out of the ring, the lower part of the lower address of the source MAC address is stored in the position of bit 1 of the decode. inserting and storing bit 1 as bit 1 meaning lower address storage;
When deleting the lower address of the source MAC address from the lower address memory that specifies packet transmission outside the ring, the lower address memory that specifies packet transmission outside the ring is replaced with the upper part of the lower address of the source MAC address. Each bit of the parallel data read from the addressed position and the bit-inverted bit of each bit of the parallel data decoded from the lower part of the lower address of the transmission source MAC address are logically ANDed to the outside of the ring. By storing the lower address portion of the lower address of the transmission source MAC address in the address specifying position of the lower address memory designating packet transmission, bit 0 is inserted into the position of decode bit 1 as bit 0 meaning no lower address storage. A low-order address memory for specifying the sending of packets out of the ring of add, drop and pass devices characterized by storing.

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