JPH09252316A - Packet transfer method and packet transfer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To process inter-network communication similarly to be innetwork communication in the case of transferring packets between terminal equipments via plural networks. SOLUTION: Servers 1, 5, 6 collect network management information of each terminal equipment connecting to its segment and assemble the collected network management information into packets and transfer them to other segments. Based on the collected network management information and the network management information included in packets transferred from other segments, each server stores a relation between an address of each segment connecting to each of the plural segments and a host layer address as a table and makes packet transfer between terminal equipments via the plural segments by referencing the table.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet transfer method and a packet transfer system for transferring packets between a plurality of terminals connected via a plurality of networks which are one address management unit.

[0002]

2. Description of the Related Art Conventionally, as one packet transfer method in a network segment in which one or more physical media (cables, etc.) are connected by repeaters, bridges, etc.
NetBEUI (NetExtended Use) supported by AN manager and Windows NT
r Interface) and the like.

According to this, basically, network information (for example, address of each terminal, packet transfer control information, etc.) is managed in a segment which is one data link unit such as Ethernet and token ring, and each of them is managed. It was centrally managed at the terminal or at the server.

In this case, each terminal compatible with these network protocols can communicate with the terminals in its segment only by simple settings, but cannot communicate with the terminals in other segments connected by a router, gateway, etc. .

It is possible to communicate each segment even in a multi-segment environment such as a router and a gateway by the TCP / IP protocol corresponding to 4 layers and 3 layers of OSI (Open System Interconnection) which is the upper protocol of each segment. As a result, terminals of all network segments can communicate with each other.

In this case, the management of the upper layer address and the lower layer address for information transfer is performed by installing a server in units of these plural segments. In this server, each server interconnected by the upper protocol is used. The address of the terminal connected to the segment is not managed uniquely, but the address space is divided between the servers in advance, and the address in that is used to maintain the uniqueness.

[0007]

As described above, since the address management is performed by the off-line distributed processing between the segments, for example, an IP packet (upper layer) is sent from the terminal A of a certain segment to the terminal B of another segment. When an IP address that is a layer address and a lower layer address (for example, a MAC address is assigned) are transferred, the server routes the segment to the corresponding segment using the IP address as a key. There is a possibility that the packet data cannot be transferred to the terminal B due to address mismatch, double assignment, or the like.

That is, in each network segment, the intra-segment address of the terminal within that segment,
Upper layer address such as IP address, 1: 1 communication, 1:
Since network management information including communication control information such as a communication method between terminals such as N communication is managed independently for each segment, inter-segment communication across a plurality of segments cannot be easily performed.

Further, in order to disconnect a terminal from a network (subnetwork) forming a certain segment and connect it to another subnetwork, it is necessary to set an IP address again each time, which is convenient for the user. Was missing.

Therefore, the present invention has been made in view of the above problems, and in a network composed of a plurality of network segments, the network management information of each segment is mutually exchanged between the servers of each segment. , All servers will share the network management information of other segments, and each server will
Terminals in other segments can be managed as if they were terminals in their own segment, and network configuration, addresses, terminal management, data transfer instructions, etc. can be performed easily, and they are composed of multiple segments. Even in a wide area network environment where users do not need to set and manage the various network management information described above, the burden on the user when connecting a terminal to the network is reduced, and the segment-to-segment connection is achieved only by specifying the upper layer address. It is an object of the present invention to provide a packet transfer method and a packet transfer system that can easily transfer packets to all the established terminals.

[0011]

A packet transfer method of the present invention is a packet transfer method for transferring a packet between a plurality of terminals connected via a plurality of networks,
For each network, at least the relationship between the intra-network address required for intra-network communication of each terminal connected to that network and the upper layer address required for inter-network communication is stored as a table and transferred from other networks. Also, network management information including at least the in-network address of each terminal connected to the network is collected, and at least the in-network address in the table is updated based on the collected network management information, and this table is updated. By performing the packet transfer between the terminals via the plurality of networks with reference to the above, when the packet transfer between the terminals via the plurality of networks, the inter-network communication can be treated like the intra-network communication.

Specifically, the lower layer address field in the table managed for each network is
By referring to the network management information transferred from another network: -When a terminal is newly connected to the network, the lower layer address of the terminal is determined and added. -If a duplicate lower layer address is detected, it is changed. Is updated.

The packet transfer system of the present invention is
In a packet transfer system for transferring packets between a plurality of terminals connected via a plurality of networks, each of the plurality of networks includes at least an in-network address of each terminal connected to the network. At least one server that manages management information is provided, and each of the servers has at least an intra-network address required for intra-network communication of each terminal connected to the network and an upper layer address required for inter-network communication. Means for storing the relationship of the above as a table, a collecting means for collecting network management information transferred from a server of another network and including at least the in-network address of each terminal connected to the network, and the collecting means. Done It comprises means for updating at least the in-network address of the table based on network management information, and packet transfer means for referring to the table and transferring packets between terminals via the plurality of networks. Thus, when packets are transferred between terminals via a plurality of networks, inter-network communication can be treated like intra-network communication.

The packet transfer method of the present invention is a packet transfer method for transferring packets between a plurality of terminals connected via a plurality of networks, and at least for each terminal connected to that network for each network. Network management information including an in-network address is collected, the collected network management information is packetized and transferred to another network, and included in the collected network management information and a packet transferred from another network. Based on the network management information, the relationship between the intra-network address of each terminal connected to each of the plurality of networks and the upper layer address required for inter-network communication is stored as a table, and with reference to this table, Terminal via the plurality of networks By carrying out the packet transfer,
When packets are transferred between terminals via multiple networks, inter-network communication can be treated like intra-network communication.

Further, the packet transfer method of the present invention is a packet transfer method for transferring a packet between a plurality of terminals connected via a plurality of networks, wherein at least the network of each terminal connected to the plurality of networks. The network management information including the internal address is collected, and based on the collected network management information, the network internal address of each terminal connected to each of the plurality of networks and the upper layer address required for inter-network communication The relationship is stored as a table, and by referring to this table, the packet transfer between the terminals via the plurality of networks is performed. It can be handled in the same way as internal communication.

Further, the packet transfer system of the present invention is
In a packet transfer system for transferring packets between a plurality of terminals connected via a plurality of networks, each of the plurality of networks includes at least an in-network address of each terminal connected to the network. One or a plurality of servers for managing management information are provided, and each of the servers collects network management information of each terminal connected to the network, and network management information collected by the collecting means. Transfer means for packetizing and transferring to a server of another network, network management information collected by the collecting means, and the network management information included in a packet transferred from the server of another network by the transferring means Based on the Means for storing, as a table, the relationship between the intra-network address of the terminal connected to each and the upper layer address required for inter-network communication, and referring to the table, packet transfer between the terminals via the plurality of networks By providing the packet transfer means for performing the packet transfer, when the packet is transferred between the terminals via the plurality of networks, the inter-network communication can be treated like the intra-network communication.

Further, the packet transfer system of the present invention is
In a packet transfer system for transferring packets between a plurality of terminals connected via a plurality of networks, each of the plurality of networks includes at least an in-network address of each terminal connected to the network. One or a plurality of servers for managing management information are provided, and each of the servers collects network management information of terminals connected to the plurality of networks, and a network collected by the collecting means. Based on the management information, a means for storing the relationship between the in-network address of each terminal connected to each of the plurality of networks and the upper layer address required for inter-network communication as a table, and referring to the table, The network between terminals can be A packet forwarding unit for performing Tsu-forwarding, by having a, when packet transfer between terminals via a plurality of networks, handle communication between the network equivalent to the communication network.

[0018]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of the overall configuration of a packet transfer system according to an embodiment of the present invention.

A segment used in the following description means an OSI in which one or a plurality of physical media (for example, a cable or the like) are connected by a repeater or a bridge.
(Open Systems Interconne
action: open type interconnection) It is one network or subnet from the network layer of the 7-layer protocol. That is, a unit that gives one network (subnet) address,
More specifically, it can be said that it is one lower layer address management unit.

When a packet is transferred between terminals connected to one segment, a lower layer address (eg MAC (Media A) is included in the header of the packet.
access control address) is used. When transferring a packet between terminals via a plurality of segments, the router performs packet routing using the upper layer address (for example, the IP address in the TCP / IP protocol) included in the header of the packet. , Packets are transferred to the corresponding segment.

In FIG. 1, an inter-segment exchange server 1, a wireless base station (BS) 2 for communicatively connecting a plurality of wireless terminals, and a router 3 are connected to a network X,
A segment 1 is configured as one subnet address management unit.

The inter-segment exchange server (hereinafter also simply referred to as a server) 1 manages the subnet address of each terminal accommodated in the network X, and
It has a function of communicating with a server connected to another segment.

An inter-segment exchange server 5 and an inter-segment exchange server 6 having a router function are connected to the network Y, and further connected to the network X via the router 3. The segment 2 as another subnet address management unit includes a router 3, servers 5 and 6 connected to the network Y, and a plurality of terminals connected to these.

A plurality of terminals may be connected to the inter-segment exchange server 5. The inter-segment exchange server (hereinafter also simply referred to as a server) 5 has a function of managing the subnet address of each terminal accommodated in the network Y and communicating with a server connected to another segment. are doing.

A wireless base station 7 accommodating a plurality of wireless terminals and a plurality of wired terminals are connected to the server 6, and a segment 3 as another subnet address management unit is formed.

The router 3 and the server 6 having a routing function transfer packets between the terminals connected to the segments 1, 2 and 3, respectively. (First Embodiment) FIG. 2 schematically shows a configuration example of an inter-segment exchange server (hereinafter, the server 1 of FIG. 1 will be described as an example) according to the first embodiment.

In FIG. 2, the server 1 comprises a network information management unit 10, a network information processing unit 20, and a communication interface unit 30. When the communication interface unit 30 receives the information for controlling and managing the network such as the network configuration and the address, that is, the control packet in which the network management information is packetized, the information included in the control packet is transferred to the network information processing unit. 20 and perform predetermined protocol processing,
The network management information is stored in the network information management unit 10.

When a request for transmitting a control packet is issued to the upper processing unit, the user, or another terminal inside the network information processing unit 20, necessary information is acquired from the network information management unit 10 and the communication interface is acquired. Part 30
A request to send a control packet to.

The communication interface section 3 which has received the transmission request
0 sends the control packet to the network. In this case, if the destination designation is necessary, the network information processing unit 20 gives an instruction, and based on the instruction, the communication interface unit 30 transmits the packet with the destination information added.

When exchanging network management information with a server in another segment, necessary information is provided to the network periodically or in response to a request from the upper processing unit, the user, or the network information processing unit 20. In order to transfer from the information management unit 10 by the inter-segment packet transfer protocol, the transfer instruction of the transfer protocol, the destination information to reach the server of one or more other segments, and the network management information It is passed to the communication interface unit 30.

The communication interface unit 30 which has received it
Configures a packet frame of the designated packet transfer protocol, stores network control information in the payload, and transmits the packet to the designated destination of the server once or multiple times depending on the number of destinations.

FIG. 3 shows a detailed configuration example of the communication interface section 30. In FIG. 3, the communication interface unit 30 includes an intra-segment communication processing unit 301,
Inter-segment communication processing unit 302, common communication interface unit 311, intra-segment communication interface unit 31
2. It is composed of an inter-segment communication interface unit 313.

The common communication interface unit 311 is used when intra-segment communication and inter-segment communication use the same communication device. For example, an interface unit corresponding to Ethernet which is a data link when the intra-segment packet transfer method is Net Beui and the inter-segment packet transfer method is TCP / IP.

When using communication devices that are different in the segment and between the segments, packet transfer is performed using the intra-segment communication interface unit 312 and the inter-segment communication interface unit 313, respectively.

The control packet including the network management information received by the common communication interface unit 311 or the intra-segment communication interface unit 312 is subjected to packet processing by the intra-segment communication processing unit 301, and necessary information is processed by the network information processing. It hands over to the unit 20 for protocol processing, extracts network management information, and stores it in the network information management unit 10. When sending, packets are constructed by the reverse route and sent.

Similarly, when exchanging information with the server of another segment, the control packet including the network management information received by the common communication interface unit 311 or the inter-segment communication interface unit 313 is the inter-segment communication processing unit 302. Then, the necessary information is passed to the network information processing unit 20 for protocol processing, the network management information is extracted and stored in the network information management unit 10. When sending, packets are constructed by the reverse route and sent.

Next, a procedure for exchanging the network management information of the terminals accommodated in each segment between the servers having the above-described configuration and sharing the network management information among the servers will be described.

FIG. 4 is a conceptual diagram for explaining a mutual exchange procedure between network management information segments. A segment 1 is composed of terminals A, B, C and a server 100 having a routing function, and a segment 2 is composed of: Terminals D, E,
F, server 101, and router 102. Each terminal including the server 100 of segment 1 and segment 2
Each terminal including the server 101 of, for example, TCP / IP
Communication shall be performed.

In this case, the table T1 as shown in FIG. 4 is stored in the network information management unit 10 of each server. That is, in the table T1, for a terminal accommodated in each segment, a segment ID for identifying the segment accommodating the terminal, an in-segment address (for example, MAC address), an upper layer address (for example, IP address) Each address) is memorized.

First, the server needs to collect the network management information of the terminals accommodated in the segment managed by the server. At that time, for example, ARP (Ad
dress Resolution Protocol
l: address resolution protocol) can also be used.
ARP protocol uses MAC as IP key
It is to resolve an address.

When terminal A of segment 1 sends an IP packet to terminal B in the same segment, terminal A knows the IP address (upper layer address) of terminal B in advance, but terminal A's MAC address (segment Internal address) does not know. At this time, the terminal A broadcasts an ARP request in the segment to obtain the MAC address of the terminal B (step S1).

This broadcasted ARP request is received by all the terminals in the segment 1 including the server 100. The IP address of terminal B is described in the ARP request. The terminal B knows that the MAC address of the own terminal is requested from the ARP request received by the broadcast, and the MAC address of the own terminal is A
Return to terminal A by RP reply. At this time, at the same time, the ARP reply is also transferred to the server 100 (step S
2).

The server 100 acquires the MAC address of the terminal B and stores it in the table T1 provided in the network information management unit 10 for a certain period of time. By repeating the above procedure, the network information of each terminal accommodated in the segment 1 is registered in the table T1 provided in the network information management unit 10 of the server 100.

Thereafter, in response to the ARP request broadcast in the segment 1, the table T of the server 100
If the IP address of the terminal issuing the request is registered in No. 1, the server 100 refers to table T1 and
An RP reply may be returned.

Also in segment 2, in the same manner as described above,
The network information of each terminal accommodated in the segment 2 is registered in the table T1 provided in the network information management unit 10 of the server 101.

In the servers 100 and 101, the network management information is exchanged with each other to extract the network management information of the terminals of the other segments and register it in its own table to generate the table T1 shown in FIG. You may do it.

Next, the server 100 of the segment 1 and the server 101 of the segment 2 perform, for example, TCP / IP communication, and from the tables stored in the respective network information management units 10, the terminals in the respective segments are displayed. The network management information of is extracted and converted into control packets and exchanged with each other (step 3).

When each of the servers 100 and 101 receives the control packet from the server of the other segment, it extracts the network management information from the control packet and registers it in the table T1 provided in each network information management unit 10.

As a result, according to the table T1 provided in the servers 100 and 101, the segment 1 and the segment 2 are
The network management information about all terminals accommodated in the network composed of
Can be managed at.

When the servers 100 and 101 collect the network management information of the terminals accommodated in the segment managed by the servers, the respective servers are ARPed.
The request may be made.

Next, with reference to FIG. 5, a mutual exchange procedure between segments of other network management information will be described. FIG.
The procedure shown in (1) shows the case of a system in which an address within a segment is independently generated within the segment.

Terminals A, B, C accommodated in segment 1
Network management information (eg, segment ID, in-segment address (eg, MAC address))
It is managed by the server 100. That is, the network information management unit 10 of the server 100 includes the table T2 as shown in FIG. 5, and the network management information of the terminals A, B, C is registered. Table T
In 2, the storage field of the upper layer address (for example, IP address) is not always necessary and may be added appropriately.

On the other hand, the terminal D accommodated in the segment 2,
E network management information (eg, segment ID,
Address in segment (eg MAC address))
Are managed by the server 101. That is,
The network information management unit 10 of the server 101 has a table T3 as shown in FIG. 5, and the network management information of the terminals D and E is registered. Table T
In 3, the storage field of the upper layer address (for example, IP address) is not always necessary and may be added appropriately.

Now, as shown in FIG. 5, for example, when the terminal F is newly connected to the segment 2, the terminal F notifies the server 101 of "#B" as the intra-segment address.
It is assumed that a control packet requesting allocation of "B" is transmitted (step S5).

Server 101 receiving this control packet
First exchanges the network management information of the terminal in the segment managed by each other with the server of the other segment (here, the server 100 of the segment 1), and the in-segment address "#BB" is used. It is checked whether it has been done (step S6).

As a result, the server 101 can determine that the intra-segment address "#BB" is used in the segment 1, so that the terminal F does not overlap with the intra-segment address given to the terminal of another segment. A control packet for assigning such an intra-segment address "#FF" is transmitted (step 7). If it can be determined that the address “#BB” requested by the terminal F is unused, that address is assigned.

By repeating the above procedure each time a new terminal is connected, the servers 100 and 101 can collect the network management information of the terminals accommodated in the segment managed by the server.

Thus, the new terminal F in segment 2
Server 1 wants to determine the address in the segment
By mutually exchanging the network management information between 00 and 101, the segment 1 and the segment 2 can be regarded as one segment and a unique intra-segment address can be determined.

When assigning an address to a newly connected terminal in the server of each segment, for example, the one generated by a random number or the like is notified to another server, which is used in another segment. If not, it may be considered unique among all segments and assigned.

Further, as a result of mutual exchange of network management information among the servers of a plurality of segments, when it is determined that the address in the segment used in a certain segment is used in another segment, A control packet to that effect may be sent to the corresponding server. At this time, the server that transmitted the control packet may change the address to another address so that the addresses do not overlap, and repeat the operation of mutually exchanging network management information with the other server each time. .

Next, with reference to FIG. 6, a mutual exchange procedure between segments of still another network management information will be described. For example, segment 1 is a wireless communication network,
When a new wireless terminal A physically connects in segment 1,
When the data link protocol is activated and the address within the segment is set by automatically communicating with the other terminals B and C, the packet (the address within the segment) communicating with the other terminal within the segment 1 is set. If there is no server 100 in the acquisition request packet of "#AA", the server 100 receives the conventional packet used only in the segment as it is (step S10), and the server of another segment (here, as a control packet) Then, the data is transferred to the server 103) (step S11).

The server 103 sends the received control packet to the terminals D, E and F of its own segment 2 (step S
12). At this time, the server 103 may broadcast. Subsequent address assignment is
Same as above.

Thus, segment 1, segment 2
Even if they are separated from each other, as long as they are connected to the upper layer, address setting and packet transfer are possible as if they were one segment.

In the Internet environment in which each segment is connected by a router, for example, when the terminal A of the segment 1 issues the ARP request control packet as described above (step S10), the control packet The server 100 which has received the message transfers it to the server 103 of another segment (step S11) and broadcasts it in the segment 2 (step 12). When the corresponding terminal responds to it, the ARP reply control packet is transferred to the original server, that is, the server 100. The server 100 that has received this ARP reply registers it in the table provided in the network information management unit 10 as described above.

By the mutual exchange procedure between the network management information segments as described above, each server 100,
The network management information of all terminals connected between the segments 101 is shared.

When each terminal transfers a communication packet in which normal user data is packetized by using the address in the segment, the servers 100 and 10 of each segment are transferred.
Reference numerals 1 and 103 monitor the intra-segment address of the communication packet sent on each segment.

When each server receives the communication packet, it refers to the table T1 or T2 or T3 stored in the network information management unit 10 to determine whether the intra-segment address of the communication packet is addressed to the terminal of another segment. Check. If it's destined for a terminal in another segment, send it to the server in that segment, or
The communication packet is transferred to the servers of all other segments. The server that receives the transferred communication packet refers to the table T1 or T2 or T3 stored in the network information management unit 10,
The intra-segment address is searched from the upper layer address, and the communication packet is transferred to the corresponding terminal.

As described above, according to the first embodiment described above, the network management information managed by the intra-segment protocol that requires less user's setting and can be performed by a simple procedure is stored between a plurality of segments. Inter-segment communication can be performed as easily as intra-segment communication by exchanging between servers.

When the inter-segment communication speed is faster, the inter-segment information is transferred to another server as a control packet rather than being retransmitted after being processed by each server. It is possible to reduce the load of the protocol processing of and to ensure the early consistency of network information among all related servers.

Further, by transferring the data packet in the same manner as the control information, it is possible to make the device common and downsized. (Second Embodiment) FIG. 7 schematically shows a configuration example of an inter-segment exchange server (hereinafter, the server 1 of FIG. 1 will be described as an example) according to a second embodiment.

In FIG. 7, the communication interface unit 31
When the control packet is received, the network information processing unit 21 extracts necessary information from the control packet and extracts it.
I will give it to you and queue it in the order of arrival. At the time of arrival of this control packet, if a request for transmitting the control packet is issued to the upper processing unit, the user, or another terminal inside the network information processing unit 20, the communication interface unit 31
To send a control packet to the network.
The communication interface unit 31 that has received the transmission request sends the control packet to the network. In this case, if destination designation is necessary, the network information processing unit 21 gives an instruction, and based on the instruction, the communication interface unit 31 transmits as a packet with destination information added.

In the case of exchanging network management information between servers, for example, in the inter-segment communication processing unit 304, packets are queued for each target server,
Upper processing unit or user, or network information processing unit 2
1 When a request to send to another server occurs internally,
These are combined into one or a plurality of packets, and the packets are transmitted to the designated destination of the server once or a plurality of times depending on the number of destinations.

As described above, according to the second embodiment, when the speed of inter-segment communication is slow, the packets exchanged within the segment are transferred as they are, and a plurality of packets are transmitted. By transmitting the data collectively, the number of packets transferred between the segments can be reduced and the transfer efficiency can be improved.

(Third Embodiment) FIG. 8 shows another configuration example of the inter-segment exchange server according to the third embodiment. In FIG. 8, the same parts as those in FIG. 2 are designated by the same reference numerals, and different parts will be described. That is, in the configuration shown in FIG. 8, the compression processing unit 4 is provided before the packet is transmitted from the communication interface unit 30 to the network.
0 is set, information is compressed if necessary, and the packet is transmitted. When the packet arrives at the compression processing unit 40 from the network, it is judged whether or not the packet is a compressed packet, and if the packet is a compressed packet, the packet is restored and the packet is passed to the communication interface unit 30.

As described above, according to the third embodiment, when the inter-segment communication speed is slow, the data compression is performed rather than transferring the packets exchanged in each segment as they are. The packet length can be reduced and the transfer efficiency can be improved by transmitting the packet later.

(Fourth Embodiment) FIG. 9 shows still another configuration example of the inter-segment exchange server according to the fourth embodiment. In FIG. 9, the same parts as those in FIG. 2 are designated by the same reference numerals, and different parts will be described.
That is, in the configuration shown in FIG. 9, the encryption processing unit 50 is provided before the packet is transmitted from the communication interface unit 30 to the network, and the packet is encrypted and transmitted if necessary. When the packet arrives at the encryption processing unit 50 from the network, it is judged whether it is an encrypted packet, and if the packet is an encrypted packet, it is restored and the packet is passed to the communication interface unit 30.

As described above, according to the fourth embodiment, when there is a risk that wiretapping of information may occur due to communication between segments, encryption is performed and data is exchanged between servers to enable segmentation. Confidentiality can be maintained between them, which will improve security.

[0078]

As described above, according to the present invention, when a packet is transferred between terminals via a plurality of networks, a packet transfer method and a packet transfer system which can treat inter-network communication as equivalent to intra-network communication. Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a packet transfer system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an inter-segment exchange server according to the first embodiment of the present invention.

FIG. 3 is a diagram showing the configuration of the inter-segment exchange server of FIG. 2 in more detail.

FIG. 4 is a conceptual diagram for explaining a mutual exchange procedure of network management information between segments.

FIG. 5 is a conceptual diagram for explaining a mutual exchange procedure of network management information between segments.

FIG. 6 is a conceptual diagram for explaining a mutual exchange procedure of network management information between segments.

FIG. 7 is a diagram showing a configuration of an inter-segment exchange server according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of an inter-segment exchange server according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of an inter-segment exchange server according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 ... Inter-segment exchange server, 10 ... Network information management unit, 20 ... Network information processing unit, 30 ... Communication interface unit.

Claims (7)

[Claims] 1. A packet transfer method for transferring a packet between a plurality of terminals connected via a plurality of networks, wherein each packet is required for at least intra-network communication of each terminal connected to the network. Stores the relationship between internal network addresses and upper layer addresses required for inter-network communication as a table, and collects network management information transferred from other networks, including at least the in-network address of each terminal connected to that network. Then, based on the collected network management information, at least the in-network address in the table is updated, and the packet is transferred between the terminals via the plurality of networks by referring to the table. Packet transfer method. 2. A method of broadcasting a packet for inquiring an in-network address to each terminal connected to each of the plurality of networks, and collecting network management information included in the packet transferred in response to the packet. The packet transfer method according to claim 1, which is characterized in that. 3. When transferring a packet between the plurality of networks, the information to be packetized is queued for each destination, and the packet queued periodically or as needed is made into one or a plurality of packets. The packet transfer method according to claim 1, further comprising: 4. The packet transfer method according to claim 1, wherein the information to be packetized is compressed when the packet is transferred between the plurality of networks. 5. The packet transfer method according to claim 1, wherein when the packet is transferred between the plurality of networks, the information to be packetized is encrypted. 6. A packet transfer system for transferring a packet between a plurality of terminals connected via a plurality of networks, wherein each of the plurality of networks includes at least a network of terminals connected to the network. At least one server that manages network management information including an internal address is provided, and each of the servers provides at least an intra-network address and inter-network communication necessary for intra-network communication of each terminal connected to the network. A means for storing the relationship of necessary upper layer addresses as a table, and a collecting means for collecting network management information transferred from a server of another network, including at least the in-network address of each terminal connected to the network, This income Means for updating at least the in-network address in the table based on the network management information collected by the means, and packet transfer means for referring to the table and performing packet transfer between terminals via the plurality of networks A packet transfer system comprising: 7. The management means broadcasts a packet for inquiring an in-network address to each terminal connected to each of the plurality of networks, and network management included in the packet transferred in response to the packet. The packet transfer system according to claim 6, wherein information is collected.