JP3514279B2 - Opponent selection type address resolution method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system for establishing communication links between communication terminals by using logical addresses of originating and terminating communication terminals, and particularly for performing closed communication between a large number of specified communication terminals. The present invention relates to a partner selection type address resolution method and apparatus.

[0002]

2. Description of the Related Art Conventionally, in a communication system in which communication links are established by establishing communication links between communication terminals, IETF has been studied as a method for solving an identifier for establishing a communication link such as a physical address from a logical address. Cla
The ssical IP over ATM method and the NHRP method are known.

In this Classical IP over ATM system,
A packet originating communication terminal in a logical subnet sends an address resolution request packet to an address resolution server (ATMARP
The address is resolved by converting the logical address (IP address) of the called communication terminal in the same logical subnet into a physical address (ATM address) by transmitting the address to the server.

Further, in the NHRP method, a packet originating communication terminal (NHC) within a certain logical subnet sends an address resolution request packet to an address resolution server (NHS), and the address resolution server (NHS) resolves the address. If not, the address resolution request packet is sent to the address resolution server (NH
The address resolution is performed by converting the logical address of the terminating side communication terminal (NHC) in a logical subnet different from the logical subnet of the packet originating side communication terminal (NHC) into a physical address by transferring to the S).

These conventional address resolution protocols are
After address resolution, the packet transmission side communication terminal sets a virtual path of the physical layer on the transmission path to the reception side communication terminal to perform communication.

[0006]

However, in the above-mentioned conventional address resolution method, when a request for closed communication is made between specific communication terminals, communication links are established between the communication terminals in the closed communication group. However, there is a problem that it is not possible to satisfy the demand for establishing a communication link between a specific communication terminal within the closed communication group and a specific communication terminal outside the closed communication group. Occurs.

In view of the above problems, an object of the present invention is not only for communication between communication terminals within the same closed communication group but also for communication between communication terminals between different closed communication groups, and for any closed communication group. It is an object of the present invention to provide a partner selection type address resolution method and apparatus for realizing communication between a communication terminal that does not belong and a communication terminal in a closed communication group.

[0008]

In order to achieve the above-mentioned object, the present invention provides a plurality of communication terminals, a communication node connecting the communication terminals with a transmission link, a caller communication terminal, and Alternatively, communication is performed by connecting a logical address of the called communication terminal to an address resolution device that converts the physical address of the called communication terminal or a logical communication link identifier between the originating and receiving communication terminals via a transmission link to perform communication between arbitrary communication terminals. A method for selecting a partner-type address in a system,
The calling side communication terminal transmits an address resolution request packet in which the logical addresses of the calling side communication terminal and the called side communication terminal are described in order to perform communication with the called side communication terminal to the address resolution device, and the address resolution is performed. When the address resolution device that has received the request packet cannot resolve the address based on the logical addresses of the originating communication terminal and the terminating communication terminal, and if there are multiple address resolution devices on the communication system, The address resolution request packet is transferred to a different address resolution device on the communication system, and the address resolution device receiving the address resolution request packet can perform address resolution based on the logical addresses of the originating communication terminal and the terminating communication terminal. The address resolution request packet sent from the calling communication terminal, If the address resolution is permitted as a result of the determination, the address resolution reply packet in which the physical address of the called communication terminal or the logical communication link identifier between the called communication terminal is described is sent. , To the source communication terminal or address resolution device that is the source of the address resolution request packet, and, if the result of the determination is that address resolution is not permitted, the source that is the source of the address resolution request packet Either the address resolution reply packet is not transmitted to the communication terminal or the address resolution device, or an address resolution refusal packet indicating that it is not permitted is transmitted, and the originating communication terminal receives the address resolution reply packet. Only when using the physical address of the called communication terminal or the logical communication link identifier between the calling communication terminal Te, by establishing a communication link between the terminating communication terminal, proposes a party selection type address resolution method that enables communication between departure communication terminals.

According to the other party selection type address resolution method,
The calling communication terminal has a communication link with the called communication terminal or can establish a communication link with the called communication terminal only when receiving the address resolution reply packet, or between the calling communication terminal and the physical address of the calling terminal. By establishing a communication link using the logical communication link identifier, communication can be performed between the originating and terminating communication terminals, and as a result, closed communication can be realized between a specific number of communication terminals.

According to a second aspect of the present invention, in the correspondent selection type address resolution method according to the first aspect, the communication system defines a closed communication group including a plurality of communication terminals.
There is no restriction on communication between communication terminals that belong to the same closed communication group or between communication terminals that do not belong to any closed communication group, but between communication terminals that belong to different closed communication groups and closed communication groups. When communication between a communication terminal that belongs to a communication terminal and a communication terminal that does not belong to any closed communication group is permitted, the calling communication terminal communicates with the called communication terminal. In order to transmit the address resolution request packet in which the logical addresses of the originating communication terminal and the terminating side communication terminal are written to the address resolving apparatus, the address resolving apparatus receiving the address resolution request packet If address resolution is possible based on the logical address of the communication terminal, the address resolution request sent from the originating communication terminal Address resolution is determined for the packet, and if the result of the determination is that address resolution is permitted, the originating communication terminal and the terminating communication terminal belong to different closed communication groups or only the originating communication terminal. Belongs to any closed communication group, and when there are a plurality of address resolution devices on the communication system, the logical address of the originating communication terminal described in the address resolution request packet is used as the address. After changing to the logical address of the resolving apparatus and assigning a packet identifier and storing the packet identifier and the logical address of the originating communication terminal in association with each other, the address resolution request packet is resolved to a different address on the communication system. If the address resolution is not permitted as a result of the determination, The address resolution request packet is transmitted to the originating communication terminal or the address resolution device that is the source of the address resolution request packet, or the address resolution refusal packet indicating that the address resolution is not permitted is transmitted. Upon receiving the address resolution reply packet for the packet, the address resolution device determines that the packet identifier described in the address resolution reply packet matches the packet identifier stored in the address resolution device, and the logic of the originating communication terminal. When the address matches the logical address of the address resolution device, the logical address of the originating communication terminal described in the address resolution reply packet is written in the logical address of the originating communication terminal changed in the address resolution request packet. Again, the physical address of the called communication terminal Or, an address resolution reply packet in which a logical communication link identifier between the originating and terminating communication terminals is described is transmitted to a transmission side communication terminal or an address resolution device which is a source of the address resolution request packet, and the transmission side communication terminal is the Only when the address resolution reply packet is received, the physical address of the called communication terminal described in the address resolution reply packet or the logical communication link identifier between the called communication terminal and the called communication terminal is used to communicate with the called communication terminal. We propose a partner selection type address resolution method that enables communication between originating and terminating communication terminals by establishing a communication link.

According to the other party selection type address resolution method,
The calling communication terminal has a communication link with the called communication terminal or can establish a communication link with the called communication terminal only when receiving the address resolution reply packet, or between the calling communication terminal and the physical address of the calling terminal. By establishing a communication link using the logical communication link identifier, when the originating communication terminal and the terminating communication terminal belong to different closed communication groups, or only the originating communication terminal belongs to any closed communication group. In this case, communication can be performed between the originating and terminating communication terminals, and as a result, closed communication can be realized between a large number of specified communication terminals. Furthermore, since the logical address of the originating communication terminal described in the address resolution request packet is changed to the logical address of the address resolution device before transmission, the receiving side caches the logical address of the originating communication terminal. There is nothing to do.

[0012] According to a third aspect of the present invention, in the other party address selection method according to the first or second aspect, the communication system has one or more closed communication groups each including a plurality of communication terminals, and the same closed area. Communication between communication terminals belonging to a communication group or between communication terminals not belonging to any closed communication group is not limited, but between communication terminals belonging to different closed communication groups and communication terminals belonging to a closed communication group. When communication between communication terminals that do not belong to any closed area communication group is permitted only when the communication is permitted, the communication terminal on the calling side is the communication terminal on the calling side and the communication terminal on the calling side in order to communicate with the communication terminal on the receiving side. The address resolution request packet in which the logical address of the called communication terminal is described is transmitted to the address resolution device, and the address resolution request packet is received. The address resolution device, if address resolution is possible based on the logical addresses of the originating communication terminal and the terminating communication terminal, determines whether or not address resolution is possible for the address resolution request packet transmitted from the originating communication terminal. However, if the result of the determination is that address resolution is permitted, if only the communication terminal on the receiving side belongs to an arbitrary communication group, the communication link to the communication terminal on the receiving side is established or established. The address resolution reply packet that describes the physical address of the communication terminal other than the called communication terminal or the logical communication link identifier between the communication terminal and the calling communication terminal is the sending side communication that is the sender of the address resolution request packet. It is sent to the terminal or address resolution device, and if the result of the determination is that address resolution is not permitted, the address Relative scan resolution which is the source of the request packet communication terminal of the calling side or the address resolution device, or does not transmit the address resolution reply packet,
Alternatively, the sender communication terminal transmits the address resolution refusal packet stating that it is not permitted, and only when the originating communication terminal receives the address resolution reply packet, the physical address of the communication terminal described in the address resolution reply packet or the calling address is issued. We propose a destination selection address resolution method that enables communication between originating and terminating communication terminals by establishing a communication link with the terminating communication terminal using a logical communication link identifier between the terminating communication terminals.

According to the partner selection type address resolution method,
The calling communication terminal has a communication link with the called communication terminal or can establish a communication link with the called communication terminal only when receiving the address resolution reply packet, or between the calling communication terminal and the physical address of the calling terminal. By establishing a communication link using the logical communication link identifier, it becomes possible to communicate between the originating and terminating communication terminals even if only the receiving side communication terminal belongs to any closed communication group, and to any closed communication group. It is possible to realize communication between a communication terminal that does not belong to the communication terminal and a communication terminal in the closed communication group, and as a result, it is possible to realize closed communication between a specific number of communication terminals. Furthermore, if only the called communication terminal belongs to an arbitrary communication group, it has a communication link to the called communication terminal or can establish a communication link with the called communication terminal other than the called communication terminal, such as a closed area. The address resolution reply packet containing the physical address of the address resolution server or the like provided in the entrance firewall or router of the communication group or the LAN or the logical communication link identifier between the communication terminal and the communication terminal on the originating side is the address resolution request packet of the address resolution request packet. Since the data is transmitted to the transmission side communication terminal or the address resolution device which is the transmission source, the transmission side does not cache the logical address of the reception side communication terminal.

Further, in claim 4, a plurality of communication terminals,
A communication node connecting the communication terminals with a transmission link,
Between the arbitrary communication terminals by connecting with a transmission link an address resolution device that converts the logical address of the originating communication terminal and / or the terminating communication terminal into the physical address of the terminating communication terminal or the logical communication link identifier between the originating and terminating communication terminals. A partner selection type address resolution device in a communication system for performing communication by means of a calling side communication terminal and a called side communication terminal for communicating with a called side communication terminal from a calling side communication terminal or another address resolution device. Packet receiving means for receiving the address resolution request packet in which the logical address of the packet is described, and whether the address resolution is possible based on the logical addresses of the originating communication terminal and the receiving communication terminal described in the received address resolution request packet. Address resolution availability determination means for determining whether or not the address resolution cannot be performed as a result of the determination, and Transfer means for transferring the address resolution request packet to different address resolution devices on the communication system when a plurality of address resolution devices exist in the system; and, as a result of the determination, address resolution is possible and address resolution is possible. When it is possible to permit, the address resolution reply packet that describes the physical address of the called communication terminal or the logical communication link identifier between the calling communication terminal,
There is proposed a partner-selection-type address resolving apparatus including an address resolving reply packet transmitting means for transmitting to an originating communication terminal or an address resolving apparatus which is a source of the address resolving request packet.

According to the other party selection type address resolution device,
Only when an address resolution request packet is received from the calling communication terminal or another address resolution device, a physical address of the communication terminal or a call originating / receiving which has a communication link with the called communication terminal or can be established. Since the address resolution reply packet in which the logical communication link identifier between the communication terminals is described is transmitted to the source communication terminal or another address resolution device which is the source of the address resolution request packet, the source communication terminal transmits the address resolution reply packet. A communication link is established using the physical address of the communication terminal or the logical communication link identifier between the originating and terminating communication terminals, which has or can establish a communication link with the terminating communication terminal described in the packet. This enables communication between the originating and terminating communication terminals, and as a result, closed communication between a large number of specified communication terminals actually takes place. It can be.

Further, in claim 5, in the partner selection type address resolution device according to claim 4, address resolution reply packet receiving means for receiving an address resolution reply packet from the receiving side communication terminal or another address resolution device, and As a result of the determination by the address resolution availability determination means, address resolution is permitted, and the originating communication terminal and the terminating communication terminal belong to different closed communication groups, or only the originating communication terminal belongs to an arbitrary closed communication group. If there is, and when there are a plurality of address resolution devices on the communication system, change the logical address of the originating communication terminal described in the address resolution request packet to the logical address of the address resolution device, A packet identifier is given, and the packet identifier and the logical address of the originating communication terminal After being stored in association with each other, second transfer means for transferring the address resolution request packet to a different address resolution device on the communication system, and an address resolution reply packet for the address resolution request packet transferred by the second transfer means. When the packet is received, the packet identifier described in the address resolution reply packet matches the packet identifier stored in the address resolution device, and the logical address of the originating communication terminal is the logical address of the address resolution device. If it matches with, the logical address of the calling communication terminal described in the address resolution reply packet is rewritten as the logical address of the calling communication terminal changed by the transfer means, and the physical address of the called communication terminal or Address that describes the logical communication link identifier between the originating and terminating communication terminals The determined reply packet, proposes a party selection type address resolution device that includes a second address resolution reply packet transmitting means for transmitting to the address resolution which is the source of the request packet communication terminal of the calling side or the address resolution device.

According to the partner selection type address resolution device,
Even when the calling side communication terminal and the called side communication terminal belong to different closed area communication groups, or when only the calling side communication terminal belongs to an arbitrary closed area communication group, the calling side communication terminal uses the address resolution device. Only when the transmitted address resolution reply packet is received, the physical address of the communication terminal that has or can establish the communication link with the called communication terminal or the logical communication link identifier between the calling communication terminal By establishing a communication link using, communication between originating and terminating communication terminals becomes possible, and as a result, closed communication can be realized between a specified number of communication terminals. In addition, since the logical address of the communication terminal on the calling side described in the address resolution request packet is changed to the logical address of the address resolution device before transmission, the receiving side must cache the logical address of the calling side. There is no.

According to a sixth aspect of the present invention, in the partner selection type address resolution device according to the fourth or fifth aspect, as a result of the determination by the address resolution availability determination means, the address resolution is permitted, and only the communication terminal on the receiving side is arbitrary. Of the communication terminal other than the called communication terminal which has a communication link or can be established with the called communication terminal when it belongs to the communication group of A third address resolution reply packet transmitting means for transmitting an address resolution reply packet in which a logical communication link identifier between the two is transmitted to the originating communication terminal or the address resolution device which is the sender of the address resolution request packet. We propose a selective address resolution device.

According to the partner selection type address resolution device,
Even when only the called communication terminal belongs to an arbitrary closed communication group, the calling communication terminal communicates with the called communication terminal only when it receives the address resolution reply packet transmitted by the address resolution device. By establishing a communication link using the physical address of the communication terminal that has or can establish the link or the logical communication link identifier between the originating and terminating communication terminals, communication between the originating and destination communication terminals becomes possible, and the result As a result, closed communication can be realized between a specific number of communication terminals. Furthermore, if only the called communication terminal belongs to an arbitrary communication group, it has a communication link to the called communication terminal or can establish a communication link with the called communication terminal other than the called communication terminal, such as a closed area. Ingress firewall or router of communication group or L
An address resolution reply packet in which a physical address of an address resolution server or the like provided in the AN or a logical communication link identifier between the communication terminal and the communication terminal on the call side is described is a communication terminal on the transmission side which is a source of the address resolution request packet. Alternatively, since it is transmitted to the address resolution device, the calling side does not cache the logical address of the called side communication terminal.

According to a seventh aspect of the present invention, in the partner selection type address resolving apparatus according to any of the fourth to sixth aspects, as a result of the determination by the address resolvability determination means, address resolution is possible, but address resolution is possible. If you can't allow
A partner-selection-type address resolution device having address resolution refusal packet transmission means for transmitting an address resolution refusal packet indicating a disallowance to a source communication terminal or an address resolution device which is a transmission source of the address resolution request packet. suggest.

According to the partner selection type address resolution device,
When the calling communication terminal receives the address resolution refusal packet transmitted by the address resolution device, it cannot establish a communication link with the called communication terminal.

[0022]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining the principle of the present invention. In the figure, 1a to 1c are transmission links, 2 is a communication node, 3 is a communication terminal on the originating side, 4 is a communication terminal on the receiving side, and 5 is an address resolution device. The originating communication terminal 3 and the terminating communication terminal 4 are connected by the communication node 2 via transmission links 1a to 1c.

In an actual communication system, a plurality of address resolution devices 5 in the figure are arranged in the communication system, and the communication terminals form a closed communication group with the plurality of communication terminals. A closed communication group exists.

The address resolution device 5 also includes a communication permission determination unit 5a and an address resolution unit 5b. The communication permission determination unit 5a includes a determination table in which the logical address of the originating communication terminal and the logical address of the terminating communication terminal in which the address can be resolved is described, and when the address resolution request packet is received, the address resolution request packet The logical address of the calling communication terminal and the logical address of the receiving communication terminal described are collated with a judgment table to determine whether the address is acceptable or not.

The address resolution unit 5b is a communication permission determination unit 5
The following process is performed based on the determination result of a. -When address resolution is permitted, the originating communication terminal and the terminating communication terminal belong to different closed communication groups respectively, or only the originating communication terminal belongs to any closed communication group, and on the communication system When a plurality of address resolution devices exist, the logical address of the originating communication terminal described in the address resolution request packet is changed to the logical address of the address resolution device 5.
A packet identifier is given and the packet identifier and the logical address of the originating communication terminal are stored in association with each other, and then this address resolution request packet is transferred to a different address resolution device on the communication system, and the address resolution request packet is stored. When the address resolution reply packet for the packet is received, the packet identifier described in the address resolution reply packet matches the packet identifier stored in the address resolution device 5, and the logical address of the originating communication terminal is If it matches the logical address of the address resolution device 5, the logical address of the calling communication terminal described in the address resolution reply packet is rewritten in the logical address of the calling communication terminal changed in the address resolution request packet. , The physical address of the called communication terminal or the calling The address resolution reply packet describing the logical communication link identifier between Shin communication terminal, and transmits to the address resolution which is the source of the request packet communication terminal of the calling side or the address resolution device.

Called party communication that has or can establish a communication link to the called communication terminal when address resolution is permitted and only the called communication terminal belongs to an arbitrary communication group. An address resolution reply packet in which a physical address of a communication terminal other than the terminal or a logical communication link identifier between the communication terminal and the communication terminal on the caller side is described is a communication terminal on the caller side or an address resolution device which is the sender of the address resolution request packet. Send to.

If the address resolution is permitted and other than the above, an address resolution reply packet in which the physical address of the called communication terminal or the logical communication link identifier between the calling communication terminal is written is sent as the address resolution request packet. It is transmitted to the originating communication terminal or address resolution device.

When address resolution is not permitted,
The address resolution reply packet is not transmitted, or an address resolution refusal packet indicating that it is not permitted is transmitted to the source communication terminal or the address resolution device that is the source of the address resolution request packet.

FIG. 2 shows an example of the format of the address resolution request packet, the address resolution reply packet, and the address resolution refusal packet described above.

The address resolution request packet is composed of a sender logical address, a receiver logical address and other information, and the address resolution reply packet is a sender logical address, a receiver logical address, other information and a receiver physical address or a sender physical address. It is composed of a logical communication link identifier between the terminating communication terminals. The address resolution refusal packet is composed of a sender logical address, a recipient logical address, other information, and information indicating the fact that the address resolution is not permitted and the reason for the rejection.

Here, in this embodiment, NHRP which resolves a physical address from a logical address is developed as a basic address resolution protocol applied to a communication network that uses a logical address and a physical address as addresses of a communication partner. A partner selection type address resolution method and apparatus will be described.

In the present embodiment, IP is used for layer 3 and ATM is used for layer 2 of the open system interconnection (0SI) reference model.

First, referring to FIG. 3, the concept of partner selection type address resolution will be described. FIG. 3 shows an example in which NHRP is used as an address resolution protocol, and NHC in the drawing shows an NHRP client which is a communication terminal.

In this case, the partner selection type address resolution is performed in the following cases (1) to (3). (1) Address resolution between communication terminals (NHC) in the same closed communication group is permitted to all communication terminals (NHC). (Communication between NHC-C and NHC-D, etc.) (2) Address resolution between communication terminals (NHC) outside the closed communication group is not involved. (As a result, address resolution will be possible as described later.) (NHC-G and NHC-H
(3) Communication between (3) Address resolution for outgoing to outside the closed communication group or for incoming from outside the remote communication group is permitted only to a specific communication terminal (NHC). (NH
Communication in which C-E is the originating side and NHC-A is the terminating side, and NHC-B is the originating side and NHC-H is the terminating side, etc.) Next, the partner selection type address resolution described in the present embodiment A communication network configuration to which the device is applied is shown in FIG. FIG. 4 shows an example in which NHRP is used as the address resolution protocol, and cases 1 to 6 in the figure show cases where the relay route of the address resolution packet is divided into address resolution request / reply.

Here, as a method of arranging the communication permission judgment function in the address resolution server (NHS) in a large-scale communication network (large-scale ATM network) using the public network as a packbone communication network, the address resolution server in the public network is arranged. The description will be given on the premise of the arrangement method of arranging only in (NHS2). That is, the address resolution server (NHS2) corresponds to the address resolution device 5 of the present invention shown in FIG.

An address resolution server (N
In order to determine the communication permission in HS2), the relay route of the address resolution reply packet must always go through the address resolution server (NHS2) in the public network, and the address resolution server (NHS2) makes the determination obtained by the communication permission determination. The value is used to determine the processing of the address resolution request packet or the address resolution reply packet.

In the following, problems in each case (case 1 to case 6) shown in FIG. 4 and FIG. 5 and countermeasures against them and a public network address resolution server (NHS2)
The processing function in will be described.

Here, the case is divided according to whether the sender or the receiver of the address resolution request packet is a closed communication group, and the relay route of the address resolution packet at the time of the address resolution request and at the time of the address resolution reply.
And the six cases shown in FIG.

In case 1 and case 3, the caller side address (address of the communication terminal NHC1 or communication terminal NHC4) in the address resolution request packet is cached by the address resolution server (NHS3 or NHS5) of the callee side. There is a problem that the address resolution server (NHS3 or NHS5) on the receiving side responds to the address resolution request from another communication terminal (NHC) which is not permitted to use the cache using this cache.

The problem is that the sender address in the address resolution request packet is set to the public network address resolution server (NH
This can be solved by the function of rewriting to the address of the address resolution server (NHS2) itself in S2).

In case 2 and case 4, the callee address (NHC3 or NH) in the address resolution reply packet is
C5 address) is the sender's address resolution server (NH
S1 or NHS4) is cached, and thereafter, in response to an address resolution request from another communication terminal (NHC) which is not permitted to communicate, the originating side address resolution server (N
There is a problem that HS1 or NHS4) uses this cache to answer.

To address this problem, in case 4, the address resolution server (NHS4) in the closed communication group 4 is restricted from caching, or the address resolution server (NHS4) uses a cache. It is solved by restricting the address resolution response that prohibits the resolution response.

In case 2, the public network address resolution server (NHS2) returns the address of the ingress firewall / router (FW / R) of the closed communication group 3 or the public network address resolution server (NHS).
By answering the address in 2), this problem is solved.

Here, in case 2, since the address of the communication terminal (NHC3) in the closed communication group 3 is not resolved, direct communication cannot be realized, but the entrance firewall / router (FW / R) to the closed communication group 3 is not realized. ) Or a direct communication to the address resolution server (NHS2) in the public network can be realized.

Further, since Case 1 and Case 2 are one address resolution operation as the address resolution request and reply, if the countermeasure of Case 2 is adopted, the address of the communication terminal (NHC1) on the calling side in Case 1 is the address on the receiving side. The problem of being cached by the address resolution server (NHS3) is solved.

In case 5 and case 6, as in case 1 and case 3, the originating side address (address of communication terminal NHC1 or NHC4) in the address resolution request packet is the destination side address resolution server (NHS3 or NS3).
The address resolution server (NHS3 or NHS5) on the called side responds to an address resolution request from another communication terminal (NHC) that has been cached by HS5) and is not permitted to communicate thereafter, using this cache. There is a problem that it ends up.

To solve this problem, since the communication terminal (NHC1 or NHC4) on the calling side directly issues an address resolution request to the address resolution server (NHS3 or NHS5) on the called side, address resolution within the public network is performed. By means such as address rewriting of the server (NHS2), it is not possible to prevent caching at the called-side address resolution server (NHS3 or NHS5).

Therefore, with respect to the problem of case 5, the address resolution server (NHS3) in the closed communication group 3 should be restricted from caching, or the address resolution server (NHS3) should be cached. It is solved by limiting the address resolution reply that prohibits the existing address resolution reply.

On the other hand, in case 6, there is a possibility that the cache of the address resolution server (NHS5) in the LAN 5 which is not contracted for the closed-area communication group service cannot be restricted.

Therefore, the problem of case 6 is solved by prohibiting the address resolution request not passing through the address resolution server (NHS4) to the communication terminal (NHC4) in the closed communication group 4.

Next, the address resolution server in the public network (NH
The communication permission determination function of S2) will be described with reference to FIG. As shown in FIG. 3, the concept of communication permission explained here is that of communication terminals (NHs) in the same closed communication group.
Communication between the communication terminal (NHC-D) and the communication terminal (NHC-D) is permitted, and the communication terminal (NHC) in the closed communication group 2 is permitted.
-E) is the calling side, the communication terminal (NHC-A) in the closed communication group 1 is the receiving side, and the communication terminal (NHC-B) in the closed communication group 1 is the calling side, and the closed communication group Communication with the outside communication terminal (NHC-H) as the receiving side is permitted.

As a determination table used for the communication permission determination in this case, a closed communication group table and a departure / arrival set table are shown in FIGS. 6 and 7. CU in the table in FIG.
.. in the G column represent closed communication group numbers, and A, B, C, D, E, F, G, in the column of logical addresses.
... indicates a logical address of the communication terminal. This describes the table by taking the closed communication group in FIG. 3 as an example.
In FIG. 7, E, B, ... In the logical address column of the originating side in the table indicate the logical address of the originating communication terminal, and A, H, ... , Shows the logical address of the called communication terminal. This describes a table taking the communication permission form of FIG. 3 as an example.

These two tables are set in the public network address resolution server (NHS2) as follows.

(A) In the closed communication group table,
IP of communication terminal (NHC) belonging to each closed communication group
Have an address. (B) The originating / exiting group table has the IP addresses of the originating and terminating groups of the communication terminal (NHC) that permits address resolution when making a call outside the closed communication group or when receiving a call from outside the closed communication group. .

Further, as shown in FIG. 8, by setting a group mask in the originating / incoming group table, table registration and determination can be performed in IP group units, and the amount of originating / incoming group table can be reduced. FIG. 8 shows an example of a communication system using an IP address as a logical address.

In the following, according to the communication permission judgment flowchart shown in FIG.
The flow of the partner selection type address resolution processing in S2) will be described.

(1) The originating side IP address and the terminating side IP address are extracted from the received address resolution request packet.

(2) Whether or not the originating side IP address belongs to the closed area communication group, the closed area communication group table is searched, and the closed area communication group number of the originating side IP address is stored. (A specific closed communication group number is given and stored even when it does not belong to the closed communication group.) (3) Whether or not the IP address of the called side belongs to the closed communication group, the closed communication group table is searched, The closed communication group number of the called side IP address is stored.
(A specific closed communication group number is given and stored even if it does not belong to the closed communication group.) (4) The closed communication group number of the sender IP address and the closed communication group number of the receiver IP address are the same. Whether or not there is is determined by using the memory of the processing of (2) and (3) above.

If they are the same, address resolution is permitted. (Communication terminal (NHC) within the same closed communication group
This is because it is a communication between them and is permitted, or because it is a communication between communication terminals (NHCs) outside the closed communication group, they are not involved in the partner selection type address resolution processing. ) (Judgment value 1) ・ If they are not the same, the process of the following (5) is continued.

(5) Source IP address and destination IP
It is determined whether or not the address exists in the entry / exit table entry. -If it exists, the process of the following (6) is continued.

If it does not exist, address resolution is not permitted. (Due to the reason that the communication with the set of the originating side IP address and the destination side IP address is not permitted.) (Judgment value 4) (6) Whether the originating side IP address belongs to the closed communication group ( The determination is made using the memory of the process of 2). -When belonging to the closed network group, address resolution is permitted with the condition that the source address in the address resolution request packet is rewritten to the address of the public network address resolution server (NHS2) and transferred. (Calling side address information is cached to the called side address resolution server (NHS), and the address resolution reply using this cache causes a communication terminal (NH
This is because the communication between C) is established. )
(Judgment value 2) ・ If it does not belong to the closed communication group, the firewall / router (FW /
R) or address resolution is permitted with the condition that the address of the public network address resolution server (NHS2) is returned. (By relaying the address resolution answer,
This is because the callee address information is cached by the callee address resolution server (NHS), and the address resolution reply using this cache establishes communication between communication terminals (NHCs) that are not permitted to communicate. ) (Judgment plant 3) By processing the address resolution packet based on the communication permission judgment value obtained as described above, the communication link can be set only between the communication terminals to which the communication permission is given, The communication by the partner selection type address resolution which is the object of the present invention, that is, the communication closed between a specific number of communication terminals is realized.

That is, the address resolution request packet is processed according to the determined value as described below. In the case of the judgment value 1, address resolution is permitted between communication terminals (NHCs) within the same closed communication group or between communication terminals (NHCs) outside the closed communication group, so address resolution is permitted,
An address resolution reply packet is transmitted to the source of the address resolution request packet.

When the judgment value is 2, the originating communication terminal (NH
Since C) belongs to the closed communication group, address resolution is permitted only when communication is permitted, provided that the source address in the address resolution request packet is rewritten to the address of the address resolution server (NHS2). Then, the address resolution request packet is transferred to another address resolution server (NHS). Further, when an address resolution reply packet for this address resolution request packet is received, the source address in the address resolution reply packet is rewritten to the address of the source communication terminal (NHC) and transmitted to the source communication terminal (NHC). To do.

In the case of the judgment value 3, since it belongs to the closed communication group, the address of the address resolution server (NHS2) is answered only when the communication is permitted.

When the judgment value is 4, the communication terminal (NHC) concerned
Since the communication between them is not permitted, the address resolution is not permitted, the address resolution refusal packet is transmitted to the source of the address resolution request packet, and the communication between the communication terminals (NHC) becomes impossible.

As described above, according to this embodiment, the originating communication terminal can establish or establish a communication link with the terminating communication terminal only when receiving the address resolution reply packet. A communication link can be established by using the physical address of the communication terminal or the logical communication link identifier between the originating and terminating communication terminals, which enables communication between the originating and terminating communication terminals. Closed communication can be realized.

The address resolution device (address resolution server NHS2 in the public network) of the present invention not only manages logical addresses of communication terminals belonging to the closed communication group,
Address resolution propriety management is performed by a set of individual outgoing and incoming communication terminals. As a result, not only communication between communication terminals within the same closed communication group, but also communication between communication terminals within different closed communication groups, and communication terminals not belonging to any closed communication group and communication terminals within the closed communication group It becomes possible to perform address selection type address resolution that realizes communication with the communication partner, and it is possible to establish a communication link regardless of whether or not it belongs to the closed communication group.

Therefore, in the prior art, only communication links between communication terminals in the same closed communication group can be established, but by using the present invention, communication links between communication terminals in different closed communication groups, and It becomes possible to establish a communication link between a communication terminal that does not belong to the closed communication group and a communication terminal that belongs to the closed communication group.

The embodiment described above is an example, and the present invention is not limited to this. For example, a similar effect can be obtained by configuring a communication system including a plurality of address resolution devices equivalent to the address resolution server (NHS2) in the public network.

[0070]

As described above, according to the partner selection type address resolving method of the present invention, the address resolving device determines the communication permission, and the communication from the communication terminal other than the communication terminal permitted the communication. Address resolution is not permitted in response to address resolution requests, so even in large-scale communication networks where there is a demand for closed communication between a large number of specified communication terminals, closed communication can be realized between a specified large number of communication terminals. can do.

In addition to the above effect, according to the partner selection type address resolution method of the present invention, the source address of the address resolution request packet is rewritten, or the communication terminal other than the destination communication terminal or the address resolution device. Since the physical address or the logical communication link identifier of is answered by the address resolution reply packet, it is possible to prevent the caching of the originating side address in another address resolution device that relays the address resolution request / reply packet. In another address resolution device, it is possible to prevent an answer using the caching address from an address resolution request from another communication terminal that is not permitted to communicate.

Further, according to the address selection method of partner selection type according to the third aspect, in addition to the above effect, communication is permitted in the communication mode in which the communication terminal on the receiving side exists in the closed communication group. Only in response to the address resolution request from the communication terminal, the physical address or logical communication link identifier of the communication terminal other than the entrance firewall or the communication terminal of the receiving side of the closed communication group is returned, or the address of the address resolution device in the Pacbone communication network or The logical communication link identifier is returned, and address resolution is not permitted for communication terminals that are not permitted to communicate, so the load on traffic to communication terminals other than the firewall of the closed communication group or the communication terminal on the receiving side is reduced. It has an excellent effect that it can be done.

Further, according to the partner selection type address resolution device of the present invention, the communication permission judgment is performed, and the address resolution is not permitted for the address resolution request from a communication terminal other than the communication terminal permitted to communicate. Even in a large-scale communication network in which there is a demand for performing closed communication between a specified number of communication terminals, closed communication can be realized between a specified number of communication terminals.

In addition to the above effects, according to the partner selection type address resolving device of the present invention, the address rewriting of the address resolving request packet is rewritten, or the communication terminal other than the receiving side communication terminal or the address resolving device. Since the physical address or the logical communication link identifier of is answered by the address resolution reply packet, it is possible to prevent the caching of the originating side address in another address resolution device that relays the address resolution request / reply packet. In another address resolution device, it is possible to prevent an answer using the caching address from an address resolution request from another communication terminal that is not permitted to communicate.

Further, according to the partner selection type address resolving apparatus of the sixth aspect, in addition to the above effects, the communication is permitted in the communication mode in which the called communication terminal exists in the closed communication group. Only in response to the address resolution request from the communication terminal, the physical address or logical communication link identifier of the communication terminal other than the entrance firewall or the communication terminal of the receiving side of the closed communication group is returned, or the address of the address resolution device in the Pacbone communication network or The logical communication link identifier is returned, and address resolution is not permitted for communication terminals that are not permitted to communicate, so the load on traffic to communication terminals other than the firewall of the closed communication group or the communication terminal on the receiving side is reduced. can do.

In addition to the above effects, according to the partner selection type address resolution device of the present invention, in the case where the address resolution is possible but the address resolution cannot be permitted, at the source of the address resolution request packet. Since an address resolution refusal packet describing that the permission is denied is transmitted to a certain originating communication terminal or address resolving device, the originating communication terminal or address resolving device that is the source of the address resolution request packet cannot communicate. You can be sure that you are not authorized.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a format of an address resolution packet according to the embodiment of the present invention.

FIG. 3 is a diagram showing an example of a communication permission form according to an embodiment of the present invention.

FIG. 4 is a diagram showing a configuration example of a large-scale communication network according to an embodiment of the present invention.

FIG. 5 is a diagram showing problems and measures / requested functions of cases 1 to 6 in FIG.

FIG. 6 is a diagram showing a closed communication group table which is one of the communication determination tables according to the embodiment of the present invention.

FIG. 7 is a diagram showing a departure / arrival set table (without a group mask) which is one of the communication determination tables in the embodiment of the present invention.

FIG. 8 is a diagram showing a departure / arrival set table (with a group mask) which is one of the communication determination tables in the embodiment of the present invention.

FIG. 9 is a flowchart illustrating a communication permission determination process performed by the address resolution server (NHS2) in the public network according to the embodiment of the present invention.

[Explanation of symbols]

1a to 1c ... Transmission link, 2 ... Communication node, 3 ... Originating communication terminal, 4 ... Receiving side communication terminal, 5 ... Address resolution device, NHC-A to NHC-H ... Communication terminal, NHS1, NS
HS3, NHS4, NHS5 ... Address resolution server, N
HS2 ... Address resolution server (partner selection type address resolution device of the present invention), FW / R ... Firewall / router.

Continued Front Page (56) References M. Laubach, Classi cal IP and ARP over ATM, Request for Comments: 1577, USA, IETF, January 1994. Luciani et. a. , NBMA Next Hop Resolution Protocol (NHRP), Request for Comments: 2332, USA, IETF, April 1998 (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/66 H04L 12/28 H04L 12/46

Claims (7)

(57) [Claims] 1. A plurality of communication terminals, a communication node that connects the communication terminals with a transmission link, a physical address of the receiving communication terminal or a destination communication terminal from a logical address of the transmitting communication terminal and / or the receiving communication terminal. A method for selecting a partner address in a communication system in which an address resolution device for converting into a logical communication link identifier is connected by a transmission link, and communication is performed between arbitrary communication terminals, wherein the originating communication terminal An address resolution device that transmits an address resolution request packet in which logical addresses of a source communication terminal and a destination communication terminal are described to perform communication between the side communication terminals to the address resolution device, and receives the address resolution request packet Is a case where address resolution cannot be performed based on the logical addresses of the originating communication terminal and the terminating communication terminal, and the communication system When there are a plurality of address resolution devices above, the address resolution request packet is transferred to a different address resolution device on the communication system, and in the address resolution device which has received the address resolution request packet, the originating communication terminal and When the address resolution is possible based on the logical address of the called communication terminal, the address resolution request judgment is carried out for the address resolution request packet transmitted from the calling communication terminal, and as a result of the judgment, the address resolution is confirmed. If permitted, the address resolution reply packet that describes the physical address of the called communication terminal or the logical communication link identifier between the called communication terminal and the calling communication terminal or address that is the sender of the address resolution request packet If the address resolution is not allowed as a result of the above determination, To the originating communication terminal or the address resolution device that is the source of the address resolution request packet, does not send an address resolution reply packet, or sends an address resolution refusal packet describing the disapproval, The caller communication terminal communicates with the callee communication terminal using the physical address of the callee communication terminal or the logical communication link identifier between the caller communication terminal only when the address resolution reply packet is received. A partner selection type address resolution method characterized by enabling communication between originating and terminating communication terminals by establishing a link. 2. A communication terminal, wherein the communication system has at least one closed communication group composed of a plurality of communication terminals, and between communication terminals belonging to the same closed communication group or not belonging to any closed communication group. There is no restriction on communication between terminals, but communication between communication terminals that belong to different closed communication groups and between communication terminals that belong to closed communication groups and communication terminals that do not belong to any closed communication group is permitted. If it is possible, the originating communication terminal sends to the address resolution device an address resolution request packet containing the logical addresses of the originating communication terminal and the terminating communication terminal in order to communicate with the terminating communication terminal. The address resolution device that has transmitted and received the address resolution request packet is based on the logical addresses of the originating communication terminal and the terminating communication terminal. If the address resolution is possible, the address resolution request packet transmitted from the calling side communication terminal is subjected to address resolution availability judgment, and if the address resolution is permitted as a result of the judgment, the calling side communication terminal And when the called communication terminals belong to different closed communication groups or only the called communication terminals belong to an arbitrary closed communication group, and when there are a plurality of address resolution devices on the communication system. , The logical address of the source communication terminal described in the address resolution request packet is changed to the logical address of the address resolution device, a packet identifier is given, and the packet identifier and the logical address of the source communication terminal are assigned. After being stored in association with each other, the address resolution request packet is transmitted to a different address on the communication system. If the result of the determination is that address resolution is not permitted, an address resolution reply packet is sent to the originating communication terminal or address resolution device that is the sender of the address resolution request packet. If not, or the address resolution refusal packet indicating that it is not permitted is transmitted, and the address resolution device that receives the address resolution reply packet for the address resolution request packet is a packet identifier described in the address resolution reply packet. Is the same as the packet identifier stored in the address resolution device, and the logical address of the communication terminal on the sending side matches the logical address of the address resolution device, the sending side described in the address resolution reply packet. Set the logical address of the communication terminal in the address resolution request packet. The address resolution reply packet in which the physical address of the called communication terminal or the logical communication link identifier between the called communication terminal is written in the changed logical address of the calling communication terminal To the originating communication terminal or the address resolution device, the originating communication terminal, only when receiving the address resolution reply packet, the physical address of the receiving communication terminal described in the address resolution reply packet or using the logical communication link identifier between sending and receiving communication terminal, according to claim 1, by establishing a communication link between the terminating communication terminal, and enables communication between departure communication terminal, wherein there that Recipient selection type address resolution method described. 3. A communication terminal, wherein the communication system has at least one closed communication group composed of a plurality of communication terminals, and between communication terminals belonging to the same closed communication group or not belonging to any closed communication group. There is no restriction on communication between terminals, but communication between communication terminals that belong to different closed communication groups and between communication terminals that belong to closed communication groups and communication terminals that do not belong to any closed communication group is permitted. If it is possible, the originating communication terminal sends to the address resolution device an address resolution request packet containing the logical addresses of the originating communication terminal and the terminating communication terminal in order to communicate with the terminating communication terminal. The address resolution device that transmitted and received the address resolution request packet is based on the logical addresses of the originating communication terminal and the terminating communication terminal. If the address resolution is possible, the address resolution request packet sent from the calling side communication terminal is subjected to address resolution availability judgment. When the address resolution is permitted as a result of the judgment, the called side communication terminal Only if it belongs to any communication group, it has a communication link to the called communication terminal or can establish a physical address of a communication terminal other than the called communication terminal or call with that communication terminal The address resolution reply packet describing the logical communication link identifier between the side communication terminals is transmitted to the source communication terminal or the address resolution device which is the source of the address resolution request packet, and as a result of the determination, the address resolution is If not permitted, the originating communication terminal or address resolution device that is the sender of the address resolution request packet Then, the address resolution reply packet is not transmitted, or an address resolution refusal packet indicating that it is not permitted is transmitted, and the originating communication terminal sends the address resolution reply packet to the address resolution reply packet only when the address resolution reply packet is received. Communication is enabled between the originating and terminating communication terminals by establishing a communication link with the terminating side communication terminal using the physical address of the communication terminal or the logical communication link identifier between the originating and terminating communication terminals described. 3. The other party selection type address resolution method according to claim 1 or 2. 4. A plurality of communication terminals, a communication node that connects the communication terminals with a transmission link, a physical address of the callee communication terminal or a callee communication terminal from the logical address of the caller communication terminal and / or the callee communication terminal. An address resolving device for converting a logical communication link identifier between a communication communication device and an address resolving device for converting a communication link identifier to a communication communication system for communicating between arbitrary communication terminals. Address resolution request packet receiving means for receiving an address resolution request packet in which the logical addresses of the originating communication terminal and the terminating communication terminal are described in order to perform communication with the terminating communication terminal from the resolution device; Address resolution is possible based on the logical address of the originating communication terminal and the terminating communication terminal described in the address resolution request packet. Address resolution availability determination means for determining whether the address resolution is not possible as a result of the determination, and when there is a plurality of address resolution devices on the communication system, the address resolution request packet is sent to the communication system. Transfer means for transferring to the different address resolution device above, and as a result of the determination, if the address resolution is possible and the address resolution is permitted, the physical address of the called communication terminal or the logical communication link between the called communication terminal A partner selection type characterized by comprising an address resolution reply packet transmitting means for transmitting an address resolution reply packet in which an identifier is described to a source communication terminal or an address resolution device which is a sender of the address resolution request packet. Address resolution device. 5. An address resolution reply packet receiving means for receiving an address resolution reply packet from a receiving side communication terminal or another address resolution device, and the address resolution is permitted as a result of the judgment of the address resolution availability judgment means, and the originating side. When the communication terminal and the called communication terminal belong to different closed communication groups respectively, or only the calling communication terminal belongs to any closed communication group, and there are a plurality of address resolution devices on the communication system. In this case, the logical address of the source communication terminal described in the address resolution request packet is changed to the logical address of the address resolution device, a packet identifier is given, and the packet identifier and the logical address of the source communication terminal are added. Are stored in association with each other, and the address resolution request packet is stored in the communication system. A second transfer means for transferring to a different address resolution device, when the second <br/> that receives the address resolution reply packet to the address resolution request packet transferred by the transfer means, according to the address resolution reply packet If the stored packet identifier matches the packet identifier stored in the address resolution device, and the logical address of the originating communication terminal matches the logical address of the address resolution device, enter in the address resolution reply packet. The logical address of the calling communication terminal which has been changed is re-described in the logical address of the calling communication terminal changed by the transfer means, and the physical address of the called communication terminal or the logical communication link identifier between the calling communication terminals is written. Originating the address resolution reply packet as the source of the address resolution request packet 5. The partner selection type address resolution device according to claim 4, further comprising a second address resolution response packet transmission means for transmitting to the side communication terminal or the address resolution device. 6. When the address resolution is permitted as a result of the determination by the address resolution availability determination means and only the communication terminal on the receiving side belongs to an arbitrary communication group, a communication link is established to the communication terminal on the receiving side. The address resolution request packet is an address resolution reply packet in which a physical address of a communication terminal other than the communication terminal on the receiving side which can be possessed or which can be established or a logical communication link identifier between the communication terminal and the communication terminal on the calling side is described. 6. The other party address selection type address resolving apparatus according to claim 4 or 5, further comprising: third address resolution reply packet transmitting means for transmitting to a transmitting side communication terminal or an address resolving apparatus which is a transmission source of. 7. If the address resolution is possible as a result of the determination by the address resolution availability determination means, but the address resolution is not permitted, to the originating communication terminal or the address resolution device that is the source of the address resolution request packet. 7. The partner selection type address resolution device according to any one of claims 4 to 6, further comprising: an address resolution refusal packet transmission means for transmitting an address resolution refusal packet indicating that the permission is denied.