JPH11215187A - Repeating method of internet protocol packet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an IP(Internet protocol) packet repeating method by which an IP packet can be repeated without through any ARP(address resolution protocol) packet which is a broadcast frame and the IP packet can be processed with a small processing load at the time of repeating the packet. SOLUTION: IP packet repeaters 21a-21c respond to ARP response packets by using the MAC (media access control) addresses of the repeater themselves when the destination IP addresses of received ARP request packets do not belong to the logical networks defined to packet communication networks 1a-1c and 4a-4c. Then the repeaters 21a-21c repeat received IP packets by only transforming the packets into the frame format for a router 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication network for performing communication using Internet Protocol (IP) packets, which is connected to each other by an IP packet relay device, and performs communication between the packet communication networks. The present invention relates to an IP packet relay method for controlling the relay of an IP packet.

[0002]

2. Description of the Related Art A local area network (LAN) as a private communication network is a widely used packet communication network, but is connected to each other by a packet communication network connection device such as a bridge or a router. By connecting, a large-scale packet communication system can be constructed.

FIG. 23 is a system configuration diagram showing a configuration example of a conventional communication system using IP packets.
In the figure, reference numerals 1a to 1c denote private communication networks, 2a to 2c access routers provided for the local communication networks 1a to 1c, and 3a to 3c.
3c is a terminal connected to the private network 1a-1c, 4a-
Reference numeral 4c denotes a wide area communication network, and reference numeral 5 denotes a router that accommodates the access routers 2a to 2c via the wide area communication networks 4a to 4c.

The access routers 2a to 2c or the router 5 is a device for relaying an IP packet. However, it is necessary to scrutinize the IP header information for each packet and perform a process corresponding to the result. It is known to take time.

On the other hand, since the bridge can perform the relay process only with the address information, the process is simpler than that of the router 5 or the like. However, since the broadcast frame is transferred to all communication networks, there is a problem in that the transmission band of the entire communication network is wasted, and a large-scale packet communication system cannot be constructed.

[0006] Therefore, an address resolution protocol (Address), which is a broadcast frame, is used.
Resolution Protocol;
As an apparatus for processing a packet (referred to as an RP) by a bridge, for example, there is a bridge apparatus (IP packet relay apparatus) disclosed in JP-A-7-50685, and FIG. 24 shows the configuration thereof. In FIG. 24, 1 is a private communication network, and 4 is a wide area communication network as a public line. Reference numeral 11 denotes a local-communication-network-side transmitting / receiving unit, 12 denotes a wide-area communication-network-side transmitting / receiving unit, 13 denotes a data storage memory, 14 denotes a bridge operation control unit including a CPU (Central Processing Unit) and a memory, and 15 denotes a filtering table. . Reference numeral 16 denotes a bridge device composed of these components.

FIG. 25 is a system configuration diagram showing an example of the configuration of a communication system constructed using such a bridge device 16. In the drawing, reference numerals 1a and 1b denote private communication networks,
Reference numerals a and 3b denote terminals, 4a denotes a wide area communication network, and 16a and 16b denote bridge devices.

Next, the operation will be described. When receiving the IP packet from the local communication networks 1a and 1b, the bridge devices 16a and 16b connect the received local networks 1a and 1b with each other.
A relationship between a source Media Access Control (MAC) address of the IP packet and a source IP address is registered as a filtering table 15 in a RAM (random access memory) or the like. FIG. 26 is an explanatory diagram showing an example of the filtering table 15 generated in this manner, where 15a is an entry relating to the terminal 3a, and 15b is an entry relating to the terminal 3b. Thereafter, each of the bridge devices 16a and 16b transmits the contents of the respective filtering tables 15 to the other party, and each of the bridge devices 16a and 16b generates and holds the filtering tables 15 having the same contents.

[0009] The bridge devices 16a and 16b that have received the ARP request packet from the local communication networks 1a and 1b are:
The filtering table 15 is searched with the requested IP address, and a corresponding MAC address is obtained.
Create a P response packet and respond. for that reason,
The bridge devices 16a and 16b can process the ARP request packet, which is a broadcast frame, without relaying the ARP request packet.

[0010]

Since the conventional IP packet relay method (bridge device) is configured as described above, when an attempt is made to construct a large-scale packet communication system, when an ARP request packet is received, There is a problem that the filtering table 15 to be searched becomes large because it is configured for the terminals 3a and 3b. In addition, since it is necessary to register the source IP address in the filtering table 15 for the IP packet to be relayed, there is a problem that it takes time for the relay process.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and can process an ARP packet, which is a broadcast frame, without relaying the IP packet. The purpose is to obtain a relay method.

[0012]

An IP packet relay method according to the present invention provides a method for receiving an ARP request packet whose set destination IP address does not belong to a logical network defined in a packet communication network. ,
A using the MAC address of the IP packet relay device itself
The RP response packet is responded, and the received IP packet is relayed only by being converted into a frame format for routing processing.

An IP packet relay method according to the present invention comprises:
Only one logical network is defined as a packet communication network.

An IP packet relay method according to the present invention comprises:
A plurality of logical networks are defined as a packet communication network.

[0015] The IP packet relay method according to the present invention comprises:
The router sets information about a logical network that defines a packet communication network.

An IP packet relay method according to the present invention comprises:
When an ARP request packet in which the address of the IP packet relay device itself is set as the destination IP address is received, an ARP response packet is responded using the MAC address of the IP packet relay device itself, and the received IP packet is routed. The relay is performed simply by converting to a processing frame format.

An IP packet relay method according to the present invention comprises:
The router sets the IP address of the IP packet relay apparatus itself.

An IP packet relay method according to the present invention comprises:
When an IP packet whose destination IP address is the address of the IP packet relay device itself is received, the process is performed by the IP packet relay device itself.

An IP packet relay method according to the present invention comprises:
The network management device sets information on a logical network that defines a packet communication network.

An IP packet relay method according to the present invention comprises:
If the set destination IP address belongs to one entry of the logical network table that defines each packet communication network, and an ARP request packet that is not an entry related to the received packet communication network is received, the corresponding entry is handled. A using the MAC address of
The RP response packet is responded, and the received IP packet is relayed only by converting the line connected to the IP packet relay device to the frame format for the routing process by identifying the line connected to the IP packet relay device from the destination MAC address. Things.

[0021] The IP packet relay method according to the present invention comprises:
If the set destination IP address belongs to one entry of a logical network table that defines each packet communication network and an ARP request packet that is not an entry related to the received packet communication network is received, the IP packet relay is performed. ARP response packet is responded using the MAC address of the device itself, and the received IP packet is converted into a frame format for routing processing by identifying the line connected to the IP packet relay device from the destination IP address. It is intended to relay just by doing.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a circuit diagram showing an I
FIG. 2 is a block diagram illustrating a configuration example of an IP packet relay device to which a P packet relay method is applied. In the figure, 21 is the IP packet relay device. Numeral 1 denotes a private network as a packet communication network which is connected to the IP packet relay apparatus 21 to perform communication by IP packets and which is denoted by the same reference numeral in FIG. It is a net. 11 is a local communication network side transmitting / receiving unit that receives data from the local communication network 1 and transmits data to the local communication network 1, 12 receives data from the wide area communication network 4,
A wide-area communication network-side transmission / reception unit for transmitting data to the wide-area communication network 4, and a data storage memory 13 for storing data transmitted and received by the local-area communication network-side transmission / reception unit 11 and the wide-area communication network-side transmission / reception unit 12 It is. These components also correspond to the components denoted by the same reference numerals in FIG. Reference numeral 22 denotes a CPU for executing various controls in the IP packet relay apparatus 21. Reference numeral 23 denotes a storage unit such as a ROM (Read Only Memory) storing the program and a RAM used as a working memory.

FIG. 2 shows such an IP packet relay apparatus 2.
1 is a system configuration diagram showing a configuration example of a communication system constructed by using No. 1. In the figure, reference numerals 1a to 1c denote local communication networks corresponding to those denoted by reference numeral 1 in FIG. 1, and reference numerals 3a to 3c denote terminals connected to the local communication networks 1a to 1c. Reference numerals 21a to 21c denote each private communication network 1a.
This is an IP packet relay device corresponding to that indicated by reference numeral 21 in FIG. Reference numerals 4a to 4c denote wide area communication networks corresponding to those indicated by reference numeral 4 in FIG. 1, and 5 denotes an IP packet relay device 21 via the wide area communication networks 4a to 4c.
a is a router that accommodates a to 21c and performs routing processing. In the following description, a LAN called Ethernet is used as the private communication networks 1a to 1c.
And using the asynchronous transfer mode (Asynchronous Transfer Mo) as the wide area communication networks 4a to 4c.
de; hereinafter, referred to as ATM).

FIG. 3 is an explanatory diagram showing a frame format of a frame on the Ethernet as the private communication networks 1a to 1c. In the figure, reference numeral 31 denotes a destination MAC address portion in which a destination MAC address of the frame is set, and reference numeral 32 denotes a source MAC address portion in which the source MAC address is set. Reference numeral 33 denotes a frame type part in which the type of the frame is set, and reference numeral 34 denotes a frame data part in which frame data is set.

FIG. 4 is an explanatory diagram showing the structure of an ARP packet when the frame type part 33 of the frame format is 0x0806 and the frame data part 34 is an ARP packet. In the figure, reference numeral 41 denotes an operation unit indicating whether this ARP packet is a request packet or a response packet. 4
Reference numeral 2 denotes a source MAC address portion in which a source MAC address of the ARP packet is set, and reference numeral 43 denotes a source IP address.
A source IP address portion in which an address is set, and 4
Reference numeral 4 denotes a destination MAC address portion in which a destination MAC address of the ARP packet is set, and reference numeral 45 denotes a destination IP address portion in which a destination IP address is set.

FIG. 5 is an explanatory diagram showing the structure of an IP packet when the frame type part 33 of the frame format is 0x0800 and the frame data part 34 is an IP packet. In the figure, reference numeral 51 denotes an IP header portion of the IP packet, and 52 denotes
This is a P data section. Reference numeral 53 denotes a time during which this IP packet can survive on the network, and is subtracted every time the packet is relayed through the router 5 (Time to Live).
ve; hereinafter, referred to as TTL) section, and 54 is a checksum section for confirming the validity of the IP header section 51. Reference numeral 55 denotes a source IP address portion in which a source IP address of the IP packet is set, and reference numeral 56 denotes a destination IP address portion in which a destination IP address of the IP packet is set.

Although several encapsulation formats of IP packets on ATM are defined, a logical link control (Logic) as shown in FIG. 6 is used as an encapsulation format for connecting to a router.
A cal link control (hereinafter referred to as LLC) encapsulation format is defined in RFC1483. In the figure, reference numeral 61 denotes an IP packet in the LLC encapsulation format. 62
Is an LLC unit, and 63 is a subnetwork attachment point (Sub Network Attach).
Ment Point; hereinafter, referred to as SNAP). Reference numeral 64 denotes an organizational unique identifier that forms the SNAP unit 63 (Organiz).
nationly Unique Identify
er; hereafter referred to as an OUI), and 65 is a protocol identifier (Protocol I).
(Dentifier; hereinafter, referred to as PID).

The content of the LLC section 62 is 0x
In the case of AAAA03, it indicates that the SNAP unit 63 exists. In addition, the SNAP unit 63 includes the OUI unit 64 and the P
The OUI section 64 includes an ID section 65.
The organization managing the value of the ID section 65 is identified. If the content of the OUI section 64 is 0x000000, the PID section 65
Is an EtherType. The contents of the PID section 65, that is, the ether type is 0
In the case of x0800, it indicates that the PID portion 65 and subsequent portions are IP packets 61.

FIG. 7 shows the IP packet relay devices 21a to 21a.
FIG. 3 is an explanatory diagram showing a network table that logically defines the local communication networks 1a to 1c connected to the local network c. In the figure, reference numeral 71 denotes the network table. 72 is an IP address part in which the IP address is stored;
Reference numeral 73 denotes an address mask unit in which mask data of the IP address is stored.
3c (local communication networks 1a to 1c).
1c), and a terminal number for identifying the terminals 3a to 3c on the network. This network table 71
A logically defined network number is obtained by calculating a logical product of the IP address part 72 and the address mask part 73, which is used for obtaining the network number.

Next, the operation will be described. Here, FIG.
Is the IP of the IP packet relay device according to the first embodiment.
FIG. 8 is a sequence diagram showing a communication procedure.
Based on the IP communication from the terminal 3a to the terminal 3c based on
The operation will be described.

Before the terminal 3a performs IP communication with the terminal 3c, the frame type part 33 of the frame format shown in FIG. 3 indicates an ARP packet, and the ARP packet operation part 41 indicates an ARP packet indicating a request packet.
The request packet 81 is transmitted to the IP packet relay device 21a.
To obtain the destination MAC address when transmitting the IP packet to the destination terminal 3c. The destination MAC address part 31 of the frame format contains the broadcast address, and the source MAC address part 32 contains the terminal 3
The MAC address of the terminal 3a is set in the source MAC address part 42 of the ARP packet.
The C address is stored in the source IP address part 43 in the own terminal 3.
The IP address of “a” is set in the destination IP address section 45, and the IP address of the destination terminal 3c is set in the destination IP address section 45.

Upon receiving the ARP request packet 81 from the terminal 3a, the IP packet relay apparatus 21a sets the frame type part 33 of the frame format and the
The operation unit 41 of the P packet recognizes that the received packet is an ARP request packet, and obtains the IP address of the destination terminal 3c from the destination IP address unit 45 of the ARP packet. Next, the terminal having the IP address, that is, the terminal 3c is connected to the private network 1a.
To determine whether or not it is connected to
The logical product of the address and the address mask unit 73 of the network table 71 is calculated, and the calculation result is compared with the IP address unit 72. As a result of the comparison, the terminal 3c is
a is determined not to be connected to the terminal 3c,
In order to inform the terminal 3a that the packet can be relayed,
An ARP response packet 82 is returned to the terminal 3a.

The ARP response packet 82
Is the destination MAC address part 31 of the frame format
Is set to the MAC address of the terminal 3a, the MAC address of the IP packet relay apparatus 21a itself is set to the source MAC address section 32, the value indicating the ARP packet is set to the frame type section 33, and the response packet is set to the operation section 41 of the ARP packet. Is the source MA
The MAC address of the IP packet relay apparatus 21a itself is stored in the C address section 42, and the terminal 3 is stored in the source IP address section 43.
The IP address of the terminal 3a is set in the destination MAC address section 44, and the IP address of the terminal 3a is set in the destination IP address section 45.

The terminal 3a uses the source IP address part 43 and the source MAC address part 42 of the ARP packet in the received ARP response packet 82 to store a destination MAC address for transmitting an IP packet to the destination terminal 3c. And the MAC address of the IP packet relay device 21a in the destination MAC address section 31 of the frame format, the MAC address of the terminal 3a in the source MAC address section 32, and the value indicating the IP packet in the frame type section 33. Each is set, and the terminal 3c is set in the destination IP address section 56 of the IP packet.
Of the terminal 3 in the source IP address section 55.
IP packet 83 in which the IP address of a is set
To the IP packet relay device 21a.

The IP packet 83 transmitted from the terminal 3a is converted into the LLC encapsulation format by the IP packet relay device 21a and transmitted to the router 5 as an IP packet 84. That is, based on the frame format of the received frame, the destination MAC address part 3
1. The transmission source MAC address section 32 and the frame type section 33 are deleted, and the LLC section 62, the OUI section 64, and the PID section 65 are added and converted into the LLC encapsulation format, which is used as a transmission frame.

The router 5 receiving the IP packet 84
Is the IP packet processing as a normal IP router process.
The checksum of the header section 51 is calculated, and it is checked whether or not it matches the checksum section 54. If they match, a routing process is performed by the destination IP address section 56, and after subtracting the TTL section 53, a new checksum value is set in the checksum section 54, and the new checksum value is set as the IP packet 85 to the IP packet relay apparatus 21c. Send.

The IP packet relay device 21c is connected to the router 5
Receives the IP packet 85 transmitted from the terminal device, and refers to the destination IP address portion 56 of the IP packet to generate the ARP request packet 86 in order to obtain the destination MAC address when transmitting the IP packet to the destination terminal 3c. 3c, and receives an ARP response packet 87 from the terminal 3c. Since the ARP sequence for exchanging the ARP request packet 86 and the ARP response packet 87 is the same as the ARP sequence for exchanging the ARP request packet 81 and the ARP response packet 82, detailed description will be omitted.

The IP packet relay device 21c, based on the received ARP response packet 87,
Is stored in a table in the IP packet relay device 21c, the MAC address of the terminal 3c is set in the destination MAC address part 31 of the frame format, and the source MAC address part is transmitted. 32 the IP packet relay device 1c
An IP packet 88 in which its own MAC address is set is generated and transmitted to the terminal 3c. Thereafter, IP communication from the terminal 3a to the terminal 3c is performed by IP packets 89 to 92 without an ARP sequence.

Next, the receiving operation from the private network 1 in the IP packet relay device 21 will be described. Here, FIG.
Is a flowchart showing the flow of the receiving operation. First, in step ST1, the IP packet relay device 21
The frame whose frame format is shown in FIG. 3 and transmitted from the local communication network 1 is received by the local communication network side transmitting / receiving unit 11. Next, step ST2
, The local communication network side transmitting / receiving section 11 writes the frame received from the local communication network 1 into the data storage memory 13 and notifies the CPU 22 that the frame has been received.

The CPU 22 that has received the notification proceeds to step ST3.
, The frame type part 33 of the frame written in the data storage memory 13 is referred to. If the frame type section 33 is IP, the process proceeds to step ST4, where the frame is converted into the LLC encapsulation format shown in FIG. 6, and then transmitted from the wide area communication network side transmitting / receiving section 12 to the wide area communication network 4. On the other hand, if the frame type part 33 is AR
If it is P, the process proceeds to step ST5, where AR shown in FIG.
Reference is made to the operation unit 41 of the P packet. As a result, if the operation unit 41 is an ARP request, the process proceeds to step ST6.

In step ST6, the CPU 22 determines the destination IP address part 45 of the ARP request packet.
7 is referred to the network table 71 shown in FIG. 7 in order to determine whether or not the destination terminal shown in FIG. As a result, if the destination terminal is connected to the private network 1, the process proceeds to step ST7, where the received frame is discarded. On the other hand, if the destination terminal is not connected to the local communication network 1, step ST8
To create an ARP response packet indicating that the IP packet addressed to the destination terminal can be relayed,
It is transmitted from the local communication network side transmitting / receiving unit 11 to the local communication network 1.

As a result of the reference of the ARP packet to the operation unit 41 in step ST5, if the operation unit 41 is an ARP response, the process proceeds to step ST9. In step ST9, the CPU 22
Uses the pair of the MAC address shown in the source MAC address part 42 of the ARP response packet and the IP address shown in the source IP address part 43 as the working memory of the storage unit 23. RA
Then, the process proceeds to step ST10. In this step ST10, the CPU 22 determines whether or not there is any pending IP packet. As a result, if there is a pending IP packet, the process proceeds to step ST11, where the pending IP packet is transmitted from the local communication network side transmitting / receiving unit 11 to the local communication network 1. On the other hand, if there is no pending IP packet, step S
Proceeding to T12, the received frame is discarded.

Next, the receiving operation of the IP packet relay device 21 from the wide area communication network 4 will be described. Here, FIG. 10 is a flowchart showing the flow of the receiving operation. First, in step ST21, the IP packet relay apparatus 21 receives the frame transmitted from the wide area communication network 4 and having the frame format shown in FIG. Next, in step ST22, the wide area communication network side transmitting / receiving section 12 writes the frame received from the wide area communication network 4 into the data storage memory 13 and notifies the CPU 22 that the frame has been received.

The CPU 22 that has received the notification proceeds to step ST2.
3, the LLC section 62, OUI section 64, and PID section 6 of the frame written in the data storage memory 13 in the LLC encapsulation format shown in FIG.
Please refer to FIG. As a result of the reference, if the frame is not an IP packet, the process proceeds to step ST24 to discard the received frame.

On the other hand, in step ST23, LLC
If the frame is an IP packet as a result of referring to the section 62, the OUI section 64, and the PID section 65, the process proceeds to step ST25. In step ST25, the CPU
Reference numeral 22 indicates that the MAC address corresponding to the destination terminal, which is shown in the destination IP address section 56 of the IP packet shown in FIG. 5, is stored in the RAM part of the storage section 23 which is used as a working memory. Is determined. As a result, if the corresponding MAC address is stored, the process proceeds to step ST26, where an IP packet in which the MAC address is set in the destination MAC address section 31 of the frame format is created, and the IP packet is transmitted from the local communication network side transmitting / receiving section 11. The data is transmitted to the private communication network 1.

If the result of determination in step ST 25 is that the MAC address corresponding to the destination terminal has not been stored, the operation proceeds to step ST 27, where the IP packet is suspended. Next, in step ST28, an ARP request packet for obtaining a MAC address corresponding to the IP address of the destination terminal is created, and the ARP request packet is transmitted from the local communication network side transmitting / receiving section 11 to the local communication network 1.

As described above, according to the first embodiment, since the relay processing of the IP packet after the MAC address to the destination terminal is obtained by the ARP sequence is only the format conversion, it is a broadcast frame. ARP packets can be processed without being relayed, so that the processing load at the time of relaying IP packets is reduced, and there is an effect that IP packet relay can be realized very easily.

In the above description, the private network 1
Packet relay device 2 for interconnecting the network and wide area communication network 4
1 has been described, but it is also possible to apply the present invention to an IP packet relay apparatus for interconnecting the private communication networks 1 and obtain the same effect as described above.

In the above description, the private network 1
In the above description, only one logical network is defined, but a plurality of logical networks may be defined, and similar effects can be obtained.

Embodiment 2 In the first embodiment, the network table that logically defines the private network 1 as a packet communication network has been described as being set in advance.
May be set. FIG. 11 is a block diagram showing a functional configuration of an IP packet relay device to which the IP packet relay method according to the second embodiment of the present invention is applied. In the figure, 1 is a private communication network as a packet communication network, 4 is a wide area communication network, and 21 is an IP.
It is a packet relay device. Reference numeral 24 denotes a device management unit.
5 is a local communication network side control unit that controls the local communication network 1 side;
Reference numeral 26 denotes a wide-area communication network-side control unit for controlling the wide-area communication network 4, and 27 denotes an IP disposed between the local-area communication network-side control unit 25 and the wide-area communication network-side control unit 26 for performing IP packet relay processing. It is a packet relay processing unit.

FIG. 12 is an explanatory diagram showing a virtual line between such an IP packet relay device and a router. In the figure, reference numeral 21 denotes the IP packet relay device, and reference numeral 5 denotes a router. Reference numeral 101 denotes a virtual path (Virtual Path; hereinafter, V) which is a virtual line between the IP packet relay apparatus 21 and the router 5.
P), and 102 is a virtual channel (Virtual Channel) for data of the VP 101.
l; hereinafter, referred to as VC) and 103 is a control VC. The data packet from the private network 1 or the data packet to the private network 1 is
C102, the data packet from the device management unit 24 of the IP packet relay device 21 or the device management unit 2
4 flows on the control VC 103.

Next, the operation will be described. Here, FIG.
FIG. 3 is a sequence diagram showing a procedure for setting network information according to the second embodiment. Hereinafter, an example in which information in the network table 71 of the IP packet relay apparatus 21 is set from the router 5 based on FIG. Will be described. Here, it is assumed that information for logically defining the private communication network 1 necessary for routing the IP packet exists in the router 5 in advance.

The IP packet relay device 21 transmits a network information request 93 to the router 5 to obtain information of its own network table 71 when the device starts up. Upon receiving the network information request 93, the router 5 receives the corresponding control VC1.
And a network information response 94 containing information on the IP packet relay device 21 connected to the network device 03,
It is returned to the IP packet relay device 21. As a result, the IP packet relay device 21 sets its own network table 71 in response to the network information response 94 from the router 5.

In this case, the example in which the network information response 94 is transmitted in response to the network information request 93 has been described. However, the network information response 94 is transmitted asynchronously from the router 5 and the network table 71 is changed. In some cases.

As described above, according to the second embodiment, since the network table 71 of the IP packet relay device 21 can be set from the router 5, the network table setting for each IP packet relay device 21 can be performed. Therefore, there is an effect that an IP network can be easily constructed.

Embodiment 3 In the first embodiment, A
A description will be given of a case where an IP packet relay apparatus that receives an RP request packet refers to a network table, determines whether an IP address of a destination IP address portion of an ARP request packet is connected to a private network, and creates an ARP response. However, an ARP response packet may be created with reference to an address table described later. FIG. 14 is an explanatory diagram showing an address table defined in the IP packet relay device to which the IP packet relay method according to the third embodiment of the present invention is applied. In the figure, reference numeral 111 denotes an address table, and 112 denotes this address table.
1 is an IP address part.

Next, the operation will be described. Here, terminal 3a to terminal 3c in the communication system shown in FIG.
An example of performing IP communication will be described. The communication sequence is basically the same as that of the first embodiment shown in FIG. 8, and the frame format and the ARP
Packets, IP packets, and the like are the same as those in the first embodiment shown in FIGS.

The terminal 3a has the IP address of the IP packet relay device 21a as the IP address of the default gateway to be transmitted when communicating with a terminal connected to a terminal other than the private network 1a. The IP address of the IP packet relay device 21c is set as the IP address of the default gateway to be transmitted when communicating with a terminal connected to a device other than the private network 1c.

Before the terminal 3a performs IP communication with the terminal 3c, the MAC address of the IP packet relay device 21a set as the default gateway is set because the terminal 3c to be the communication partner is not connected to the private network 1a. ARP request packet 81 for requesting IP
The packet is transmitted to the packet relay device 21a. Upon receiving the ARP request packet 81 from the terminal 3a, the IP packet relay apparatus 21a recognizes that it is an ARP request packet from the frame type part 33 of the frame format and the operation part 41 of the ARP packet, and The IP address of the IP address section 45 is compared with the IP address of the IP address section 112 of the address table 111. If the results of the comparison match, I
An ARP response packet 82 for transmitting the MAC address of the P packet relay device 21a itself is created and transmitted to the terminal 3a.

The terminal 3a checks the source IP address 43 and the source MAC of the received ARP response packet 82.
The IP address and MAC of the IP packet relay device 21a as the default gateway are
The address is stored in a built-in table, and the MAC address of the IP packet relay apparatus 21a is stored in the destination MAC address section 31 of the frame format.
The MAC address of the terminal 3a is set in the C address section 32, the value indicating the IP packet is set in the frame type section 33, and the IP address of the terminal 3c is set in the destination IP address section 56 of the IP packet, and the source IP address section is set. 55 in which the IP address of the terminal 3a has been set, respectively.
A P packet 83 is generated and the IP packet relay device 21
Send to a. The subsequent sequence is the same as in the first embodiment, and a description thereof will not be repeated.

As described above, according to the third embodiment, when the default gateway is set for the terminals 3a to 3c, the information required by the IP packet relay devices 21a to 21c includes the own IP address. Has the effect that only the address table 111 that indicates

Here, also in the third embodiment, the address table 111 can be set from the router 5 as in the case of the second embodiment. In such a case, an IP address for logically accommodating the private communication network 1 is set in the router 5 in correspondence with the wide area communication network 4 connected to the IP packet relay device 21. The IP address is notified to the IP packet relay device 21 as network information.

Embodiment 4 In the first and third embodiments, the description has been given of the case where the processing is performed on the assumption that the IP packet is always relayed by the IP packet relay apparatus.
It is also possible to process P packets. In this case, the processing of IP packets other than the IP packet addressed to the IP packet relay device is the same as that in the first embodiment.

FIG. 15 is a block diagram showing a functional configuration of an IP packet relay apparatus to which such an IP packet relay method according to the fourth embodiment of the present invention is applied. In the figure, 1 is a local communication network, 4 is a wide area communication network, 21 is an IP packet relay device, 25 is a local communication network side control unit, 26 is a wide area communication network side control unit, 27 is an IP packet relay processing unit, These are the parts corresponding to those shown with the same reference numerals in FIG. An IP packet termination processing unit 28 processes an IP packet addressed to the IP packet relay device 21.

Next, the operation will be described. Here, an operation when an IP packet is received will be described. The IP address of the IP packet relay device 21 is as shown in FIG.
4 is defined in advance as the address table 111 shown in FIG. The IP packet received from the local area network 1 or the wide area network 4 is passed from the local area network control unit 25 or the wide area network control unit 26 to the IP packet relay processing unit 27. The IP packet relay processing unit 27
When the packet is received, the destination IP address portion 56 of the IP packet shown in FIG.
Is compared with the IP address section 112. As a result, the IP packet in which both match is sent to the IP packet termination processing unit 28.
And the IP packet termination processing unit 28 executes the processing of the notified IP packet.

As described above, according to the fourth embodiment, since the IP packet relay device 21 can process the IP packet addressed to the IP packet relay device 21, for example, the network control packet addressed to the IP packet relay device 21 can be processed. And the like can be processed.

Embodiment 5 In the second embodiment, I
Although the case where the network information of the P packet relay device is set from the router has been described, a separate network management device may be provided, and the setting may be performed from the network management device. FIG. 16 is a system configuration diagram showing a configuration example of a communication system to which the IP packet relay method according to the fifth embodiment of the present invention is applied. In the figure, 1a and 1b are private communication networks, 3a and 3b are terminals,
4a and 4b are wide area communication networks, 5 is a router, 21a and 21b
Are IP packet relay devices, which correspond to those shown with the same reference numerals in FIG. Also, 6
Is a router equivalent to the router 5, 7 is a wide area communication line connecting the router 5 and the router 6, and 1h is a private network connected to the router 6. Reference numeral 8 denotes a network management device that is connected to the router 6 via the private branch exchange network 1h and manages network information of each of the IP packet relay devices 21a and 21b.

The functional configuration of the IP packet relay device 21 to which the IP packet relay method according to the fifth embodiment is applied is the same as that of the fourth embodiment shown in FIG. Then, the description is omitted. FIG.
FIG. 7 is an explanatory diagram showing a virtual line between the IP packet relay device 21 and the router 5. Unlike the case of the second embodiment, the VP 101 has only the data VC 102.

Next, the operation will be described. Here, FIG.
FIG. 8 is a sequence diagram showing a procedure for setting network information according to the fifth embodiment. Hereinafter, an example in which the network table 71 of the IP packet relay device 21 is set from the network management device 8 based on FIG. Will be described. Here, it is assumed that the IP packet relay apparatus 21 has its own IP address and the IP address of the network management apparatus 8 set in advance.

The IP packet relay device 21 transmits a network information request 95 to the network management device 8 in order to obtain information of its own network table 71 when the device starts up. This network information request 95 is transmitted to the destination IP address section 56 shown in FIG.
To the IP address of the network management device
As an IP packet in which the IP address of the IP packet relay device 1 is set in the address section 55, the VP 101
Is transmitted on the data VC 102, and is relayed from the router 5 to the network management device 8 via the router 6.

When receiving the network information request 95, the network management device 8 generates and transmits a network information response 96 containing information on the IP packet relay device 21 that transmitted the network information request 95. This network information response 96 is transmitted to the destination IP address section 56 shown in FIG.
This is an IP packet in which the IP address of the packet relay device 21 is set, and is relayed from the router 6 to the IP packet relay device 21 via the router 5. As a result, the IP packet relay apparatus 21 processes the network information response 96 in the IP packet termination processing section 28 because the destination IP address section 56 set in the received network information response 96 matches its own IP address. By doing so, the own network table 71
Set.

Here, the IP packet relay device 2
Although the network information response 96 is transmitted from the network management device 8 to the network information request 95 from the network device 1, the network information response 96 is transmitted asynchronously from the network management device 8 and thereby the IP packet relay is performed. The network table 71 of the device 21 may be changed.

The network information request 95 includes a simple network management protocol (S
simple Network Management
A trap (TRAP) packet of Protocol (hereinafter referred to as SNMP) and an SNMP set request (Set-Re) are included in the network information response 96.
quest) packets can also be applied.

As described above, according to the fifth embodiment, it is possible to set each IP packet relay device 21 connected to a plurality of routers from one network management device 8, so that the IP There is an effect that a network can be constructed.

Embodiment 6 FIG. In the first embodiment, I
Although the communication system constructed by connecting the P packet relay device to the router via the wide area communication network has been described, the communication system may be constructed by connecting the IP packet relay device and the ATM switch via the wide area communication network. FIG. 19 is a system configuration diagram showing a configuration example of a communication system to which such an IP packet relay method according to the sixth embodiment of the present invention is applied. In the drawing, reference numerals 1a to 1c denote private communication networks, 3
a to 3c are terminals, 4a to 4c are wide area communication networks, 21a to 2a
Reference numeral 1c denotes an IP packet relay device, which corresponds to each unit shown in FIG. 9 is provided in place of the router 5 shown in FIG.
It is an ATM switch to which each of the IP packet relay devices 21a to 21c is connected via the wide area communication networks 4a to 4c.

FIG. 20 shows an IP packet relay device 21.
FIG. 4 is an explanatory diagram showing a virtual line between the ATM switch 9 and a virtual line VP 104;
a, the data VC 106 virtually connected to the IP packet relay apparatus 21b from the IP packet relay apparatus 2b
1a is a data VC virtually connected to the IP packet relay device 21c.

FIG. 21 is an explanatory diagram showing a network table defined in the IP packet relay apparatus 21a. In the figure, reference numeral 71 denotes the network table. Further, reference numeral 72 denotes an IP address portion, and 73, an address mask portion, which are the same as the portions denoted by the same reference numerals in FIG. The network table 71 includes an IP address section 72 and an address mask section 73.
Is a table that defines information about a logical network obtained from a logical product of. Reference numeral 74 denotes a network identification unit, which indicates to which interface of the IP packet relay apparatus 21a the logical network is connected. Reference numeral 75 denotes a MAC address part, which has a meaning when the network identification part 74 is a wide area communication network, and sets a MAC address used when an ARP request packet to a terminal belonging to a logical network is received. Reference numeral 76 denotes a VC identification unit, which is used when receiving an IP packet addressed to the MAC address set in the MAC address unit 75 (virtual channel ID).
ntifier; hereinafter, referred to as VCI).

Next, the operation will be described. Here, as in the case of the first embodiment, the case of IP communication from terminal 3a to terminal 3c will be described as an example based on the sequence diagram showing the procedure of IP communication of IP packet relay apparatus 21 shown in FIG. The operation will be described. Note that the terminal 3a transmits the ARP request packet 81 in the same manner as in the first embodiment.

The IP packet relay device 21a, which has received the ARP request packet 81 from the terminal 3a, sets the IP address of the destination IP address section 45 of the ARP packet shown in FIG.
Reference is made to which entry of the network table 71 shown in FIG. 21 the address belongs. For example, the IP
If it is assumed that the address belongs to the IP-b or Mask-b network, the network identification unit 74 is referred to. By referring to the network identification unit 74, the I
Recognizing that the P address is connected to the wide area communication network 4a of the IP packet relay apparatus 21a, the P address is transmitted to the terminal 3c.
In order to inform that the P packet can be relayed, an ARP response packet 82 is generated and returned to the terminal 3a. In the ARP response packet 82, the source MAC address part 32 of the frame in the frame format of FIG. 3 and the source MAC address part 42 of the ARP packet shown in FIG. MAC-b is set.

When receiving the ARP response packet 82, the terminal 3a receives the destination MAC address 3
An IP packet 83 with the MAC-b set to 1 is generated and transmitted to the IP packet relay device 21a. I
Upon receiving the IP packet 83, the P-packet relay device 21a receives the IP packet 83 and stores the MA in the destination MAC address portion 31 of the frame.
By referring to the MAC address part 75 of the network table 71 using the C address, that is, MAC-b, the value of the corresponding VC identification part 76, that is, VCI-b is obtained. In this example, since the VCI-b indicates the data VC 106 virtually connected to the IP packet relay device 21c, the VCI-b converts the IP packet 83 into the LLC encapsulation format, Transmit on VC106. The subsequent sequence is the same as in the first embodiment, and a description thereof will not be repeated.

As described above, according to the sixth embodiment, it is possible to construct an IP network including the IP packet relay device 21 and the ATM switch 9 without connecting to a router. There is an effect of improving.

The IP address defined by the MAC address section 75 is a local address whose second bit of the MAC address is “1” and is identifiable only in this network. Can easily determine the relay frame.

Embodiment 7 FIG. In the sixth embodiment, I
The P-packet relay device selects the data VC to be transmitted based on the information of the destination MAC address portion of the frame, but may select the data VC to be transmitted based on the information of the destination IP address portion of the IP packet. Good. FIG. 22 is an explanatory diagram showing a network table defined in the IP packet relay device to which the IP packet relay method according to the seventh embodiment of the present invention is applied.
1 is a network table, 72 is an IP address part, 7
3 is an address mask unit, 74 is a network identification unit, 7
Reference numeral 6 denotes a VC identification unit, which is the same as the portion denoted by the same reference numeral in FIG. The network table 71 is the same as that of the sixth embodiment shown in FIG. 21 except that the MAC address part 75 is not provided.

An example of the configuration of a communication system to which the IP packet relay method according to the seventh embodiment is applied, and a virtual line between the IP packet relay device and the ATM switch are shown in the system configuration diagram of FIG. Since they are the same as those of the sixth embodiment shown in the explanatory diagram shown in FIG. 20, their description will be omitted.

Next, the operation will be described. Here, as in the case of the first embodiment, the case of IP communication from terminal 3a to terminal 3c will be described as an example based on the sequence diagram showing the procedure of IP communication of IP packet relay apparatus 21 shown in FIG. The operation will be described. Note that the terminal 3a transmits the ARP request packet 81 in the same manner as in the first embodiment.

The IP packet relay device 21a, which has received the ARP request packet 81 from the terminal 3a, sets the IP address of the destination IP address portion 45 of the ARP packet shown in FIG.
Reference is made to which entry of the network table 71 in FIG. 22 the address belongs. For example, assuming that the IP address belongs to the networks of IP-b and Mask-b, the IP address is referred to by referring to the network identification unit 74 of the network table 71.
It recognizes that it is connected to the wide area communication network 4a of the packet relay device 21a. Then, it generates an ARP response packet 82 for notifying that the IP packet addressed to the terminal 3c can be relayed, and returns it to the terminal 3a. The ARP response packet 82 includes the source MAC address part 32 of the frame and the source MAC address part 42 of the ARP packet with the IP packet relay device 21.
a own MAC address is set.

The terminal 3a that has received the ARP response packet 82 sends the destination MAC address 31
To generate an IP packet 83 in which the MAC address of the IP packet relay apparatus 21a itself is set, and transmits the generated IP packet 83 to the IP packet relay apparatus 21a. When receiving the IP packet 83, the IP packet relay apparatus 21a refers to which entry in the network table 71 the IP address of the destination IP address section 56 of the IP packet shown in FIG. For example, if the IP address is IP-
b, belonging to the network of Mask-b, the value of the VC identification unit 76 of the network table 71,
That is, on the data VC 106 indicated by VCI-b,
After the received IP packet 83 is converted into the LLC encapsulation format, it is transmitted as an IP packet 84. The subsequent sequence is the same as in the first embodiment, and a description thereof will not be repeated.

As described above, according to the seventh embodiment, the data VC to be transmitted can be selected based on the information of the destination IP address portion of the IP packet. By using only the address, the same effect as in the sixth embodiment can be obtained.

[0089]

As described above, according to the present invention, the destination IP address of the received ARP request packet is
If the packet does not belong to the logical network defined in the packet communication network, the ARP response packet is responded using the MAC address of the IP packet relay device itself, and the received IP packet is converted into a frame format for routing processing. Since there is no need to refer to the source address at the time of receiving an IP packet as in the related art, and because the processing is performed in accordance with the logical network that defines each packet communication network, the conventional Thus, there is an effect that there is no need to perform processing corresponding to the terminal.

According to the present invention, since information on a logical network defining a packet communication network is set by a router, it is necessary to set a network table for each IP packet relay apparatus. Thus, there is an effect that the IP network can be easily constructed.

According to the present invention, the received ARP
If the destination IP address of the request packet is the address of the IP packet relay device itself, the response of the ARP response packet is sent to the MAC address of the IP packet relay device.
Since the received IP packet is converted into a frame format for routing processing and relayed by using the address, when setting the default gateway for the terminal, the information required by the IP packet relay apparatus is itself. There is an effect that only the address table indicating the IP address of the IP address is used.

Further, according to the present invention, since the setting of the IP address of the IP packet relay device itself is performed by the router, it is not necessary to set the address table for each IP packet relay device. .

According to the present invention, if the destination IP address of the received IP packet is the address of the IP packet relay device itself, the processing is performed by the IP packet relay device itself. There is an effect that it becomes possible to process a network control packet or the like addressed to the relay device.

Further, according to the present invention, since information on a logical network defining a packet communication network is set by the network management device, one network management device is connected to a plurality of routers. IP
Since the setting of the packet relay device becomes possible, there is an effect that the IP network can be easily constructed.

According to the present invention, the received ARP
If the destination IP address of the request packet belongs to one entry of the logical network table that defines each packet communication network, and the entry is not an entry related to the received packet communication network, the response of the ARP response packet corresponds to the entry. Is performed using the MAC address of the IP packet, the line connected to the IP packet relay device is identified from the destination MAC address of the IP packet, and the received IP packet is converted into a frame format for routing processing and relayed. Thus, it is possible to construct an IP network including an IP packet relay device and an ATM switch without connecting to a router, which has the effect of improving communication characteristics.

According to the present invention, the received ARP
If the destination IP address of the request packet belongs to one entry of the logical network table that defines each packet communication network, and the entry is not an entry related to the received packet communication network, the response of the ARP response packet is returned to the IP packet. MA of the relay device itself
Since the C-address is used to identify the line connected to the IP packet relay device from the destination IP address of the IP packet, the received IP packet is converted into a frame format for routing processing and relayed. V to be transmitted from the destination IP address of the IP packet
Since C can be selected, an IP network including an IP packet relay device and an ATM switch can be constructed without connecting to a router, and there is an effect that communication characteristics are improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an IP packet relay device to which an IP packet relay method according to a first embodiment of the present invention is applied.

FIG. 2 is a system configuration diagram showing a configuration example of a communication system to which an IP packet relay method according to a first embodiment is applied;

FIG. 3 is an explanatory diagram showing a frame format on Ethernet according to the first embodiment.

FIG. 4 is an explanatory diagram showing a configuration of an ARP packet according to the first embodiment.

FIG. 5 is an explanatory diagram showing a configuration of an IP packet according to the first embodiment.

FIG. 6 is an explanatory diagram showing an LLC encapsulation format according to the first embodiment.

FIG. 7 is an explanatory diagram showing a network table used in the first embodiment.

FIG. 8 is a sequence diagram showing a procedure of IP communication according to the first embodiment.

FIG. 9 is a flowchart showing a procedure of a reception process from a private communication network according to the first embodiment.

FIG. 10 is a flowchart showing a procedure of a reception process from a wide area communication network according to the first embodiment.

FIG. 11 is a block diagram showing a functional configuration of an IP packet relay device to which an IP packet relay method according to a second embodiment of the present invention is applied.

FIG. 12 is an explanatory diagram showing a virtual line between an IP packet relay device and a router according to the second embodiment.

FIG. 13 is a sequence diagram showing a procedure for setting network information according to Embodiment 2 of the present invention.

FIG. 14 is an explanatory diagram showing an address table used in the IP packet relay method according to the third embodiment of the present invention.

FIG. 15 is a block diagram showing a functional configuration of an IP packet relay device to which an IP packet relay method according to a fourth embodiment of the present invention is applied.

FIG. 16 is a system configuration diagram showing a configuration example of a communication system to which an IP packet relay method according to a fifth embodiment of the present invention is applied.

FIG. 17 is an explanatory diagram showing a virtual line between an IP packet relay device and a router according to the fifth embodiment.

FIG. 18 is a sequence diagram showing a procedure for setting network information according to Embodiment 5 of the present invention.

FIG. 19 is a system configuration diagram showing a configuration example of a communication system to which an IP packet relay method according to a sixth embodiment of the present invention is applied.

FIG. 20 is an explanatory diagram showing a virtual line between the IP packet relay device and the ATM switch according to the sixth embodiment.

FIG. 21 is an explanatory diagram showing a network table used in the sixth embodiment.

FIG. 22 is an explanatory diagram showing a network table used in the IP packet relay method according to the seventh embodiment of the present invention.

FIG. 23 is a diagram illustrating a system configuration showing a configuration example of a communication system to which a conventional IP packet relay method is applied.

FIG. 24 is a block diagram showing a configuration of a bridge device to which a conventional IP packet relay method is applied.

FIG. 25 is a system configuration diagram showing a configuration example of a communication system constructed using a conventional bridge device.

FIG. 26 is an explanatory diagram showing a filtering table used in a conventional bridge device.

[Explanation of symbols]

1, 1a-1c private communication network (packet communication network), 4,
4a-4c Wide area communication network (packet communication network), 5, 6
Router, 8 network management device, 21, 21a-2
1c IP packet relay device, 81,86 ARP request packet, 82,87 ARP response packet, 83-85, 88-92 IP packet.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Naoyoshi Okazaki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Koichi Hiramatsu 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Hiroshi Nakamura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Teruko Fujii 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Yuji Atsui 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Shunsuke Tsutsumi 3-9-1-2 Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation Telephone Co., Ltd.

Claims (10)

[Claims] 1. An internet protocol packet relay method for controlling the relay of internet protocol packets communicated between packet communication networks interconnected by an internet protocol packet relay device, wherein said internet protocol packet relay device comprises: If the destination Internet Protocol address of the address resolution protocol request packet received from one of the packet communication networks does not belong to the logical network defined in the packet communication network that received it, the Internet Protocol packet The address resolution protocol response packet is responded to using the media access control address of the relay device itself, and the address resolution protocol request is returned. Internet Protocol packet relay method characterized by the Internet protocol packet received bets packet from the received packet communication network, relays and converts the frame format for the routing process. 2. The method according to claim 1, wherein only one logical network is defined in the packet communication network. 3. The Internet protocol packet relay method according to claim 1, wherein a plurality of logical networks are defined in the packet communication network. 4. The internet protocol packet relay method according to claim 1, wherein information on a logical network defining the packet communication network is set from a router performing a routing process. 5. An internet protocol packet relay method for controlling the relay of internet protocol packets communicated between packet communication networks interconnected by an internet protocol packet relay device, wherein said internet protocol packet relay device comprises: When the destination Internet protocol address of the address resolution protocol request packet received from one of the packet communication networks is the address of the Internet protocol packet relay device itself, the media access address of the Internet protocol packet relay device itself is used. Responds with an address resolution protocol response packet, and receives the address resolution protocol request packet. And the Internet Protocol packet received from the packet communication network, Internet Protocol packet relay wherein the relaying is converted into the frame format for the routing process. 6. The internet protocol packet relay method according to claim 5, wherein the internet protocol address of the internet protocol packet relay device itself is set from a router that performs a routing process. 7. If the destination Internet protocol address of the Internet protocol packet is the address of the Internet protocol packet relay device that has received the Internet protocol packet, the processing of the received Internet protocol packet is performed by the Internet protocol packet relay device itself. The Internet protocol packet relay method according to claim 1 or 5, wherein the method is performed. 8. When the destination Internet protocol address of the Internet protocol packet is the address of the Internet protocol packet relay device that has received the Internet protocol packet, the processing of the received Internet protocol packet is performed by the Internet protocol packet relay device itself. 2. The Internet protocol packet relay according to claim 1, wherein information on a logical network defining the packet communication network is set from a network management device that manages network information of the Internet protocol packet relay device. Method. 9. An internet protocol packet relay method for controlling the relay of internet protocol packets communicated between packet communication networks interconnected by an internet protocol packet relay device, wherein said internet protocol packet relay device comprises: The destination Internet Protocol address of the address resolution protocol request packet received from one of the packet communication networks belongs to one entry of a logical network table that defines each of the packet communication networks, and the entry corresponds to the address. If the entry is not related to the packet communication network that received the resolution protocol request packet, the address resolution is performed using the media access control address corresponding to the entry. A line connected to the Internet protocol packet relay device based on a destination media access control address of the Internet protocol packet received from the packet communication network that has received the address resolution protocol request packet. An Internet Protocol packet relay method comprising: identifying an Internet Protocol packet; converting the Internet Protocol packet into a frame format for routing processing; 10. An internet protocol packet relay method for controlling relay of internet protocol packets communicated between packet communication networks interconnected by an internet protocol packet relay device, wherein said internet protocol packet relay device comprises: The destination Internet Protocol address of the address resolution protocol request packet received from one of the packet communication networks belongs to one entry of a logical network table that defines each of the packet communication networks, and the entry corresponds to the address. If the entry is not an entry related to the packet communication network that has received the resolution protocol request packet, the media access control of the Internet protocol packet relay device itself is not performed. A response packet using an address resolution protocol response packet, and connecting to the Internet protocol packet relay device from the destination Internet protocol address of the Internet protocol packet received from the packet communication network that received the address resolution protocol request packet. An internet protocol packet relay method for identifying a line that is being used, converting the internet protocol packet into a frame format for routing processing of the internet protocol packet, and relaying the converted packet.