JP2000209210A - Data repeater, data relay method and with medium recording data relay program recorded therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer data at a high transmission rate among a plurality of networks. SOLUTION: A layer 2-forwarding router 10 manages a flow table, that arranges information of data link headers for each flow which is a stream of a group of packets to the same destination in addition to a path table that is used for data transfer by a conventional Internet protocol IP datagram system and managed by a network layer. The layer 2-forwarding router 10 retrieves no path table managed by the network layer on the basis of information of the IP header but retrieves the flow, table on the basis of information of a data link header to decide a transfer destination of a received packet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data relay device and a data relay method for transferring data at high speed between a plurality of networks, and a recording medium storing a data relay program for realizing the data relay method.

[0002]

2. Description of the Related Art For example, a LAN (Local Area Network)
And MAN (Metropolitan Area Network), WAN (Wid
A so-called router is known as a relay device for connecting a plurality of networks such as an e Area Network). The router has a routing table for selecting a route for transferring data therein, and upon receiving the data, the router transfers the data based on information in an IP (Internet Protocol) header attached to the data. Select the route to be taken.

The IP header has a configuration as shown in FIG. That is, the version (version) is the IP
, For example, information indicating version 4 is recorded.

Hlen (header length) indicates the length of the IP header in units of 32 bits (4 octets).

[0005] Tos (type of service) indicates the quality of service such as data priority, low delay, high throughput, high reliability, and low cost, and is set according to the specification of a user or the characteristics of an application protocol. .

[0006] The length indicates the total length of the IP header and the data following it in octets.

[0007] The id is assigned by the source in order to identify the original IP datagram when reconstructing the fragmented IP datagram.

The offset includes a flag for controlling the fragmentation of the IP datagram, and a fragment offset indicating the position of the fragment in the first data by an offset value in units of 8 octets.

[0009] ttl (time to live) is an 8-bit integer value indicating the maximum time that an IP datagram can exist in the Internet, and is decremented every time a router is relayed.

Protocol is, for example, TCP (Tran
smission Control Protocol) or UDP (User Datagram)
Protocol) for identifying a higher-level protocol of the IP.

[0011] Checksum represents a checksum that guarantees the accuracy of the IP header.

Src IP address (source I)
P address) is an IP indicating the source of the IP datagram.
Address and the destination IP address (de
“stination IP address” is an IP address indicating the transmission destination of the IP datagram.

When data is transferred between a plurality of networks, the router basically checks the dest IP address in the IP header having the above-described configuration for each transmitted packet as shown in FIG. Then, a routing table managed in the network layer is searched based on the information.
Then, the router determines a destination interface and a next hop gateway based on the search result.

[0014]

By the way, in the conventional router described above, when searching a routing table managed in the network layer, it is necessary to perform a longest-match for finding an entry corresponding to the longest subnet mask. Was.

[0015] The above-mentioned dest IP address
As shown in FIG. 15, the IP address including is composed of 32 bits, and is generally divided into a network section, a host section, and a subnet section formed by further dividing the host section. The subnet mask is information indicating which part of the 32-bit IP address is to be the network part and the subnet part. The router checks the IP address, searches for a network corresponding to the subnet mask to which the node to which data should be transferred belongs, and determines the route.

However, in this IP address, the network section, subnet section, and host section have 32
The bits have a variable length, and there is a problem that the router requires a very long processing time to search for a subnet mask to which data is to be transferred.

Further, in the conventional router, every time data is transferred, the above-described ttl subtraction processing and check
It was necessary to perform processing such as replacement of ksum.

The present invention has been made in view of such circumstances, and eliminates a heavy load process in a conventional router required by performing data transfer in a network layer, thereby achieving high-speed data transfer. It is an object of the present invention to provide a data relay device and a data relay method capable of performing transfer. Another object of the present invention is to provide a recording medium on which a data relay program for realizing the data relay method is recorded.

[0019]

According to the present invention, there is provided a data relay apparatus for achieving the above object, comprising: a data link layer information included in a header added to data transferred between a plurality of networks; A storage unit in which a data transfer path table in which a correspondence relationship with a transfer path is described is stored; and a relay unit that relays and transfers data between a plurality of networks having different types of data link layers. The means is characterized in that the data transfer path table stored in the storage means is searched based on the data link layer information included in the header added to the data to be relayed, and the data transfer destination is determined.

The data relay device according to the present invention configured as described above relays and transfers data to a transfer destination determined based on information of the data link layer.

Further, the data relay method according to the present invention comprises:
A data transfer path table that describes a correspondence relationship between data link layer information included in a header added to data transferred between a plurality of networks and a data transfer path,
When data is relayed and transferred between a plurality of networks having different types of data link layers, the data is stored in storage means based on data link layer information included in a header attached to the relayed data. The data transfer path table stored in the storage means is searched to determine a data transfer destination.

The data relay method according to the present invention as described above relays and transfers data based on information of the data link layer.

Still further, a recording medium on which the data relay program according to the present invention is recorded has a data relay program for performing a process of relaying and transferring data between a plurality of networks having different types of data link layers. A data relay program, the data relay program comprising: a data describing a correspondence relationship between data link layer information included in a header attached to data transferred between a plurality of networks and a data transfer path; The transfer route table is searched based on the information of the data link layer included in the header attached to the data to be relayed, and the transfer destination of the data is determined.

The recording medium having the data relay program according to the present invention configured as described above is provided with a data relay for relaying and transferring data to a transfer destination determined based on information of a data link layer. Supply the program.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In an embodiment to which the present invention is applied, for example, as shown in FIG.
Synchronous Transfer Mode). ) (Hereinafter referred to as an ATM network).
And the IEEE (The Institute of Electrical and Elec
IEEESt approved by tronics Engineers, Inc.)
d. 1394-1995 IEEE Standard for a High Performance
A network (hereinafter, IEEE 139) compliant with the serial Bus standard (hereinafter, abbreviated as IEEE 1394 standard).
4 networks. ) Is a layer 2-forwarding router 10 for performing data transfer between the routers. First, these ATMs and the IEEE 1394 standard will be briefly described.

In the ATM, in order to enable the same information transfer processing regardless of the communication speed, routing information is added to a header portion called an ATM cell header for each fixed-length transfer information called an ATM cell, and based on this, Multiplexing and routing of information.

The ATM cell header has a configuration as shown in FIG. GFC (General Flow Control) is used for flow control on a user / network interface.

A VPI (Virtual Path Identifier) and a VCI (Virtual Channel Identifier) are used to identify an ATM connection, and further, a PT (Payload Ty).
The assignment of “pe” enables notification of forward congestion at the cell level and the like.

The CLP (Cell Loss Priority) is
This indicates the priority of cell loss control that may be performed when congestion or the like occurs.

Further, HEC (Header Error Check)
Is a CRC (Cycric R) which has a 1-bit error correction and a multi-bit error detection capability for detecting and correcting header errors.
edundancy Check).

The ATM cell header having such a configuration is used in an OSI (Open Systems) defining a protocol hierarchy.
A, which belongs to the so-called data link layer, in the basic reference model of Interconnection (open system interconnection)
This is specified by the TM layer.

As shown in FIG. 3, the OSI is hierarchically divided into a physical layer, a data link layer, a network layer, a transport layer, a session layer, a presentation layer, and an application layer. It is organized.

The first physical layer defines physical standards such as the shape of the connector at the end of the cable used for connection, the number and type of pins, and standards for electrical signals. Standards are also included. 0 in the physical layer
Or, a bit string consisting of 1 is exchanged.

The data link layer of the second layer plays a role of dividing the transmission of a bit string in the physical layer as a unit of meaningful information called a packet or a frame. The data link layer packetizes data, performs data transfer between adjacent systems together with an error detection code and order information of the packet, and controls transmission errors.

The third network layer is for relaying data transmission and routing control between network systems. In a wide area network, communication cannot be performed unless a route for transmitting data is established. Therefore, a route control based on a network address is performed in a network layer.

The fourth transport layer includes, for example,
It realizes a function for guaranteeing the quality of communication, such as controlling retransmission to recover an error that has occurred during communication, or adjusting the order of packets that arrive intermittently.

The fifth session layer controls communication so as to maintain order as a dialogue (dialog). For example, the fifth session layer controls transmission right and establishes synchronization. .

The sixth presentation layer is for converting character sets and character codes, and converting data structures.

The seventh application layer provides services that can use application programs on a console such as a computer. For example, the application layer is used to provide functions such as e-mail, file transfer, and remote login.

In the above-described ATM layer, a 53-octet ATM cell including an ATM cell header and data is generated, and so-called cut-through transfer can be performed. In addition, in the ATM layer, when performing data transfer via the Internet, as shown in FIG. 4, an IP datagram includes LLC / SNAP (Logical Link Control) in an IP datagram.
/ Sub-Network Access Protocol) header and AAL5 (ATM Adaptation Layer) for reassociation.
5) Generate packets consisting of multiples of 48 octets with trailers and padding added as needed. At the ATM layer, this packet is divided into 48 octet cells, and each cell has 5 octet A
With a TM cell header attached, 53 octets of ATM
A cell is formed and the ATM cell is transferred.

On the other hand, the IEEE 1394 standard is an interface standard that supports high-speed data transfer and real-time transfer for the purpose of an interface for multimedia data transfer. In the IEEE 1394 standard, a transfer operation performed in a network is called a subaction, and the following two types of subactions are defined. That is, as two sub-actions, a synchronous transfer mode that guarantees a transfer band called “isochronous” is defined.
An asynchronous transfer mode called "asynchronous" is defined.

The header portion of the packet in the IEEE 1394 standard differs between "isochronous" and "asynchronous".

The header part in "isochronous" (hereinafter referred to as "isochronous")
This is called a 1394 synchronization header. ) Has a configuration as shown in FIG. 5, and includes a data length indicating the size of the data block following the 1394 synchronization header, and a tag (isochronous data format) indicating the classification of the packet in the upper layer.
t tag) and channel (isochro)
nous channel) and sy (synchron
and a header_CRC indicating the CRC of the 1394 synchronization header.

The header part of "asynchronous" (hereinafter referred to as 1394 asynchronous header) has a structure as shown in FIG. 6, and des which indicates the address of the receiving side.
t ID (destination ID), tl (transaction label) representing a transaction label, and rt (retry co
de), and tcode (tr
ansaction code) and pri indicating the priority of the packet.
(Priority) and srcID indicating the sender's address
(Source ID) and a header_CRC indicating the CRC of the 1394 asynchronous header. In addition, 1394
In the asynchronous header, as information specific to the packet type, for example, dest offset (destination offset)
And datalength and extended_tcod
e etc. are provided.

The 1394 synchronous header and the 1394 asynchronous header having such a configuration are defined by the link layer belonging to the data link layer in the basic reference model of OSI described above. In the link layer, 1
A packet including a 394 synchronous header or a 1394 asynchronous header and data is generated and transferred. Further, in the link layer, when performing data transfer via the Internet, as shown in FIG. 7, after a fragment header for reassembly is added to an IP datagram, 139
A packet is formed by adding a 4 synchronous header or a 1394 asynchronous header, and the packet is transferred. In the link layer, at the time of forming the packet, the IP datagram is divided according to, for example, a transfer rate or a band reserved for use in data transmission.
A fragment header and a 1394 synchronous header or a 1394 asynchronous header are added to the datagram to form a plurality of packets.

The ATM network to which the above-described ATM is applied and the IEEE 1 standard conforming to the IEEE 1394 standard.
As shown in FIG. 8, a layer 2-forwarding router 10 for transferring data in a network connected to the 394 network is a CPU serving as a relay unit.
11, a main memory 12 as storage means, and a line unit 1
3 and a line unit 14, and also includes a power supply unit for supplying power (not shown) and various ports. These components are connected to each other by a bus 15.

The main memory 12 is, for example, a DRAM (Dy
(Namic Random Access Memory) and a nonvolatile flash memory. The main memory 12 stores a routing table including routing information for transferring an IP datagram received from a connected network to another network. The main memory 12 has a layer 2-
Various kinds of information necessary for operating the forwarding router 10 and a flow table described later are stored.

The line unit 13 has an interface for connecting to an IEEE 1394 network, and has a function as a connection unit with the network. This line unit 1
A plurality 3 is provided so as to correspond to the number of networks to which the layer 2 forwarding router 10 is connected.

The line unit 14 has an interface for connecting to the ATM network, and functions as a connection unit with the network similarly to the line unit 13. The line unit 14 is connected to the layer 2 forwarding router 10. A plurality of networks are provided so as to correspond to the number of networks.

The CPU 11 controls each section, searches desired route information from the above-mentioned route table,
It has a function of searching for information of a flow table described later.

[0052] Such a layer 2 forwarding
As shown in FIG. 9, the router 10 is used at the time of data transfer according to the normal IP datagram method, and in addition to the above-described routing table managed at the network layer, a flow of a group of packets to the same destination. A flow table, which is a data transfer path table in which information of an ATM cell header, a 1394 synchronous header, or a 1394 asynchronous header (hereinafter, appropriately referred to as a data link header) for each flow, is stored in the main memory 12, Managing. This flow table records information of protocol numbers such as TCP and UDP and port numbers.
In the forwarding router 10, flows are classified based on this information. Further, only the address to which data is to be transferred may be recorded as a flow table, and flows can be classified based on simplified information.

In the following description, V in the ATM cell header
Information indicating logical port numbers such as channel numbers and offsets in PI, VCI, 1394 synchronous header or 1394 asynchronous header will be referred to as channel identifiers.

The flow table is configured, for example, as shown in FIG. That is, in the flow table, among the interfaces provided in the plurality of line units 13 or the line units 14, the type of the interface for inputting the flow, the unit number indicating the physical port number, and the channel identifier are recorded. In addition, the flow table includes, as information on the flow relay destination, the interface type that outputs the flow, the unit number, the channel number, and The identifier is recorded. In the case of a multicast flow in which a plurality of output destinations exist for one flow, the flow table has a plurality of output side information for one input side information.
When a data transmission band to be used for transmission is reserved, information indicating the band is added to the flow table.

Layer 2 forwarding router 10
Is the information of the network layer of the received packet, I
Check the information of the data link header without checking the P header. When the layer 2-forwarding router 10 recognizes that the packet belongs to the flow input from the interface with the unit number 3 connected to the ATM network and the channel identifier 50, for example, based on the flow table, , An interface connected to the IEEE 1394 network and having a unit number of 2 and a channel identifier of 20 is determined as an output destination of the packet, and the packet is transferred with a guaranteed bandwidth of 3 Mbps.

Layer 2 forwarding router 10
Relays data by the operation shown in FIG. That is, layer 2 forwarding
The router 10, as shown in FIG.
In step S2, when a packet is received, the CPU 11 determines whether or not a flow channel identifier is added to the packet as information in the data link header in step S2.

Here, when the channel identifier for the flow is not recognized, the process goes to step S5 in the layer 2-forwarding router 10 to perform the packet transfer process by the normal IP datagram method. . Layer 2 forwarding router 10
In step S5, based on the destination IP address "dest IP address",
The east-match is performed, and the routing table held in the main memory 12 is searched by the CPU 11. Then, the layer 2-forwarding router 10 is the next relay router to which the packet should be transmitted based on the search result of the routing table.
Decide next hop gateway and its interface,
The packet transmission processing in step S6 is performed.

On the other hand, if the flow channel identifier is recognized in step S2, the layer 2-forwarding router 10 proceeds to step S3
Shifts to the processing in. In step S3, the layer 2-forwarding router 10 searches the flow table held in the main memory 12 by the CPU 11 based on the interface and the channel identifier that received the packet, and the interface and the channel identifier to which the packet should be transmitted. And decide. And
In step S4, the CPU 11 determines whether a corresponding entry exists in the flow table.

Here, if the corresponding entry does not exist, the layer 2 forwarding router 10
The process shifts to the process in step S5, and performs a packet transfer process using a normal IP datagram method.

If it is determined in step S4 that a corresponding entry exists, the layer 2-forwarding router 10 transmits a packet from the interface determined in step S3, and ends a series of processing.

As described above, since the layer 2 forwarding router 10 has a mechanism for allocating an individual channel for each flow and notifying a correspondence between a flow and a channel identifier between adjacent nodes,
When transferring a packet, dest I in the IP header
There is no need to check the Pad address or routing table,
processing with a large load, such as guest-match,
There is no need to perform processes such as tl subtraction and checksum replacement. Therefore, in the layer 2-forwarding router 10, a packet is transferred at high speed by obtaining an interface to which a packet is to be output and a channel identifier based on information of a data link header added to each packet. can do.

The data relay program for realizing a series of processes at the time of data relay described above is a layer 2-
It may be stored in the main memory 12 or the like of the forwarding router 10 or may be provided in a form recorded on a recording medium such as a CD-ROM. Layer 2-
The forwarding router 10 can perform the above-described series of processing by writing and storing the data relay program recorded on the recording medium in the main memory 12, for example.

The above-described ATM network and IEEE
The layer 2 forwarding router 10 connected to the E1394 network is a media cruising (Media Cruisin) which has been proposed as a network architecture replacing the current Internet architecture.
Applicable to the system in g).

Media cruising is to overcome the difficulty of high-speed transfer of a large amount of data in the existing Internet, and secures a normal best-effort mode and a band to be used for ensuring communication quality. -It is possible to switch between guaranteed modes. In this media cruising, it is assumed that a wide range of network forms from a wide area to homes is supported.

The above-described ATM network and IEEE1
A system in which the 394 network is applied to media cruising is as shown in FIG. 12, for example. That is, in media cruising, the backbone network 50 is constructed by an ATM network, and the home network 70 as a home network is constructed by an IEEE 1394 network.
The backbone network 50 and the home network 70 are connected by a subscriber network 60.

The backbone network 50 is very large and utilizes the high speed communication technology of ATM. For example, the backbone router 51 that connects a backbone ATM network made of a large-capacity optical fiber,
For example, an ATM switch with an extended function such as high-speed signaling is used.

The subscriber network 60 is located around the backbone network 50. For example, an ADSL (Asymmetric Digital Subscriber) using an optical fiber by FTTH (Fiber To The Home) or a copper wire.
r Line) and the like are connected by the edge router 61 to the backbone. Like the backbone router 51, the edge router 61 is, for example, an ATM switch in which functions such as high-speed signaling are extended.

The home network 70 is an IEEE13 connection in which computers, AV (Audio Visual) devices and the like are connected by a serial bus conforming to the IEEE1394 standard.
The home router 71 is used for connection with the subscriber network 60. home·
The router 71 is small and inexpensive, has an interface corresponding to ATM as an external network interface, and has an interface corresponding to IEEE 1394 standard or Ethernet as an internal network interface.

The routers belonging to each of these networks have different resources and capabilities depending on the networks to which they belong.
This is equivalent to the router 10, performs the above-described processing, and transfers packets.

For example, when data is transferred from the home network 70 to another home network (not shown), the home router 71 transmits the 1394 synchronization header of the packet having the configuration shown in FIG. Or 1
Check the channel identifier for the flow in the 394 asynchronous header. Then, the home router 71 searches the stored flow table based on the interface and the channel identifier that have received the packet, determines the interface and the channel identifier to which the packet is to be transmitted, and transmits the packet. At this time, the packet has a data link header of 13 as shown in FIG.
The 94 synchronous header or the 1394 asynchronous header is replaced with the ATM cell header.

Next, at the edge of the subscriber network 60,
The router 61 determines, based on the interface that received the packet and the channel identifier in the ATM cell header,
The stored flow table is searched to determine an interface to which a packet is to be transmitted and a channel identifier.

Further, the backbone network 50
The backbone router 51 searches the stored flow table based on the interface receiving the packet and the channel identifier in the ATM cell header. Then, the backbone router 51 determines the interface to which the packet is to be transmitted and the channel identifier, and transmits the packet.

When the backbone network 50 is composed of a plurality of ATM networks, a packet is transmitted to each backbone network in each ATM network.
When the router 51 performs the same processing, the data is sequentially transferred between the ATM networks by cut-through transfer.

By repeating such a transfer of the packet, the data link header finally becomes
ATM cell header to 1394 synchronization header or 1394
It is replaced with an asynchronous header and reaches a receiving terminal of a home network (not shown).

As described above, the above-described layer 2-forwarding router 10 can be applied as the backbone router 51, the edge router 61, and the home router 71 in media cruising. Packets can be transferred at high speed based on the information of the header. The transfer of packets in media cruising may be performed in a normal best effort mode, or may be performed in a mode in which a band to be used is guaranteed. When the transfer is performed in the mode in which the bandwidth is guaranteed, information indicating the bandwidth to be used is recorded in the flow table.

As described above, the layer 2 forwarding router 1 shown as an embodiment of the present invention
0 indicates that packet transfer can be performed at high speed by performing packet transfer not based on network layer information but based on data link layer information.

The present invention is not limited to the above-described embodiment. For example, it is possible to apply a network constituted by Ethernet instead of the IEEE 1394 network. It is needless to say that other modifications can be made without departing from the spirit of the present invention.

[0078]

As described in detail above, the data relay device according to the present invention provides a data link layer information included in a header added to data transferred between a plurality of networks, and a data transfer path. And a relay unit for relaying and transferring data between a plurality of networks having different types of data link layers. The data transfer path table stored in the storage means is searched based on the data link layer information included in the header attached to the data to be relayed, and the data transfer destination is determined. Therefore, the data relay device according to the present invention can transfer data at high speed.

Further, the data relay method according to the present invention
A data transfer path table that describes a correspondence relationship between data link layer information included in a header added to data transferred between a plurality of networks and a data transfer path,
When data is relayed and transferred between a plurality of networks having different types of data link layers, the data is stored in storage means based on data link layer information included in a header attached to the relayed data. Thus, the data transfer path table stored in the storage means is searched, and the data transfer destination is determined, so that the data can be transferred at a high speed.

Further, the recording medium on which the data relay program according to the present invention is recorded has a data relay program for performing a process of relaying and transferring data between a plurality of networks having different types of data link layers. A data relay program, the data relay program comprising: a data describing a correspondence relationship between data link layer information included in a header attached to data transferred between a plurality of networks and a data transfer path; The transfer path table is searched based on the information of the data link layer included in the header attached to the data to be relayed, and the transfer destination of the data is determined. Therefore, the recording medium on which the data relay program according to the present invention is recorded can provide a data relay program capable of transferring data at a high speed. Thus, data transfer can be performed at high speed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a network system to which a layer 2-forwarding router shown as an embodiment of the present invention is applied, which illustrates an ATM network and IEEE.
FIG. 1 is a diagram showing a network system connected to a 1394 network.

FIG. 2 is a diagram showing an example of a format of an ATM cell header.

FIG. 3 is a diagram showing a basic reference model of OSI.

FIG. 4 is a diagram showing a configuration of a packet in which an ATM cell header is added to an IP datagram.

FIG. 5 is a diagram showing an example of a format of a 1394 synchronization header.

FIG. 6 is a diagram illustrating an example of a format of a 1394 asynchronous header.

FIG. 7: 1394 synchronization header or 1 in IP datagram
FIG. 14 is a diagram illustrating a configuration of a packet to which a 394 asynchronous header is added.

FIG. 8 is a block diagram showing a configuration of the layer 2-forwarding router.

FIG. 9 is a conceptual diagram illustrating a process in the layer 2-forwarding router.

FIG. 10 is a diagram showing an example of a flow table stored in the layer 2-forwarding router.

FIG. 11 is a flowchart showing a series of processing steps in the layer 2-forwarding router.

FIG. 12 is a diagram showing an example of a system in which the above-mentioned layer 2 forwarding router is applied to media cruising.

FIG. 13 is a diagram illustrating an example of a format of an IP header.

FIG. 14 is a conceptual diagram illustrating processing in a conventional router.

FIG. 15 is a diagram illustrating an example of a configuration of an IP address.

[Description of Signs] 10 Layer 2-forwarding router 11
CPU, 12 main memory, 13 line section, 1
4 Line section

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Atsushi Onoe, 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Fumio Teraoka 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Atsushi Shionozaki 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Ryutaro Kawamura 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph Within Telephone Co., Ltd. (72) Inventor Akihiro Tsutsui Nippon Telegraph and Telephone Corporation 3-9-1-2, Nishi-Shinjuku, Japan Nippon Telegraph and Telephone Co., Ltd. Telephone Co., Ltd. (72) Inventor Hiroyuki Tanaka 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Co., Ltd.

Claims (9)

[Claims] 1. A data transfer path table in which a correspondence relation between data link layer information included in a header added to data transferred between a plurality of networks and a transfer path of the data is stored. Storage means; and relay means for relaying and transferring data between a plurality of networks having different types of data link layers, wherein the relay means includes a data link layer included in a header attached to the data to be relayed. A data transfer path table stored in the storage means, based on the information, to determine a transfer destination of the data. 2. The plurality of networks can each occupy a data transmission band used for transmitting the data, and the relay unit includes a plurality of different types of data link layers having different types of data link layers. 2. The data transmission band according to claim 1, wherein, when data is relayed and transferred between networks, the data transmission band is determined based on data link layer information included in a header attached to the data to be relayed. Data relay device. 3. The data relay device according to claim 1, wherein at least one of the plurality of networks is an ATM-compatible network, and at least one of the plurality of networks is a network compliant with the IEEE 1394 standard. 4. A data transfer path table in which a correspondence between data link layer information included in a header added to data transferred between a plurality of networks and a transfer path of the data is described. When relaying and transferring data between a plurality of networks having different types of data link layers, based on information of the data link layer included in the header attached to the data to be relayed, A data relay method, wherein the data transfer path table stored in the storage means is searched to determine a transfer destination of the data. 5. The plurality of networks are each capable of occupying a data transmission band used for transmitting the data, and transmitting data between the plurality of networks having different types of data link layers. 5. The data relay method according to claim 4, wherein when relaying and transferring, the data transmission band is determined based on information of a data link layer included in a header attached to data to be relayed. 6. The data relay method according to claim 4, wherein at least one of the plurality of networks is an ATM-compatible network, and at least one of the plurality of networks is a network conforming to the IEEE 1394 standard. 7. A recording medium storing a data relay program for performing a process of relaying and transferring data between a plurality of networks having different types of data link layers, wherein the data relay program comprises a plurality of networks. The data transfer path table describing the correspondence between the data link layer information included in the header added to the data transferred between the networks and the data transfer path is added to the header added to the data to be relayed. A recording medium on which a data relay program is recorded, wherein a search is performed based on information of a data link layer included to determine a transfer destination of the data. 8. The plurality of networks each occupy a data transmission band used for transmitting the data, and the data relay program includes a plurality of data link layers having different types of data link layers. 8. The data transmission band is determined based on information of a data link layer included in a header attached to data to be relayed when data is relayed and transferred between the networks. Recording medium on which the data relay program is recorded. 9. The data relay program according to claim 1, wherein at least one of the plurality of networks is an ATM-compatible network, and at least one of the plurality of networks is an IEEE-compatible network.
8. The recording medium according to claim 7, wherein the recording medium is adapted to transfer data in a network conforming to the E1394 standard.