JP3655623B2 - Router device, data communication network system, and data transfer method - Google Patents

Description

  The present invention relates to a router device for transferring a datagram between networks, a data communication network system including a plurality of router devices, and a data transfer method.

  The router device is used when connecting LANs and plays a role of transferring a datagram from one LAN to the other LAN. In the datagram, in addition to the communication information data to be transferred, the network layer address of the transmission source and final destination (for example, IP address in the case of IP) is described, and the router device uses the address information of the datagram. The output interface and the next transfer destination node (host that becomes a router device or a communication terminal) are determined.

  A conventional datagram transfer method of the router device will be described with reference to FIG.

First, taking a router device connected to Ethernet ^(R) as a non-virtual connection type LAN as an example, a datagram transfer procedure will be described. Upon receiving the Ethernet ^(R) frame (data link frame) from LAN, the receiving unit 911, to change the datagram handle the data link frame at the network layer. Next, the datagram analyzing unit 921 determines the network layer address of the output interface and the next forwarding node (host or router device) from the address of the final destination of the datagram, and sends it to the datagram processing unit 922 of the corresponding output interface. The datagram is passed through the transfer unit 930. The datagram processing unit 922 to which the datagram has been passed performs network layer processing (in the case of IP, processing for reducing TTL (Time To Live), checksum calculation, optional processing, etc.). Finally, the transmission unit 913 determines an Ethernet ^(R) address (data link layer address) from the network layer address of the next forwarding node, constructs an Ethernet ^(R) frame from the address and datagram, Output.

  In ATM, which is a virtual connection type LAN, datagram transfer is performed in substantially the same manner. First, when an ATM cell is received from the LAN, it is changed to an AAL frame (data link frame), and the frame is changed to a datagram handled in the network layer. Next, the network layer address of the output interface and the next forwarding node is determined from the final destination address of the datagram, and the network layer processing is performed. Finally, the transmission unit determines a virtual connection identifier to be transferred from the network layer address of the next transfer node, constructs an ATM cell from the identifier and the datagram, and outputs it to the LAN.

  As described above, in the router device connected to the virtual connection type LAN or the router device connected to the non-virtual connection type LAN, when the datagram is transferred, the datagram analysis unit (in the case of IP, The output destination is determined by referring to header information such as source address, destination address, service type (Type Of Service), and higher layer information such as port address). For this reason, the datagram analyzer takes time for transfer processing, and the datagram cannot be transferred at high speed.

  By the way, when the requested service quality of the datagram to be transferred is different, it is desirable not only to process the datagram according to the arrival order but also to perform processing considering the requested service quality. A function provided for this purpose is a scheduler, which controls the order of passing datagrams to the next function in consideration of not only the arrival order but also the required service quality.

  However, since information on the quality of service required for each datagram is obtained by referring to the contents of the datagram, the result obtained after receiving the processing of the datagram analysis unit 921 as shown in FIG. Based on the above, priority control processing (scheduling) must be performed. This is effective when priority is given to output processing from a higher service quality when the capacity of the transmission interface to the next node is not sufficient.

  However, if the analysis capability of the datagram analysis unit itself is not sufficient, the processing wait time may become a performance problem, but before the priority information is still known. For this reason, there is a problem that scheduling in consideration of service quality cannot be performed, and the scheduler has to perform arrival order processing.

  As described above, the conventional router device cannot determine the transfer destination until the contents of the datagram are referred to.

  An object of the present invention is to provide a router device, a data communication network system, and a data transfer method that improve transfer efficiency by knowing a transfer destination before referring to the contents of a datagram.

The present invention relates to a router device for transferring a datagram between networks, a plurality of connection interfaces for connecting to each of a plurality of networks including at least one virtual connection network and at least one non-virtual connection network, and a virtual connection Storage means for storing the correspondence between the identifier and the connection interface as the transfer destination and the correspondence between the virtual connection identifier and the network address, and the storage means based on the virtual connection identifier of the datagram input from the virtual connection The first connection identifier analyzing means for determining the connection interface to which the datagram is transferred, and the virtual connection identifier of the datagram input from the virtual connection. A second connection identifier analyzing means for determining a network address as a transfer destination of the datagram with reference to the storage means, and a connection interface as the transfer destination by the first connection identifier analyzing means. A first transfer means for transferring the datagram to the connection interface connected to another virtual connection, and a network that is the transfer destination by the second connection identifier analysis means A second transfer means for transferring the datagram to the connection interface connected to at least one non-virtual connection toward the destination network address when the address is determined; It is characterized by.
The present invention also provides a datagram between networks using a router device having a plurality of connection interfaces for connecting to each of a plurality of networks including at least one virtual connection network and at least one non-virtual connection network. A storage step of storing a correspondence relationship between a virtual connection identifier and a connection interface as a transfer destination and a correspondence relationship between a virtual connection identifier and a network address in the storage means of the router device; A first determination step of determining a connection interface as a transfer destination of the datagram with reference to the storage means based on a virtual connection identifier of the datagram input from the router to the router device; A second determination step of determining a network address to which the datagram is to be transferred with reference to the storage means based on a virtual connection identifier of the datagram input to the router device; and the first determination step When the connection interface to be the transfer destination is determined by the first transfer step of transferring the datagram to the connection interface connected to another virtual connection and the transfer by the second determination step A second transfer step of transferring the datagram to the connection interface connected to at least one non-virtual connection toward the transfer destination network address when a transfer destination network address is determined. It is characterized by that.
The present invention also provides a data transfer for transferring a datagram between networks using at least two router devices having a plurality of connection interfaces for connecting to each of a plurality of networks including at least one virtual connection network. In the method, a storage step of storing a correspondence relationship between a virtual connection identifier and a connection interface serving as a transfer destination in a storage unit provided in a certain router device, and a datagram input from the virtual connection to the certain router device A determination step of determining a connection interface as a transfer destination of the datagram with reference to the storage means based on the virtual connection identifier, and the connection interface determined as the determination step to the connection interface as the transfer destination Transfer step And a first sending step of sending the datagram along the other virtual connection identifier from the connection interface serving as the transfer destination onto the second virtual connection connected to the other router device; In the other router device, a reception step of receiving the datagram from the connection interface serving as the transfer destination of the certain router device on the second virtual connection; and from the datagram, the transfer destination A deletion step of deleting the other virtual connection identifier in the connection interface, and the other router device without using the other virtual connection identifier and without adding another virtual connection identifier. A second sending step for sending the datagram from another router device to the outside. Characterized in that it comprises and.
Further, the present invention provides a data transfer method for transferring a datagram between networks using a router device having a plurality of connection interfaces for connecting to each of a plurality of networks including at least one virtual connection network. A storage step of storing a correspondence relationship between a virtual connection identifier and a connection interface serving as a transfer destination in the storage means of the router device, and a connection interface serving as a transfer destination of a datagram input from the virtual connection, A determination step of referring to the storage means based on a virtual connection identifier of the received virtual connection; a transfer step of transferring the datagram to the determined connection interface; and the virtual connection Use identifier It not, and without the addition of other virtual connection identifier, characterized in that it comprises a sending step of sending the datagrams from the router device.
According to the present invention, in the data communication network system including a plurality of router devices that transfer datagrams between networks, the first router device is connected to each of the plurality of networks including at least one virtual connection network. A first storage unit configured to store a first correspondence between a first set of a plurality of connection interfaces, a first input virtual connection identifier and a connection interface serving as a first transfer destination; Based on the first input virtual connection identifier of the first datagram input from one input virtual connection, the connection interface to be the first transfer destination of the datagram is referred to by referring to the first storage means A first connection identifier analyzing means for determining the first connection identifier solution; First transfer means for transferring the first datagram to the connection interface as the first transfer destination determined by the means, and the second router device has at least one virtual connection A second set of a plurality of connection interfaces for connecting to each of a plurality of networks including the network, a second input virtual connection identifier, and a second set of the plurality of connection interfaces. A second storage means for storing a correspondence relationship with the next-stage network address to be used when the virtual connection network is connected, and a second datagram input from the second input virtual connection. Based on the input virtual connection identifier, referring to the second storage means, the datagram A second connection identifier analyzing means for determining a connection interface serving as a second transfer destination, and a second connection identifier serving as the second transfer destination determined by the second connection identifier analyzing means; And a second transfer means for transferring the datagram.
The present invention also provides data between networks using a first router device and a second router device each having a plurality of connection interfaces for connecting to each of a plurality of networks including at least one virtual connection network. In the data transfer method for transferring a gram, a first storage for storing a correspondence relationship between a first virtual connection identifier and a connection interface serving as a first transfer destination in a storage means provided in the first router device And referring to the storage means provided in the first router device based on the virtual connection identifier of the datagram input from the first virtual connection to the first router device, A first determination step for determining a connection interface as a transfer destination, and the first determination step. A first transfer step of transferring the datagram input from the first virtual connection to the determined connection interface serving as the first transfer destination; and storage means provided in the second router device And a second virtual connection identifier and a connection interface to be a second transfer destination, which is to be used when at least one non-virtual connection network is connected to the connection interface of the second router device. A second storage means for storing a correspondence relationship with a connection interface serving as a second transfer destination connected to the network address; and a datagram input from the second virtual connection to the second router device On the basis of the virtual connection identifier of the second router, the storage means provided in the second router device is referred to A second determination step for determining a connection interface to be a transfer destination of a gram, and the second virtual connection to be input to the connection interface to be the second transfer destination determined by the second determination step A second transfer step of transferring the datagram.

  In the present invention, without referring to the contents of the datagram, the connection interface to which the datagram is transferred is determined by referring to the storage means based on the virtual connection identifier of the input datagram. The datagram can be forwarded to the connection interface. The transfer means may include means for performing a network layer process corresponding to the network protocol on the datagram.

  More preferably, means for applying this network layer processing to the datagram exists for each connection interface. This is because the input datagram is distributed to the output interface at high speed based on the virtual connection identifier, and the network layer processing is performed in parallel at each output interface.

  As described above, by obtaining information from the virtual connection identifier before referring to the datagram, the trouble of the router device can be reduced and the transfer efficiency of the router device can be improved.

  According to the present invention, the transfer destination can be determined from the virtual connection identifier of the input datagram without performing processing for viewing the contents of the datagram, and the transfer efficiency of the router device can be improved.

  Hereinafter, embodiments of the invention will be described with reference to the drawings.

  The present invention provides a virtual connection of a received data link frame instead of performing a datagram transfer based on a network layer address of a transfer destination obtained by referring to the contents of the datagram extracted from the received data link frame in the router device. Datagram transfer is performed by referring to the identifier.

  In order to determine the transfer destination of the datagram based on the virtual connection identifier of the received data link frame, it is only necessary that the transmission node of the datagram flows only the specific datagram through the specific virtual connection.

The specific datagram is, for example, a datagram in which one or more pieces of information listed below are the same.
Protocol type (eg IP, IPX)
IP version (eg IPv4, IPv6)
Protocol identifier (eg TCP, UDP)
·destination address
-Logical sum of destination address and mask
Destination transport layer port
・ Source address
・ The logical sum of the source address and mask
-Source transport layer port
ST-2 stream ID (Stream ID; for IPv5)
-Flow ID (flow ID; for IPv6)
-TOS (Type of service; for IPv4)
-Traffic class (Traffic Class; IPv6)
Flowing a specific datagram through a specific virtual connection can be realized, for example, by using a transmission node having a configuration as shown in FIG.

  Hereinafter, a procedure in which the transmission node in FIG. 1 transmits a datagram will be described.

  For example, when transmitting a datagram to the destination A, the datagram analysis unit 1 refers to the routing table 2 in which the correspondence between the destination, the output I / F, and the output virtual connection identifier is registered, using the destination A as a key. It is determined that the output I / F of the datagram is atm1 and the output virtual connection is 1. Then, the datagram is sent to the I / F corresponding to atm1. In the I / F transmission unit 4, the datagram is assembled into an AAL frame that is a data link frame, divided into ATM cells, and transmitted to the virtual connection 1.

  Here, the routing table 2 of the datagram analysis unit 1 searches using “destination” as a key, but it can be searched not only from “destination” but also from other information such as “service quality” and “source address”. You may have a routing table.

  As described below, in each embodiment of the router device of the present invention, for example, by using a transmission node as shown in FIG. 1, it is set so that only a specific datagram flows through a specific virtual connection. To do.

(First embodiment)
FIG. 2 shows a configuration example of the router device according to the first embodiment of the present invention.

The router device of this embodiment is connected to two virtual connection LANs 41 and 42 and one non-virtual connection LAN 43. Here, the virtual connection type LAN will be described using ATM-LAN as an example, and the non-virtual connection type LAN will be described using Ethernet ^(R) as an example.

  As illustrated in FIG. 2, the router device according to the present embodiment includes a reception unit 11, a transmission unit 13, a datagram analysis unit 21, a datagram processing unit 22, and a transfer unit 30 for each connected LAN. The interface connected to the virtual connection type LAN has a connection identifier analysis unit 12. In addition, a transfer unit 30 for interconnecting these LAN compatible parts is provided.

In the figure, in order to distinguish which LAN each of a plurality of blocks such as a receiving unit is a block for, for example, receiving units 11 ₁ , 11 ₂ , 11 ₃ are indicated.

In the figure, 10 ₁ to 10 ₃ are I / Fs.

  Here, IP (Internet Protocol) is taken as an example as a network protocol for transferring datagrams. Of course, the present invention can be applied not only to IP but also to other network protocols such as IPX.

The receiving unit 11 receives a data link frame from the LAN and performs processing suitable for the LAN. In the case of the Ethernet ^(R) LAN, a data link frame addressed to itself is extracted, and a CRC check is performed to detect an error in the data link frame. Thereafter, the datagram is constructed and the network protocol to be used is specified from the data link frame. The constructed datagram and the received virtual connection identifier are passed to the connection identifier analyzer 12.

  If it is an ATM-LAN, an error in an ATM cell is detected, an assembly error is detected in an AAL frame, a network protocol is determined, and a datagram is constructed. The configured datagram and the received VPI / VCI are passed to the connection identifier analysis unit 12.

  The datagram analyzing unit 21 refers to the contents of the datagram (source information, destination address, flow ID, header information such as TOS and higher layer information such as port address), and the network address of the output interface and the next node. To decide. In order to realize this function, for example, as shown in FIG. 3, the datagram analysis unit 21 is provided with a routing table 210 that can refer to the output interface and the next-stage network address from the destination address of the datagram.

  When the output interface is a virtual connection type LAN, an output virtual connection identifier can be inserted instead of the next-stage network address.

  Here, in order to explain both the case where the next-stage network address is written in the routing table and the case where the output virtual connection identifier is written, in the case where the output I / F is a non-virtual connection type LAN, the next-stage network address is A description will be given of the case where the output virtual connection identifier is written when the output I / F is a virtual connection type LAN.

  The datagram analysis unit 21 passes the datagram through the transfer unit 30 to the datagram processing unit 22 of the output interface determined according to such a route table.

  The above routing table is referenced only by the destination address, but as described above, the output interface may be known from the contents of various datagrams.

  The connection identifier analysis unit 12 exists only at the interface connected to the virtual connection type LAN. In the datagram analysis unit 21, the output interface is determined from the content of the datagram, but instead of referring to the content of the datagram, the connection identifier analysis unit 12 refers to the virtual connection identifier of the received data link frame, Determine the output interface. Further, the next stage network address or the output virtual connection identifier may be determined. In order to perform this function, for example, as shown in FIG. 4, the connection identifier analysis unit 12 prepares a transfer table 120 that can refer to the output I / F and the next-stage network address or the output virtual connection identifier from the virtual connection identifier.

  The transfer table may be set manually or automatically using a protocol with the transmission node. The automatic configuration can be realized by exchanging the virtual connection identifier and the datagram type (destination network address, transport layer port, etc.) carried in the virtual connection between the own router device and the adjacent node.

  In accordance with this transfer table, it is determined whether the datagram is sent to the datagram analysis unit 21 or sent to the datagram processing unit 22 of the I / F that is transmitted via the transfer unit 30. That is, the datagram received through the connection existing in this transfer table is transferred to the datagram processing unit 22 belonging to the corresponding output I / F. On the other hand, a data link frame having a connection identifier not included in the transfer table or a datagram written to be passed to the datagram analysis unit 21 is passed to the datagram analysis unit 21 to see the contents of the datagram.

  The transfer unit 30 receives the datagram from the datagram analysis unit 21 or the connection identifier analysis unit 12, and passes the datagram to the datagram processing unit 22 belonging to the specified output I / F. At this time, not only the datagram but also the network address or output virtual connection identifier of the next node retrieved from the route table of the datagram analysis unit 21 or the transfer table of the connection identifier analysis unit 12 is passed to the datagram processing unit 22.

  The transfer unit 30 can be configured by a bus or a switch. The datagram processing unit 22 performs rewriting of the header of the datagram (in the case of IP, processing for reducing TTL (Time To Live), option processing, checksum calculation). When the datagram is larger than the maximum frame length of the LAN, the datagram is divided so as to be within the maximum frame length. These processes differ depending on which network protocol is used.

  The transmission unit 13 performs processing suitable for the LAN in order to transmit the datagram to the LAN. For example, in the case of ATM-LAN, it is changed to a data link frame (AAL frame), divided into ATM cell sizes, and sent with an output connection identifier specified.

  If the output virtual connection identifier is not specified in either the routing table or the forwarding table, the network address of the next node is specified in the routing table or the forwarding table. The output virtual connection identifier is determined from the network address of the designated next-stage node with reference to the table in which the correspondence relationship between the network address and the virtual connection identifier provided in the transmission unit 13 is registered. The cell is output to the LAN using the determined output virtual connection.

  When the output virtual connection identifier is obtained from the routing table or the forwarding table, an ATM cell is constructed from the datagram using the identifier and output to the LAN.

  Next, the datagram transfer operation of the router device of this embodiment will be described.

  As shown in FIG. 5, I / F1 has three virtual connections (virtual connections 1, 2 and 10) and I / F2 has one virtual connection (virtual connection 3). Assume that the transfer table of the unit 12 and the route table of the datagram analysis unit 21 are set as shown in the figure. These settings may be performed manually as in the transfer table described above, or may be performed using an automatically performed protocol.

  It is assumed that the virtual connection 1 is set so that only the destination A datagram is sent, and the virtual connection 2 is set so that only the destination B datagram is sent. This setting is realized by using, for example, the transmission apparatus described with reference to FIG. It is assumed that the destination A is in the direction of I / F2, and the destination B is in the direction of I / F3. Here, it is assumed that the setting is such that only one destination datagram is sent to one virtual connection. For example, a datagram to be transmitted to the virtual connection is transmitted by the transmission device described in FIG. As described above, it is possible to set so that only a specific datagram flows between the router device and the adjacent node so that the original address and the destination address are set to be the same.

Here, it is assumed that a datagram has flowed to the virtual connection 1. First, the receiving unit 11 ₁ receives this datagram, and passes the received datagram and its virtual connection identifier to the connection identifier analyzing unit 12 ₁ .

Since the connection identifier analysis unit 12 ₁ knows that the datagram is a datagram input from the virtual connection ₁ , it refers to the transfer table 1201 using the virtual connection 1 (input connection identifier 1) as a key. This reference shows that the datagram should be output to the virtual connection 3 of the I / F2.

  Thus, according to this embodiment, the output destination can be determined without referring to the datagram.

When the output destination is determined as described above, the datagram and the output virtual connection identifier 3 (virtual connection 3) are passed through the transfer unit 30 to the datagram processing unit 22 ₂ of the I / F2. This datagram is subjected to network layer processing by the datagram processing unit 22 ₂ , then passes through the transmission unit 13 ₂ and is transmitted to the virtual connection 3 determined from the previous forwarding table.

  In this way, the transfer from the virtual connection type LAN to the virtual connection type LAN is completed.

  If the network address of the next node is transferred to the transfer unit 30 instead of the output virtual connection identifier in the transfer table, the transfer unit 30 passes the datagram and the network address of the next node to the datagram processing unit 22. . The datagram processing unit 22 performs network layer processing on the datagram, and then passes the datagram to the transmission unit 13. The transmission unit 13 determines the output virtual connection identifier from the network address of the next node, and then transfers the datagram to the LAN.

  Next, an example of transfer from a virtual connection type LAN to a non-virtual connection type LAN will be described.

It is assumed that a datagram is input from virtual connection 2 of I / F1. After the reception unit 11 ₁ receives the datagram, the connection identifier analysis unit 12 ₁ refers to the transfer table 120 ₁ using the virtual connection identifier 2 of the datagram as a key. By this reference, the output I / F 3 and the network address C of the next node are determined. Then, the connection identifier analysis unit 12 _1, the network address of the datagram and the next hop node, through the transfer unit 30, and passes the datagram processing unit 22 ₃ I / F3. After the data layer processing unit 22 ₃ performs network layer processing, the datagram and the network address of the next node are passed to the transmission unit 13 ₃ . The transmitting unit 13 _3, after determining the data link address from the network address of the next node and forwards the datagram to the LAN.

In the above, the transfer destination is determined using the connection identifier without referring to the contents of the datagram, but the conventional method can also be used. If the connection destination does not know the transfer destination, the datagram can be transferred to the datagram analysis unit 21 ₁ and the transfer destination can be determined from the contents of the datagram.

The data link frame input from the virtual connection 10 is received by the receiving unit 11 ₁ , where it is changed to a datagram, and then the transfer identifier 120 ₁ is referred to by the connection identifier analyzing unit 12 ₁ . Here, as a result of the reference, since there is no corresponding item in the transfer table 120 ₁ , the datagram is passed to the datagram analysis unit 21. If it is written to pass the transfer table 120 ₁ to the datagram analysis unit 21 ₁ also passes the datagram to datagram analysis unit 21 _1.

The datagram analysis unit 21 ₁ refers to the contents of the datagram and recognizes that this datagram is destined for the destination B. Next, with reference to the routing table 210 _1, datagrams destined destination B is the output I / F3, it can be seen that the next stage network address is C. Therefore, the datagram and the network address C of the next node are passed from the datagram processing unit 22 _{3 of} the I / F ₃ to the transmission unit 13 ₃ through the transfer unit 30 and sent to the non-virtual connection type LAN.

  As described above, the destination address of the input datagram can be known from the virtual connection ID of the datagram input by the router device. Therefore, the output I / F, the address of the next-stage router device, and the output virtual connection ID when the output destination is a virtual connection network can be determined without looking at the contents of the datagram. As a result, transfer efficiency can be improved.

  FIG. 2 shows an example in which the datagram analysis unit 21 and the datagram processing unit 22 are provided corresponding to the respective interfaces. However, one set of the datagram analysis unit 21 and the data is provided on a single router device with a plurality of interfaces. An example in which the gram processing unit 22 is shared is also conceivable. An example of such a router device is shown in FIG.

  A procedure for transferring datagrams in the router apparatus of FIG. 6 will be described below. The details of the operation in each block are the same as those of the router device of FIG.

  It is assumed that the datagram of the destination D flows through the virtual connection 1 and various datagrams flow through the virtual connection 10. These settings can be realized by using a transmission apparatus as described with reference to FIG.

When the data link frame is inputted from the virtual connection 1, the receiving unit 11 ₂ is changed to the datagram received data link frame. The datagram received by the virtual connection 1 is sent to the output I / F 3 by referring to the transfer table 120 ₂ in the connection identifier analysis unit 12 ₂ , and the next stage network address is C. I understand that. Next, the datagram through the datagram processing unit 22 from the transfer unit 30, transfer unit 30, over a transmission unit 13 _3, are transmitted in the same manner as the example of FIG. 5.

When the data link frame is received by the virtual connection 10, it is changed to the datagram by the receiving unit 11 _2. Then, the connection identifier analyzer 12 ₂ searches the transfer table 120 ₂ . As a result of the search, if it is confirmed that there is no virtual connection 10 in this forwarding table, the datagram is passed to the datagram analysis unit 21 via the forwarding unit 30. The datagram analysis unit 21 can know the output I / F 3 and the next-stage network address B by referring to the route table 210. The datagram as before passes the processing unit 22, is passed from the transfer unit 30 to the transmission unit 13 _3, and transmitted.

  A modification of the router device of FIG. 6 is shown in FIG. This router apparatus removes the change from the data link frame to the datagram and the change from the datagram to the data link frame from the functions of the reception unit 11 and the transmission unit 13, and instead of the transfer unit 30 and the datagram analysis unit 21. A data link frame / datagram conversion unit 50 having this function is provided between the transfer unit 30 and the datagram processing unit 22.

Virtual connection 1 or the entered data link frame from the virtual connection 10, the operation until it is transmitted from the transmitting unit 13 _3, it is possible to easily understand the operation of the router device of Fig. 6, its details are omitted .

  In the router device of FIG. 7, unlike the router device of FIG. 6, data transfer can be performed without the processing of the datagram analysis unit 21, the datagram processing unit 22, and the data link frame / datagram conversion unit 50. .

That is, the data link frame received from the virtual connection 2 of I / F2 is subjected to a process of checksum such as data link layer of the data link receiver 11 _2. Thereafter, the connection analysis unit 12 ₂ refers to the transfer table 120 ₂ . As a result of the reference, it can be seen that this data link frame may be output to the virtual connection 3 of the I / F 1. The data link frame is transferred from the transfer unit 30 to the transmission unit 13 ₁ , subjected to data link processing by the transmission unit 13 ₁ , and then transmitted to the virtual connection type LAN.

(Second Embodiment)
In the second embodiment, a router device that performs priority control processing at the input unit for each service quality of the datagram when the datagram is transferred by the router device is shown.

  FIG. 8 shows the configuration of the router device of this embodiment. The configuration and functions of the receiving unit (11), connection identifier analyzing unit (12), datagram analyzing unit (21), datagram processing unit (22), transfer unit (30), and transmitting unit (13) are basically the same. Is the same as the router device of the first embodiment.

  The difference between the present embodiment and the first embodiment is the internal configuration of the schedulers 60 and 61 and the connection identifier analysis unit (12).

  The schedulers 60 and 61 change the output order according to the required service quality of each datagram, not the order in which the datagrams are received. For example, the datagram output order can be changed by dividing the datagram into buffers for each required service quality and changing the extraction rate from the buffer according to the service quality.

  The connection identifier analysis unit 12 is provided with a QOS table 126 as shown in FIG. The QOS table 126 determines service quality from the connection identifier. By changing the QOS table 126, information that can be determined from the connection identifier changes.

  A specific example of the datagram transfer of this router apparatus will be described with reference to FIG.

  As in the first embodiment, virtual connections 1 and 2 are set, only a datagram of service quality 1 is input to virtual connection 1, and only a datagram of service quality 2 is input to virtual connection 2. Suppose that it is set to be. This setting can be carried out, for example, by using a transmission apparatus as described with reference to FIG. It is assumed that service quality 1 has a higher priority than service quality 2.

  In the QOS table 126, virtual connection 1 corresponds to service quality 1 and virtual connection 2 corresponds to service quality 2. This setting may be performed manually, or an automatically set protocol may be used. The automatic configuration can be realized by exchanging the virtual connection identifier and the quality of service of the datagram carried in the virtual connection between the own router device and the adjacent node.

  It is assumed that the route table 210 of the datagram analysis unit 21 is set as shown in the figure.

Here, upon receiving a datagram the virtual connection 1, the receiving unit 11 ₁ receives, the processing of the data link layer at the receiving unit 11 _1. Thereafter, the connection identifier analysis unit 12 ₁ refers to the QOS table 126 ₁ . Here, as a result of the reference, it is recognized that this datagram has quality of service 1.

  Thus, according to the present embodiment, the quality of service can be determined without referring to the datagram.

Next, add the datagram to the buffer 1 in the scheduler 60 _1. The scheduler 60 _1, according to the priority of the datagram, extracting the datagram from the buffer, through the transfer unit 30, and sends the datagram analysis unit 21.

  The order of extraction is, for example, a method in which a service quality 1 datagram having a high priority is extracted from the buffer and then extracted from the service quality 2 buffer.

As in the first embodiment, the datagram sent to the datagram analysis unit 21 is obtained after the output I / F and the network address of the next node are determined from the destination of the datagram by referring to the routing table 210. The data is passed through the datagram processing unit 22 to the output destination scheduler 61 ₂ and transmitted by the transmission unit 13 ₂ , and the transfer ends.

It goes without saying that the datagram transfer from the scheduler 61 ₂ of the output I / F to the transmitter 13 ₂ can also be performed according to the priority order.

Similarly, the datagram entered from the virtual connection 2 through the receiving unit 111, a connection by the search for QOS table 126 ₁ of the identifier analyzer 12 ₁ it can be seen that a quality of service 2. Then, the datagram is put in the service quality 2 buffer of the scheduler 60 ₁ , and then the same processing as described above is performed.

Also, the datagram entered from the virtual connection 10, since the virtual connection identifier corresponding to the QOS table 126 _first connection identifier analysis unit 12 ₁ is not written, the lowest priority buffers of the scheduler 60 ₁ After that, processing is performed in the same manner as described above.

  As described above, the QOS class of the input datagram can be known from the virtual connection ID of the datagram input by the router device. Therefore, each QOS class can be classified without referring to the datagram. Thus, when datagram scheduling is performed at the input stage, scheduling according to the QOS class can be performed even if the datagram transfer unit 30, the datagram analysis unit 21, and the datagram processing unit 22 are slow.

  FIG. 11 shows an example in which the datagram analysis unit 21 and the datagram processing unit 22 are provided for each I / F. In this example as well, the received data link frame is processed in the data link layer by the receiving unit 11 and the service quality is determined by the QOS table in the connection identifier analyzing unit 12 as in the example of FIG. The same applies until the datagram is transferred to the scheduler 60 according to the service quality.

  Here, the datagram output from the scheduler 60 is transferred to the datagram analysis unit 21, where the output I / F and the network address of the next node or the output virtual connection identifier are determined from the destination address of the datagram. . Thereafter, the data is transferred to the datagram processing unit 22 of the output I / F by the transfer unit 30, passed to the scheduler 61, and output.

  It goes without saying that the datagram transfer from the scheduler 61 of the output I / F to the transmission unit 13 can also be performed according to the priority order.

(Third embodiment)
In the first embodiment, the transfer destination can be determined without referring to the contents of the datagram. In the second embodiment, the service quality can be determined without referring to the contents of the datagram.

  In the present embodiment, an example is shown in which both the transfer destination and the service quality can be determined without referring to the contents of the datagram.

  FIG. 12 is a diagram illustrating the configuration of the router device according to the present embodiment.

  It is set so that the datagram of the destination A is input to the virtual connection 1 of the I / F 1 and the datagram of the service quality 2 is input to the virtual connection 2. Assume that the transmission side of this virtual connection is a transmission node as described in FIG.

Transfer Table 129 ₁ and routing table 210 of the datagram analysis unit 21 of the connection identifier analysis unit 12 is assumed to be set as shown in FIG. A procedure for transferring datagrams input from the virtual connections 1 and 2 of the I / F 1 will be described.

When the receiving unit 11 ₁ of the I / F ₁ receives a datagram from the virtual connection 1, the receiving unit 11 ₁ performs data link processing on the datagram and then passes it to the connection identifier analyzing unit 12 ₁ . The connection identifier analysis unit 12 ₁ refers to the transfer table 129 ₁ . From this reference, it can be seen that the datagram coming from the virtual connection 1 is the output I / F 2 with the service quality 1 and the output virtual connection is 3.

The datagram is placed in the buffer of the scheduler 60 ₁ Quality of Service 1, receives the priority control of the transfer order by the scheduler 60 ₁ is passed together with the output virtual connection identifier 3 to the transfer section 30. Thereafter, performs network processing in datagram processing unit 22 performs the schedule pass datagrams, etc. to the scheduler 61 ₂ I / F2, and outputs them to the virtual connection 3 passes to the transmission unit 13 _2.

To the transfer unit 30 from the scheduler 60 _1, but pass the datagram and the virtual connection identifier 3, the quality of service 1 in addition to these also pass, it can be used for the priority control of the scheduler 61 _2.

The datagram received by the virtual connection 2 is transferred from the receiving unit 11 ₁ to the connection identifier analyzing unit 12 ₁ . When you search for the transfer table 129 ₁ at the connection identifier analysis unit 12, the service quality is 2, the output I / F and the address it is understood that not determined.

Therefore, it is put in the service quality 2 buffer of the scheduler 60 ₁ , and next, since the output I / F is not decided, the data is passed to the datagram analysis unit 21 through the transfer unit 30. The datagram analysis unit 21 refers to the destination of the datagram. When the destination is B, the datagram analysis unit 21 searches the routing table 210 for the output I / F and the network address of the next node. In this case, the output I / F is 3 and the network address of the next node is D.

Next, the datagram is transferred to the datagram processing unit 22 for network processing, and then transferred to the scheduler 613 of the I / F 3 through the transfer unit 30. Then, the transmitting unit 13 _3, after analyzing the data link address from the next stage of the network address, to build a data link frame, and sends it to the LAN.

  In the above example, the transfer table of the connection identifier analysis unit 12 can determine all of the service quality, output I / F, and network address of the next node from the input virtual connection identifier, or can determine only the service quality. However, it is also possible to determine the output I / F and the network address of the next stage node.

  As described above, the destination address and service quality of the input datagram can be known from the virtual connection ID of the datagram input by the router device. As a result, the efficiency of the router device can be greatly improved.

  FIG. 13 shows another embodiment in which the transfer destination and the service quality can be determined without referring to the contents of the datagram, as in FIG.

  FIG. 13 is an embodiment in which the datagram analysis unit 21 and the datagram processing unit 22 of FIG. 12 are provided for each I / F.

  Hereinafter, with respect to the operation of FIG. 13, differences from FIG. 12 will be described.

In FIG. 12, the data is transferred from the scheduler 60 ₁ to the transfer unit 30, but in the router device of FIG. 13, the scheduler 60 ₁ determines whether to transfer to the datagram analysis unit 21 ₁ or to the transfer unit 30.

  It is assumed that the datagram received by each virtual connection is set similarly to FIG.

In the datagram received by the virtual connection 1 in FIG. 13, the output I / F is known in the transfer table of the connection identifier analysis unit. Therefore, the datagram and the next-stage network address or the output virtual connection identifier are passed through the transfer unit 30 to the datagram processing unit 22 ₂ of the output I / F.

The datagram received by the virtual connection 2 does not know the output I / F in the transfer table of the connection identifier analysis unit. Therefore, the data is passed to the datagram analysis unit 21 ₁ , the routing table 210 ₁ is searched from the destination of the datagram, the output I / F and the next stage network address or the output virtual connection identifier are determined, and then output through the transfer unit 30. It passes to the datagram processing unit 22 ₃ I / F.

In each of the above embodiments, the number of virtual connection type LANs and non-virtual connection type LANs connected to the router device is arbitrary. In addition to ATM-LAN and Ethernet ^(R) , various types of LAN can be connected.

(Fourth embodiment)
Next, the router connecting the ATM network determines the output I / F and the virtual connection identifier using the input virtual connection identifier (VPI / VCI) without looking at the datagram of the network layer, and the AAL frame. An example of a router that transfers as (AAL PDU or AAL SDU) will be described with reference to FIG.

In FIG. 14, a plurality of ATM NICs (network interface cards) 1000 and a CPU board 1100 that performs network layer processing are connected to one general-purpose bus (1021 in the figure). In addition, (Ethernet ^(R) NIC in this case) 2000 may be connected to NIC for the non-virtual connection. Here, a general-purpose bus is taken as an example, but a switch may be used. In the CPU board 1100, network layer protocol processing is processed by software. In the ATM NIC 1000, an AAL frame is divided into ATM cells and an ATM cell is assembled into an AAL frame.

  There are two methods for transferring between the ATM NIC and the ATM or non-virtual connection NIC and between the CPU boards.

In the first method, the reception buffer 1003 and the transmission buffer 1006 of the ATM NIC 1000 are shown to the CPU as a shared memory so that the memory looks like the memory of the CPU. Thereby, the ATM NIC 1000 and the CPU board 1100 can be read and written from the CPU. In addition, transfer between ATM NICs is possible when the CPU reads from the ATM NIC 1000 and writes to another ATM NIC 1000. Also, between the ATM NIC and Ethernet ^(R) for the NIC, by replacing one of the ATM NIC 100 to the Ethernet ^(R) for NIC2000, it can be transferred as well.

In the second method, when reading from the ATM NIC 1000, the CPU board 1100 or another ATM is designated by specifying the address, data size, and memory address of the transfer destination of the reception buffer 1003 of the ATM NIC 1000 in the bus transmission unit 1004. NIC1000, or performs a data transfer NIC2000 Ethernet ^(R). When writing to the ATM NIC 1000, the memory address of the transmission buffer 1006 of the transfer destination ATM NIC 1000, the memory address of the transmission source, and the transfer data size are written to the bus transmission unit 1004 and transferred to the transmission buffer 1006. Further, by replacing the destination ATM NIC 1000 in NIC2000 Ethernet ^(R), it can be transferred as well.

  In the following, a procedure in which a cell received from an ATM network is transferred by performing network layer processing and a procedure in which an AAL frame is transferred are shown.

  The ATM NIC 1000 receives an ATM cell from the ATM network by the ATM receiving unit 1001, assembles the ATM cell into an AAL frame by the AAL reception processing unit 1002, and stores the AAL PDU and the received VPI / VCI in the reception buffer 1003. . When data enters the reception buffer 1003, the bus transmission unit 1004 notifies the CPU board 1100 that the data has been received and the input I / F. After recognizing that the data has been received, the CPU board 1100 reads the input VPI / VCI. The input VPI / VCI may be notified to the CPU board 1100 by the ATM NIC 1000 when notifying data reception. Next, the connection identifier analysis unit 1105 in the CPU board 1100 determines the output I / F, VPI / VCI, or next-stage network layer address from the input I / F and VPI / VCI.

  The processing from here is divided into the case where the network layer processing is performed and the case where the AAL frame is transferred (AAL transfer). First, a case where network layer processing is performed will be described.

(1) When performing network layer processing When the output I / F of the connection identifier analysis unit 1105 is the CPU board 1100, the AAL frame is transferred from the reception buffer 1003 of the ATM NIC 1000 to the network layer protocol selection unit 1101.

  The network layer protocol selection unit 1101 removes the header / trailer of the data in the AAL frame to the corresponding network layer processing unit (IP processing unit 1103, IPX processing unit 1104, etc.) according to the protocol type field in the AAL frame to form a datagram. Convert and pass. The network layer processing unit performs processing unique to each network layer. For example, the IP processing unit 1103 reduces the TTL field in the packet and selects a router to be sent next from the destination address.

  The datagram processed by the network layer processing unit attaches a header having a protocol type field indicating the network layer to the datagram by the network layer protocol multiplexing unit 1102. Then, the output VPI / VCI is obtained from the address of the router selected above, and the datagram to which the header is attached is converted into an AAL frame. A transfer destination memory address is designated in the transmission buffer 1006 of the I / F that outputs this AAL frame and transferred. Further, the output VPI / VCI obtained above is added and written to the transmission buffer 1006. After the AAL transmission processing unit 1007 divides the AAL frame in the transmission buffer 1006 into ATM cells, the ATM transmission unit 1008 Is output to the ATM network using the output VPI / VCI written in the transmission buffer 1006.

  In the above description, the output AAL frame and the output VPI / VCI are separately transferred to the output ATMNIC. However, the AAL frame and the output VPI / VCI can be simultaneously transferred.

When the output I / F is an Ethernet ^(R) for NIC2000 transfers the AAL frame obtained by converting the datagram it has been processed at the network layer processing unit in the transmission buffer 2005. Then, when converting to an AAL frame, an Ethernet ^(R) address is determined from the address of the selected router (next-layer network layer address), and this Ethernet ^(R) address is added and written to the transmission buffer 2005. . Thereafter, the AAL frame in the transmission buffer 2005 is added with the Ethernet ^(R) address and transmitted from the Ethernet ^(R) transmission unit 2006.

(2) In the case of AAL transfer When the output I / F is other than the CPU board 1100 in the connection identifier analysis unit 1105, the AAL frame is sent to the output I / F written in the connection management table through the general-purpose bus. The position of the transmission buffer 1006 for the output I / F and the output I / F are designated. The AAL frame is transferred from the ATM NIC to another ATM NIC by one of the two transfer methods described above, and stored in the transmission buffer 1006 of the transmission I / F. At this time, the connection identifier analysis unit 1105 enters the VPI / VCI to be transmitted in the transmission buffer 1006. Next, the AAL transmission processing unit 1007 converts the AAL frame into an ATM cell, and the ATM transmission unit 1008 transmits the ATM cell to the ATM network using the VPI / VCI entered in the transmission buffer 1006.

  In the above, the output AAL frame and the output VPI / VCI are separately transferred to the output ATMNIC, but the connection identifier analysis unit 1105 changes the input VPI / VCI of the reception buffer 1003 to the output VPI / VCI, and the AAL frame And the output VPI / VCI can be simultaneously transferred to the transmission buffer.

When the output I / F is NIC2000 for Ethernet ^(R), there is a method of AAL transfer the following two. One is that the AAL frame is sent from the ATM NIC that received the ATM cell to the Ethernet ^(R) NIC of the output I / F written in the connection management table in the same manner as in the case where the output I / F is ATM NIC. In addition to the transfer, the connection identifier analysis unit 1105 enters the next-stage network layer address written in the connection management table in the transmission buffer 2005. In this case, the Ethernet ^(R) transmitting unit 2006 has a function of determining the Ethernet ^(R) address from the next-stage network layer address, and the corresponding Ethernet from the next-stage network layer address written in the transmission buffer 2005 is added. ^{(R) An} address is obtained, added to the AAL frame in the transmission buffer 2005, and transmitted to the network.

The other is provided as a function of the network layer protocol multiplexing unit 1102 (see the description in the case of network layer processing ^), and only the function of determining the Ethernet ^(R) address from the next network layer address. It is a method to divert. In this case, the AAL frame is transferred from the ATM NIC that has received the ATM cell, and the corresponding network address is obtained from the address along the next-stage network written in the connection management table, and this Ethernet ^(R) address is transmitted. It will fill in the buffer 2005.

  By using the above method, multiple normal ATM NICs or non-virtual connection NICs can be pointed to the general-purpose bus, and high-speed transfer can be performed by transferring the AAL frame without network layer processing. .

  Next, FIG. 15 shows an embodiment obtained by modifying FIG. 14 described above. Since the operation is almost the same, only the differences are shown. In FIG. 14, the connection identifier analysis unit 1105 is provided in the CPU board 1100, whereas in FIG. 15, each ATMNIC 1000 has a connection identifier analysis unit 1009. As a result, an additional mechanism of the ATM NIC 1000 is required, but the processing on the CPU board 1100 is not necessary, and the processing of the CPU is lightened.

In FIG. 16, by preparing a plurality of general-purpose buses, cards connected to other general-purpose buses are not affected by AAL frame transfer between ATM NICs or between ATM NICs and non-virtual connection NICs. Is. ATM NIC1000 and NIC2000 Ethernet ^(R) described above is connected to the general purpose bus 2. Display card NIC2000 except for the ATM NIC1000 and Ethernet ^(R) is connected to the general purpose bus 1. The general-purpose buses are connected by a bridge 1200. As a result, the AAL frame transferred between the ATM NICs or between the ATM NIC and the non-virtual connection NIC is transferred only within the general-purpose bus 2, and does not reach the general-purpose bus 1 by the bridge 1200. Since the CPU 1100 and the display card 1300 do not affect what is connected to other than the general-purpose bus 2, the influence of AAL transfer can be reduced.

  The present invention is not limited to the above-described embodiment, and can be implemented with various modifications within the technical scope thereof.

The figure which shows the structural example of the transmitter used for embodiment of this invention The figure which shows the structure of the router apparatus which concerns on the 1st Embodiment of this invention. The figure which shows the structure of the datagram identifier analysis part of the embodiment The figure which shows the structure of the connection identifier analysis part of the embodiment The figure for demonstrating the operation | movement of the datagram transfer of the embodiment The figure which shows the other structural example of the router apparatus of the embodiment The figure which shows the further another structural example of the router apparatus of the embodiment. The figure which shows the structure of the router apparatus which concerns on the 2nd Embodiment of this invention. The figure which shows the structure of the connection identifier analysis part of the embodiment The figure for demonstrating the operation | movement of the datagram transfer of the embodiment The figure which shows the other structural example of the router apparatus of the embodiment The figure which shows the structure of the router apparatus which concerns on the 3rd Embodiment of this invention. The figure which shows the other structural example of the router apparatus of the embodiment The figure which shows the structure of the router apparatus which concerns on the 4th Embodiment of this invention. The figure which shows the other structural example of the router apparatus of the embodiment Diagram showing an example of connection configuration using multiple general-purpose buses The figure which shows an example of the conventional router apparatus The figure which shows the other example of the conventional router apparatus

Explanation of symbols

1 ... datagram analysis unit, 3 ... I / F, 4 ... transmission _{unit, 10 1 ~10 3 ... I /} F, 11 1 ~11 3 ... receiving unit, 12, 12 ₁ to 12 ₃ ... connection identifier analysis unit, 13 _{1 to} 13 ₃ ... transmission unit, 21, 21 _{1 to} 21 ₃ ... datagram analysis unit, 22, 22 _{1 to} 22 ₃ ... datagram processing unit, 30 ... transfer unit, 41, 42 ... virtual connection type LAN, 43 , 44 ... Non-virtual connection type LAN, 50 ... Data link / data frame conversion unit, 60 ₁ , 60 ₂ , 61 _{1 to} 61 ₃ ... Scheduler, 1000 ... ATM NIC, 1001 ... ATM reception unit, 1002 ... AAL reception processing unit , 1003 ... reception buffer, 1004 ... bus transmission unit, 1005 ... bus reception unit, 1006 ... transmission buffer, 1007 ... AAL transmission processing unit, 1008 ... ATM transmission unit, 1009 ... connection 1101 ... Network board protocol selection unit, 1102 ... Network layer protocol multiplexing unit, 1103 ... IP processing unit, 1104 ... IPX processing unit, 1105 ... Connection identifier analysis unit, 1021, 1029, 1031 ... General-purpose bus, 1023, 1025 ... ATM network, 1027 ... Internal bus, 1200 ... Bridge, 1300 ... Display card, 2000 ... NIC for Ethernet ^(R) , 2001 ... Ethernet ^(R) receiver, 2002 ... Receive buffer, 2003 ... Bus transmission unit, 2004 ... Bus reception unit, 2005 ... Transmission buffer, 2006 ... Ethernet ^(R) transmission unit

Claims (13)

In router devices that transfer datagrams between networks,
A plurality of connection interfaces for connecting to a plurality of networks including at least one virtual connection network and at least one non-virtual connection network;
Storage means for storing the correspondence between the virtual connection identifier and the connection interface as the transfer destination and the correspondence between the virtual connection identifier and the network address;
Based on a virtual connection identifier of a datagram input from a virtual connection via the connection interface connected to a virtual connection network, the datagram is transferred by referring to the correspondence stored in the storage means First connection identifier analyzing means for determining a connection interface to be a destination;
Based on the virtual connection identifier of the datagram input from the virtual connection, a second connection for determining a network address as a transfer destination of the datagram with reference to the correspondence stored in the storage means An identifier analysis means;
First transfer means for transferring the datagram to the connection interface when the connection interface as the transfer destination is determined by the first connection identifier analysis means;
When the transfer destination network address is determined by the second connection identifier analyzing means, the datagram is transferred to the connection interface connected to at least one non-virtual connection network indicated by the network address. A router apparatus comprising: a second transfer unit.   The router apparatus according to claim 1, wherein the connection interface serving as the forwarding destination sends the datagram to a data link address determined based on a network address determined as the forwarding destination.   The router apparatus according to claim 1, wherein the transfer destination of the datagram is determined without referring to the content of the datagram. In a data transfer method for transferring a datagram between networks using a router device having a plurality of connection interfaces for connecting to a plurality of networks including at least one virtual connection network and at least one non-virtual connection network,
Storing in the storage means of the router device the correspondence between the virtual connection identifier in the virtual connection network and the connection interface and the correspondence between the virtual connection identifier and the network address in the non-virtual connection network;
Based on a virtual connection identifier given to a datagram inputted to the router device from a virtual connection through the connection interface connected to a virtual connection network, the correspondence relation stored in the storage means is referred to. A first determination step of determining a connection interface to which the datagram is transferred;
Based on a virtual connection identifier given to a datagram inputted to the router device from a virtual connection through the connection interface connected to a virtual connection network, the correspondence relation stored in the storage means is referred to. A second determination step of determining a network address to which the datagram is transferred;
A first transfer step of transferring the datagram to the connection interface when the connection interface as the transfer destination is determined in the first determination step;
A second transfer of the datagram to the connection interface connected to at least one non-virtual connection network indicated by the network address when the transfer destination network address is determined in the second determination step; A data transfer method comprising the steps of:   5. The data transfer method according to claim 4, wherein, in the second transfer step, the datagram is transmitted to a data link address determined based on a network address determined as a transfer destination.   5. The data transfer method according to claim 4, wherein, in the second determination step, the transfer destination of the datagram is determined without referring to the content of the datagram. In a data transfer method for transferring a datagram between networks using at least two router devices having a plurality of connection interfaces for connecting to a plurality of networks including at least one virtual connection network,
In a storage means provided in a router device, a storage step of storing a correspondence relationship between a virtual connection identifier in the virtual connection network and the connection interface;
Based on the virtual connection identifier of the datagram inputted to the certain router device from the certain virtual connection via the connection interface connected to the virtual connection network, referring to the correspondence relation stored in the storage unit, A determining step for determining a connection interface to which the datagram is transferred;
A forwarding step for forwarding the datagram to the connection interface determined by the determining step;
A first sending step for sending the datagram via a second virtual connection set between the connection interface and another router device;
In the other router device, a reception step of receiving the datagram transmitted by the certain router device via the second virtual connection;
A deletion step of deleting a virtual connection identifier in the virtual connection network from the datagram;
A second sending step for sending the datagram from the other router device to the network to which the router device is connected without using the virtual connection identifier in the virtual connection network in the other router device. A data transfer method characterized by the above.   8. The data transfer method according to claim 7, wherein, in the second sending step, when the datagram is sent from the other router device, the datagram is sent by a non-virtual connection.   In the second sending step, when the datagram is sent from the other router device, the datagram is sent to a network indicated by a network address associated with the datagram. The data transfer method according to 7 or 8.   In the second transmission step, when the datagram is transmitted from the other router device, the data is directed toward the network indicated by the network address associated with the datagram without referring to the content of the datagram. The data transfer method according to claim 7, wherein a gram is transmitted. In a data transfer method for transferring a datagram between networks using a router device having a plurality of connection interfaces for connecting to a plurality of networks including at least one virtual connection network,
A storage step of storing a correspondence relationship between a virtual connection identifier and a connection interface in the virtual connection network in the storage unit of the router device;
A connection interface for transferring a datagram input from a certain virtual connection set in the virtual connection network is stored in the storage unit based on a virtual connection identifier of the virtual connection when the datagram is received. A determining step for determining with reference to the correspondence relationship;
A transfer step of transferring the datagram to the determined connection interface to be transferred;
A data transfer method comprising: a sending step of sending the datagram from the router device without using a virtual connection identifier in the virtual connection network. In a data communication network system including a plurality of router devices for transferring datagrams between networks,
The first router device
A first connection interface group comprising a plurality of connection interfaces for connecting to a plurality of networks including at least one virtual connection network;
A first storage means for storing a first correspondence between a first input virtual connection identifier in the virtual connection network and a connection interface serving as a first transfer destination to which the datagram is to be transferred;
The first correspondence stored in the first storage means based on the first input virtual connection identifier of the first datagram input from the first input virtual connection set in the virtual connection network A first connection identifier analyzing means for determining a connection interface to be a first transfer destination of the datagram;
First transfer means for transferring the first datagram to the connection interface serving as the first transfer destination determined by the first connection identifier analyzing means;
The second router device
A second connection interface group comprising a plurality of connection interfaces for connecting to a plurality of networks including at least one virtual connection network;
A second input virtual connection identifier in the virtual connection network and a second network address used when connecting at least one non-virtual connection network to the second connection interface group consisting of the plurality of connection interfaces. A second storage means for storing the correspondence relationship;
The second correspondence relationship stored in the second storage means based on the second input virtual connection identifier of the second datagram input from the second input virtual connection set in the virtual connection network A second connection identifier analyzing means for determining a connection interface to be a second transfer destination of the datagram;
Data communication comprising: second transfer means for transferring the second datagram to the connection interface serving as the second transfer destination determined by the second connection identifier analyzing means. Network system. Data transfer for transferring datagrams between networks using a first router device and a second router device having a plurality of connection interfaces for connecting to a plurality of networks including at least one virtual connection network In the method
In a first storage means provided in the first router device, a first virtual connection identifier in a virtual connection network and a first connection interface serving as a first transfer destination to which the datagram is to be transferred A first storage step for storing the correspondence relationship;
Based on the virtual connection identifier of the datagram input to the first router device from the first virtual connection set in the virtual connection network, the first correspondence relationship stored in the first storage means is obtained. A first determination step of determining a connection interface to which the datagram is transferred;
A first transfer step of transferring the datagram input from the first virtual connection to the connection interface serving as the first transfer destination determined in the first determination step;
When at least one non-virtual connection network is connected to the second storage means provided in the second router device, the second virtual connection identifier in the virtual connection network, and the connection interface of the second router device A second storage step for storing a second correspondence relationship with a connection interface serving as a second transfer destination to which the datagram is to be transferred, connected to the next-stage network address used in
Based on the virtual connection identifier of the datagram input from the second virtual connection set in the virtual connection network to the second router device, refer to the second correspondence stored in the second storage means A second determination step of determining a connection interface to which the datagram is to be transferred;
And a second transfer step of transferring the datagram input from the second virtual connection to the connection interface serving as the second transfer destination determined in the second determination step. Data transfer method.

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