JP3315849B2 - Node device, network system and network system construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet routing technique in a network system in which a plurality of node devices are connected via a transmission line.

[0002]

2. Description of the Related Art In a large-scale network system, a packet transmitted from a transmitting device is transmitted to a remote receiving device via some node devices. In such a network system, in order to ensure connection quality and reliability, a plurality of paths that follow different node devices and transmission paths are prepared as paths (packet paths) between the transmitting device and the receiving device. Often done. Here, conventionally,
The routing of a packet according to such a path is performed in each node device according to a correspondence between a transmission destination and a transmission destination registered in a routing table provided in advance. It was realized by relaying.

A technique related to such conventional packet routing is described in the 22nd edition of "1988 Handbook of the Institute of Electronics, Information and Communication Engineers, Vol. 2" (The Institute of Electronics, Information and Communication Engineers, Ohmsha). Section 1 Basic structure of exchange The technique described in H.2114 is known.

[0004]

In the packet routing technique in the network system described above, the routing of the packet is realized by providing a routing table in each node device. When changing the configuration,
It is necessary to update the registered contents of the routing table as well.

[0005] However, updating the registered contents of the routing table requires some special means or manual operation.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a network system which does not require updating the routing table of each node device even when the configuration of the network system is changed. Another object is to provide a method for constructing such a network system.

[0007]

To achieve the above object, the present invention provides, for example, a node device used in a network system in which a plurality of node devices are connected by a transmission line, each of which is connected to one transmission line. A command packet received from a transmission line connected to the main port of one of the two port groups having one main port and one or more subports, and the destination of the command packet is not the own node device In this case, the configuration of the network system for relaying to a transmission path connected to each of the main port and the sub port of the other port group
Independent means and a command packet received from a transmission path connected to the main port of one of the port groups, when the destination of the command packet is the own node device, the command packet is taken in, and a response to the command packet is taken. Means for transmitting a response packet to a transmission path connected to a main port that has received the command packet , independent of the configuration of the network system .

Further, a network system constructed using such a node device, that is, a plurality of node devices, a plurality of ports each connecting a transmission line, and a command packet addressed to the node device is transmitted from each port. And at least two main ports of each of the two port groups of each of the node devices are connected to each of the terminal devices by one transmission line or a plurality of The one or more paths connected by a transmission path and one or more other node devices and connecting each of the node devices and each of the terminal devices;
In the above route, all of the other node devices existing in the route receive a command packet from the terminal device on the main port of one port group from the transmission line forming the route,
A path for transmitting the command packet from the main port or the sub port of the other port group to a transmission path forming a path, or a path consisting of only a transmission path connected to a port of the terminal station device. To provide a network system.

[0009] Further, a method for constructing such a network system is provided. That is, a plurality of the above-described node devices, a plurality of ports respectively connecting the transmission lines, a means for transmitting a command packet addressed to the node device from each port, and a response to the command packet received by each port and transmitted by itself. A method for constructing a network using two terminal devices having means for capturing a response packet, which is a primitive network system in which one port of the two terminal devices is connected to each other. However, the following rules (i), (ii) and (iii) (i) When adding a new node device at a position obtained by dividing an existing transmission line into two transmission lines, The main port of one port group and the main port of the other port group are respectively connected to the other ends of the two divided transmission lines to which no node device or terminal device is connected.

(Ii) When an additional transmission line is added between two node devices connected by an existing transmission line, the existing transmission line connecting the two node devices of the two node devices is The sub ports of the port group to which the connected main port or sub port belongs are connected to each other by a new transmission path.

(Iii) When a transmission line is further added between the terminal device and the node device connected by the existing transmission line, the existing node device connects the terminal device and the node device. A sub-port of a group of ports to which a main port or a sub-port to which a transmission line is connected and a port not used by the terminal station device are connected by a new transmission line. In order to construct a network system by sequentially adding node devices and transmission paths according to the following.

According to such a construction method, the configuration of the network system described above can be obtained. In the above-described network system, a command packet transmitted from each terminal device is transmitted to the other node devices existing in the route from the transmission line forming the route through the main port of one port group. A path for receiving a command packet from the device and transmitting the command packet from the main port or sub port of the other port group to a transmission path forming a path, or a path consisting of only a transmission path connected to the port of the terminal device Therefore, the command packet is always relayed to the destination node device by the fixed routing of each node device. In addition, other command packets that follow the path from which the command packet is received at the subport of the node device are discarded without being relayed.

That is, according to the present invention, there is provided a network system for transmitting a command packet from two terminal devices to each node device. Further, in such a network system according to the present invention, if the above-described features are maintained, processing such as changing the routing table even when the configuration of the network system is changed by adding a node device is performed. do not need. Further, the proliferation of unnecessary command packets can be suppressed to some extent. In addition, it is possible to prevent the propagation of command packets that are unnecessary to some extent.

The examples of the node device, the network system, and the method of constructing the network system provided by the present invention have been described above.

[0015]

Embodiments of a network system according to the present invention will be described below.

First, FIG. 1 shows a configuration of a node device used in the network system according to the present invention. This node device is used as a node device of a network system as shown in FIGS. 2 (1), (2) and (3). In FIG. 2, reference numeral 10 denotes a node device, and reference numeral 6 denotes a transmission line connecting the node devices.

Now, in the node device shown in FIG.
1 is a packet processing unit, 2 is an overall control unit, 3 is a frame processing unit, 4 is a modem unit, 5 is a LAPB frame insertion / extraction unit,
6 is a transmission line.

As shown in FIG. 1, six transmission lines 6 can be connected to the node device. The connection port of each transmission path 6 is called a port. The six transmission lines 6 are divided into two groups every three lines. In this description,
For convenience, one group will be called the E side and the other group will be called the W side. That is, this node device has three ports on each of the E side and the W side. Accordingly, one-to-one, one-to-two, one-to-three connections are possible for the W or E side as shown in FIGS. 2a, 2b and 2c.

Here, in the first embodiment, one port is selected as a port of a different type from the other ports on each of the E side and the W side. In the following description,
The selected port is called an M (main) port, and the remaining ports are called S (sub) ports. In FIG. 1, the three transmission paths on the left are transmission paths on the E side, and the three transmission paths on the right are
The book is the transmission path on the E side. The uppermost transmission line on the E side and the W side is connected to the M port, and the remaining ports are the S ports. In this description, each transmission path is described as an optical fiber transmission path for transmitting an optical signal.

Next, the LAPB processing unit 1 includes six LAPB control units 110 and a memory 120 connected to each other by a common bus.
And a processor 130. Further, the LAPB control unit 110 includes the transmission buffer 103 and the reception buffer 10.
2. It is composed of a LAPB protocol control unit 101.

In such a configuration, for example, an optical signal input from the W-side transmission path 6 is
Demodulated to an electrical signal by LAPB frame insertion / extraction unit 5
Passed to. The LAPB frame insertion / extraction unit 5 recognizes a communication frame on the received signal, extracts a LAPB frame included in a predetermined position in the recognized communication frame, and
Transfer to LAPB processing unit 1. Further, the communication frame from which the extracted LAPB frame is deleted is passed to the frame processing unit 3. next,
The frame processing unit 3 converts the communication frame passed from the LAPB frame insertion / extraction unit 5 into a communication determined in accordance with the destination of the communication frame described in the header of the communication frame, a predetermined routing table, and the like as in the related art. The frame is passed to the LAPB frame insertion / extraction unit 5 corresponding to the port on the E side connected to the transmission line to relay the frame. Upon receiving the communication frame, the LAPB frame insertion / extraction unit 5 places the LAPB received from the LAPB processing unit 1 at a predetermined position in the communication frame.
The frame is inserted and passed to the modem 4. The modulation / demodulation unit 4
An electrical signal representing the received communication frame is modulated into an optical signal and output to a transmission line to be connected.

On the other hand, the LAPB control section 110 of the LAPB processing section 1 having received the LAPB frame from the modulation / demodulation section 5 causes the LAPB protocol processing section 101 to store the packet stored in the information section of the LAPB frame in the reception buffer 102, The processor 130 is notified that there is a received packet. The processor 130 that has received the notification transfers the information stored in the reception buffer 102 to the memory 120, analyzes the information, and controls the routing of the packet. That is, whether the packet is addressed to the own node device, whether the port receiving the packet is an M port or an S port,
Depending on the type of the packet, etc., it is determined whether or not the LAPB frame is to be relayed, to which port to relay the LAPB frame (it may be relayed to a plurality of ports), and whether or not to pass the packet to the overall control unit 2. . If a packet is to be passed to the overall control unit 2, the packet is passed to the overall control unit 2,
When a packet is to be relayed, the packet captured in the memory 120 is transferred to the transmission buffer 103 of the LAPB processing unit 110 corresponding to the port on the E side to be relayed. Further, even when the processor 130 receives a packet to be transmitted from the overall control unit 2, the processor 130 transmits the packet to the transmission buffer 103 of the LAPB processing unit 110 corresponding to the port to which the packet is to be transmitted.
This packet is transferred to The details of the above-described routing control of the packet by the processor 130 will be described later.

The protocol processing unit 101 of the LAPB control unit 110, which has received the packet from the processor 130 and transferred to the transmission buffer 103, stores the LA in which the packet is stored.
A PB frame is created and passed to the LAPB frame insertion / extraction unit 5. As described above, the LAPB frame is inserted into a predetermined position of the communication frame by the LAPB frame insertion / extraction unit 5 and output to the transmission line 6 via the modulation / demodulation unit 4.

As described above, in the node device according to the present embodiment, the routing of the packet stored and transferred in the communication frame and the LAPB frame constructed on the communication frame is performed independently. In the present embodiment, the routing of the packet is realized by fixed routing in the node device.

Here, the relationship between the communication frame, the LAPB frame, and the packet will be described.

FIG. 3 shows the relationship between the communication frame, the LAPB frame, and the packet.

As shown in (1) in the figure, the communication frame is
It consists of a header part and a data part. The header section includes other management / control information of the communication frame. The data section stores data actually transmitted and received by the user.

As shown in (2) in the figure, the LAPB frame is a link access procedure-balanced (LAPB) adopted in CCITT Recommendation X.25 X.75, which is one of HDLC.
And has a header section and an information section. LAPB in the header
Frame type (information format used for transferring information of upper layer, unnumbered format used for connection control of logical link, etc.) and contents (command SABM, DISC, UI
) Is stored, and the address of the source or destination is stored. In the present embodiment, the information format
The packet is stored in the information section of the LAPB frame.

Here, as shown by the broken lines in the figure, each bit forming one LAPB frame is divided and stored at a predetermined position in a header portion of a plurality of communication frames and transferred. The above-described LAPB frame extraction / insertion unit 5 actually extracts and inserts these bits.

Next, the packet stored in the information section of the LAPB frame in the information format is composed of a data destination and a transmission source, data, a type indicating the type of data, and the like as shown in (3) in the figure. You. As the data, (4)
As shown in (5), there are command data and response data. Corresponding to this, there are types such as command and response.

Here, the control of the connection of the logical link for transmitting and receiving the LAPB frame between the adjacent node devices is performed by the LAPB control unit 1 of the packet processing unit 1.
01 is performed by the LAPB protocol control unit 101.

FIG. 4 shows a typical communication sequence of a LAPB frame.

The figure shows a LAPB frame extraction / insertion unit 5, a modulation / demodulation unit 4, a transmission / reception unit 4, between the LAPB protocol control units 101 of two adjacent (directly connected via transmission lines) node devices (1) and (2). 6 shows the LAPB frame transmitted / received via the P.6.

As shown in the figure, the connection of the logical link is, for example, a command SABM (asynchronous balanced mode) in an unnumbered format transferred from the LAPB protocol controller 103 (1) to the other LAPB protocol controller 103 (2). LAPB protocol control unit 1 according to the LAPB frame
03 (2) is an unnumbered command that accepts this
This is set by transferring a LAPB frame of UI (unnumbered information) to the LAPB protocol control unit 103 (1).

When the logical link is established, the two LAPB protocol controllers 103 (1) and 103 (2) mutually exchange the information format LAPB.
Information (packets in the present embodiment) can be transmitted and received using the frame I. That is, also in the present embodiment, the LAPB protocol control unit 1 actually performs the operation related to the packet in the node device described above.
03 makes such a logical link connection.

As shown in the figure, the disconnection of the logical link of the LAPB frame is performed by, for example, the APB protocol controller 1.
03 (1) to the other LAPB protocol control unit 103
According to the LAPB frame of the command DISC (disconnection) in the unnumbered format transferred to (2), the LAPB protocol control unit 1
03 (2) is an unnumbered command that accepts this
This is set by transferring a LAPB frame of UI (unnumbered information) to the LAPB protocol control unit 103 (1).

Now, details of the above-described packet routing control in the node device will be described.

That is, the packet processing unit 1 of the node device
Processor 130 performs packet routing according to the following rules.

I. When the Type of the Received Packet is a Command (i) If the type of the received packet is a command and the port that received the packet is an S port, the packet is discarded. That is, the packet received at the S port is discarded without being relayed to another node device or taken into the own node device.

(Ii) The type of the received packet is a command, the port receiving the packet is an M port,
When the destination is the own node device, the general control unit 2
Transfer the contents of the packet. Also, a response packet is transmitted from the M port that has received the command packet to the node device that has transmitted the command packet. That is, the packet received by the M port is taken into the own node device and the response packet is transmitted from the M port, and is not relayed to another node device.

(Iii) If the type of the received packet is a command, the destination is not the own node device, and the port receiving the packet is the M port on the E side, the M port on the W side and the S port In each LAPB control unit 100 corresponding to all
Forward the packet. That is, from the M port on the E side,
The packet is relayed to all the other node devices connected to the side.

(Iv) If the type of the received packet is a command, the destination is not the own node device, and the port that received the packet is the M port on the W side, the M port on the E side and the S port The packet is transferred to each LAPB control unit 100 corresponding to all of the packets. In other words, from the M port on the W side, E
The packet is relayed to all the other node devices connected to the side.

II. When the type of the received packet is a response (i) When the type of the received packet is a response and the destination is its own node device, the contents of the packet are transferred to the overall control unit 2. I do. That is, the packet is fetched into the own node device, and is not relayed to another node device.

(Ii) If the destination is not the own node device and the port that received the packet is the port on the E side, the packet is transferred to each LAPB control unit 100 corresponding to the M port on the W side. In other words, the port on the W side
The packet is relayed to another node device connected to the M port.

(Iii) If the destination is not the own node device and the port receiving the packet is the W-side port,
The packet is transferred to each LAPB control unit 100 corresponding to the M port on the E side. That is, the packet is relayed from the received port on the W side to another node device connected to the M port on the E side.

III. Transmission of Command Packet The node device that transmits the command packet as a transmission source includes both the M port and the S port of the W side and the E side connected to another node device. Send packets of the same command to the same destination.

The node device according to the present embodiment has been described above.

Hereinafter, a network system using such a node device will be described.

Here, a network system capable of performing appropriate routing by controlling the packet routing in each of the above-described node devices even when the configuration of the network system is changed due to the addition of the node device will be described.

A method for constructing a network according to the present embodiment will be described.

First, a command packet is received from the two node devices between the two node devices.
A case where another node device for transmitting a response packet is provided in one node device or a case where another node device is added will be described. In addition, such a structure is 2
A node device for relaying a communication frame is provided between two node devices, and when setting up a plurality of paths for a communication frame, a command for inquiring about the status of the relay node device is transmitted from the node devices at both ends in a packet. Each relay node device can be used as a configuration for notifying its own status to the node devices at both ends by a response packet.

The construction of the network system in this case is performed according to the following rules. That is, first, FIG.
As shown in (1), the E side M port of the node device F
Consider a primitive network system in which the W side M port of the node device G is connected by a transmission line e. This primitive network
The network may be an existing network system that actually exists, or may be virtually assumed when constructing the network system.

When a new node device is added to a position where a certain transmission line is divided into two transmission lines, two W / M ports and two E port M ports of the additional node device are added. Connect the end to which the other node of the transmission path is not connected. Further, when a transmission path is further added between two node apparatuses already connected by one transmission path, an existing transmission path connecting the two node apparatuses of the two node apparatuses is connected. The S ports on the same side as the connected side are connected by a new transmission line.

That is, for example, in the primitive network shown in FIG. 5A, when two node devices F and G are divided into connection transmission lines and one node device H is provided therebetween, FIG. As shown in (2), the transmission line e is divided into a transmission line f and a transmission line g, and the W side M port of the node device H to be added is connected to the E side of the transmission line f. Further, the E side M port of the additional node device H is connected to the W side of the transmission path g at the other end.
Connect

When it is desired to duplicate the transmission path between the nodes in this network, as shown in FIG. 5 (3), the E side S ports of the node devices F and H are connected to the network. Transmission path h,
Connect i. Also, the S ports on the W side of the node devices H and G
To the transmission lines h and i.

As shown in FIG. 5 (4), when the transmission path h is further divided and a node device I is added in between, the transmission path h is divided into two and the transmission path j is added to the E side. The node M side W port is connected. Also, if the transmission path h is 2
On the W side of the other divided transmission line k, the E
Connect the side M port. Further, in the case where the transmission path i is further divided and the node device j is added during the division, the node device J is added between the transmission lines 1 and m obtained by dividing the transmission line i into two in the same procedure. be able to.

According to the network system constructed as described above using the above-described node devices, a command packet is transmitted from the node devices F and G at both ends of FIG. 5 to any other node device. This indicates that the packet can be forwarded, and that a response packet can be forwarded from any other node device to the node devices F and G at both ends.

FIGS. 6 (1) to 6 (3) show how command packets are routed in the network system shown in FIGS. 5 (2) to 5 (4).

As an example, the case of the network system of FIG. 5D will be described. For example, when a command packet is transmitted from the node device F to the node device J, as shown in FIG. The packet transmitted from F is input to the W side M ports of the node devices H and I, and is relayed to the E side M and S ports of the node devices H and I. The packet issued from the E side M port of the node device I is input to the W side S port of the node device H, and is discarded by the node device H. The location is indicated by x.

The packets issued from the E side M port and the S port of the node device H are transmitted to the W of the node devices F and J.
It is input to the side M port. The node device J that has received the packet addressed to the own node device captures the packet. That is, the packet of the command transmitted from the node device E to the node device j is transmitted to the destination without being lost on the way in the network system constructed by the construction method described above using the node device shown above. Routed to node device J. FIG.
(3) As understood from the above, the packet of the command transmitted from the node device F to the node device H or the node device I is similarly arrived at the destination node device and taken in by the destination node device. become.

On the other hand, as shown in FIG. 6 (3), the same applies to the case where a command packet is transmitted from the node device G. For example, a command packet is transmitted from the node device G to the node device I. In this case, the packet transmitted from the node device G is input to the E side M ports of the node devices H and J, and is relayed to the W side M and S ports of the node devices H and J. The packet transmitted from the W side M port of the node device J is input to the E side S port of the node device H, and is discarded by the node device H. The location is indicated by x. on the other hand,
The packets issued from the W-side M port and the S port of the node device H are input to the e-side M ports of the node devices F and I. The node device I that has received the packet addressed to the own node device captures the packet. That is, the packet of the command transmitted from the node device G to the node device I uses the node device shown above, and in the network system constructed by the construction method described above,
The destination node device I without being lost on the way
Routed to. Also, as can be understood from FIG. 6C, the packet of the command transmitted from the node device G to the node device H or the node device J also reaches the destination node device in the same manner. Will be captured.

Further, as indicated by the mark x in the figure, some unnecessary packets can suppress unnecessary propagation of packets discarded in the node device to some extent.

FIGS. 7 (1) to 7 (3) show how the response packet is routed in the network system shown in FIGS. 5 (2) to 5 (4).

As an example, the case of the network system of FIG. 5D will be described. For example, when a response packet is transmitted from the node device J to the node device E, as shown in FIG. The device J outputs the response packet to the W-side M port. Then, the node device H receives the response packet from the W-side S port and relays the packet to the E-side M port. The node device E that has received this packet confirms that the destination of the packet is its own node device, and takes in the packet. Also,
When transmitting a response packet from the node device I to the node device F, the node device I outputs the response packet to the E-side M port. Then, the node device H receives a response packet from the E side S port and sends it to the W side M port.
Relay to Node device F that has received this packet
Confirms that the destination of the packet is its own node device,
Capture this packet. Further, a packet of a response from the node device H to the node device E or the node device F is transferred and captured on a transmission path connecting the node device H and the M port of the destination node device.

Next, when constructing a network provided with another node device which receives a command packet from one node device and transmits a response packet to this node device, or in a network system such as this, The case where the node device is added will be described.

The construction of the network system in this case is performed in accordance with the following rules. That is, as shown in FIG. 8A, first, a primitive network consisting of one node device A for transmitting a command packet. Thinking about

When adding a node device to be connected to a certain existing node device, the M port on the W side of the node device to be added is replaced with the unused M port or S port on the E side of the existing node device. And a transmission line.

For example, as shown in FIG. 8B, when a node device B connected to the node device A is added,
The W-side M port of the additional node device B is connected to the transmission path a connected to the E-side S port of the node device A. Further, when a node device C to be connected to the additional node device B is added, the transmission line b is connected to the E side M port of the node device B, and the W side of the node device C is further connected to the transmission line b. Connect the M port.

When a node device D connected to the node device A is further added, a transmission line c connected to an unused S port on the E side of the node device A is added.
The W-side M port of the additional node device D is connected to the transmission line c. When the node device E connected to the node device B is added, since the transmission line b is already connected to the E side M port of the node device B, the transmission line d is connected to the E side S port. And the W side M port of the node equipment E to be added is connected.

FIGS. 9 (1) and 9 (2) show how a command packet is routed in the network system shown in FIGS. 8 (2) and (3), and FIG. 10 (1) shows how a response packet is routed. (2) Show. As understood from the figure, according to the network system constructed in this way, a command packet can be transmitted from an end node device to an arbitrary node device, and a response from any node device to the node device A can be transmitted. Can return packets.

Next, when constructing a network provided with another node device for receiving a command packet from one node device and transmitting a response packet to this node device, or such a network system A description will be given of another method that can be used when another node device is added to FIG. Now, in this method, the construction of the network system is performed according to the following rules.

That is, also in this case, as shown in FIG. 11A, first, a primitive network consisting of one node device K for transmitting a command packet is considered.

When adding a node device to be connected to a certain existing node device, the M port on the W side of the node device to be added is replaced with the unused M port or S port on the E side of the existing node device. And a transmission line.

When a new node device is added to a position where a certain transmission line is divided into two transmission lines, the W-side M port of the additional node device is set to one of two divided transmission lines. Connected to the transmission line connected to the E-side port of the existing node device, and divided the E-side M port or S port of the additional node device into two existing transmission lines. Connect to the transmission line connected to the W-side port of the device.

When a transmission line is further added between two node devices already connected by one transmission line, an existing transmission line connecting the two node devices of the two node devices is used. The available ports on the same side as the connected side are connected by a new transmission path.

For example, in the case of adding a node device M connected to the node device K in the primitive network system as shown in FIG.
W of the additional node device M is connected to the transmission line o connected to the S port on the
Connect the side M port. Further, an additional node device
To add a node device L connected to M, a transmission line p is connected to the E-side M port of the node device M, and a transmission line p is further added.
To the W-side M port of the node device L.

Further, in this network system, when a further transmission line r is added between the node device M and the node device L, as shown in FIG.
The transmission line r is connected to an unused S port of the node device M, and the transmission line r is connected to an unused S port on the W side of the node device L. In addition, when a new node device N connected to the node device M is added, FIG.
(3) As shown, the transmission line q is connected to an unused S port on the E side of the node device M, and the W side M port of the node device N is connected to the transmission line q.

When the additional node device O is provided at a position where the transmission line p is further divided into two, as shown in FIG. 11 (4), the additional node device O is disposed on the transmission line s where the transmission line p is divided into two. W side M port is connected. The E side M port of the additional node device O is connected to the W side of the transmission line t at the other end.

Here, the routing of the command packet in the network system shown in FIGS. 11 (2) to (4) is shown in FIGS. 12 (1) to 12 (3), and the routing of the response packet is shown in FIG. 1) to (3) are shown. As can be understood from the drawing, according to the network system constructed in this way, a command packet can be transmitted from the end node device K to any node device, and a response from any node device to the node device K can be made. Can be returned.

The network system according to the embodiment of the present invention has been described.

In the above description, both the W side and the E side have S
Although two ports are provided, the number of S ports may be arbitrary. For example, one or three may be used.

Further, in the embodiment, the packet transferred by the LAPB frame has been described as an example, but the present invention can be similarly applied to other packets.

In the above description, the node device located at the end of the network system has been described as having a configuration in which the M port and the S port are provided on both the W side and the E side.
It is not always necessary to provide a port that is not connected to another node device. Also, as understood from the above explanation,
It is not necessary to distinguish between the main port and the subport of the node device located at the end in the network system. Also, in place of the port not connected to another node device,
An appropriate interface with a system outside the network system described above may be provided.

[0084]

As described above, according to the present invention, the present invention can be implemented even when the configuration of the network system is changed.
A network system that does not require updating of the routing table of each node device can be provided. In addition, a method for constructing such a network system can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a node device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a network system configured using the node devices according to the embodiment of the present invention.

FIG. 3 shows a packet used in the embodiment of the present invention;
FIG. 3 is a diagram illustrating a relationship between a LAPB frame and a communication frame.

FIG. 4 is a diagram showing a procedure for establishing and disconnecting a logical link of a LAPB frame.

FIG. 5 is a diagram showing a first construction method of a network system according to the embodiment of the present invention.

FIG. 6 is a diagram showing how command packets are routed in the network system according to the first construction method according to the embodiment of the present invention;

FIG. 7 is a diagram showing how a response packet is routed in the network system according to the first construction method according to the embodiment of the present invention;

FIG. 8 is a diagram showing a second construction method of the network system according to the embodiment of the present invention.

FIG. 9 is a diagram showing how command packets are routed in the network system according to the second construction method according to the embodiment of the present invention;

FIG. 10 is a diagram showing how a response packet is routed in a network system according to a second construction method according to the embodiment of the present invention;

FIG. 11 is a diagram showing a third construction method of the network system according to the embodiment of the present invention.

FIG. 12 is a diagram showing how a command packet is routed in a network system according to a third construction method according to the embodiment of the present invention;

FIG. 13 is a diagram showing how a response packet is routed in a network system according to a third construction method according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 packet processing unit 2 overall control unit 3 frame processing unit 4 modulation and demodulation unit 5 LAPB frame insertion / extraction unit 6 transmission line 101 LAPB protocol control unit 102 reception buffer 103 transmission buffer 110 LAPB control unit 120 memory 130 processor

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masahiro Ito 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Within the Information and Communication Division, Hitachi, Ltd. (72) Inventor Yasuo Amemiya 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd.Information-communications Division (72) Inventor Yukio Kobayashi 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo No. Within Nippon Telegraph and Telephone Corporation (72) Shinji Matsuoka, inventor 3-19-2, Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Yoshiaki Sato 3-19, Nishi-Shinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation (72) Inventor Kazuyuki Matsumura 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Electric (56) References JP-A-7-170279 (JP, A) JP-A-7-264244 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12 / 56

Claims (8)

(57) [Claims] 1. A node device used in a network system in which a plurality of node devices are connected by a transmission line, wherein two port groups each having one main port and one or more subports connected to one transmission line are provided. If a command packet received from a transmission path connected to the main port of one port group is not the own node device, the command packet is connected to each of the main port and the subport of the other port group. Depend on the configuration of the network system that relays to the transmission path
Means have a command packet received from a transmission path connected to the main port of one set of ports, if the destination of the command packet is this node device, fetches the command packet, in response to the command packet Sends a certain response packet to a transmission path connected to the main port that received the command packet
A node device that does not depend on the configuration of the network system . 2. The node device according to claim 1, wherein a response packet received from a transmission line connected to a main port or a subport of one port group is relayed to a transmission line connected to a main port of the other port group. The net
A node device that does not depend on the configuration of the work system . 3. A terminal device comprising: a plurality of node devices according to claim 1; a plurality of ports each connecting a transmission path; and means for transmitting a command packet addressed to the node device from each port. At least two main ports of the two port groups of each of the node devices are respectively connected to each terminal device by one transmission line or a plurality of transmission lines and one or more other node devices. Are connected by one or more routes formed by the at least one node device, and the one or more routes connecting each of the node devices and the terminal devices are all formed by the other node devices existing in the route. A command packet from the terminal device at the main port of one port group from the transmission line to be transmitted, and route the command packet from the main port or subport of the other port group. Route and transmits to the transmission line to form or network system characterized in that it comprises at least one of transmission path only from consisting path connected to the port of the terminal device. 4. The network system according to claim 3, wherein said node device receives a response packet received from a transmission line connected to a main port or a subport connected to one of the port groups, and transmits the response packet to a main port of the other port group. Means for relaying to a transmission path connected to the network, wherein the two terminal devices have means for taking in a response packet which is a response to a command packet transmitted by itself received at each port. system. 5. A terminal device comprising: a plurality of node devices according to claim 1; a plurality of ports each connecting a transmission line; and means for transmitting a command packet addressed to the node device from each port. At least a main port of one port group of each of the node devices is connected to the terminal device by one or more transmission lines or a plurality of transmission lines and one or more other node devices. The one or more routes that connect the node devices and the terminal devices are all connected to the other node devices existing in the route.
A path for receiving a command packet from the terminal device at the main port of one port group from the transmission path forming the path, and transmitting the command packet from the main port or sub port of the other port group to the transmission path forming the path;
Alternatively, the network system includes at least one of a path consisting of only a transmission path connected to a port of the terminal device. 6. The network system according to claim 5, wherein the node device receives a response packet received from a transmission line connected to a main port or a subport connected to one of the port groups, and sends the response packet to a main port of the other port group. Means for relaying to a transmission line connected to the terminal station, wherein the terminal station device has means for receiving a response packet which is a response to a command packet received by each port and transmitted by itself. 7. A plurality of node devices according to claim 2, a plurality of ports each connecting a transmission line, means for transmitting a command packet from each port to the node device, A method for constructing a network using two terminal devices, comprising: means for capturing a response packet that is a response to a transmitted command packet, wherein a primitive connecting one port of the two terminal devices is connected. Assuming a network system, the following rules (i), (ii),
(iii) (i) When adding a new node device at a position obtained by dividing an existing transmission line into two transmission lines, a main port of one port group and the other port group of the added node device Is connected to the other end of the two transmission lines to which no node device or terminal device is connected. (ii) When further adding a transmission line between two node devices connected by an existing transmission line, the existing transmission line connecting the two node devices of the two node devices is connected. The subports of the port group to which the main port or the subport belongs are connected to each other by a new transmission path. (iii) When further adding a transmission path between the terminal device and the node device connected by the existing transmission line, the existing transmission line connecting the terminal device and the node device of the node device is The sub port of the port group to which the connected main port or sub port belongs and the unused port of the terminal device are connected by a new transmission line.
A network system construction method characterized by constructing a network system by sequentially adding a node device and a transmission path according to (1). 8. A plurality of node devices according to claim 2, a plurality of ports each connecting a transmission line, means for transmitting a command packet addressed to the node device from each port, And a terminal device having means for capturing a response packet that is a response to the transmitted command packet, comprising: a source network system including the terminal device; One port group is defined as a W-side port group, and the other port group is defined as an E-side port group.
(ii), (iii), (iv), (v), (vi) (i) When adding a node device connected to the terminal device, the main port of the W-side port group of the added node device Is connected to an unused port of the terminal equipment by a transmission line. (ii) When adding a node device to be connected to an existing node device, replace the main port of the W-side port group of the node device to be added with the unused main port of the E-side port group of the existing node device. Alternatively, it is connected to a sub port by a transmission line. (iii) When a new node device is added at a position where the existing transmission line is divided into two transmission lines, the main node of the W-side port group of the added node device is connected. The port is connected to the transmission line connected to the E-side port of the existing node device of the two divided transmission lines, and the E-side main port or subport of the additional node device is The connection is made to the transmission line connected to the W-side port of the existing node device of the two transmission lines thus obtained. (iv) When a new node device is added at a position where the existing transmission line connecting the terminal device and the node device is divided into two transmission lines, the W-side port of the added node device The main port of the group was connected to the transmission line connected to the port of the terminal device of the two divided transmission lines, and the main port or subport on the E side of the additional node device was divided into two. The connection is made to the transmission line connected to the W-side port of the existing node device of the two transmission lines. (v) When further adding a transmission line between two node devices connected by an existing transmission line, the existing transmission line connecting the two node devices of the two node devices is connected. The unused main ports and sub ports of the port group to which the main port or sub port belongs are connected by a new transmission path. (vi) When further adding a transmission line between the terminal device and the node device connected by the existing transmission line, the sub-port of the W-side port group of the node device and the use of the terminal device are used. Ports that are not connected by a new transmission path. A network system construction method characterized by constructing a network system by sequentially adding a node device and a transmission path according to (1).