JPH06326711A - Interconnection method for networks - Google Patents

Abstract

PURPOSE:To prevent useless line connection by stopping reception supervision of a BPDU when the state of a port transits to blocking during STP operation so as to interrupt the line. CONSTITUTION:LANs 1, 2 are connected via a bridge and data are sent between them. When a state of ports 22b, 23b transits to a blocking state in other receiver side bridges 22, 23 not interposed in a data path of a spanning tree, reception supervision of a composition control BPDU is stopped to interrupt lines 41, 43. Upon the receipt of the BPDU representing revision of topology due to a fault of a bridge 21 or a failure of an HSD40 interposed in the HSD40 being a data path afterward, the lines 41, 43 having been interrupted are connected to attain data communication.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network interconnection method for connecting different networks for data communication, and more particularly to a local area network (LA).
N) regarding the connection method.

[0002]

2. Description of the Related Art Conventionally, in this type of connection method, when connecting LANs using various data transmission lines, it is possible to prevent data congestion due to loops and delay due to increase in traffic. Therefore, the spanning tree algorithm and protocol (hereinafter referred to as “STP”) are operated. The STP is a routing method in a bridge, and when data communication between the bridges, a loop-free LAN theoretically having a tree structure is constructed on the composite LAN. Then, in this STP, the bridge identifier of each bridge, the path cost of each bridge port, and the port identifier (hereinafter referred to as "bridge information") can be managed, and the active topology (active form) of the LAN can be given to the administrator. Allows you to choose.

The bridge effectively connects the port in the forwarding state to the transmission line of the LAN and relays the data frame in both directions via the port in the forwarding state. Also, in a bridge, a blocking port does not relay data frames in either direction, but is included in the active topology and if a component (transmission line or other bridge) fails or is taken away. When it is added or added, it shifts to the forwarding state and the data frame can be relayed. The bridges send configuration control bridge protocol data units (hereinafter referred to as “configuration control BPDUs”) to each other in order to communicate and calculate bridge information, and the configuration control BPDUs convey information carried over the entire LAN. Is distinguished from the concept of a configuration message expressing A frame carrying this BPDU is received by all bridges connected to the LAN from which the frame was sent, with the bridge group address in the destination field.

In the LAN, the above configuration control BP transmitted
The DU quickly learns the spanning tree path to the bridge with the highest priority roots identifier, along with the underlying information that other partial roots and paths are denied, to form only one data path. I was deleting the data loop.

[0005]

However, in the above connection method, STP is implemented to cause one of the ports of the bridge to transit from the forwarding state to the blocking state,
If the configuration control BPDU is periodically transmitted, the line connection state continues because of only this configuration control BPDU transmission. For example, when the above line is a public line network, the line occupation time becomes long and wasteful. There was the problem of being charged.

The present invention has been made in view of the above problems, and when the port status changes to blocking during the STP operation, BPDU reception monitoring is stopped and the line is disconnected.
An object of the present invention is to provide a network interconnection method that prevents useless connection of lines.

[0007]

In order to achieve the above object, according to the present invention, a plurality of bridges and a LAN, which is a plurality of networks for data communication constructed from a transmission line connecting the bridges, are provided. When connecting via the bridge, and when LANs are connected by a plurality of routes by different types of lines, the transmitting side bridge and the receiving side bridge with the higher priority order are set based on the preset priority order of each bridge. In a method of interconnecting LANs, a data path is set by a high-speed digital leased line that is a predetermined line connected to, and data is transmitted from one LAN to the other LAN via the data path.
When the data path is set, the line connected via a receiving bridge other than the receiving bridge with high priority, for example, a public line network is disconnected, and the receiving with high priority is performed. There is provided a network interconnection method having a line setting step of setting the disconnected public line network to a connection state in accordance with a topology change BPDU which is an instruction from the side bridge.

[0008]

In another receiving side bridge which does not intervene in the data path of the spanning tree, when the port status changes to blocking, reception monitoring of the configuration control BPDU is stopped and the line is disconnected, and then the bridge intervening in the data path. BP indicating topology change due to a failure in the network or an accident in the data path
When the DU is received, the disconnected line is connected to enable data communication.

Therefore, since the lines other than the data path are disconnected, the charges can be reduced when the other lines are the public line network, and the lines can be connected in response to the reception of the topology change. Data communication can be performed efficiently.

[0010]

Embodiments of the present invention will be described with reference to the drawings of FIGS. 1 to 3 are configuration diagrams showing an embodiment of a LAN using the connection method according to the present invention. The LANs shown in FIGS. 1 to 3 are the same, and the same reference numerals are given to the respective components.

1 to 3, the LAN 1 includes bridges 11 and 12 and port 1 of the bridges 11 and 12.
1a and 12a are respectively connected to the transmission line 13, and the LAN 2 includes bridges 21, 22, and 23.
And the ports 21a, 2 of the bridges 21, 22, 23
2a and 23a are respectively connected to the transmission line 24, and the LAN 3 includes bridges 31 and 32.
And a transmission line 33 to which the ports 31a and 32a of the bridges 31 and 32 are connected, respectively.

LAN1 and LAN2 are connected via a high-speed digital leased line (hereinafter referred to as "HSD") 40 connecting the port 11b of the bridge 11 and the port 21b of the bridge 21, and the port 11 of the bridge 11 is connected.
c and a port 22b of the bridge 22 are connected via a public line network (hereinafter referred to as "ISDN") 41. LAN1 and LAN3 are port 1 of bridge 12
2b and the port 31b of the bridge 31 are connected via a transmission line 42. The LAN 2 and the LAN 3 are connected via an ISDN 43 that connects the port 23b of the bridge 23 and the port 32b of the bridge 32.

In each bridge, STP is operating,
When connecting multiple LANs, a LAN with an arbitrary topology is configured into one spanning tree during STP operation, and only one data path exists between any two end bridges. The state of the port of the bridge that does not intervene is blocked to avoid a data loop.

In the present embodiment, in the case of performing data communication between LAN1 and LAN2, for example, data transmission from LAN1 to LAN2, bridge connection LAN freely connected
From, we have to determine the active topology on one tree. To determine the active topology, the roots bridge of the bridge connection LAN, each LA
It is necessary to determine N designated ports and roots ports of each bridge. These items are determined by each parameter of the configuration control BPDU transmitted from each port 11a to 11c of the bridge 11 (see FIG. 1).

The format of the configuration control BPDU is, as shown in FIG. 4, a protocol identifier, a protocol version identifier, a BPDU type, a flag, a roots identifier, a roots path cost, a bridge identifier, a port identifier, a message age, a maximum age, It consists of parameters of hello time and forward delay. The protocol identifier represents STP.

The protocol version identifier represents the version of the above protocol. BPDU type is
Fig. 5 represents a configuration control BPDU. The flag is a topology change confirmation flag set by the bridge that sends this configuration control BPDU as a response to the topology change notification BPDU received by the designated bridge, and all that are transmitted in a fixed cycle following the detection or notification of the topology change. In the configuration control BPDU of the above, a flag indicating the topology change flag set by the roots bridge.

The root identifier represents a unique bridge identifier of a bridge which is supposed to be a root for transmitting the configuration control BPDU. This parameter is carried on all bridges that agree with the roots. The roots path cost represents the path cost from the transmitting bridge to the roots bridge indicated by the roots identifier above. This parameter is the LA that is receiving the configuration control BPDU.
Carried on to determine which bridge on N is being offered the lower cost route to the roots.

The bridge identifier represents the unique bridge identifier of the bridge transmitting the configuration control BPDU. This parameter is carried to enable the bridge to do the following: That is, the bridge identifier determines if more than one bridge with the same cost path to the roots is connected to a LAN, and which one is selected as the designated bridge for that LAN, and more than one on the same bridge. Port is connected to the same LAN, and is carried in order to detect the case where direct communication is performed without passing through a component path operating in STP.

The port identifier represents the identifier of the port of the bridge to which the configuration control BPDU is transmitted. This parameter uniquely identifies the port on that bridge. That is, it is used to determine which port should be connected when more than one port is connected to one LAN on the same bridge. The message age represents the elapsed timer value indicating the life of the configuration control message since the configuration control BPDU was generated by the roots of the configuration control BPDU. This parameter is used to force the bridge to discard information beyond the maximum age.

The maximum age represents a timeout value used by all bridges in the bridge connection LAN, and is set by roots. This parameter is used to ensure that a constant value is used to test the lifetime of the configuration information stored at each bridge in the bridged LAN. Hello time represents the interval time between configuration control BPDUs generated by the roots.
This parameter is not used directly by the spanning tree algorithm, but is carried by the configuration control BPDU to facilitate monitoring of protocol performance by management functions.

The forward delay represents a timeout value used by all bridges in the bridge connection LAN, and is set by roots. This parameter is carried to ensure that each bridge in the bridged LAN uses a constant value for the forward delay timer when transitioning the port state to the forward state. It is also used as a dynamic timer-out value in the filtering database when changing to an active topology.

As a result, in this embodiment, the bridge having the highest priority of the bridge identifier is selected as the roots bridge, and the bridge 11, for example, is selected. Each LA
For the designated port of N, a port having the smallest sum of the path costs of the ports passing through to the roots bridge (roots path cost) is selected from the ports connected to one LAN. However, if the root path costs of two or more ports connected to one LAN are equal, the priority of the bridge identifier is used first, and the priority of that port identifier is used to specify the designated port of that LAN. Select. In this embodiment, for example, the port 21b of the bridge 21 is selected as the designated port.

For the roots port of each bridge, the port with the lowest roots path cost in one bridge is selected. However, if two or more ports have the same root path cost, the port with the highest priority in the port identifier is selected as the root port of the bridge.
In this embodiment, as the roots port, for example, the port 11b of the bridge 11 and the port 21b of the bridge 21 are selected.

When the bridges 22 and 23 receive the configuration control BPDU, they send a message to the bridges 11 and 32 that the ports 22b and 23b are blocking (see FIG. 2), and the blocking port 22 is transmitted.
The timer monitoring the BPTU reception interval on the b and 23b sides is stopped. Bridge 1 that received the above message
1, 32 are ISDN 41, 4 according to the above message.
Disconnect the line of 3 and B to the above ports 22b and 23b
Stop sending PTUs.

Next, HSD is caused by an accident in the data path.
When the line of 40 is disconnected, the bridge 21 informs the B from the bridge 11 which is monitoring reception.
The PDU detects that the PDU cannot be received, and transmits the podology change notification BPTU (see FIG. 5) indicating the change of the active podology to the bridges 22 and 23 via the transmission path 24.

The format of the topology change notification BPDU is, as shown in FIG. 5, a protocol identifier representing STP, a protocol version identifier representing the version of the above protocol, and a B representing the configuration change notification BPDU.
It is composed of PDU type parameters. Upon receiving the topology change notification BPDU, the bridges 22 and 23 put the contents of the topology change notification in the user / user data (see FIG. 6) of the call setup message,
It transmits to the bridges 11 and 32.

The format of the user / user data of the call setup message is, as shown in FIG. 6, the user / user information element identifier representing the information element of the call setup and the user / user content length representing the content length of this data. , A protocol identifier and parameters of user information, and the content of the topology change notification is set in the user information as an option.

The bridges 11 and 32 receive the ISD according to the call setup message containing the topology change notification.
The lines of N41 and N43 are connected, and the bridge 11 transmits the configuration control BPDU from each of the ports 11a and 11c. Thus, in this embodiment, as the roots port, for example, the port 11c of the bridge 11 and the port 2 of the bridge 22 are used.
2b is selected, a timer that monitors the reception interval of the BPDU on the port 22b side is activated to enable transmission of the BPDU, and at the same time, via the line of the ISDN 41.
Data can be transmitted from the transmission side bridge 11 of the LAN 1 to the reception side bridge 21 of the LAN 2. When the bridge 23 receives the configuration control BPDU,
Similarly to the above, a message indicating that the port 23b is blocking is transmitted to the bridge 32, and the timer monitoring the reception interval of the BPTU on the blocking port 23b side is stopped.

Further, in the present embodiment, when a failure occurs in the bridge 21, for example, the BPDU is not transmitted from the bridge 21 to the bridges 22 and 23.
The bridges 22 and 23 are BPs on the ports 22a and 23a side
Since the failure can be detected by monitoring the reception of the DU, the topology change notification can be transmitted to the call setup message bridges 11 and 32 having the content as in the above.

Therefore, in the present embodiment, the line of the port in the blocking state is disconnected in the arbitrary LAN during the STP operation, so that the line which does not need the data transfer is not connected and the line is the public line network. In Case of,
It is possible to prevent unnecessary charges by shortening the line occupation time. Further, in the present embodiment, when the BPDU including the contents of the topology change notification is received, the disconnected line is reconnected, so that the data communication can be efficiently performed.

In the above embodiment, the case where the bridge on the transmission side disconnects the unnecessary line has been described, but the present invention is not limited to this, and the unnecessary line is disconnected by the bridge on the reception side, for example. Is also possible. This case will be described with reference to the configuration diagram of FIG.
When b and 23b transit to the blocking state, the receiving bridges 22 and 23 stop the timer that monitors the reception interval of the BPDU, and disconnect the ISDN 41 and 43 lines. Then, by the subsequent notification of the change of the active topology, the ports 22b, 2 of the receiving side bridges 22, 23 are
3b makes a transition to the listening state, activates a timer for BPDU reception monitoring, and connects the lines of ISDN 41 and 43.

Therefore, in this embodiment, the line of the port in the blocking state is disconnected by the bridge on the receiving side in an arbitrary LAN during the STP operation, so that the line which does not need the data transfer is not connected. Similarly, the occupied time of unnecessary lines is shortened, useless billing can be prevented, and when the BPDU including the contents of the topology change notification is received, the disconnected line is reconnected by the bridge on the receiving side. Therefore, data communication can be performed efficiently.

[0033]

As described above, according to the present invention, a plurality of networks that are constructed from a plurality of bridges and a transmission line connecting the bridges and perform data communication are connected via the bridges. In addition, when the networks are connected by a plurality of routes by different types of lines, a transmission side bridge and a reception side bridge with a high priority are connected based on a preset priority order of each bridge. In a network interconnection method for setting a data path by a line and transmitting data from one network to another network via the data path, when the data path is set, the reception with the high priority is performed. In addition to disconnecting the line connected through the receiving bridge other than the receiving bridge, Depending on the data path change instruction from the position of high reception side bridge, because it has the cross-sectional state of the line setting step of setting a line connection state, the port state of transition to blocking during STP operation, BPD
It is possible to prevent unnecessary connection of the line by stopping the reception monitoring of U and disconnecting the line.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a LAN using a connection method according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of a LAN using the connection method according to the present invention.

FIG. 3 is a configuration diagram showing an embodiment of a LAN using the connection method according to the present invention.

FIG. 4 is a diagram showing a format of a configuration control BPDU.

FIG. 5 is a diagram showing a format of a topology change notification BPDU.

FIG. 6 is a diagram showing a format of user-user data of a call setup message.

[Explanation of symbols]

11, 12, 21-23, 31, 32 Bridges 11a-11c, 21a, 21b, 22a, 22b Ports 13, 24, 33 Transmission line 40 High-speed digital leased line (HSD) 41, 43 Public line network (ISDN)

Claims (4)

[Claims] 1. A plurality of bridges and a plurality of networks that are constructed from a transmission line connecting the bridges and perform data communication are connected via the bridges,
When the networks are connected by a plurality of routes by different lines, based on a preset priority of each bridge, a predetermined line connecting the transmitting side bridge and the receiving side bridge having the higher priority order In a method for interconnecting networks, wherein a data path is set and data is transmitted from one network to another network via the data path, when the data path is set, the receiving bridge having a high priority Other than the above, the line connected via the receiving side bridge is set to the disconnected state, and the line in the disconnected state is set to the connected state in response to the data route change instruction from the receiving side bridge with the higher priority. A method for interconnecting networks, comprising: 2. A predetermined bridge is exchanged between bridges in each network and between bridges connected by the line, and the predetermined message is monitored in the line setting step. 2. The interconnection method according to claim 1, wherein if the predetermined message is not transmitted within a predetermined time from the above, it is judged as the data path change instruction and the line in the disconnected state is set to the connected state. . 3. In the line setting step, when a data path is set by a predetermined line to which the receiving bridge having a high priority is connected, the other receiving bridge sets the port state to blocking. Sending a message, interrupting the monitoring of the message from the sending bridge, and when the other receiving bridge receives a message indicating a topology change from the higher priority receiving bridge, the sending bridge In addition to making a call by changing the topology, the port in the blocking state is transited to the listening state, and monitoring of the message from the transmitting side bridge is started, and the transmitting side bridge receives the blocking from the other receiving side bridge. Message is received, the line connected to the other receiving bridge is set to the disconnection state. In addition, when there is a call from the receiving side bridge or the transmitting side bridge due to a change in topology, the line in the disconnected state is set to the connected state and transmission of a predetermined message to the other receiving side bridge is started. The method for interconnecting networks according to claim 1 or 2, characterized in that: 4. In the line setting step, when a data path is set by a line to which the receiving bridge with a high priority is connected, a message to the effect that the other receiving bridge sets the port state to blocking When a line intervening by the transmitting side bridge is set to a disconnection state and the other receiving side bridge receives a message indicating a topology change from the receiving side bridge or the transmitting side bridge having the higher priority. 2. The line in the disconnection state is set to the connection state, the port in the blocking state is transited to the listening state, and monitoring of the message from the transmitting side bridge is started.
Or the method of interconnecting networks according to 2.