JP2001186164A - Data repeater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data repeater that can transmit data, immediately after a port-up for a device, in which the loop of a transmission path is not formed. SOLUTION: When any port 36 undergoes a port-up state, the contents of an STP use propriety flag of the port 36 are checked (S22). When the port 36 is an application object of a spanning-tree protocol ('YES' in S22), the spanning-tree buildup processing is conducted according to a conventional method (S24-S34). When the port 36 is not an application object of the spanning- tree protocol (NO in S22), after conducting 'Listening and Learning' for a very short time (S36-S38), the port is shifted to a 'Forwarding' state (S32).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data relay device using a spanning tree protocol, and more particularly, to a data relay device capable of omitting a spanning tree construction process by a user setting.

[0002]

2. Description of the Related Art In a data relay apparatus called a bridge, IEEE (IEEE) is used to suppress the propagation of relay data due to multiplexing of paths and to prevent data from circulating due to the formation of a loop in a transmission path. Institut
e of Electrical and Electronics Engineers) 80
Spanning tree protocol standardized in 2.1D (may be abbreviated as "STP" in this specification).
The route control is performed according to the following. The spanning tree protocol is a communication protocol for uniquely setting a communication path extending between LANs as a tree structure called a spanning tree. Based on this protocol, BPDU (Bridge Protocol Data Uni
By exchanging data frames called t) periodically, the route information is updated.

In the spanning tree protocol, in order to stabilize a data transmission path at the time of port-up and to prevent a transmission path loop from occurring, a standard is established such that normal communication with other devices cannot be performed for a certain period of time. I have.
This is because the spanning tree protocol is assumed to be used mainly in a bus-type network that can cause a closed loop.

That is, referring to FIG. 10, when a port is raised from a port down state, the port logically stops transmitting and receiving data (Blocking state).
(S100), a state in which the port waits for network stability (Listening state) (S102), and a state in which the port takes in a frame flowing on the network and prepares to perform an operation according to the spanning tree (Learning state) ( After S104), the port 36 finally reaches a state of forwarding network data (forwarding state) (S106).

[0005] Listening state and Learn
In the ing state, the same state is maintained for a certain time (for example, 15 seconds). In the meantime, if it is determined that the network is not stable or that it is not related to the construction of the spanning tree, the state transits to the Blocking state. Also, in the Forwarding state, if a situation such as a failure in data relay occurs, the state transits to the Blocking state in order to reconstruct the spanning tree. Even in the Blocking state, if a factor that changes the topology of the spanning tree, such as a port up or a port down, occurs, the Listenin again.
g state and Learning state,
There is a case where the state transits to the ringing state.

[0006]

However, in a switch type (star type) network in which each port of a data relay device and a device are connected one-to-one, a loop of a transmission path is not necessarily formed depending on the connected device. Not always. In such a case, there is no problem even if data communication is started immediately after port-up. Nevertheless, in the data relay device adopting the conventional spanning tree protocol, Listening and Learn
Since a certain time is required for ing, there is a problem that data received immediately after port-up is not transmitted to another device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a data transmission apparatus capable of transmitting data immediately after port-up to a device in which a transmission path loop is not formed. It is to provide a relay device.

Another object of the present invention is to prevent a loop of a transmission path from being formed and to reduce network traffic even when a device adopting the Spanning Tree Protocol and a device not adopting the Spanning Tree Protocol are mixedly connected. An object of the present invention is to provide a data relay device that can reduce the number of data relay devices.

[0009]

According to a first aspect of the present invention, there is provided a data relay device using a spanning tree protocol, wherein each of the data relay device includes a plurality of ports to which devices are connected, and a spanning tree. STP applicability selection means for selecting the applicability of the protocol on a port-by-port basis, and a processing time for constructing a spanning tree based on the selection result by the STP applicability selection means, connected to the STP applicability selection means. And a spanning tree construction means for deciding and constructing a spanning tree.

[0010] The processing time of the processing for constructing the spanning tree protocol can be determined based on the setting of the user. For this reason, for a port that can perform data communication without using a spanning tree, by shortening the above-described processing time, data communication becomes possible immediately after the port is up.

A data relay device according to a second aspect of the present invention is a data relay device using a spanning tree protocol, wherein each of the plurality of ports to which devices are connected and whether the spanning tree protocol can be applied is determined. STP applicability selection means for selecting on a port basis, reception judgment means for judging whether or not information for constructing a spanning tree has been received from a connected device for each of a plurality of ports, and STP applicability It is connected to the selection means and the reception judgment means, determines the processing time of the processing for constructing the spanning tree based on the selection result by the STP applicability selection means and the judgment result by the reception judgment means, and constructs the spanning tree. Spanning tree construction means.

If the user receives information for updating the spanning tree even if the port is set not to apply the spanning tree protocol, the spanning tree can be constructed in the same manner as usual. For this reason, it is possible to avoid formation of a loop of the transmission path due to not using the spanning tree protocol, and it is possible to reduce network traffic.

According to a third aspect of the present invention, in addition to the configuration of the second aspect of the present invention, the spanning tree construction means includes:
Regarding the port that has received the information for updating the spanning tree, regardless of the selection result by the STP applicability selecting unit, when the spanning tree protocol is applied by the STP applicability unit, the same processing as that of the selected port is performed. Is constructed.

[0014] According to a fourth aspect of the present invention, in addition to the configuration of the second or third aspect, the spanning tree constructing means includes a port down for a port having received information for updating the spanning tree. ST
When the spanning tree protocol is applied by the P application applicability means, the same processing as that of the selected port is maintained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a bridge (data relay device) 20 according to an embodiment of the present invention has a plurality of ports 36 for connecting various devices and a plurality of ports 36 respectively. A plurality of MAC (Media Access Control) devices 34 connected and controlling transmission and reception of frames
A spanning tree management table 40 for storing information about the spanning tree, a plurality of MAC devices 34,
Spanning tree management table 40, CPU described later
(Central Processing Unit) 30 and a certain M
The transfer destination of the frame received via the AC device 34 is determined based on the spanning tree management table 40, and is transmitted to another MAC device 34.
(Application Specific Integrated Circuit) designed to perform a process of outputting
t) 32, a user I / F (Interface) 38 for receiving data input from a user, a plurality of MAC devices 34,
It is connected to the ASIC 32, the spanning tree management table 40, and the user I / F 38, determines a state according to data input from a user, information about the port 36, and updates the contents of the spanning tree management table 40 based on the received BPDU. And a CPU 30.

In the spanning tree management table 40,
The first table shown in FIG. 2 and the second table shown in FIG. 3 are stored. Referring to FIG. 2, the first table includes the number of MAC device 34 and the status related to data relay of MAC device 34 (any one of the four statuses described with reference to FIG. 10). And information on the topology of the spanning tree (information indicating the position of the port 36 in the spanning tree), timer information indicating the time at which the port was raised or the time at which the BPDU was received, and whether to perform the spanning tree construction processing as usual. A flag indicating whether or not to perform the processing of the spanning tree structure as usual (a user setting flag) is stored as a set.

That is, the bridge 2 according to the present embodiment
At 0, it is possible to set whether to perform the processing for constructing the spanning tree for each port 36 as usual or to omit the learning and listening processing.

Referring to FIG. 3, information on bridge 20 is stored in the second table.
0 (information indicating the position of the bridge 20 in the spanning tree), the ID (identifier) of the bridge that is the root of the spanning tree, and the designated bridge ID (the bridge of the data transmission side (upstream)). I
D) are stored as a set.

Referring to FIG. 4, various processes are executed on CPU 30. The user I / F management process 56 updates the contents of the spanning tree management table 40 according to a command input by the user via the user I / F 38.

The port management process 54 includes a plurality of MACs.
The device 34 updates the contents of the spanning tree management table 40 based on an interrupt signal generated each time the device 34 detects a port up or a port down, and transmits the interrupt signal to a spanning tree management process 52 described later.

The spanning tree management process 52 determines a transfer destination of the data received via a certain MAC device 34 based on the spanning tree management table 40, relays the data, and outputs an interrupt signal output from the port management process 54. And BP received via the MAC device 34
The contents of the spanning tree management table 40 are updated based on the DU.

Hereinafter, the processing performed by each process will be described in more detail with reference to FIGS. Referring to FIG. 5, the user operates the port 36 via the user I / F 38.
And information indicating whether or not to construct a spanning tree by applying the spanning tree protocol to the port 36 as usual, and input those two pieces of information to the user I / F management process 56. The user I / F management process 56 writes information on whether or not to apply a normal spanning tree protocol to the user setting flag and the STP availability flag of the designated port number (S12). That is, for a port that performs processing in accordance with a normal spanning tree protocol, an identification symbol of “permitted” is written in the user setting flag and the STP availability flag. For ports that do not perform processing according to the normal spanning tree, an identification symbol of “No” is written in the two flags. The processing of S12 is performed for all the port numbers specified by the user (S14).

Referring to FIG. 6, when any port 36 is ported up, the MAC corresponding to that port 36
An interrupt signal is output from the device 34. Upon receiving the port-up interrupt signal, the port management process 54 transmits to the spanning tree management process 52 information about the port 36 that transmitted the interrupt signal, together with the interrupt signal.

Upon receiving the interrupt signal, the spanning tree management process 52 checks the contents of the STP enable / disable flag of the port 36 that has transmitted the interrupt signal (S2).
2). If the port 36 is subject to the application of the spanning tree protocol (YES in S22), the spanning tree management process 52 displays “List” in the “state of relay” column of the spanning tree management table 40.
ning ", for example, for 15 seconds
The ng state is maintained (S24).

In the meantime, if the network is not stable (YES in S26), the spanning tree management table 4
“Blocking” in the “Status related to relay” column of 0
And the state transits to the Blocking state (S3
4). Thereafter, the processing of the spanning tree management process 52 ends.

If the network is stabilized during that time (NO in S26), the spanning tree management process 52
Writes "Learning" in the "state of relaying" column of the spanning tree management table 40, for example, maintaining the learning state for 15 seconds (S2).
8).

In the meantime, if the spanning tree cannot be constructed (YES in S30), “Blocki” is entered in the “state of relay” column of the spanning tree management table 40.
ng ”and transits to the Blocking state (S
34). Thereafter, the processing of the spanning tree management process 52 ends.

If a spanning tree can be constructed during that time (NO in S30), the spanning tree management process 52
Writes “Forwarding” in the “state of relay” column of the spanning tree management table 40,
The state transits to the orwarding state (S32). For
When transitioning to the awarding state, data communication is performed with the device connected to the port.

If the port 36 is not subject to the spanning tree protocol (NO in S22),
The spanning tree management process 52 displays “L” in the “state of relay” column of the spanning tree management table 40.
and the listening state is maintained for an extremely short time (here, 1 second) (S3
6). Further, the spanning tree management process 52 includes:
“Learning” is written in the “relay-related state” column of the spanning tree management table 40, and “Learning” is written.
The ing state is maintained for a very short time (here, 1 second) (S36).

Thereafter, the spanning tree management process 5
2 writes “Forwarding” in the “state of relay” column of the spanning tree management table 40;
The state transits to the Forwarding state (S32).

As described above, whether or not to apply the spanning tree protocol based on the user setting is determined by the port 3
It is determined every 6. However, even if the port 36 is determined not to apply the spanning tree protocol by the user, the BPDU may be received from a device connected to the port 36. In such a case, stable data relay can be performed by automatically changing the setting to apply the spanning tree protocol.

Referring to FIG. 7, the state transition for each of the ports 36 for which the STP availability flag is set to "not" will be described. Each port 36 takes three states: a port down state, an STP off state, and an STP on state. When the port 36 is down, the port down state is maintained.

When the port 36 goes up from the port down state, the state transits to the STP off state once. In this state, the STP in the spanning tree management table 40
The usability flag is set to “No”, which means that the spanning tree protocol is not applied. In the STP off state, the STP off state is maintained unless a BPDU is received. If the port goes down with the STP off,
Transition to the port down state.

When a BPDU is received in the STP off mode,
The STP availability flag is set to “enabled” and the state transits to the STP on state. After transitioning to the STP ON state,
The STP on state is maintained until the port is brought down.
When the port goes down, the state transits to the port down state.

Referring to FIG. 8, the processing of the process when a BPDU is received will be described. The spanning tree management process 52 includes the port 36 and the MAC device 34
When the BPDU is received via the port, it is determined whether the user setting flag of the spanning tree management table 40 for the port 36 is “OK” or “NO” (S
42). If the user setting flag is “OK” (Yes in S42), the spanning tree management process 52
The spanning tree management table 40 is updated based on the PDU (S44).

If the user setting flag is "No" (S4
2), and examines the contents of the STP availability flag (S4).
6). If the STP use availability flag is enabled (the state of the port 36 is the STP on state) (Yes in S46), the process of S44 is executed. The STP availability flag is not valid (port 36
Is in the STP off state) (No in S46), S
The state of the port 36 is changed to the STP on state by changing the TP use permission flag to “permitted” (S4).
8). Then, in order to construct a spanning tree, FIG.
The processing after S24 shown in FIG.

Referring to FIG. 9, when one of ports 36 goes down and a corresponding MAC device 34 transmits an interrupt signal to spanning tree management process 52 via port management process 54, spanning The tree management process 52 copies the contents of the user setting flag to the STP availability flag (S52). Thereby, S
The TP availability flag is updated to the original state.

When the port 36 goes down, the STP availability flag may be maintained in the current state without returning the port 36 to the original state.

As described above, according to the bridge 20 according to the present embodiment, the user can set whether or not to apply the spanning tree protocol for each port. Therefore, for a port that can perform data communication without using a spanning tree, data communication becomes possible immediately after port up.

Also, when a BPDU is received even on a port for which the user has set not to apply the spanning tree protocol, the setting is changed and the spanning tree protocol is applied. For this reason, it is possible to avoid formation of a loop of the transmission path due to not using the spanning tree protocol, and it is possible to reduce network traffic.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a bridge (data relay device) according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a first table stored in a spanning tree management table.

FIG. 3 is a diagram showing an example of a second table stored in a spanning tree management table.

FIG. 4 is a diagram for explaining various processes executed on a CPU.

FIG. 5 is a flowchart showing a process of a user I / F management process 56;

FIG. 6 is a flowchart showing processing at the time of port up.

FIG. 7 is a state transition diagram of a port in which an STP availability flag is set to “not”;

FIG. 8 is a flowchart showing processing of a spanning tree management process 52 when a BPDU is received.

FIG. 9 is a flowchart showing processing of a spanning tree management process 52 when a port goes down.

FIG. 10 is a flowchart showing a process based on a spanning tree protocol.

[Explanation of symbols]

20 bridge (data relay device), 34 MAC devices 34, 36 ports, 38 user I / F, 40 spanning tree management table, 52 spanning tree management process, 54 port management process, 56 user I / F management process.

Claims (4)

[Claims] 1. A data relay device using a spanning tree protocol, each of which includes a plurality of ports to which devices are connected, and STP application availability selection means for selecting availability of the spanning tree protocol on a port basis, A spanning tree constructing means connected to the STP applicability selecting means for determining a processing time of a process for constructing a spanning tree based on a selection result by the STP applicability selecting means and constructing a spanning tree. , Data relay device. 2. A data relay device using a spanning tree protocol, each of which includes a plurality of ports to which devices are connected, and STP application availability selection means for selecting availability of the spanning tree protocol on a port basis. For each of the plurality of ports, a reception determining unit that determines whether or not information for constructing a spanning tree has been received from a connected device, and connected to the STP applicability selection unit and the reception determination unit, A spanning tree construction unit that determines a processing time of a process of constructing a spanning tree based on a selection result of the STP applicability selection unit and a determination result of the reception determination unit, and constructs a spanning tree. Data relay device. 3. The spanning tree constructing means, wherein the port that has received the information for updating the spanning tree is sent by the STP applicability means regardless of the selection result by the STP applicability selecting means. 3. The data relay device according to claim 2, wherein when the protocol is applied, the same processing as that of the selected port is performed to construct a spanning tree. 4. The system according to claim 1, wherein the spanning tree constructing unit is configured to determine, for a port that has received the information for updating the spanning tree, a port selected to apply the spanning tree protocol by the STP applicability unit until the port is downed. 4. The data relay device according to claim 2, wherein the data relay device keeps performing the same processing.