JPH0637795A - Fault control system - Google Patents

Abstract

PURPOSE:To bypass a fault quickly only with a layer 2 function by sending a frame reception disabling notice to an adjacent exchange of a sender so as to return a frame when a prescribed frame is received. CONSTITUTION:An exchange X receives a frame whose data link identifier is alpha from a line B at first, and selects a line A from matrix data and sends the frame through the line. An exchange Y similarly selects a line D and sends a frame therethrough. When the line D is faulty, the exchange Y uses a transmission reception control processing section 11 to detect the fault and informs the fault to a routing control processing section 12. When the exchange Y receives the frame whose data link identifier is alpha from the line A, the exchange Y sends a reception disabling notice of the data link identifier alpha to the line A and returns the received frame. The exchange X informs the reception to a routing control processing section 2 and sends the frame to a line B upon the receipt of the frame whose data link identifier is alpha.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is CCITT Recommendation Q92.
The present invention relates to a failure control method in a switch for data communication that provides a LAP-F protocol in a frame mode bearer service defined in 2.

[0002]

2. Description of the Related Art Conventionally, in a failure control method in a frame mode bearer service, a received frame is discarded and a bypass operation is performed by a layer 3 function when no bypass line exists.

[0003]

In the conventional fault control method described above, when a fault occurs, only the frame is discarded in layer 2, so in order to secure the detour route,
Since the detouring operation by the layer 3 function is required, the processing amount is large,
It has the drawback of not being able to take immediate action.

[0004]

A fault control system of the present invention includes a frame transmission / reception control processing unit which controls transmission / reception of frames and detects a fault when a line fault occurs on a communication path and outputs fault information. In a switch for data communication which has a routing control processing unit for performing routing control and provides a LAP-F protocol in a frame mode bearer service, the routing control processing unit sends the frame from the frame transmission / reception control processing unit. A means for receiving and selecting an outgoing line based on a data link identifier to send the frame, and a frame having a data link identifier passing through the faulty line are recognized based on the fault information, and there is no detour line in the own exchange. in case of,
A configuration is provided that includes means for sending a reception impossible notification corresponding to the data link identifier to the transmitting side and stopping the frame flow corresponding to the data link identifier, and means for returning the received frame to the transmitting side after stopping the frame flow. is there.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an internal configuration of a switch X and a switch Y and respective lines for explaining an embodiment of the present invention. Exchange X and exchange Y are CCITT Recommendation Q9
A switch for data communication that provides a LAP-F protocol in a frame mode bearer service defined by No. 22, and has a routing control processing unit and a frame transmission / reception control processing unit in a central processing unit (not shown), respectively. The central processing unit reads out software programs stored in a storage device (not shown) and executes respective processes. Line A is exchange X and exchange Y
, And lines B and C are connected to the exchange X, and lines D and E are connected to the exchange Y.

The frame transmission / reception control processing units 1 and 11 include means for controlling transmission / reception of frames, means for detecting a line fault when a line fault occurs on a communication path, and a routing control processing unit for detecting the detected line fault. 2 and 12 to notify. Routing control processing unit 2, 12
Is a means for receiving a frame from the frame transmission / reception control processing units 1 and 11, selecting an outgoing line by the data link identifier (DLCi) and transmitting the received frame, and a line fault notification from the frame transmission / reception control processing units 1 and 11. And a frame with a data link identifier that passes through the faulty line is recognized based on the fault information, and if there is no detour line in the local exchange, a reception disable notification corresponding to the data link identifier is sent to the sending side. It comprises means for stopping the frame flow corresponding to the data link identifier, and means for returning the received frame to the transmitting side after stopping the frame flow.

An example of data held by the routing control processing unit 2 of the exchange X will be described with reference to FIG. Figure 2
(A) is matrix data showing the respective destination lines and states of the three types of data link identifiers α, β, γ of the frame handled by the exchange X. The vertical axis is the line type and the horizontal axis is the data link identifier, and the states are indicated by numerical values: 0, transmission is possible, 1: transmission is not possible, and 2: failure is occurring.

For example, FIG. 2A shows that when the frame of the data link identifier α is received, it can be transmitted only to the line A and the line B. Similarly, FIG. 2B also shows an example showing the destination lines and states of the three types of data link identifiers α, β, γ in the exchange Y, and also shows the state when a fault occurs in the line D. ing.

Next, an example of the relationship between the frame flow and the fault information will be described with reference to FIG. In FIG. 3, time progresses from top to bottom. First, the exchange X first receives the frame of the data link identifier α from the line B, selects the line A from the matrix data of FIG. Similarly, the exchange Y also receives the frame of the data link identifier α from the line A, selects the line D from the matrix data of FIG. Then, it is assumed that the line D becomes an obstacle.

In the exchange Y, the frame transmission / reception control processing section 11 detects a failure of the line D and notifies the routing control processing section 12 of the failure notification. By this notification, the matrix data transits as shown in FIG. 2B, and the destination line to the data link identifier α disappears. Thereafter, when the exchange Y receives a frame of the data link identifier α from the line A, the data link identifier α is transmitted to the line A.
The reception not possible notification is sent, and the received frame is also returned.

When the exchange X receives the reception prohibition notification of the data link identifier α, it notifies the routing control processing unit 2, and when the frame of the data link identifier α is received thereafter, the frame is transmitted to the line B, and the transmission line of the destination line is sequentially transmitted. The frame can be sent to an exchange.

In this way, a frame having a certain data link identifier can be transmitted by bypassing the fault.

[0014]

As described above, according to the present invention, when an exchange recognizes a certain line fault and receives a frame having a data link identifier that uses only that line, the exchange receives the frame. By sending the disapproval notice and returning the frame, it is possible to promptly perform fault bypass with only the layer 2 function.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal configuration of an exchange and a connection line for explaining an embodiment of the present invention.

2 (a) is a diagram showing an example of routing data held in a routing control processing unit of the exchange X of FIG. 1. FIG.
FIG. 2B is a diagram showing an example of routing data held by the routing control processing unit of the exchange Y of FIG.

FIG. 3 is a diagram showing an example of a flow of frames and signals in each processing unit of the exchange shown in FIG.

[Explanation of symbols]

 1, 11 Frame transmission / reception control processing unit 2, 12 Routing control processing unit AE line X, Y switch

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H04L 12/56 H04Q 1/20 101 8426-5K 8529-5K H04L 11/20 102 Z

Claims (1)

[Claims] 1. A frame transmission / reception control processing unit for controlling transmission / reception of frames and detecting a fault when a line fault occurs on a communication path and outputting fault information, and a routing control processing unit for performing routing control. In the exchange for data communication that provides the LAP-F protocol in the frame mode bearer service, the routing control processing unit receives the frame from the frame transmission / reception control processing unit and selects an outgoing line by a data link identifier. And a frame having a data link identifier that passes through the faulty line is recognized based on the fault information, and if there is no detour line in the local exchange, a notification of unreceivability corresponding to the data link identifier is given. To the sender to stop the frame flow corresponding to this data link identifier , Fault control method characterized by comprising a means for returning to the sender of the received frame to the after stopping the frame flow.