Fault evaluating system for transmission apparatus

#The present invention relates to a fault evaluating system and, more particularly, to a fault evaluating system for four switching packages which are mutually duplexed in both the transmission and reception directions and bridge-connected to oppose each other.

#In a transmission apparatus, a conventional fault evaluating system for four packages A, B, C, and D which are duplexed in both the transmission and reception directions such that the duplexed opposing packages are connected to intersect each other has an arrangement in which fault detection units A-3, B-3, C-3, and D-3 are connected to the monitor points of the switching packages A, B, C, and D, respectively, as shown in FIG. 3. The monitor results are collected to a package E which mainly performs alarm processing. A fault package is specified by the firmware in an alarm processing unit E-1 on the basis of the monitor results at the respective monitor points.

#In the above-described conventional fault evaluating system, fault information from the respective monitor points of the switching packages A, B, C, and D are temporarily collected to the package E for performing alarm processing. Thereafter, a fault package is evaluated on the basis of the fault evaluating logic of the firmware in the package E. This increases the burden of the firmware. Additionally, since the firmware is interposed, the fault evaluating operation depends upon the operation period of the firmware. As a result, a long time is required from fault detection by hardware to fault evaluation. Therefore, when a fault is detected, relief processing for a main signal, which is performed by redundant system switching by selection units A-5, B-5, C-5, and D-5 on the basis of control of the alarm processing unit E-1, is undesirably delayed.

#FIG. 1 is a block diagram showing an example of a switching package used in the present invention;

#FIG. 2 is a block diagram schematically showing a fault evaluating system according to an embodiment of the present invention using the switching package shown in FIG. 1; and

#FIG. 3 is a block diagram schematically showing a conventional fault evaluating system.

#An embodiment of the present invention will be described below with reference to the accompanying drawings.

#FIG. 1 shows an example of a switching package used in a fault evaluating system of the present invention. The switching package shown in FIG. 1 constitutes a transmission/reception package. The main signal transmission system has a fault information insertion unit 1 which inserts fault information in a free time slot of the main signal and commonly transmits the main signal to two partner switching packages. On the other hand, the main signal reception system has a fault information extraction unit 2 for extracting fault information inserted in main signals from the two partner switching packages, a fault detection unit 3 for detecting a fault by monitoring the states of the signals from the two partner switching packages, a fault evaluating unit 4 for performing fault evaluation on the basis of the fault information of the switching package, which is extracted from the main signal by the fault information extraction unit 2, and a selection unit 5 for selecting one of the partner switching packages in accordance with the fault evaluating result from the fault evaluating unit 4.

#FIG. 2 shows a fault evaluating system according to an embodiment of the present invention using the switching package shown in FIG. 1. In this embodiment, switching packages A and B and switching packages C and D, which are arranged to oppose each other and perform time-divisional transmission using a plurality of time slots, are duplexed in both the transmission and reception directions and bridged to each other, thereby constituting transmission/reception packages. More specifically, the transmission system of the switching package A is connected to the reception systems of the switching packages C and D, and the transmission system of the switching package B is connected to the reception systems of the switching packages C and D. In addition, the transmission system of the switching package C is connected to the reception systems of the switching packages A and B, and the transmission system of the switching package D is connected to the reception systems of the switching packages A and B. The switching packages A, B, C, and D respectively comprise fault information insertion units 11, 21, 31, and 41, fault information extraction units 12, 22, 32, and 42, fault detection units 13, 23, 33, and 43, fault evaluating units 14, 24, 34, and 44, and selection units 15, 25, 35, and 45, each of which has the same arrangement as that shown in FIG. 1.