Description of the problem

1, a bureau by the OSN7500 equipment under the access network often occurs ECC oscillation, resulting in frequent de-regulation of the network elements;

2, OSN7500 device host version 5.21.13.47P01, network management version T2000V2R2CO1;

3, OSN7500 equipment for the gateway network element, under the hanging of several SNCP and MSP ring, under the hanging of the network element appears to be out of control, while the gateway network element can be normal login.

4, each time a failure occurs, from the ECC routing table found that there will be more and more distance of 60 or more network elements, but these network elements are not the actual network elements.

5、Soft reset or hard reset master control is ineffective. Change the gateway, but as long as you pass through this network element, the effect is still not improved.

6、Temporarily solve the problem of network element de-regulation by closing all the SNCP rings and MSP rings formed with this gateway network element and all the way to ECC.

Processing

1, soft reset or hard reset master control is invalid. Change the gateway, but as long as the effect of this network element can not be improved.

2, by closing all the SNCP ring and MSP ring with this gateway network element all the way to the ECC, temporarily solve the problem of network element decontrol, but there is no fundamental solution.

3, replace the main control board, found that after the replacement of all network elements can be logged on normally, query the ECC routing table no longer appear in the distance of 60 or more network elements;

4, the single board back to the company to analyze the return to be analyzed pieces inserted into the 7500 network elements

and this network element as a gateway network element, hanging down other network elements as a non-gateway network element, in the gateway network element to send data to other network elements (through the ECC transmission), found that there are sporadic errors appear, the phenomenon is that the low data from 1 to 0. The data transmission path is: the board SDRAM - CPU - SD701 - zl80007 - downstream network elements The data transfer path is: SDRAM - CPU - SD701 - zl80007 - downstream network element, and no error code is found due to the underlying error checking mechanism on the SDRAM to CPU side and the HDLC checking mechanism on the SD701 to zl80007 side.

5, through the analysis found to be due to the ECC transmission path on the SD701 chip in the data transmission of sporadic error code caused by a single board in the laboratory compared to test the emergence of error code single board and a normal single board board on the power supply and clock and so on the external causes that may cause the error code, did not find anomalies, so it is judged to be the chip itself generates the error code;

Root cause

1, the gateway network element with too many network elements, in fact, only with more than 70 network elements, this problem can be ruled out;

2, OSI protocol caused by closing the OSI protocol failure remains;

3, OSN7500 main control board failure;

4, single-board version of the problem, check the information to confirm that this version does not have this problem;

5, the key point is to query the routing table found that there will be more and more distance of 60 or more network elements, the routing table is obviously abnormal.

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