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NQA Delay Data Is Unstable After ICMP Fast Is Configured on the NE40

Publication Date:  2013-09-03 Views:  58 Downloads:  0
Issue Description
NE40 version: V3R5C01B323SPC001; NE80E version: V3R3C02B697; NMS version: V5R3C01
Networking: NE40----NE80E---NE80E---NMS
Symptom: The NQA delay data on the NE40 is unstable in the report on the NMS because ICMP Echo Request messages are sent to the CPU on the main control board, sometimes leading to a long delay in the report. Run the icmp fast enable command on the NE40. Boards on the NE40E directly respond to received ICMP Echo Request messages without sending them to the CPU on the main control board. After ICMP fast is configured on the NE40, the delay data in the report is unstable.
In the following report, some delays are around 8 ms and some suddenly become over 20 ms.
Time                                       Path Name                   Average Delay
2010-07-19 07:45:00 Guangzhou_BR1-Qingyuan_AR1 8.55
2010-07-19 07:50:00 Guangzhou_BR1-Qingyuan_AR1 24.43
2010-07-19 07:55:00 Guangzhou_BR1-Qingyuan_AR1 8.71
2010-07-19 08:00:00 Guangzhou_BR1-Qingyuan_AR1 22.56
2010-07-19 08:05:00 Guangzhou_BR1-Qingyuan_AR1 22.86
2010-07-19 08:10:00 Guangzhou_BR1-Qingyuan_AR1 8.95
2010-07-19 08:15:00 Guangzhou_BR1-Qingyuan_AR1 26.27
2010-07-19 08:20:00 Guangzhou_BR1-Qingyuan_AR1 8.69
2010-07-19 08:25:00 Guangzhou_BR1-Qingyuan_AR1 32.59
2010-07-19 08:30:00 Guangzhou_BR1-Qingyuan_AR1 9.84
2010-07-19 08:35:00 Guangzhou_BR1-Qingyuan_AR1 8.55
2010-07-19 08:40:00 Guangzhou_BR1-Qingyuan_AR1 8.98
2010-07-19 08:45:00 Guangzhou_BR1-Qingyuan_AR1 9.00
Handling Process
Possible causes:
1. The NE40&NE80E or the upstream link is unstable.
2. The NQA data configuration on the NE40 is incorrect.
Analysis procedure:
1. Ping from an NE80E to the IP address of the NE40. The delay data is stable, indicating that the NE40&NE80E and links are stable.
2. Check the NQA data configuration on the NMS. The type of NQA data delivered by the NMS is UDP jitter, which causes the problem.
ICMP Echo Request messages are not sent to the main control board but are replied by boards on the NE40. However, the NMS delivers UDP data packets that must be sent to the main control board, leading to unstable delay data in the report on the NMS.
Root Cause
ICMP Echo Request messages are not sent to the main control board but are replied by boards on the NE40. However, the NMS delivers UDP data packets that must be sent to the main control board, leading to unstable delay data in the report on the NMS. 
Solution
Change the type of NQA data from UDP jitter to ICMP.
Suggestions

When NQA is configured between the NMS and device, check the NQA configuration and type of NQA data delivered by the NMS.

END