In a certain network the 23-EOW board clock 2 port port has been connected with other vendors E-BSC clock input . In normal circumstances the clock is normal but after a fiber cut in the OSN ring as in the attached file the E-BSC fails to extract the clock and generates bit errors.
LTI alarm at OSN 7500
SYNC loss alrarm at other vendor E-BSC
(1) The NMS displays that the clock configuration of NE is "westbound clock source 1/internal clock source".This is correct.
(2) check the clock from clock subnet configuratoin->> clock quality clock source quality and found that the system was receiving G8.11 clock from 11SL64.
(3) checked the clock view Analyze the networkwide clock protection subnet, Because the westbound clock source for NE3 is unusable, NE3 changes to trace its "east clock source".
(4) Added the 8sl64 and 11SL64 sourced in the clock source priority ->> Priority table for phase locked sources of 2nd External clock output.
(5) Verified from the E-BSC and the clock is now received even during fiber cut.
In normal conditions the BSC extracts clock from the EOW board. The clock to the EOW board is actually provided from the line board 8SL64(W) and 11SL64(P). After the fiber cut the huawei OSN starts to extract clock from protection path but eow clock is unavailable because its priority is not defined in "Priority table for phase-locked sources of 2nd External clock output".
Since the NE is not directly receiving working clock from west sidew so we add 8-SL64 and 11SL64 in “Priority Table For Phase-Locked Sources of 1st/2nd External Clock Output”.