Description of the problem

Metro2050 equipment 11-SL4 and 12-SL4 group single-ended unrecoverable 1+1 linear multiplexing segments, and the opposite end is also metro2050 equipment for 1+1 unrecoverable grouping. When the primary single board of the opposite end flashes BD_STATUS, the primary of this end reports R_LOS, and after replacing the primary single board of the opposite end, this end switches to the standby channel, and because the primary and standby channels are normal, unplugging and plugging the standby optical fiber collection, it still works in the standby channel.

The local version 4.01.16.13P03 uses the old LMSP protocol, while the counterpart version 4.01.18.10P02 uses the new LMSP protocol.

Processing

1, analyze the k bytes of this end, because it is an old protocol, it needs the primary and backup channels to receive 0x3000 or valid k bytes before the protocol considers the channel normal. From the following k bytes, it is found that the primary of this end has never been able to receive 0x3000, and the protocol thinks that the primary channel is abnormal, which leads to stopping the protocol of this end or unplugging the standby optical fiber can not be restored to the primary channel.

id1 nodir 1105 RST_APSC 0x0004 2014-11-25 16:34:19 0x4aafb789

id1 nodir 1106 K_ON_OFF 0x0001 2014-11-25 16:34:19 0x4aafbae8

id1 nodir 1107 SF_CLR 0x0000 2014-11-25 16:34:19 0x4ab44b28

id1 nodir 1108 K_RECV 0x0000 2014-11-25 16:34:19 0x4ab44ee3 // Invalid k-byte 0x0000 received by master channel

id1 nodir 1109 OTHERS 0x0800 2014-11-25 16:34:19 0x4ab44ff4

id1 nodir 1110 SF_CLR 0x0002 2014-11-25 16:34:19 0x4ab47682

id1 nodir 1111 K_RECV 0x3000 2014-11-25 16:34:19 0x4ab47a3e // Alternate channel received normal 0x3000

id1 nodir 1112 OTHERS 0x0802 2014-11-25 16:34:19 0x4ab47b4f

id1 nodir 1113 K_SENDS 0x0000 2014-11-25 16:34:24 0x4afcaa9e

id1 nodir 1114 OTHERS 0x0000 2014-11-25 16:34:24 0x4afcafec

id1 nodir 1115 STATE_TRAN 0x0007 2014-11-25 16:34:25 0x4b0bfe41

id1 nodir 1116 K_SENDS 0x3000 2014-11-25 16:34:25 0x4b0bff75

id1 nodir 1117 OTHERS 0x0000 2014-11-25 16:34:25 0x4b0c0085

id1 nodir 1118 K_SENDS 0x3000 2014-11-25 16:34:25 0x4b0c01bc

id1 nodir 1119 OTHERS 0x0002 2014-11-25 16:34:25 0x4b0c02cc

id1 nodir 1120 T1_START 0x0000 2014-11-25 16:34:25 0x4b0c03de

id1 nodir 1121 T1_EXPIRE 0x0000 2014-11-25 16:34:26 0x4b0e9b24

id1 nodir 1122 K_SENDS 0x0000 2014-11-25 16:34:26 0x4b0e9c66

id1 nodir 1123 OTHERS 0x0000 2014-11-25 16:34:26 0x4b0e9d77

id1 nodir 1124 K_SENDS 0xd100 2014-11-25 16:34:26 0x4b0e9eb3 //Protocol assumes that the primary did not receive the normal k bytes, all send 0xd100

id1 nodir 1125 OTHERS 0x0002 2014-11-25 16:34:26 0x4b0e9fc4

2, check whether the master channel of the opposite end device sends 0x3000, and found that the opposite end has sent 0x3000 a long time ago

3, according to the above analysis, it may be that the primary optical boards at both ends are faulty, or the opposite end sends 0x3000 abnormally.

4, replace the two ends of the optical board failure continues, and finally in the opposite end of the primary channel to re-send 0x3000k bytes, this end can be restored to the primary channel normally.

Root cause

The opposite end sends 0x3000k bytes abnormally causing the local end to be unable to receive 0x3000, thus the local end protocol considers the primary channel abnormal and is unable to recover to the primary channel.

Solution

Disable the multiplexing segment protocol at the opposite end and resend 0x3000 bytes, the fault is restored.

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