This article discusses an issue where a QFX5200 device that has JNPR optical transceiver QSFP-100G-PSM4 connected to a QFX10002 device goes down intermittently with no errors on the interfaces, and lists the Junos OS releases in which the issue is resolved.

The following symptoms may be seen:

1. Intermittent tx/rx optics error is seen on the interface and cleared.

Mar  1 22:16:24  JTAC fpc0 qsfp-0/0/24 Chan# 0: Rx power low alarm set 
Mar  1 22:16:24  JTAC fpc0 qsfp-0/0/24 Chan# 0: Rx power low warning set 
Mar  1 22:16:24  JTAC fpc0 qsfp-0/0/24 Chan# 1: Rx power low alarm set 
Mar  1 22:16:24  JTAC fpc0 qsfp-0/0/24 Chan# 1: Rx power low warning set 
Mar  1 22:16:24  JTAC fpc0 qsfp-0/0/24 Chan# 2: Rx power low alarm set 
Mar  1 22:16:24  JTAC fpc0 qsfp-0/0/24 Chan# 2: Rx power low warning set 
Mar  1 22:16:24  JTAC fpc0 qsfp-0/0/24 Chan# 3: Rx power low alarm set 
Mar  1 22:16:24  JTAC fpc0 qsfp-0/0/24 Chan# 3: Rx power low warning set

Mar 15 11:52:16  JTAC fpc0 qsfp-0/0/24 Chan# 2: Tx bias low alarm set 
Mar 15 11:52:16  JTAC fpc0 qsfp-0/0/24 Chan# 2: Tx bias high warning set 
Mar 15 11:52:16  JTAC fpc0 qsfp-0/0/24 Chan# 2: Tx bias low warning set 
Mar 15 11:52:16  JTAC fpc0 qsfp-0/0/24 Chan# 3: Tx bias high alarm set 
Mar 15 11:52:16  JTAC fpc0 qsfp-0/0/24 Chan# 3: Tx bias low alarm set 
Mar 15 11:52:16  JTAC fpc0 qsfp-0/0/24 Chan# 3: Tx bias high warning set 
Mar 15 11:52:16  JTAC fpc0 qsfp-0/0/24 Chan# 3: Tx bias low warning set 
Mar 15 11:53:49  JTAC fpc0 qsfp-0/0/24 Chan# 2: Tx bias high alarm cleared 
Mar 15 11:53:49  JTAC fpc0 qsfp-0/0/24 Chan# 2: Tx bias low alarm cleared 
Mar 15 11:53:49  JTAC fpc0 qsfp-0/0/24 Chan# 2: Tx bias high warning cleared 
Mar 15 11:53:49  JTAC fpc0 qsfp-0/0/24 Chan# 2: Tx bias low warning cleared 
Mar 15 11:53:49  JTAC fpc0 qsfp-0/0/24 Chan# 3: Tx bias high alarm cleared 
Mar 15 11:53:49  JTAC fpc0 qsfp-0/0/24 Chan# 3: Tx bias low alarm cleared 
Mar 15 11:53:49  JTAC fpc0 qsfp-0/0/24 Chan# 3: Tx bias high warning cleared 
Mar 15 11:53:49  JTAC fpc0 qsfp-0/0/24 Chan# 3: Tx bias low warning cleared

2. After a few days, the interface may go down.

Mar 26 12:08:18  JTAC fpc0 qsfp_tk_read_mem_page: qsfp-0/0/24 failed to select addr 127 err 4294967295 
Mar 26 12:08:18  JTAC fpc0 qsfp_tk_read_mem_page: qsfp-0/0/24 failed to select addr 127 err 4294967295 
Mar 26 12:08:18  JTAC fpc0 qsfp_tk_select_mem_page: qsfp-0/0/24 failed to select mem page 0 addr 0x7f err 1000 
Mar 26 12:08:18  JTAC fpc0 qsfp_tk_select_mem_page: qsfp-0/0/24 failed to select mem page 0 addr 0x7f err 1000 
Mar 26 12:08:18  JTAC fpc0 qsfp_tk_eeprom_scanning_check: qsfp-0/0/24 failed scanning eeprom addr 0x80 err 4294967295 
Mar 26 12:08:18  JTAC fpc0 qsfp_tk_eeprom_scanning_check: qsfp-0/0/24 failed scanning eeprom addr 0x80 err 4294967295 

This issue is resolved in Junos OS Release 17.2R3, 17.2X75-D41, 17.3R3, 17.4R1, and 17.4R.

Meanwhile as a workaround, you can remove and reinsert the optics. When an interface is down, the only way to bring it back up is to remove/re-insert the optics.