When inserting an unqualified SFP-T on EX4600, this might lead to protocols, circuits and interfaces bounce and eventually can lead to unforeseen outages.
Please use Juniper Qualified Transceivers to avoid such issues.
Please refer to the below to find the support/qualified modules that can be used in EX4600:
https://apps.juniper.net/home/ex4600/hardware-compatibility
Also, SFP-T insert/reseat should be done in a MW as recommended in the below PR:
https://prsearch.juniper.net/problemreport/PR1641556
One of the log might be seen in the syslog's:
XX 1 15:09:30 XX fpc0 sfp-0/0/XX SFP plugged in
XX 1 15:09:31 XX fpc0 sfp-0/0/XX(XX), SFP 26:
XX 1 15:09:33 XX fpc0 DCBCM[ge-0/0/XX]: Created SFP-T phy object
XX 1 15:09:33 XX fpc0 FXPC_OLIVE_PHY_WRITE_FAILURE: FAILED to read the phy for port: XX @ addr: 86 - length: 2
XX 1 15:09:33 XX fpc0 DCBCM[ge-0/0/XX]: Failed to read XCVR phy at i2c_dev:67 reg:0 failed... retrying 0
XX 1 15:09:33 XX fpc0 DCBCM[ge-0/0/XX]: Failed to read XCVR phy at i2c_dev:67 reg:0 failed... retrying 1
XX 1 15:09:33 XX fpc0 DCBCM[ge-0/0/XX]: Failed to read XCVR phy at i2c_dev:67 reg:0 failed... giving up!
XX 1 15:09:33 XX fpc0 DCBCM[ge-0/0/XX]: dcbcm_xcvr_phy_mdio_sgmii_lnk_op - Failed to MDIO read:
XX 1 15:09:33 XX fpc0 ala88e1111_reg_read: Failed (1000) to read register phy_addr 0x67, reg 0x0
XX 1 15:09:39 XX dc-pfe: SCHED: Thread 42 (PFE Manager) aborted, hogged 5094 ms
XX 1 15:09:33 XX fpc0 Fails in function ala88e1111_dev_reset
XX 1 15:09:33 XX fpc0 DCBCM[ge-0/0/XX]: Failed to reset xcvr phy
XX 1 15:09:34 XX fpc0 DCBCM[ge-0/0/XX]: SFP-T phy reset done
XX 1 15:09:34 XX fpc0 DCBCM: ge-0/0/XX Fail to reset xcvr phy
XX 1 15:09:34 XX fpc0 ifp ge-0/0/XX ifd_set_flapped
XX 1 15:09:34 XX fpc0 [DCBCM] dcbcm_pic_ifdconfig: ifd - ge-0/0/XX, OLD CFG spd = spd = 0, dpx = 0 NEW CFG spd = 1000000000, dpx = 2
XX 1 15:09:34 XX fpc0 dcbcm_kconfig_params_set_macsec_port: Probing port 18
XX 1 15:09:34 XX fpc0 u=0 p=18 Using SDK PHY driver for BCM84756/7/9
XX 1 15:09:40 XX fpc0 SCHED: Thread 42 (PFE Manager) aborted, hogged 5094 ms
Use transceivers qualified by Juniper.
SFP-T insert/reseat should be done in a MW on EX4600.