The customer had upgraded the Junos OS from 18.4 to 22.2R3-S2.8, they observed the LSI interface flapping after manually switchover the RE mastership.

The customer had a large scale network, and configured with many VPLS instances, there are many PE neighbors in each VPLS instances. So, there are more than 19K LSI interfaces in the system.

Based on the JTAC lab test, the MX480 router with RE-S-2X00x6 and MPC7E cards, the device worked fine after configuring 20K VPLS instances and 20K LSI interface.

The customer had enabled the GRES and NSR, based on the test, if the NSR database has not been fully synchronized between REs, the LSI interfaces may flap if the customer manually switchover the RE mastership.

If the NSR database is fully synchronized, no issue observed in this scale.