This Article explains the root cause and recovery of the Backup member ports down state with EX4400-48MP/24MP two member VC after a power outage 

The customer was having unstable power source because of it there were multiple power outages seen and at one of the incident all the mge ports of the backup of a two member EX4400-48MP VC went down. And this issue was recreated a couple of times at local JTAC lab

Setup:

PD device------mge-0/0/0-EX43000-48MP(fpc0)------------2VC-ports-------EX43000-48MP(FPC1)mge-1/0/0--------PD device

Issue verification: [FPC1 was Primary and FPC0 was backup]

-After power outage, ports of backup[FPC0] was moved to DOWN state

labroot@sjc02-spi-acc-cnc> show interfaces terse mge-0/0/0   
Aug 18 12:50:15
Interface        Admin Link Proto  Local         Remote
mge-0/0/0        up  down
mge-0/0/0.0       up  down eth-switch

{master:1}

-Whereas ports of Primary[FPC1] was staying UP

labroot@sjc02-spi-acc-cnc> show interfaces terse mge-1/0/0   
Aug 18 12:50:18
Interface        Admin Link Proto  Local         Remote
mge-1/0/0        up  up
mge-1/0/0.0       up  up  eth-switch

 

-There is a timing issue because of it during VC boot up some time the ports of the backup member are not moved out of super isolation mode.

-Super isolation is a mode to keep the ports out of all functionalities, it should be brought out of super isolation mode to make them operational.

-The reason for this issue is that the out of super isolation call missed on dev_port_start conduction.

-Because of it Opcode-12 IPC message is not received in the system. Due to that ports are in downstate.

-This applies only for ex4400-48mp and ex4400-24mp

-Power outage in the device is trigger of the issue but this is not seen always and very rare to observe.

-Impact: As the ports are down, there will be traffic impact.

-Workaround: Disable and enable the ports to bring them UP
-This issue is fixed on 22.3R2-S2.10

 

2023-09-13: Initial Version