WAN interface repeatedly down and up

In order to triage the scenario

Check for stateMonitor.log for the "WAN interface down" alarm.

a) Find the interface which is down

b) show network-interface to check the status of the interface (incase of flap sceanrio)

Incase of interface which down, will have below outputs for certain PCLI commands.

Below commands were run assuming interface name which is down is WAN1

# show arp | grep "WAN1"
RO-WAN1-NI 50  10.10.10.101   00:00:00:00:00:00  Expired


# show device-interface name WAN1
========================================
 RO1-node1:WAN1
========================================
 Type:                ethernet
 Forwarding:          true
 PCI Address:         0000:03:00.1
 MAC Address:         90:ec:xx::xx:xx

 Admin Status:        up
 Operational Status:  Down
 Provisional Status:  up
 Redundancy Status:   non-redundant
 Speed:               1 Gb/s
 Duplex:              full

Stop the 128T.service 

a) Once the interface is released in Linux space, check the Ifconfig status of physical interface

b) Verify dmesg logs on Linux shell for any "NIC Link is Down" messages

Check if there are any issues at physical level.