LACP fallback allows an interface that is part of a LAG to continue forwarding traffic even when LACP negotiation temporarily fails -- such as during a Mobility Gateway reboot or upgrade.
This enables the upgrade to proceed without removing interfaces from the LAG, since fallback mode keeps the link operational until LACP becomes available again.

The no interface loopback command removes an unwanted loopback interface, ensuring it no longer interferes with routing and network operations.

When using UBT (User-Based Tunneling), packets are encapsulated, which increases their size.
HTTPS traffic is sensitive to MTU issues -- if packets exceed the path MTU and PMTUD is not functioning, sessions break or stall.
To prevent this, Path MTU Discovery must be enabled, ensuring devices automatically determine the correct MTU and avoid fragmentation-related issues.
Jumbo frames or manual fragmentation do not solve the underlying PMTU mismatch, and fragmentation is generally avoided for tunneled traffic.

client-mode = Selects client mode. In this mode, all clients connecting to the port are sent for authentication.
device-mode = Selects device mode. In this mode, only the first client connecting to the port is sent for authentication. Once this client is authenticated, the port is considered as open and all subsequent clients trying to connect on that port are not sent for authentication.