Thank you for reaching out. As you know, 128T Routers leverage BFD to monitor multiple capabilities of paths between 128T Routers:
- Path Availability
- Path Health (Jitter, Packet Loss, Latency, and MOS Score)
- Presence of Stateful Tracking Devices (Firewalls, CG NAT devices, etc).
While these capabilities provide fine-grained analytics and service SLA monitoring, they can be problematic for metered connections. As of software version 3.1.9 with the default BFD settings, the 128T router will expend 1.6 GB per month per peer path. In many environments, the LTE path is often the path of last resort, so the path availability and fine-grained SLA measurements don't need to be as aggressive.
The following recommended configuration changes for metered connections will reduce BFD Bandwidth Usage to 146 MB per month per peer path:
Typically adjacencies are dynamically discovered and automatically generated, leveraging settings contained within the neighborhood object. As such, it is recommended to place these configurations in the neighborhood that is being leveraged for LTE network interfaces.
EDIT: one can also add to the neighborhood configuration to disable the firewall detection test (udp-transform mode always-transform) to save an additional 30 MB per month per peer path.
If you have a specific circumstance that needs a more thorough investigation, please let us know!