This counter provides a count of host, switch, or network restart activity, incrementing when this interface receives a RESTART message. A RESTART message clears call state, potentially for many VCs at once, rather than affecting a single call, so this counter incrementing at all is worth investigating on its own; it typically follows something like a peer switch reboot or a signaling process crash rather than routine call churn. A single increment coinciding with every VC on a link briefly dropping and re-establishing points to the far end having just restarted its signaling stack.