I'm having a problem on both PPTP and L2TP tunnels periodically where the TX drops are occurring. The WAN interface shows no TX drops.
I've attached an example of this situation showing a small packet loss (11245 out of 11269 / .2% loss). When I watch the counters on the interface, it seems most of the time the packet loss is caused by a TX drop on the VPN interface. The WAN interface shows no TX drops. The WAN interface bandwidth utilization is very low (less than 1mbps) and circuit capacity is about 20mbps down / 5mbps up.
Does anyone know how a PPTP or L2TP interface decides whether to drop a TX packet?