This counter tracks flow control frames transmitted by the device, explicitly including both XOFF and XON pause frames. Flow control pause frames are the router telling an overwhelmed downstream switch or device to briefly halt incoming traffic, so a climbing count here suggests the CDD-564 itself is becoming a bottleneck on its Ethernet side -- worth correlating with the DMA-underrun counter to see if it's the same internal bandwidth pressure causing both. If this counter starts incrementing right as a site begins receiving a high-bitrate satellite feed destined for Ethernet delivery, that correlation suggests the router is pausing the LAN switch because it can't drain its own internal buffers fast enough.