# Bubble

These counters occur when an unexpected idle flit is transmitted or received.

The transmit port sends idle flits until it can continue sending the rest of the packet. The category is calculated as follows:

1. The maximum value between the sum of the XmitWastedBW and XmitWaitData or the neighbor's PortRcvBubble.

2. Then divide the previous value by the port's utilization to provide context.