--- Underruns ---
Description: The number of times that the transmitter has been running faster than the switch can handle. Common Causes: This can occur in a high throughput situation where an interface is being hit with a high volume of bursty traffic from many other interfaces all at once. Interface resets may be occurring along with the underruns.
--- output buffer failures ---
description: Cisco IOS sh interfaces counter. The number of failed buffers and the number of buffers swapped out. Common Causes: As an example, consider a scenario where a 1gig multicast stream is being forwarded to 24 100 Mbps ports. If an egress interface is over-subscribed, it would be normal to see output buffer failures incrementing along with Out-Discards.