Missed frame
When a frame arrives at the device and there is no buffer available,
the hardware drops the frame and increments the missed frame
counter.
L & F bits not set
On serial interfaces, the hardware sets input-descriptor information
for arriving frames. If the buffer can accept the complete frame
upon arrival, the hardware sets both the last and first bits of the
frame, indicating that the buffer accepted the complete frame. If
either of the bits is not set, the packet is dropped, the L & F bits
not set counter is incremented, and the buffer is cleared for reuse.
Note: It is unlikely that the L & F bits not set counter will be
affected by traffic.
Output frame counters:
DMA/FIFO underrun errors
The number of times the serial interface card could not retrieve
data fast enough from the system packet buffer memory to transmit
them onto the network.
Output aborts sent
The number of transmissions that were aborted as requested by
upper-level software.
Configuring the X.25 Network Interface
Chapter27. Configuring and Monitoring the X.25 Network Interface 359