Total number of frames received on the network (T1)
interface that are discarded by this channel unit.
Possible reasons for discard are:
Frame contained HDLC abort (7 or more ones in a row)
Frame had a CRC error
Frame had a non-integral number of bytes
Frame was too short (less than 5 bytes)
Frame was too long (more than 8192 bytes)
Frame had bad RFC-1973 (PPP) header - this error only
occurs if destination port is set for PPP protocol.
Frame was discarded due to lack of buffer space.
Only frames whose DLCI is addressed to a port on
this channel unit are counted.