This field reports the number of single collision packets transmitted on the interface, exposed here as cienaCesPmExtendedTxRxTotalStatsBinTxSingleCollPkts. On this Ciena CES port's PM data, a single collision followed by a successful retransmit is routine background noise on a shared or half-duplex segment, so this counter climbing steadily (without TxExCollPkts or TxLateCollPkts climbing alongside it) is generally benign; and this is the running grand-total counter for the extended Tx/Rx PM group, tallied since the bin's own StartTime (in practice since the PM instance was created or last reset), so treat it as a lifetime tally rather than a per-interval number. For example, a link under light load might show a low but steady 20,000 single-collision frames for this bin; it's the rate of growth, not the presence of a nonzero number, that would flag a real problem.