What does the "late-dropped out pkts" mean when doing a show frame pvc?

[randtaylor]

I am trying to implement DTS on a 7500. When I turn on the traffic shaping, I begin to have a large number of late-dropped out pkts on PVCs that I am not even doing traffic shaping on:

kylex7500b#sh fram pvc 636

PVC Statistics for interface Serial5/1/1 (Frame Relay DTE)

DLCI = 636, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial5/1/1.10

input pkts 7655 output pkts 7736 in bytes 1460777 out bytes 2019806 dropped pkts 85 in pkts dropped 0

out pkts dropped 85 out bytes dropped 59816

late-dropped out pkts 85 late-dropped out bytes 59816

in FECN pkts 0 in BECN pkts 0 out FECN pkts 0 out BECN pkts 0 in DE pkts 0 out DE pkts 0

out bcast pkts 290 out bcast bytes 22076

Before turning on DTS, I have 0 late-dropped out pkts. What could be the cause? Thanks.

[pradeepde]

I suppose this parameter(late-dropped out pkts) is the same as traffic shaping drops.For traffic shaping we have a buffer and inorder to slow down the rate ,we are keeping the packets in the queue.Bytes are first delayed by the shaping mechanism and stored in this queue. If the queue fills up, then packets are dropped. By default, the queue type is FCFS (First Come First Serve) or FIFO, but can be changed to WFQ, PQ, CQ or CBWFQ. When this buffer becomes full, the drops will happen. The parameter "traffic shaping drops" in "show frame relay pvc" command shows the number of drops in the shaping queue.