| For instance, if the first ATM cell containing a new | IP packet gets lost, the switch may continue to transmit the other 28 | cells in the packet even though these are now useless garbage data that | don't need to be forwarded. There are various hacks at this problem, and to be honest I haven't payed much attention to them. The ones I've looked at tend to involve a specially-marked cell that indicates one or the other end of a packet, or a train of cells each of which is marked. A switch needing to discard a cell will attempt to discard all the related cells, for instance by discarding all cells until an end-of-packet or start-of-packet or whatever is encountered. Some of the schemes are even fairly clever about trying to avoid packet shredding, however none of them are remotely as clever or as effective at congestion avoidance and management as RED is. RED on TCP flows in an ATM switch would impress me. Sean.