set dcc_sliding_window [<number>]
The DCC specification requires that data cannot be sent via a DCC SEND connection until all previous data have been acknowledged by the receiver. For high latency/high bandwidth connections (ie, anything faster than 28.8k), this can have serious consequences on throughput because at least half of the time the connection is idle waiting for an acknowledgement to be returned. Although strict conformance to the DCC specification requires that this value be set to 1 (and it is, as the default), there are no technical impediments to sending more than one packet of data at a time, and real world experience bears this out.
Significant gains in throughput can be achieved by setting this value to two (2). Values of 3 or more get modest gains compared to the next lower value. You can set <number> to be arbitrarily high because EPIC will never send a packet of data if sending that packet will block. Thus, setting this value to an absurdly high value (such as 1,000) will yield optimal throughput.