UUCP links over 1200 baud modems, connecting only at night for cheap rates, but stymied by busy signals, down hosts, deep queues of other data, stalled daemons,

UUCP links over 1200 baud modems, connecting only at night for cheap rates, but stymied by busy signals, down hosts, deep queues of other data, stalled daemons, out-of-date routing tables. Trans-oceanic links had high costs and limited available bandwidth, and priority queueing could impose quite a delay.