An economical optical network is constituted by effectively using network resources by using the minimum number of, or minimum capacity of 3R repeaters. The segmented data structure includes segment IDs, corresponding data segments and a packet header arranged so that all data is aligned on 8-byte boundaries for efficient processing by 64-bit processors. The capacitor is configured to define a transfer function of the equalizer. The user device is also operable to compute its position based upon received navigation signals. The second delay period is greater than the first delay period.