an improved method and system for transmitting a stream of data bytes through a channel whose capacity may change during transmission . by utilization of selective regions of sequence number space , the enhanced radio link protocol provides the benefits of large byte sequence numbers while transmitting a fraction of the sequence number bits in the majority of over - the - air frames . frame header sequence numbers are shortened by dividing the byte sequence number by a page size , and by performing a modulo function on the byte sequence number .