How to calculate a total by comparing current and next row

I have a table with some rows:

I have a few questions to accomplish the task altogether. Is it possible to calculate total of transmitted and received based on checked_date and ip and connect_time using mysql query? If yes, can I use logical operators to calculate total of transmitted and received? To get correct total transmitted and received I need to use a formula like:

if connect_time[i] > connect_time[j] 
then total += transmitted[i]+transmitted[j] 
else total += ABS(transmitted[i]-transmitted[j]) 
end

How to get it done with this formula, does anyone have an idea? P.S. i = current row and j = next row.