Router or Modem causing lag

[heavenlykid]

Ok i know this is kinda a goofy but recently while playing starcraft on Battle Net Im getting weird lag problems. Its not all the time just at random points not sure whats causing it. I've wiresharked to make sure router wasnt doing any goofy crap and it seems fine. I tried to plug straight to modem and Im still getting lag but only in online games. Any Suggestions??? And not jus me alot of people are complaining about lag problems on battle net. Maybe its just blizzard but im not sure just wanna know if there is anything i can do to find the cause of the problem.