By Marina Lopes NEW YORK (Reuters) – ATT Inc said on Monday it expects to expand its ultra-fast fiber network and TV services to up to 21 U.S. cities, including Chicago and Atlanta. ATT, which is fighting rivals such as Google Inc as well as cable companies with its fiber-based product, is considering providing broadband Internet speeds of up to 1 gigabit per second and its U-verse television service in cities, including Chicago, Los Angeles and Miami. Earlier this month, ATT announced it was in discussions with North Carolina Next Generation Network to bring U-verse with high-speed internet to North Carolina.