Communication across the central ranges is difficult. The southern portion of the Annamese Cordillera has two identifiable regions. One consists of plateaus of approximately 1,700 feet (520 metres) in elevation that have experienced little erosion, as in the Dac Lac Plateau near Buon Me Thuot. The second region is characterized by heavily eroded plateaus: in the vicinity of Pleiku, the Kontum Plateau is about 2,500 feet (760 metres) above sea level; and in the Da Lat area, the Di Linh Plateau is about 4,900 feet (1,500 metres).

The description fits Vihn, the city in Vietnam. The area is constituted by the low-level land that makes up for a fifth of the country's population. There is the Red River that is fronted by the hills that rise gently to cover the land and the high mountains in the Northwest; the Annan Highlands that covers much of the landscape. Because of such a rugged landscape, the telecommunication is often difficult at most times.