Most routing protocols have metric structures and algorithms that are not compatible with other protocols. In a network with multiple routing protocols, the exchange of route information and the capability to select the best path across the multiple protocols are critical.elect the Best Path. Administrative distance is the first criterion that a router uses to determine which routing protocol to use if two protocols provide route information for the same destination. Administrative distance is a measure of the trustworthiness of the source of the routing information.
In July 2013, China heralded the opening of the New Century Global Center, an immense 18.9-million-square-foot (1.75 million square meters) structure that many are calling the largest building in the world.
Taipei 101 in Taipei, Taiwan, set records in three of the four skyscraper categories at the time it opened in 2004; at the time the Burj Khalifa opened in 2010 it remained the world's tallest inhabited building 509.2 m (1,671 ft) as measured to its architectural height (spire).