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.
Burj Khalifa in Dubai, United Arab Emirates is the tallest building in the world. Shanghai Tower in Shanghai, China is the 2nd tallest building in the world. The Abraj Al-Bait Towers in Mecca, Saudi Arabia, is the tallest hotel, and the 3rd tallest building in the world.
Tallest residential building in the world: 23 Marina in Dubai  --- 395m (1,296 ft.), with 90 storeys.  Tallest hotel in the world: Makkah Royal Clock Tower Hotels ---  601m (1,972 ft.) with 95 storeys.  Tallest structure in the world: Burj Khalifa, Dubai ---  828m (2,717 ft.).  Tallest tower in the world: Tokyo Sky Tree, Japan ---  634m (2,080 ft.).  First Building to have more than 100 storeys: Empire State  Building (New York City, USA) --- 381m (1,250 ft.), 102 storeys.