Tier 1 ISPs are the top of the hierarchy. Tier 1 ISPs are huge organizations that connect directly with each other through private peering, physically joining their individual network backbones together to create the global Internet backbone. Within their own networks, the Tier 1 ISPs own the routers, high-speed data links, and other pieces of equipment that join them to other Tier 1 ISP networks. This includes the undersea cables that connect the continents.