A backbone in a computer network refers to that part of the network infrastructure which carries the majority of traffic on the network at high speeds and connecting various networks with each other. It primarily consists of routers and switches which are connected by fiber optical links. Big companies with offices distributed in different geographical locations have their own backbone system for interconnectivity. Similar is the case with Internet backbones, where the computer connects to a network from a particular ISP and the ISP in turn connects to the main Internet backbone for access to the worldwide network. Read more internet and working of internet.