Most WANs are meshes of some type. The original ARPANET was a mesh. Today, the Internet consists of several meshes called backbones which have incredibly high speed telephone lines between them, often using satellite or radar transmission methods. The hosts in the backbones are not used for normal uses, but are specially devoted to forwarding traffic over the backbone. Hanging off each backbone host is another WAN that connects a variety of other WANs and LANs. End-user computers are found usually only on these LANs. Fig. 23.11.6 shows a hypothetical backbone with several LANs of various types hanging off it.