The PING command, for example, uses ICMP to test an Internet connection. IP specifies the addressing scheme. Messages are routed based on the IP address. ISDN may be transmitted via telephone networks, packet switched networks, telex, CATV networks, and more. LANs can be connected over any distance via telephone lines and radio waves.
Some networks do without connecting media altogether, communicating instead via radio waves.
Network A network is a group of two or more computer systems linked together. OC3 OC3 is an optical fibre line. OSPF is an interior gateway protocol that uses link-state technology for routing within a group of routers. PING sends a packet to the specified address and waits for a reply. PPP provides a common solution for the easy connection of a wide variety of hosts, bridges and routers.