The similarities between LAN and WAN are:1) They involve two or more nodes.2) The networks communicate by the use of protocols.3) The can both be used in small geographical areas, although, WAN can go far distances ranging from towns to countries.
Both network types use the same basic protocols for communication. LANs are faster and more efficient due to size and proximity, and they have a higher rate of data-transfer. WANs typically connect multiple LANs together, so they have a much heavier workload and must cover a broader scope. In general, though, a WAN is just a much larger version of a LAN.