Networks can be divided into two categories i.e., those using point-to-point connections and those using broadcast channels. Broadcast channels are sometimes referred to as multi-access channels or random access channels. The protocols used to determine who goes next on a multi-access channel belong to a sublayer of the data link layer called the MAC (Medium Access Control) sublayer. The MAC sublayer is especially important in LANs, nearly all of which use a multi-access channel to communicate. WAN, in contrast, uses point-to-point links except for satellite networks.