View source for Media Access Control Address

'''Media Access Control Addresses''' (usually shortened to the acronymic form, '''MAC Addresses''') are the [[physical network|network]] [[address]]es for [[network interface]]s, on [[Ethernet]] and other [[local area network|LANs]] which use the Ethernet [[packet]] format (including its [[physical network]] addresses). They are 48 bits long, [[globally unique]], and only uniquely identify network interfaces; they do not include any other operationally useful information, such as ''where'', in the particular [[internetwork]] to which the given network interface is attached, it actually is.

MAC Addresses are assigned permanently to network interfaces at the time of manufacture, from a [[namespace]] in which each manufacturer is perpetually assigned a section of the namespace. That way, users do not have to assign addresses to network interfaces, before attaching them to a physical network, as they used to have to do in the early days of networking, when network interface addresses were often only 8 bits long, and were not globally unique.

==See also==

* [[Address Resolution Protocol]]

[[Category: Networking]]