The Local AreaTransport Protocol (LAT) is a high-speed asynchronous protocol in DECnet
that was formerly used in host communications and carried multiplexed terminal traffic to and from timesharing hosts. The LAT protocol supported the lower layers of the OSI reference model up to the transport layer and was used for the transmission of small amounts of data to hosts
. The LAT protocol was used as a virtual terminal protocol in Ethernet environments and was one of the non-routable protocols, which is why it could only be used in smaller local networks that operated without routers.