Lantronix ETS Reference Manual - 2.6   Lat

Concepts

LAT

2-5

LAN Manager node lookups take a text resource name and resolve it into a hardware address. For this 

reason, node and resource names must be unique on the network, and the ETS will print an error message 

if any configuration that violates this rule is attempted.

Note:

NetBIOS can be run over TCP/IP, but the ETS does not support this mode of 

operation.

2.6   LAT

Digital Equipment Corporation’s LAT (Local Area Transport) networking software is designed to ease the 

process of accessing and managing local area networks. 

LAT is significantly different from other protocols in two important ways. First, LAT is not routable. There 

is no way to divide LAT networks into smaller subnetworks and use routers to reduce traffic between nodes. 

Second, LAT is a timer-driven protocol. Packets are expected at certain intervals, and the protocol cannot 

adapt to slow network links dynamically. For these reasons, LAT traffic over wide areas is typically carried 

inside (or encapsulated in) TCP/IP or IPX/SPX packets. The latter two protocols are fully routable, and 

can handle wide-area, slow network links. 

Note:

If LAT is bridged across slow links, session time-outs and errors are likely.

LAT software is built around the concept of services. A service may be provided by a dedicated device, 

such as a printer, or by a network host. A device that offers one or more services, such as your ETS, is called 

a node.

Services have names, and there can be more than one service on a network with the same name. For 

example, you could attach eight modems to a server and set up the service modem to use ports 1-8; a user 

who typed Connect Modem would not necessarily know which port would be used for the connection. Note 

that if a service is provided by the local ETS and also a by remote node, there is no guarantee that a connect 

command issued locally would result in a connection to the local service (although this can be explicitly 

requested).