Echelon LNS - Manual (Page 52)

LNS Programmer's Guide 38
An application that accesses the LNS Server remotely can do so as a Lightweight Client
or as a Full Client. A Lightweight Client is an application that communicates with the
physical network through the LNS Server PC, via a TCP/IP connection. A Full Client is
as application that has its own network interface, and thus communicates with the LNS
Server PC through the network, as well as directly with devices on the network. A Full
Client is as application that has its own Network Service Device connecting to the
network and to the LNS Server PC. The Network Services Device uses an LNS network
interface, and either a regular L
ON
W
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channel or a L
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/IP channel, to do so.
A remote Full client communicates with the LNS Server PC through the network, as well
as directly with devices on the network.
Note that some applications, known as Independent Clients, can access a network
without connecting to the LNS Server or to the global database. Independent clients can
only be used for monitor and control operations.
When enabling remote client access with the LNS Server application, the LNS Server
starts listening at TCP port 2540 by default. Any Lightweight client can then access your
LNS Server, if they are aware of your LNS Server's IP address and TCP base port
numbers. If you wish to completely disable access by Lightweight clients, see the
available options that are detailed in the help file for the LNS Server application. If you
wish to restrict access by remote LNS applications to specific IP addresses or IP address
ranges, use the PermissionString property. For more information on the use the
PermissionString property, see the LNS Object Server Reference help file.
The following sections detail the various ways local and remote applications
communicate with the LNS Server and the L
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network.
Local Client Applications
Local Client applications run on the LNS Server PC – the same PC that contains the
LNS global database. This is shown in Figure 3.4. In this configuration, the PC running
the application contains an LNS network interface that is used to communicate directly
with the physical network. For descriptions of the network interfaces you can use with
LNS, see Chapter 11, LNS Network Interfaces.
Each network contains a NetworkServiceDevice object that is shared by the LNS
Server PC, and all local applications that have that network open.