Echelon LNS - Manual (Page 111)

LNS Programmer's Guide 97
When you discover that a physical device has been permanently removed from the
network, you should remove the AppDevice object associated with the device from the
LNS database. See Removing Devices on page 137 for information on removing devices.
Before doing so, you should note that device detachment might only signal that a repair
operation is under way. For example, if a device is discovered missing, but a new device
with the same program ID (or the same location field information) is added to the
network and attached to the same channel within the next 15 minutes, then you could
assume that the new device is a replacement for the removed device. In this case, you
need to update the LNS database to recognize the replacement. For instructions on this,
see Replacing Devices on page 132.
Note that when a router becomes unattached from the network, LNS will usually be
unable to communicate with any devices on the far side of the router, and devices on
channels connected by the router will be unable to communicate with each other. In this
case, LNS will generate an OnAttachmentEvent for the router, but not for each affected
device.
System Management Mode Considerations
The network installation scenarios described in this chapter make reference to the
system management mode (i.e. the MgmtMode property of the System object) at various
points. The system management mode determines whether or not changes made to the
LNS database that affect the configuration of devices on the network are propagated to
those devices as the changes are committed to the LNS database, or if the configuration
changes are propagated to the devices later. The system management mode affects all
client applications connected to a network, since the configuration of the network must
be managed consistently.
This section provides information you need to be aware of when using the MgmtMode
property. The section begins with a description of the two values you can assign to the
MgmtMode property: lcaMgmtModePropagateConfigUpdates and
lcaMgmtModeDeferConfigUpdates.
NOTE: New names for the system management mode settings have been provided in
Turbo Edition. The old values still exist in LNS for compatibility reasons, but the
documentation refers only to the new values. The new
lcaMgmtModeDeferConfigUpdates
value maps to the old lcaOffNet value, and the
new
lcaMgmtModePropagateConfigUpdates
value maps to the old lcaOnNet value.
lcaMgmtModePropagateConfigUpdates
When the system management mode is set to lcaMgmtModePropagateConfigUpdates,
changes made to the database that affect the configuration of one or more physical
devices are propagated to those devices as the changes are committed to the database. If
the modification is performed as part of a transaction, the changes are propagated to the
devices during the call to CommitTransaction(). If the modification is not performed
as a part of a transaction, the changes are propagated as the property causing the change
is written to, or the method causing the change is invoked, and the LNS database is
updated.
Note that if LNS fails to update the devices, a network service warning in the range
4030-4089 (lcaErrNsWarningFirst- lcaErrNsWarningLast) will be returned. In