Echelon OpenLDV - Manual (Page 112)

104 Extending xDriver
The events shown in Figure 15 that occur within the LNS application represent
a typical LNS application that opens a downlink session. Your application can
vary from these steps.
In addition, the events that occur within the lookup extension component in the
flow chart represent the minimal tasks that a lookup extension component must
perform during a downlink session. This flow chart refers to the methods that
you can use when programming your custom lookup extension component. For
more information about these methods, see Appendix C, Custom Lookup
Extension Component Programming, on page 161.
Uplink Sessions
An xDriver session is considered an uplink session if an RNI initiates the session
by requesting a connection to an OpenLDV application. This request for
connection is usually caused when the RNI receives a message with a qualifying
message code.
For xDriver to receive the request, the xDriver Connection Broker must be
running. For information about the xDriver Connection Broker, see Starting the
Connection Broker on page 135.
There must also be at least one xDriver profile with uplink session handling
enabled for xDriver to receive the uplink session request. You can use the
OpenLDV xDriver Profile Editor to create an xDriver profile that has uplink
session handling enabled. Using the Profile Editor, you can assign the profile a
port, which the Connection Broker uses to listen for uplink session requests. The
profile handles all uplink session requests on that port. For more information
about xDriver profiles and the xDriver Profile Editor, see xDriver Profiles on page
134.
Figure 16 shows the application flow for a downlink session.
User Application
7
x.Profile.RNI
Lookup Extension Connection Broker
OpenLDV
Application
1
3
2
6
4 5
Database
SmartServer
SmartServer
Figure 16. Uplink Session Overview
The application flow for an uplink session includes the following steps (see
Figure 16):
1. An RNI (for example, a SmartServer) requests an uplink session. When
the request for connection is made, the Connection Broker receives an