Channel identification

The physical transmission wrapper has the responsibility to determine the logical channel that an arriving transmission belongs to. Essentially it must utilize some key piece of information to lookup the channel details in the channel cache. The key information can be design time or runtime. In the Sample application that key is the 'channel name', a soft coded design time value that may be changed at deployment time (it is a promoted property from the Identify Channel sub flow).

The physical transmission wrapper must place a copy of the channel data in the following location:

Environment.PMP.Variables.Channel

A copy of the channel data can be obtained using the Channel API. The sample application does this as follows:

CREATE LASTCHILD OF Environment.PMP.Variables AS refChannel NAME 'Channel';
CALL Cache.GetChannelByName(Cache.GetFlowInstanceCacheId(rEnv), Channel_Name, refChannel);

Older versions of FTM also required that the wrapper flow set the mapper label as part of this work. For FTM V2.1, Fix Pack 1 and later, the core physical transmission flow is doing this and so it is no longer necessary for the wrapper flow to do it.