|Context Tag 0||deviceInstanceRangeLowLimit||0..4194303||Optional (but if used, must be paired)|
|Context Tag 1||deviceInstanceRangeHighLimit||0..4194303||Optional|
As to the Who-Is. Workstations (and other BACnet clients) should NOT issue unbounded Who-Is commands. They will flood large networks and drop most of the resulting I-Ams anyway, no matter how fast the workstation. And if the PC itself does not drop the packets, IP routers, and BACnet routers in the way will.
The right approach is to divide the address space into segments using the Device Instance Low and High Range Limits of the Who-Is messages (see http://www.bacnetwiki.com/wiki/index.php?title=Who-Is), to elicit more manageable responses.
In fact, this range should be made smaller and smaller until it is 0, or until there are no responses, to confirm that ALL devices are discovered.
|APDU BBMD BVLC BVLL DADR DNET Encoding I-Am LSAP MAC NPCI NPDU NSAP NSDU SA SADR SNET|
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