Best Practices - I-Am

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  1. Do not issue I-Am on startup. Although the specification calls for this, large networks (thousands of devices) on power-up can generate a flood of I-Ams. Devices are still discoverable by the BACnet client issuing a Who-Is, to which the device can respond with an I-Am.
  2. I-Ams as a response to a Who-Is should be directed at the device which issues the Who-Is. Although a broadcast I-Am response is legal, a directed one reduces the amount of broadcast traffic on the networks.
  3. Who-Is requests should be directed to smaller and smaller sections of the valid address space. A Who-Is with no range limits, or a very large range, could generate thousands of I-Ams, which can easily flood Routers, IP Stacks etc.