User's Manual

User Manual
3000 SERIES 3
rd
GENERATION ACTIVE RFID
Now using the default SP values, a SP load of 1 means '1 message per 5 minutes'. If we convert this
to the number of messages per second, we get the value 1 / (5 * 60) = 0.003 messages per second. A
single MR-SP link is capable of handling 2 messages per second by default. However a single MR-
MR links is capable of handling 1 message per second. This results in a SP load capability of 1 * 5 * 60
= 300. The network itself consumes some of this bandwidth to establish and maintain the network
coherence and layout. Also, packet loss or retries can occur. As a rule of thumb, roughly 10% of the
available bandwidth is consumed by internal use and packet loss or retries, assuming stable
connections between Infrastructure nodes. The further away an MR is from the GW (in hops), the
more bandwidth is consumed by the intermediate MRs. As a result, an Infrastructure node is capable
of handling a SP load of 0.90 * 300 = 270. If the SP load that you calculated gets close to this number,
you should place an additional MR to increase the available bandwidth.
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Illustration 28: Example SP Load calculations, with every SP default at load 1, every
Infrastructure node combination of its own SP load and additional accumulative SP
Load