Microwave Data Systems MDS entraNET 900, System Manual

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30 MDS entraNET 900 System Guide (Preliminary) MDS 05-4055A01, Rev. A
(208 ms), and
Slow
(508 ms). These values provide relatively
quick association times where Fast is very fast (
≈
5 sec) and the
other end, the largest recommended value, the 508 ms period is
slow (
≈
60 sec). [Fast, Normal, Moderate Slow; Normal]
TIP: Increasing the Beacon Period will provide a small
improvement in network data throughput. Shortening it
decreases the time needed for Remotes to associate with
the AP. A short period is usually only a benefit when there
are mobile Remotes in the network.
•
Hop Pattern Seed
(Access Point Only)
—A user-selectable
value to be added to the hop pattern formula in an unlikely event
of identical hop patterns of two co-located or nearby networks.
Changing the seed value will minimize possible RF-signal col-
lisions of transceivers. (This field is only changeable on an
Access Point. Remotes read the AP’s value upon association.) [1
to 65,000; 1]
•
Fragment Threshold
—Before transmitting over the air, if
a packet exceeds this number of bytes, the transceiver sends the
packet in multiple fragments that are reassembled before being
delivered over the Ethernet interface at the receiving end. Use
smaller values on high interference locations. (
See “Network
Performance Notes” on Page 54 .) [(256–1600 bytes; 1600]
TIP: In an interference-free environment this value should be
large to maximize throughput. If interference exists then
the value should be set to smaller values. The smaller the
packet the less chance of it being interfered with at the cost
of slightly reduced throughput.
•
RTS Threshold
—Number of bytes for the over-the-air
RTS/CTS handshake boundary. ( See “Network Performance
Notes” on Page 54 .) [0 to 1600 bytes; 500]
TIP: Lower the
RTS Threshold
as the number of Remotes or
overall over-the-air traffic increases. Using RTS/CTS is a
trade-off, giving up some throughput in order to prevent
collisions in a busy over-the-air network.
The
RTS Threshold
should be enabled and set with a value
smaller than the
Fragmentation Threshold
described
above. RTS forces the Remotes to request permission
from the AP before sending a packet. The AP sends a CTS
control packet to grant permission to one Remote. All
other Remotes stop transmitting for the specified amount
of time.
•
RSSI Threshold
—Level (dBm) below which connection is
deemed to have degraded, and an critical event is generated and
logged. [0 to -120; Not Programmed]