GE MDS MDS iNET 900, Справочное руководство

Страница: 70 / 190

60 iNET Series Reference Manual 05-2806A01, Rev. H
At Every AP Radio
Parameter settings that should be reviewed for AP radios providing ser-
vice to mobile remotes:
•
Compression
[
disabled
]—Disable radio compression. Data com-
pression is best performed by the middleware running on the
mobile laptop PC. Gains in efficiency are made because middle-
ware compresses data at a higher stack level, and it aggregates
multiple data frames and streams into a single packet. Compres-
sion at the radio level, although highly efficient, works at the
individual packet level.
•
Dwell Time
[
Set to the minimum value
]—This setting controls the
amount of time that the unit spends on each frequency between
hops. Although overall throughput appears to decrease by this
setting the effects of multipath fading are minimized through
frequency diversity.
•
Beacon Period
[
Set to the fastest value
]—This parameter defines
the interval at which the Access Point transmits a synchroniza-
tion beacon to all remotes. A faster setting minimizes resyn-
chronization times when remote radios roam between access
points or in highly interrupted coverage areas (dense buildings,
for example).
•
RTS Threshold
[
0 -1600 bytes
]—Enable RTS flow at a small value.
This setting is a wireless equivalent to RTS/CTS flow control in
a wired communications circuit. This mechanism prevents
packet collisions caused by the “Hidden Node” scenario, in
which remotes can’t hear each other before transmitting. When
this value is set below 100 or above 1500, it is effectively dis-
abled.
2.6 CONFIGURING THE SERIAL
PORTS
2.6.1 Overview
The transceiver includes an embedded serial device server that provides
transparent encapsulation over IP. In this capacity, it acts as a gateway
between serial and IP remote devices. Two common scenarios are PC
applications using IP to talk to remote devices, and serial PC applica-
tions talking to remote serial devices over an IP network.
Essentially the same data services are available for both serial ports:
COM1
and
COM2
. Note that the transceiver’s
COM1
port is DCE and
COM2
is DTE. Therefore, if the RTU to be connected is also DTE, then
a null-modem cable will need to be used when connecting to
COM2
.