the packets' short or long retry counts reached the MAC's short
retry limit or long retry limit, respectively.
9. Wireless LAN. Load– is the number of routing packets
transmitted per data packet delivered at destination.The load (in
bits/sec) is submitted to the wireless LAN MAC by its higher
layers in this node.3.9.5 Network Modeling Scenarios
The experimental scenario presented the SCADA system of
twenty stations of Neinvah governorate connected together by WMN
network with routing protocol DSR, which is used in investigating FTP
data traffic loads, and 802.11g is the network standard used
(because802.11g modulation is two to three times more power efficient
than other 802.11, and the length of time needed to transmit/receive a
meaningful amount of application data can be five times shorter on an
802.11g network than on another 802.11 WLAN [ 80 ]); see Figure
3.13.This experiment aimed to identify the capability of using WMN
network with DSR as a routing protocol to connect long distances SCADA
stations with minimum transmitted data losses and delay. The parameters
of a routing protocol which is used in this scenario were carefully designed
as outlined in Figure 3.1 4 , which presents the general parameters
configured in the experiment. The parameters of the wireless LAN card are
changed depending on the distance from each node to the next hop
(transmitted power, and packet reception-power threshold).Table 3. 9 shows
the distances and calculated transmission and sensitivity power values
between each node and the next hopwith omnidirectional antenna is used at
each node. Using directional antenna will reduce those values.In this
network, each node has more than one neighbor ,so the transmission power
used depends on the longest neighbor distance except for the central station
(Mosul400 server),which needs more adjustments, to avoid extra load on it.