Allen-Bradley 1783-WAPAK9, Руководство пользователя

Страница: 248 / 612

248 Rockwell Automation Publication 1783-UM006A-EN-P - May 2014
Chapter 7 Configuring Radio Settings
•
To set the 2.4 GHz, 802.11g radio to serve only 802.11g client devices, set
any Orthogonal Frequency Division Multiplexing (OFDM) data rate (6,
9, 12, 18, 24, 36, 48, 54) to Basic.
•
To set only the 5 GHz radio for 54 Mbps service, set the 54 Mbps rate to
Basic and set the other data rates to Disabled.
You can configure the wireless access point to set the data rates automatically to
optimize either the range or the throughput. When you enter range for the data
rate setting, the wireless access point sets the 1 Mbps rate to basic and the other
rates to enabled.
The range setting lets the access point to extend the coverage area by
compromising on the data rate. Therefore, if you have a client that is not able to
connect to the access point while other clients can, one reason can be that the
client is not within the coverage area of the access point. In such a case, the range
option helps extend the coverage area and increases the ability of the client to
connect to the access point.
Typically the trade-off is between throughput and range. When the signal
degrades (possibly due to distance from the access point,) the rates renegotiate
down to maintain the link (but at a lower data rate). Contrast that against a link
configured for a higher throughput that drops when the signal degrades enough
to no longer sustain a configured high data rate, or roam to another access point
with sufficient coverage, if one is available.
The balance between the two (throughput versus range) is one of those design
decisions that has to be made based on resources available to the wireless project,
for example:
•
type of traffic the users pass
•
service level desired
•
the quality of the RF environment
When you enter throughput for the data rate setting, the wireless access point sets
all four data rates to basic.
TIP
When a wireless network has a mixed environment of 802.11b clients and
802.11g clients, make sure that data rates 1, 2, 5.5, and 11 Mbps are set to
required (basic) and that all other data rates are set to enable. The 802.11b
adapters don’t recognize the 54 Mbps data rate and don’t operate if data rates
higher than 11 Mbps are set to require on the connecting access point.