Brocade Mobility RFS7000-GR Controller System Reference Guide (Supporting software release 4.1.0.0-040GR and later) - Manual (Page 218)

204 Brocade Mobility RFS7000-GR Controller System Reference Guide
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Viewing access port adoption defaults
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13. In most cases, the default settings for the Advanced Properties section are sufficient for most
users. If needed, additional radio settings can be modified for the following properties:
Antenna Diversity Use the drop-down menu to configure the Antenna Diversity settings for Access
Ports using external antennas. Options include:
•
Full Diversity: Utilizes both antennas to provide antenna diversity.
•
Primary Only: Enables only the primary antenna.
•
Secondary Only: Enables only the secondary antenna.
Antenna Diversity should only be enabled if the Access Port has two matching
external antennas. Default value is Full Diversity.
Maximum MUs Sets the maximum number of MUs that can associate to a radio. The maximum
number of stations that can associate to a radio are 256.
Adoption Preference ID The Adoption Preference ID defines the preference ID of the switch. The value can
be set between 1 and 65535. To make the radios preferred, the Access Port
preference ID should be same as adoption preference ID.
The adoption preference id is used for RP load-balancing. A switch will
preferentially adopt Access Ports which have the same adoption-preference-id as
the switch itself.
Short Preambles only If using an 802.11 bg radio, select this checkbox for the radio to transmit using a
short preamble. Short preambles improve throughput. However, some devices
(SpectraLink phones) require long preambles. This checkbox does not display if
using an 802.11a radio.
RTS Threshold Specify a Request To Send (RTS) threshold (in bytes) for use by the WLAN's
adopted Access Ports.
RTS is a transmitting station's signal that requests a Clear To Send (CTS) response
from a receiving station. This RTS/CTS procedure clears the air where many MUs
(or nodes) are contending for transmission time. Benefits include fewer data
collisions and better communication with nodes that are hard to find (or hidden)
because of other active nodes in the transmission path.
Control RTS/CTS by setting an RTS threshold. This setting initiates an RTS/CTS
exchange for data frames larger than the threshold, and simply sends (without
RTS/CTS) any data frames that are smaller than the threshold.
Consider the trade-offs when setting an appropriate RTS threshold for the WLAN's
Access Ports. A lower RTS threshold causes more frequent RTS/CTS exchanges.
This consumes more bandwidth because of the additional latency (RTS/CTS
exchanges) before transmissions can commence. A disadvantage is the reduction
in data-frame throughput. An advantage is quicker system recovery from
electromagnetic interference and data collisions. Environments with more wireless
traffic and contention for transmission make the best use of a lower RTS
threshold.
A higher RTS threshold minimizes RTS/CTS exchanges, consuming less bandwidth
for data transmissions. A disadvantage is less help to nodes that encounter
interference and collisions. An advantage is faster data-frame throughput.
Environments with less wireless traffic and contention for transmission make the
best use of a higher RTS threshold. Default is 2346.
In 802.11b/g mixed RTS/CTS happens automatically. There is no way to disable
RTS/CTS unless the network and all the devices used are 802.11g or 802.11a
only. The proper co-existance of 802.11b and 802.11g is ensured thru RTS/CTS
mechanism. On 802.11g radios CTS-to-self is enabled irrespective of whether or
not 11b rates are enabled or disabled.
When ERP Protection is ON, the 11bg radio will perform a CTS-to-self before it
transmits the frame.