Motorola Series Switch WS5100 User Manual

Page 160

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4-86 WS5100 Series Switch System Reference Guide

12.Refer to the

Status

field for the current state of the requests made from applet. This field displays error

messages if something goes wrong in the transaction between the applet and the switch.

13.Click

OK

to use the changes to the running configuration and close the dialog.

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.

Beacon Interval

Specify a beacon interval in units of 1,000 microseconds (K-us). This is a multiple of the DTIM
value, for example, 100: 10. (See "DTIM Period," below). A beacon is a packet broadcast by
the adopted access ports to keep the network synchronized. Included in a beacon is
information such as the WLAN service area, the radio-port address, the broadcast
destination addresses, a time stamp, and indicators about traffic and delivery such as a
DTIM.

Increase the DTIM/beacon settings (lengthening the time) to let nodes sleep longer and
preserve battery life. Decrease these settings (shortening the time) to support streaming-
multicast audio and video applications that are jitter-sensitive. Default is 100 K-us.

DTIM Period

Specify a period for the Delivery Traffic Indication Message (DTIM). This is a divisor of the
beacon interval (in milliseconds), for example, 10 : 100. (See "Beacon Interval," above). A
DTIM is periodically included in the beacon frame transmitted from adopted access ports.
The DTIM period determines how often the beacon contains a DTIM, for example, 1 DTIM
for every 10 beacons. The DTIM indicates that broadcast and multicast frames (buffered at
the access port) are soon to arrive. These are simple data frames that require no
acknowledgement, so nodes sometimes miss them. Increase the DTIM/beacon settings
(lengthening the time) to let nodes sleep longer and preserve their battery life. Decrease
these settings (shortening the time) to support streaming-multicast audio and video
applications that are jitter-sensitive. The default DTIM period is 2 beacons.

Self Healing Offset

When an access port increases its power to compensate for a failed access port i, power is
increased to the country's regulatory maximum. Set the Self Healing Offset to reduce the
country's regulatory maximum power if access ports are situated close to each other or if
access ports s use external antennas. For additional information on determining the offset
value, see the documentation shipped with the access port.

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