CyberGuard SG300 User Manual page 87

Preamble Type: The preamble is part of the physical wireless protocol. Using a short
preamble can give higher throughput. However, some wireless clients may not support
short preambles.
Enable RTS: RTS (Request to Send) is used to negotiate when wireless clients can
transmit.
If you have two wireless clients that are out of range of each other, but both still within
range of the access point, they may both attempt to transmit at the same time, causing a
collision. Enabling RTS avoids these collisions, and thus increases performance.
RTS incurs an overhead for transmitting, so enabling it when it is not needed decreases
performance. Since the access point is in range of all wireless clients, you would not
normally enable RTS for an access point.
RTS Threshold: The minimum packet size for which RTS is enabled. Collisions are less
likely for smaller packets, and so the overhead of using RTS for these may not be
worthwhile.
Enable Fragmentation: Normally, when a packet has an error, the entire packet must be
retransmitted. If packet fragmentation is enabled, the packet is split up into smaller
fragments, and thus only the fragment that has an error needs to be retransmitted, which
increases performance.
Fragmentation incurs an overhead per fragment, so enabling it when it is not needed
decreases performance.
Fragmentation Length: Using smaller fragments decreases the amount that is
retransmitted when there is an error, but it also increases the total overhead for each
packet.
Beacon Interval (ms): Beacon frames are used to coordinate the wireless network.
Sending beacon frames more often (i.e.using a lower becon interval) increases
responsiveness, but decreases performance due to higher overheads.
DTIM Interval (beacons): Specify how often a Delivery Traffic Indication Message is
sent. A DTIM is periodically included in the beacon frame. A DTIM is used to indicate to
clients in power saving mode that there are packets for them to receive. Sending a DTIM
more often increases responsiveness for clients in power saving mode, but uses more
power since the clients must stay awake longer.
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Network Setup