Teletronics TT 2400 - Manual (Page 49)

degrade performance in WLANs where stations are far apart and unable to sense each other to avoid collisions (aka
Hidden Nodes). If you are experiencing excessive collisions, you can try turning RTS/CTS on or (if already on) reduce
RTS/CTS Threshold on the affected stations.
Beacon Period
In wireless networking, a beacon is a packet sent by a connected device to inform other devices of its presence and
readiness. When a wirelessly networked device sends a beacon, it includes with it a beacon interval, which specifies
the period of time before it will send the beacon again. The interval tells receiving devices on the network how long
they can wait in low-power mode before waking up to handle the beacon. Network managers can adjust the beacon
interval, usually measured in milliseconds (ms) or its equivalent, kilo microseconds (Kmsec).
DTIM interval
Delivery Traffic Indication Message. A DTIM is a signal sent as part of a beacon by an access point to a client device in
sleep mode, alerting the device to a packet awaiting delivery. A DTIM interval, also known as a Data Beacon Rate, is
the frequency at which an access point's beacon will include a DTIM. This frequency is usually measured in
milliseconds (ms) or its equivalent, kilo microseconds (Kmsec).
802.11d
802.11d is a wireless network communications specification for use in countries where systems using other standards
in the 802.11 family are not allowed to operate. The 802.11d specification is well suited for systems that want to
provide global Roaming.
ACK Timeout
When a packet is sent out from 802.11 Station A it will then wait for an 'ACKnowledgement frame' from 802.11 Station
B. Station A will only wait for a certain amount of time (ACK timeout) or ACK window. If the ACK is NOT received within
that timeout period then the packet will be re-transmitted from Station A resulting in reduced throughput. When sending
LOTS of packets as in 802.11g and 802.11a the constant re-transmission could cost severe performance degradation
due to the ACK frame not making it back to 802.11 Station A in time. This will have a dramatic impact on the throughput
of the link regardless of the quantity of signal strength and good receiver sensitivity.