Cerio OW-200N2 User Manual page 196

Access Point (AP) in IEEE 802.11 will send out a special approximated 50-byte frame, called "Beacon". Beacon
is broadcast to all the stations, provides the basic information of AP such as SSID, channel, encryption keys,
signal strength, time stamp, support data rate.
All the radio stations received beacon recognizes the existence of such AP, and may proceed next actions if the
information from AP matches the requirement. Beacon is sent on a periodic basis, the time interval can be
adjusted.
By increasing the beacon interval, you can reduce the number of beacons and associated
overhead, but that will likely delay the association and roaming process because stations
scanning for available access points may miss the beacons. You can decrease the beacon
interval, which increases the rate of beacons. This will make the association and roaming process
very responsive; however, the network will incur additional overhead and throughput will go down.
DTIM Interval : The DTIM interval is in the range of 1~255. The default is 1.
DTIM is defined as Delivery Traffic Indication Message. It is used to notify the wireless stations, which support
power saving mode, when to wake up to receive multicast frame. DTIM is necessary and critical in wireless
environment as a mechanism to fulfill power-saving synchronization.
A DTIM interval is a count of the number of beacon frames that must occur before the access
point sends the buffered multicast frames. For instance, if DTIM Interval is set to 3, then the
Wi-Fi clients will expect to receive a multicast frame after receiving three Beacon frame. The
higher DTIM interval will help power saving and possibly decrease wireless throughput in
multicast applications.
500mW eXtreme Power 11Na Outdoor Bridge
196
User's Manual