D-Link DWS-4026 User Manual page 419

Software User Manual
12/10/09
Field
Mode
RTS Threshold
DTIM Period
Beacon Period
Load Balancing
Document 34CSFP6XXUWS-SWUM100-D7
Table 260: Radio Settings (Cont.)
Description
The Mode defines the Physical Layer (PHY) standard the radio uses.
Select one of the following modes for each radio interface.
Radio 1 supports:
• IEEE 802.11a is a PHY standard that specifies operating in the 5 GHz U-NII band using
orthogonal frequency division multiplexing (OFDM). It supports data rates ranging from 6 to
54 Mbps.
• IEEE 802.11a/n operates in the 5 GHz ISM band and includes support for both 802.11a and
802.11n devices. IEEE 802.11n is an extension of the 802.11 standard that includes multiple-
input multiple-output (MIMO) technology. IEEE 802.11n supports data ranges of up to 248
Mbps and nearly twice the indoor range of 802.11 b, 802.11g, and 802.11a.
• 5 GHz IEEE 802.11n is the recommended mode for networks with 802.11n devices that
operate in the 5 GHz frequency that do not need to support 802.11a or 802.11b/g devices.
IEEE 802.11n can achieve a higher throughput when it does not need to be compatible with
legacy devices (802.11b/g or 802.11a).
Radio 2 supports:
• IEEE 802.11b/g operates in the 2.4 GHz ISM band. IEEE 802.11b is an enhancement of the
initial 802.11 PHY to include 5.5 Mbps and 11 Mbps data rates. It uses direct sequence
spread spectrum (DSSS) or frequency hopping spread spectrum (FHSS) as well as
complementary code keying (CCK) to provide the higher data rates. It supports data rates
ranging from 1 to 11 Mbps. IEEE 802.11g is a higher speed extension (up to 54 Mbps) to the
802.11b PHY. It uses orthogonal frequency division multiplexing (OFDM). It supports data
rates ranging from 1 to 54 Mbps.
• IEEE 802.11b/g/n operates in the 2.4 GHz ISM band and includes support for 802.11b,
802.11g, and 802.11n devices.
• 2.4 GHz IEEE 802.11n is the recommended mode for networks with 802.11n devices that
operate in the 2.4 GHz frequency that do not need to support 802.11a or 802.11b/g devices.
IEEE 802.11n can achieve a higher throughput when it does not need to be compatible with
legacy devices (802.11b/g or 802.11a).
Specify a Request to Send (RTS) Threshold value between 0 and 2347.
The RTS threshold indicates the number of octets in an MPDU, below which an RTS/CTS
handshake is not performed.
Changing the RTS threshold can help control traffic flow through the AP, especially one with
a lot of clients. If you specify a low threshold value, RTS packets will be sent more frequently.
This will consume more bandwidth and reduce the throughput of the packet. On the other
hand, sending more RTS packets can help the network recover from interference or collisions
which might occur on a busy network, or on a network experiencing electromagnetic
interference.
The Delivery Traffic Information Map (DTIM) message is an element included in some
frames. It indicates which client stations, currently sleeping in low-power mode, have data
buffered on the access point awaiting pick-up.
The DTIM period you specify indicates how often the clients served by this access point
should check for buffered data still on the AP awaiting pickup.
Specify a DTIM period within the given range (1–255).
The measurement is in beacons. For example, if you set this field to 1, clients will check for
buffered data on the AP at every beacon. If you set this field to 10, clients will check on every
10th beacon.
Beacon frames are transmitted by an access point at regular intervals to announce the
existence of the wireless network. The default behavior is to send a beacon frame once every
100 milliseconds (or 10 per second).
The Beacon Interval value is set in milliseconds. Enter a value from 20 to 2000.
If you enable load balancing, you can control the amount of traffic that is allowed on the AP.
D-Link Unified Access System
Basic Setup
Beacon
Page 419