4

Advanced Configuration

Table 4-7Wi-Fi Advanced Menu

Field or Button

Description

Beacon Interval

Enter a value between 1 and 65,535 milliseconds. The

 

Beacon Interval value indicates the frequency interval of the

 

beacon. A beacon is a packet broadcast by the device to

 

synchronize the other wireless network.

 

 

RTS Threshold

This value should remain at its default setting of 2347. The

 

range is 0-2347 bytes. Should you encounter inconsistent

 

data flow, only minor modifications are recommended. If a

 

network packet is smaller than the preset RTS threshold

 

size, the RTS/CTS mechanism will not be enabled. The

 

device sends Request to Send (RTS) frames to a particular

 

receiving wireless client on the network and negotiates the

 

sending of a data frame. After receiving an RTS, the

 

wireless client responds with a Clear to Send (CTS) frame to

 

acknowledge the right to begin transmission.

 

 

Preamble Type

The Preamble defines the length of the CRC block (Cyclic

 

Redundancy Check is a common technique for detecting

 

data transmission errors) for communication between the

 

wireless router and the roaming wireless network adapters.

 

Note: High network traffic areas should use the shorter

 

preamble type.

 

 

Fragmentation

The range is 256-2346 bytes. It specifies the maximum size

Threshold

for a packet before data is fragmented into multiple

 

packets. If you experience a high packet error rate, you may

 

slightly increase the Fragmentation Threshold. Setting the

 

Fragmentation Threshold too low may result in poor

 

network performance. Only minor modifications of this

 

value are recommended.

 

 

DTIM Interval

The default value is 3. This value, between 1 and 255

 

milliseconds, indicates the interval of the Delivery Traffic

 

Indication Message (DTIM). A DTIM field is a countdown

 

field informing clients of the next window for listening to

 

broadcast and multicast messages. When the router has

 

buffered broadcast or multicast messages for associated

 

clients, it

 

sends the next DTIM with a DTIM Interval value. Its clients

 

hear the beacons and awaken to receive the broadcast and

 

multicast messages.

 

 

CTS Protection Mode

CTS (Clear To Send) is a function used to minimize

 

collisions among wireless devices on a wireless LAN. CTS

 

will make sure the wireless network is clear before a

 

wireless client attempts to send wireless data. Enabling CTS

 

will add overhead and may lower wireless through put.

 

None: CTS is typically used in a pure 802.11g environment.

 

If CTS is set to “Disable” in a mixed mode environment

 

populated by 802.11b clients, wireless collisions may occur

 

frequently. If set to Enable, CTS will always be used to

 

make sure the wireless LAN is clear before sending data. If

 

set to Auto, CTS will monitor the wireless network and

 

automatically decide whether to implement CTS based on

 

the amount of traffic and collisions that occurs on the

 

wireless LAN.

 

 

4-8

JAN 2011

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Motorola CPEI 890 user manual Field or Button Description