Appendix D Wireless LANs

NWA1300-NJ User’s Guide

119

Fragmentation Threshold

A Fragmentation Threshold is the maximum data fragment size (between 256 
and 2432 bytes) that can be sent in the wireless network before the AP will 
fragment the packet into smaller data frames.

A large Fragmentation Threshold is recommended for networks not prone to 
interference while you should set a smaller threshold for busy networks or 
networks that are prone to interference.

If the Fragmentation Threshold value is smaller than the RTS/CTS value (see 
previously) you set then the RTS (Request To Send)/CTS (Clear to Send) 
handshake will never occur as data frames will be fragmented before they reach 
RTS/CTS size.

Preamble Type

Preamble is used to signal that data is coming to the receiver. Short and long refer 
to the length of the synchronization field in a packet.

Short preamble increases performance as less time sending preamble means 
more time for sending data. All IEEE 802.11 compliant wireless adapters support 
long preamble, but not all support short preamble. 

Use long preamble if you are unsure what preamble mode other wireless devices 
on the network support, and to provide more reliable communications in busy 
wireless networks. 

Use short preamble if you are sure all wireless devices on the network support it, 
and to provide more efficient communications.

Use the dynamic setting to automatically use short preamble when all wireless 
devices on the network support it, otherwise the NWA1300-NJ uses long 
preamble.

Note: The wireless devices MUST

use the same preamble mode in order to 

communicate.

IEEE 802.11g Wireless LAN

IEEE 802.11g is fully compatible with the IEEE 802.11b standard. This means an 
IEEE 802.11b adapter can interface directly with an IEEE 802.11g access point 
(and vice versa) at 11 Mbps or lower depending on range. IEEE 802.11g has