Fragmentation Threshold; Preamble Type - ZyXEL Communications NWD2105 User Manual

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I f t he RTS/ CTS value is great er t han t he Fr a gm e n t a t ion Th r e sh old value ( see

next ) , t hen t he RTS ( Request To Send) / CTS ( Clear t o Send) handshake will never

occur as dat a fram es w ill be fragm ent ed befor e t hey reach RTS/ CTS size.

Note: Enabling the RTS Threshold causes redundant network overhead that could

negatively affect the throughput performance instead of providing a remedy.

Fragmentation Threshold

A Fr a gm e n t a t ion Th r e sh old is t he m axim um dat a fragm ent size ( bet ween 256

and 2432 byt es) t hat can be sent in t he wireless net work before t he AP will

fragm ent t he packet int o sm aller dat a fram es.

A large Fr a gm e n t a t ion Th r e sh old is recom m ended for net works not prone t o

int erference w hile you should set a sm aller t hreshold for busy net works or

net works t hat are prone t o int erference.

I f t he Fr a gm e nt a t ion Th r e sh old value is sm aller t han t he RTS/ CTS value ( see

previously) you set t hen t he RTS ( Request To Send) / CTS ( Clear t o Send)

handshake will never occur as dat a fram es will be fragm ent ed before t hey reach

RTS/ CTS size.

Pream ble is used t o signal t hat dat a is com ing t o t he receiver. Short and long refer

t o t he lengt h of t he synchronizat ion field in a packet .

Short pream ble increases perform ance as less t im e sending pream ble m eans

m ore t im e for sending dat a. All I EEE 802.11 com pliant wireless adapt ers support

long pream ble, but not all support short pream ble.

Use long pream ble if you are unsure w hat pream ble m ode ot her wireless devices

on t he net w ork support , and t o provide m ore reliable com m unicat ions in busy

wireless net works.

Use short pream ble if you are sure all wireless devices on t he net work support it ,

and t o provide m ore efficient com m unicat ions.

Use t he dynam ic set t ing t o aut om at ically use short pream ble when all wireless

devices on t he net work support it , ot herwise t he NWD2105 uses long pream ble.

Note: The wireless devices MUST use the same preamble mode in order to

communicate.

NWD2105 User's Guide

Appendix A Wireless LANs

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