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5.9 What is WEP?
An option of IEEE 802.11 function is that offers frame transmission privacy similar to a wired network.
The Wired Equivalent Privacy generates secret shared encryption keys that both source and destination stations can use to
alert frame bits to avoid disclosure to eavesdroppers.
WEP relies on a secret key that is shared between a mobile station (e.g. a laptop with a wireless Ethernet card) and an ac-
cess point (i.e. a base station). The secret key is used to encrypt packets before they are transmitted, and an integrity check
is used to ensure that packets are not modified in transit.
5.10 What is Fragment Threshold?
The proposed protocol uses the frame fragmentation mechanism defined in IEEE 802.11 to achieve parallel transmissions.
A large data frame is fragmented into several fragments each of size equal to fragment threshold. By tuning the fragment
threshold value, we can get varying fragment sizes. The determination of an efficient fragment threshold is an important
issue in this scheme. If the fragment threshold is small; the overlap part of the master and parallel transmissions is large.
This means the spatial reuse ratio of parallel transmissions is high. In contrast, with a large fragment threshold, the overlap
is small and the spatial reuse ratio is low. However high fragment threshold leads to low fragment overhead. Hence there is
a trade-off between spatial re-use and fragment overhead.
Fragment threshold is the maximu m packet size used for fragmentation. Packets larger than the size programmed in this
field will be fragmented.
If you find that your corrupted packets or asymmetric packet reception (all send packets, for example).
You may want to try lowering your fragmentation threshold. This will cause packets to be bro ken into smaller fragments.
These small fragments, if corrupted, can be resent faster than a larger fragment.
Fragmentation increases overhead, so you'll want to keep this value as close to the maximu m value as possible.
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