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 access 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 maximum 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 broken 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 maximum value as
possible.
