The hardware
encryption engine would have a shorter packet servicing time, because
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Cherita Corbett, John Copeland, and Raheem Beyah
the software implementation would need to interrupt the host, transfer the
packet to the host for encryption, allow the host to perform encryption, and
retrieve the encrypted packet from host. While the CPU may very well be
capable of handling the RI request in a timely fashion, the overhead of the
OS raises concern regarding the split of the architecture between hardware
and software. This decision directly impacts the packet servicing time, and
based on how dependent the RI is on the host, the performance of the host
may become the prominent factor in the packet servicing time. Capturing notable
di?®erences in packet servicing time contributes to the identification of
a wireless system.
4.2 Implementation of 802.11 Services
The 802.11 standard [2] mandates a suite of services to which an RI must
adhere to be in compliance with the standard for interoperability. However,
the standard does not dictate how these services are to be implemented. This
ambiguous mandate leads to the development of proprietary solutions among
di?®erent manufacturers. To cope with the changing conditions of a wireless
environment, these services may fragment packets, retransmit packets, adjust
transmission rates, reserve the link, probe for a better network, or opt to poll
for packets to conserve power.
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