Ieee 802.11 Layers Description - Black Box LW0050A Manual

PRO 11 SERIES WIRELESS ETHERNET
Distribution System
Access
Point
BSS
The standard also defines the concept of a "portal." A portal is a device that
interconnects an 802.11 LAN and another 802 LAN. This concept is an abstract
description of part of the functionality of a "translation bridge."
Even though the standard does not necessarily require it, typical installations will
have the Access Point and the Portal on a single physical entity. For example, the
Pro 11 Series Access Point provides both functions.
E.2 IEEE 802.11 Layers Description
As in any 802.x protocol, the 802.11 protocol covers the Media Access Control
Layer (MAC) and Physical Layer (PHY). The Standard currently defines a single
MAC which interacts with three PHYs (all of them running at 1 or 2 Mbps) as
follows:
• Frequency Hopping Spread Spectrum (FHSS) in the 2.4-GHz Band
• Direct Sequence Spread Spectrum (DSSS) in the 2.4-GHz Band, and
• Infrared
802.2
802.11 MAC
FH
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ESS
Figure E-1. Typical 802.11 LAN.
DS IR
Access
Point
BSS
Data Link
Layer
PHY Layer