Proxim RangeLAN2 7401, Руководство пользователя

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6. Understanding RangeLAN2
This chapter lays the background for understanding the radio
parameters that can be configured when a RangeLAN2 7420 is
installed. Refer to Chapters 3 and 4 for instructions on installing
the software driver.
RangeLAN2 radios use a radio technology called frequency
hopping spread spectrum. This means that the radio signal is
constantly moving from one frequency to another while sending
packets of data. This hopping technique allows for multiple
hopping patterns to be used in the same area while minimizing
interference.
RangeLAN2 Software Parameters
Station Type
In order for RangeLAN2 devices to communicate, in each subnet-
work there must be one unit that coordinates the hops. This
device is called the Master. It might help you to think of the
Master as the conductor of a frequency hopping orchestra. The
Master keeps time so all units know when to hop and to what
frequency.
Units classified as Stations synchronize to the Master and follow
its signal to learn what frequency in the pattern the Master is
currently using.
An acting “Master” can be configured either as a Master or
Alternate Master. Alternate Masters act either as a Master or a
Station. If an Alternate Master unit is unable to locate any other
Master within range, it acts as a Master. If a Master is already
present, then the Alternate Master acts as a Station. When there
are multiple Alternate Masters, they coordinate amongst them-
selves to determine who will become the Master.