HP ProCurve 520wl Wireless Access Point - Manual (Page 54)

Advanced Configuration
Coverage
The number of Access Points in a set area determines the network coverage for that area. A large number of
Access Points covering a small area is a high-density cell. A few Access Points, or even a single unit, covering the
same small area would result in a low-density cell, even though in both cases the actual area did not change — only
the number of Access Points covering the area changed.
In a typical office, a high density area consists of a number of Access Points installed every 20 feet and each
Access Point generates a small radio cell with a diameter of about 10 feet. In contrast, a typical warehouse might have
a low density area consisting of large cells (with a diameter of about 90 feet) and Access Points installed every
200 feet.
Figure 4-5 Low Density vs. Ultra High Density Network
The Distance Between Cells parameter supports five values: Large, Medium, Small, Minicell, and Microcell.
! CAUTION
The distance between APs should not be approximated. It is calculated by means of a manual Site Survey, in
which an AP is set up and clients are tested throughout the area to determine signal strength and coverage,
and local limits such as physical interference are investigated. From these measurements the appropriate cell
size and density is determined, and the optimum distance between APs is calculated to suit your particular
business requirements. Contact your reseller for information on how to conduct a Site Survey.
Multicast Rate
The multicast rate determines the rate at which broadcast and multicast packets are transmitted by the Access Point to
the wireless network. Stations that are closer to the Access Point can receive multicast packets at a faster data rate
than stations that are farther away from the AP. Therefore, you should set the Multicast Rate based on the size of the
Access Point’s cell. For example, if the Access Point’s cell is very small (that is, Distance Between APs is set to
Microcell), you can expect that all stations should be able to successfully receive multicast packets at 11 MBits/sec so
you can set Multicast Rate to 11 Mbits/sec. However, if the Access Point’s cell is large, you need to accommodate
stations that may not be able to receive multicast packets at the higher rates; in this case, you should set Multicast
Rate to 1 or 2 Mbits/sec.
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