SMC Networks EliteConnect SMCE21011, User Manual, Page: 89 / 258

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HAPTER
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| Wireless Settings
Radio Settings
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ADIO
S
ETTINGS
The IEEE 802.11n interfaces include configuration options for radio signal
characteristics and wireless security features.
The access point can operate in two modes, mixed 802.11g/n, or mixed
802.11a/n only. Also note that 802.11g is backward compatible with
802.11b, and 802.11n is backward compatible with both 802.11b/g and
802.11a at slower data transmit rates.
Each radio supports eight virtual access point (VAP) interfaces, referred to
as VAP0 ~ VAP7. Each VAP functions as a separate access point, and can
be configured with its own Service Set Identification (SSID) and security
settings. However, most radio signal parameters apply to both VAP
interfaces. The configuration options are nearly identical, and are therefore
both covered in this section of the manual. Traffic to specific VAPs can be
segregated based on user groups or application traffic. Both VAPs can have
up to 64 wireless clients, whereby the clients associate with these VAPs the
same as they would with a physical access point.
Packets from 802.11n clients are referred to as High Throughput (HT)
Greenfield packets, in other words packets that can be transmitted at rates
of up to 300 Mbps assuming that HT Channel Bandwidth is set to 20/
40Mhz, see HT Channel Bandwidth next page.
802.11b/g packets are referred to as non-HT packets, being transmitted at
lower throughput rates (see Radio Mode). HT mixed format frames contain
a preamble compatible with the non-HT receivers. HT Greenfield frames do
not contain a non-HT compatible part. Support for HT Greenfield format is
optional. An HT station that does not support the reception of an HT
Greenfield format frame must be able to detect that an HT Greenfield
format frame is an HT transmission (as opposed to a non-HT transmission).
In this case the receiver must decode the high throughput signal (HT-SIG)
in the packet header and determine if the HT-SIG cyclic redundancy check
(CRC) passes. (Default: Mixed)