Glossary - ZyXEL Communications AC240 User Manual

4.3 Glossary

1. What is the IEEE 802.11g standard?
802.11g is the new IEEE standard for high-speed wireless LAN
communications that allows for an up to 54 Mbps data rate in the 2.4
GHz band. 802.11g is quickly becoming the next mainstream
wireless LAN technology for home, office and public networks.
802.11g defines the use of the same OFDM modulation technique
specified in IEEE 802.11a for the 5 GHz frequency band and applies
it in the same 2.4 GHz frequency band as IEEE 802.11b. The
802.11g standard requires backward compatibility with 802.11b.
The standard specifically calls for:
A. A new physical layer for the 802.11 Medium Access Control
(MAC) in the 2.4 GHz frequency band, known as the extended
rate PHY (ERP). The ERP adds OFDM as a mandatory new
coding scheme for 6, 12 and 24 Mbps (mandatory speeds), and 18,
36, 48 and 54 Mbps (optional speeds). The ERP includes the
modulation schemes found in 802.11b including CCK for 11 and
5.5 Mbps and Barker code modulation for 2 and 1 Mbps.
B. A protection mechanism called RTS/CTS that governs how
802.11g devices and 802.11b devices interoperate.
2. What is the IEEE 802.11b standard?
The IEEE 802.11b was developed by the Wireless LAN standard
subcommittee, which formulates the standard for the industry. The
objective is to enable wireless LAN hardware from different
manufacturers to communicate.
3. What IEEE 802.11 features does the AC240 support?
The AC240 supports the following IEEE 802.11 functions:
CSMA/CA plus Acknowledge Protocol

Multi-Channel Roaming

Automatic Rate Selection

RTS/CTS Feature

Fragmentation

Power Management

4. What is Ad-hoc?
An Ad-hoc integrated wireless LAN is a group of computers, each
with a Wireless LAN adapter, that are connected as an independent
wireless LAN. Ad hoc wireless LAN is applicable at a departmental
scale for a branch or SOHO operation.
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