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LANCOM L-300 Access Point Serie
Chapter 1: Introduction
1.2
Wireless LANs in accordance with 802.11n
The new wireless LAN standard 802.11n features a number of technical deve-
lopments that provide up to five-times the performance in wireless LANs. The
changes have not yet been officially approved by the IEEE, but the foreseeable
technological leap is so enticing that the industry is already bringing updated
WLAN devices to market before the standards have been adopted. Current
discussions are embodied by what is known as "draft 2.0", which is the basis
for devices currently available on the market.
Some of the improvements refer to the physical layer (PHY), which describes
the transmission of individual bits over the physical medium—in this case the
air represents the physical medium. Other additions are concerned with the
MAC (medium access control) that among other things governs access to the
transmission medium. The two areas are treated separately below.
1.2.1
Advantages of 802.11n
The new technology includes the following advantages:
10
Establishing access to the Internet
Connecting two LANs over a wireless link (point-to-point mode)
Connecting devices with an Ethernet interface via an access point (client
mode)
Extending an existing Ethernet network with a wireless LAN (bridge mode)
WDS (Wireless Distribution Systems)
Central administration using a LANCOM WLAN Controller
Any reference to "802.11n" in this document always implies the cur-
rent draft 2.0, which is not a standard adopted by the IEEE.
You can find additional information on this subject in the LCOS refe-
rence manual or in the technical papers relating to this topic.
Higher effective data throughput
802.11n draft 2.0 includes a number of new mechanisms to significantly
increase available bandwidth. Current wireless LAN standards based on
802.11a/g enable physical data rates (gross data rates) of up to 54 Mbps,
which turn out to be approx. 22 Mbps net. Networks based on 802.11n
currently achieve a gross data throughput of up to 300 Mbps (in reality
approx. 120 to 130 Mbps net) – theoretically the standard defines up to
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