Introduction
Manual Documentation Number: ES1AWB-2907m
pn6908-rev003
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104 –
www.bb-elec.com
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445 –
www.bb-europe.com
Chapter
1
3
The enabling technology for ES1AWB wireless serial servers is based on the
IEEE 802 standard. Some background on the standard follows.
802.11 Wireless Networking
IEEE 802.11
is a set of standards that defines how multiple devices can
communicate on a wireless network. The standard has grown into a set of
several standards that define various features and functions. The 802.11b
standard defines the physical and data link layers for a wireless network
using the 2.4 GHz frequency band, a band that does not require licensing. As
a part of the IEEE family of standards, 802.11 WLANs are easily connected
to 802.3 (Ethernet) LANs. Higher layer LAN protocols, network operating
systems and internetworking protocols such as TCP/IP integrate seamlessly.
Under the IEEE 802.11 standard there can be two different types of devices
on the wireless network:
stations
and
access points (AP)
. A
station
may be a
PC equipped with a wireless network adapter or it can be a wireless serial
server such as the ES1AWB. An 802.11
access point
is a radio with an
interface that allows connection to a wired LAN. Access points run bridging
software to facilitate the connection from wireless to wired network. The
access point becomes the base station for the WLAN. It aggregates access to
the wired network for multiple wireless stations. An access point may be a
standalone device, such as a wireless router or switch, or a card in a PC.
Wireless Network Configurations
The 802.11 standard defines two modes of operation:
infrastructure mode
and
ad hoc mode
.
Infrastructure mode
makes use of one or more access
points connected to a wired LAN. Wireless stations communicate with access
points to gain access to each other and/or the LAN. In the Basic Service Set
(BSS) several stations communicate with one access point, which is
connected to a wired LAN. In the Extended Service Set (ESS) two or more
access points connect to the LAN creating a sub network.
In
ad hoc mode
, also called Independent Basic Service Set (IBSS), access
points are not used. Wireless stations communicate directly with each other
in a peer-to-peer fashion. This mode allows individual computers to set up a
network where wireless infrastructure does not exist.
ES1AWB wireless serial servers can be configured to operate in
infrastructure or ad hoc mode. From the Web Configuration and
Management Interface you can set up the type of network, naming the
network (specifying the SSID, or service set identifier) and other parameters.
