ZyXEL N4100 Guia Do Utilizador
Chapter 25 Wireless LAN
N4100 User’s Guide
190
• An access point is a radio with a wired connection to a network, which can
connect with numerous wireless clients and let them access the network.
• A bridge is a radio that relays communications between access points and
wireless clients, extending a network’s range.
Traditionally, a wireless network operates in one of two ways.
• An “infrastructure” type of network has one or more access points and one or
more wireless clients. The wireless clients connect to the access points.
• An “ad-hoc” type of network is one in which there is no access point. Wireless
clients connect to one another in order to exchange information.
Network Names
Each network must have a name, referred to as the SSID - “Service Set
IDentifier”. The “service set” is the network, so the “service set identifier” is the
network’s name. This helps you identify your wireless network when wireless
networks’ coverage areas overlap and you have a variety of networks to choose
from.
IDentifier”. The “service set” is the network, so the “service set identifier” is the
network’s name. This helps you identify your wireless network when wireless
networks’ coverage areas overlap and you have a variety of networks to choose
from.
Radio Channels
In the radio spectrum, there are certain frequency bands allocated for unlicensed,
civilian use. For the purposes of wireless networking, these bands are divided into
numerous channels. This allows a variety of networks to exist in the same place
without interfering with one another. When you create a network, you must select
a channel to use.
civilian use. For the purposes of wireless networking, these bands are divided into
numerous channels. This allows a variety of networks to exist in the same place
without interfering with one another. When you create a network, you must select
a channel to use.
Since the available unlicensed spectrum varies from one country to another, the
number of available channels also varies.
number of available channels also varies.
Wireless Security
By their nature, radio communications are simple to intercept. For wireless data
networks, this means that anyone within range of a wireless network without
security can not only read the data passing over the airwaves, but also join the
network. Once an unauthorized person has access to the network she/he can
either steal information or introduce malware (malicious software) intended to
compromise the network. For these reasons, a variety of security systems have
been developed to ensure that only authorized people can use a wireless data
network, or understand the data carried on it.
networks, this means that anyone within range of a wireless network without
security can not only read the data passing over the airwaves, but also join the
network. Once an unauthorized person has access to the network she/he can
either steal information or introduce malware (malicious software) intended to
compromise the network. For these reasons, a variety of security systems have
been developed to ensure that only authorized people can use a wireless data
network, or understand the data carried on it.
These security standards do two things. First, they authenticate. This means that
only people presenting the right credentials (often a username and password, or a
“key” phrase) can access the network. Second, they encrypt. This means that the
information sent over the air is encoded. Only people with the code key can
only people presenting the right credentials (often a username and password, or a
“key” phrase) can access the network. Second, they encrypt. This means that the
information sent over the air is encoded. Only people with the code key can