Wlan Standards - HP iPAQ h6315 Networking Manual

Virtual private network
A virtual private network (VPN) allows two or more private networks to be connected over a publicly
accessed network. In a sense, VPNs are similar to WANs or a securely encrypted tunnel, but the key
feature of VPNs is that they can use public networks like the Internet, rather than rely on expensive,
privately leased lines. Additionally, VPNs have the same security and encryption features as private
networks.
Voice over IP
Voice over Internet Protocol (VoIP) is the ability to make telephone calls and send faxes over IP-based
data networks with a suitable quality of service and superior cost-benefit ratio.
Terminal Services client
The Terminal Services client establishes a session with the server. User keyboard and mouse activity is
sent by way of a network to control the server session. Applications launched in the session use the
resources (processor and memory, for example) on the server, and displayed output is resent to the
user display screen. Multiple clients can connect to the server simultaneously.
Subnet
By definition, a subnet (short for subnetwork) is an identifiably separate part of an organization's
network. Typically, a subnet can represent all the machines (computers, laptops, handheld devices,
printers, etc.) at one geographic location, in one building, or on the same LAN. Having an
organization's network divided into subnets allows it to be connected to the Internet with a single
shared network address.

WLAN standards

IEEE wireless standards such as 802.11 have undergone many improvements and addendums since
they were first defined. The following list offers a high-level description of each of the better known
standards:
• 802.11, which operates in the 2.4-GHz frequency band and offers only 2 megabits per
second (Mbit/s) of overall throughput, was the original implemented standard.
• 802.11b is the most widely used form of Wi-Fi today. The radio operates within the 2.4-Ghz
frequency band but allows a maximum data throughput of 11 Mbit/s.
• 802.11a is a short-range, but extremely high-speed, Wi-Fi network. This standard is not compatible
with existing 802.11b networks. This high-speed Wi-Fi network operates in the 5-Ghz frequency
band and can transfer data at a maximum speed of 54 Mbit/s.
• 802.11g is compatible with existing 802.11b networks, but also enables higher speeds. Its
maximum speed is 54 Mbit/s, but 802.11g operates in the 2.4-Ghz frequency band.
Note: The 54-Mbit/s maximum speed of 802.11g is obtained only when the network contains other 802.11g-based devices.
Users who mix 802.11b devices in that network will see a maximum throughput value of only 11 Mbit/s.
• The 802.1X standard defines the method of encapsulating Extensible Authentication
Protocols (EAPs) over wired or wireless Ethernet networks. This standard does not define any
specific security protocol, but is based on EAP types documented and ratified by the Internet
Engineering Task Force (IETF).
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