Extreme Networks Summit WM20, Руководство пользователя

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Glossary
Summit WM20 User Guide, Software Release 4.2
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PoE Power over Ethernet. The Power over Ethernet standard (802.3af)
defines how power can be provided to network devices over existing
Ethernet connection, eliminating the need for additional external
power supplies.
POST
Power On Self Test, a diagnostic testing sequence performed by a
computer to determine if its hardware elements are present and
powered on. If so, the computer begins its boot sequence.
push-to-talk (PTT)
The push-to-talk (PTT) is feature on wireless telephones that allows
them to operate like a walkie-talkie in a group, instead of standard
telephone operation. The PTT feature requires that the network be
configured to allow multicast traffic.
A PTT call is initiated by selecting a channel and pressing the "talk"
key on the wireless telephone. All wireless telephones on the same
network that are monitoring the channel will hear the transmission.
On a PTT call you hold the button to talk and release it to listen.
Q
QoS Quality of Service. A term for a number of techniques that intelligently
match the needs of specific applications to the network resources
available, using such technologies as Frame Relay, Asynchronous
Transfer Mode (ATM), Ethernet and 802.1 networks, SONET, and
IP-routed networks. QoS features provide better network service by
supporting dedicated bandwidth, improving loss characteristics,
avoiding and managing network congestion, shaping network traffic,
setting traffic priorities across the network.
Quality-of-Service (QoS): A set of service requirements to be met by
the network while transporting a flow. (RFC2386)
R
RADIUS Remote Authentication Dial-In User Service. An authentication and
accounting system that checks User Name and Password and
authorizes access to a network. The RADIUS specification is
maintained by a working group of the IETF (RFC2865 RADIUS,
RFC2866 RADIUS Accounting, RFC2868 RADIUS Attributes for
Tunnel Protocol Support).
RF Radio Frequency, a frequency in the electromagnetic spectrum
associated with radio wave propagation. When an RF current is
supplied to an antenna, an electromagnetic field is created that can
propagate through space. These frequencies in the electromagnetic
spectrum range from Ultra-low frequency (ULF) -- 0-3 Hz to
Extremely high frequency (EHF) -- 30GHz - 300 GHz. The middle
ranges are: Low frequency (LF) -- 30 kHz - 300 kHz, Medium
frequency (MF) -- 300 kHz - 3 MHz, High frequency (HF) -- 3MHz - 30
MHz, Very high frequency (VHF) -- 30 MHz - 300 MHz, Ultra-high
frequency (UHF)-- 300MHz - 3 GHz.
P (Continued)