Cerio 100GX-N, Руководство пользователя

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Short Preamble : By default, it’s “Enable”. To Disable is to use Long 128-bit Preamble
Synchronization field.
The preamble is used to signal "here is a train of data coming" to the receiver. The short
preamble provides 72-bit Synchronization field to improve WLAN transmission efficiency
with less overhead.
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IGMP Snooping : the process of listening to Internet Group Management Protocol (IGMP)
network traffic. The feature allows a network switch to listen in on the IGMP conversation
between hosts and routers. By listening to these conversations the switch maintains a
map of which links need which IP multicast streams. Multicasts may be filtered from the
links which do not need them and thus controls which ports receive specific multicast
traffic.
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Greenfield : In wireless WLAN technology, greenfield mode is a feature of major
components of the 802.11n specification. The greenfield mode feature is designed to
improve efficiency by eliminating support for 802.11b/g devices in an all draft-n network. In
greenfield mode the network can be set to ignore all earlier standards.
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WMM QoS : This affects traffic flowing from the access point to the client station.
Configuring QoS options consists of setting parameters on existing queues for different
types of wireless traffic. You can configure different minimum and maximum wait times for
the transmission of packets in each queue based on the requirements of the media being
sent. Queues automatically provide minimum transmission delay for Voice, Video,
multimedia, and mission critical applications, and rely on best-effort parameters for
traditional IP data.
As an Example, time-sensitive Voice & Video, and multimedia are given effectively higher
priority for transmission (lower wait times for channel access), while other applications and
traditional IP data which are less time-sensitive but often more data-intensive are expected
to tolerate longer wait times.