Features Overview; Power Over Ethernet; Head Of Line Blocking; Flow Control Support (Ieee 802.3X) - Dell PowerConnect 3424 User Manual

Features Overview

This section describes the device features. For a complete list of all updated device features, see the
latest software version Release Notes.

Power over Ethernet

Power over Ethernet (PoE) provides power to devices over existing LAN cabling, without updating
or modifying the network infrastructure. PoE removes the need for placing network devices next to
power sources. PoE can be used in the following applications:
• IP Phones
• Wireless Access Points
• IP Gateways
• PDAs
• Audio and video remote monitoring
For more information about Power over Ethernet, see "Managing Power over Ethernet".

Head of Line Blocking

Head of Line (HOL) blocking results in traffic delays and frame loss caused by traffic competing
for the same egress port resources. HOL blocking queues packets, and the packets at the head of
the queue are forwarded before packets at the end of the queue.

Flow Control Support (IEEE 802.3X)

Flow control enables lower speed devices to communicate with higher speed devices, by requesting
that the higher speed device refrains from sending packets. Transmissions are temporarily halted to
prevent buffer overflows.
For information on configuring Flow Control for ports or LAGs, see "Defining Port Configuration"
or "Defining LAG Parameters."

Back Pressure Support

On half-duplex links, the receiving port prevents buffer overflows by occupying the link so that it is
unavailable for additional traffic.
For information on configuring Flow Control for ports or LAGs, see "Defining Port Configuration"
or "Defining LAG Parameters."

Virtual Cable Testing (VCT)

VCT detects and reports copper link cabling occurrences such as open cables and cable shorts. For
more information on testing cables, see "Running Cable Diagnostics".
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Introduction