Ieee802.1P Priority Tagging - D-Link DGE-530T Manual

DGE-530T Gigabit Ethernet Adapter Card
To test the diagnostic, first disconnect the cable from the remote end node so there is just an
open cable connected to the DGE-530T. Click the appropriate adapter from the tree view above
and then click the Start VCT button. The results which will appear in the table below will display
the cable pairs, the status of the corresponding cable, the distance to the fault, and the status of
the test. If the selected adapter is connected and has an uplink, the Digital Signal Processor
(DSP) will be activated and will report the speed of the connection (10, 100, 1000Mbps) and the
length of the cable.

IEEE802.1p Priority Tagging

With the growing number of network applications, local area networks (LANs) must deliver data
for a wide variety applications. Email, file transfers, database queries, voice over IP (VoIP), video-
conferencing and multimedia must all be delivered to the end-user's. Some of the traffic, such as
video-conferencing, is of a higher priority, with a slight delay of packets resulting in noticeable
degeneration of video and audio quality, while other traffic, such as email will not be noticeably
affected by tiny delays. The large number of programs run over today's networks serves to impede
the ability to deliver time-critical data. Even if bandwidth is not usually a problem on your
network, during peak hours bursts in network traffic can result in the delay of time-critical traffic.
IEEE802.1p defines seven levels of prioritization for Ethernet packets. High priority packets will
be sent through a network using 802.1p-compliant switches first. Lower priority packets will be
transferred whenever bandwidth is available. When properly setup, this ensures that time-critical
data arrives on time and is not affected by other traffic.
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