Ieee 802.1P Priority Tagging; Ieee 802.1Q Vlans; Flow Control - D-Link dge-530t User Manual

Section 3 - Advanced Features

IEEE 802.1p Priority Tagging

With the growing number of network applications, local area networks (LANs) must deliver data for a wide variety of applications.
Email, file transfers, database queries, voice over IP (VoIP), video-conferencing and multimedia must all be delivered to the
end-users. 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. Other traffic, such as e-mail, will not be noticeably affected by tiny delays.
The large number of programs that run over today's networks serve to impede the ability to deliver time-critical data. Even
if bandwidth is not usually a problem on your network, during peak hour bursts in network traffic can result in the delay of
time-critical traffic.
IEEE 802.1p 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
set up, this ensures that time-critical data arrives on time and is not affected by other traffic.

IEEE 802.1Q VLANs

The IEEE 802.1Q VLAN can help improve network performance and security by segmenting the network into VLANs. IEEE 802.1Q
VLANs can limit broadcast and node-to-node (unicast) traffic to a single VLAN. This limits the effects of broadcast storms and
provides additional security for your network.
For VLANs to function, the computer in which this NIC is installed must be using Windows® 2000, 2003, XP, Vista® or 7 as its
operating system.

Flow Control

The DGE-530T implements IEEE 802.3x compliant flow control for full-duplex, which provides traffic management functions
for full-duplex operation. Flow control allows for enhanced full-duplex operation with switches. When operating at full-duplex
(requiring a direct connection to a switch) and the switch's data buffer is about to overflow, a Pause frame will be transmitted to
the DGE-530T. The ensuing idle time keeps the buffer from overflowing and prevents data from being lost. This enhancement
can improve network throughput, avoid collisions and prevent lost data, helping the network achieve optimal performance.
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