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4.5 Quality of Service
4.5.1 QoS overview
Quality of Service (QoS) is an advanced traffic prioritization feature that allows you to establish control over network traffic. QoS
enables you to assign various grades of network service to different types of traffic, such as multi-media, video, protocol-specific,
time critical, and file-backup traffic.
QoS reduces bandwidth limitations, delay, loss, and jitter. It also provides increased reliability for delivery of your data and
allows you to prioritize certain applications across your network. You can define exactly how you want the switch to treat
selected applications and types of traffic.
You can use QoS on your system to:
Control a wide variety of network traffic by:
Classifying traffic based on packet attributes.
Assigning priorities to traffic (for example, to set higher priorities to time-critical or business-critical
applications).
Applying security policy through traffic filtering.
Provide predictable throughput for multimedia applications such as video conferencing or voice
over IP by minimizing delay and jitter.
Improve performance for specific types of traffic and preserve performance as the amount of traffic
grows.
Reduce the need to constantly add bandwidth to the network.
Manage network congestion.
The
QoS
page of the PoE Web Smart Switch contains three types of QoS mode – the
First-In-First-Out
mode,
All-High-before-Low
mode or
Weighted-Round-Robin
mode can be selected. All the three modes rely on predefined fields
within the packet to determine the output queue.
First-In-First-Out
Mode –The output queue assignment is determined with first-come, first-served (FCFS) behaviour.
All-High-before-Low
Mode - The output queue assignment is determined by the ToS or CoS field in the packets with strict
priority.
Weighted-Round-Robin
Mode –The output queue assignment is determined by the ToS or CoS field in the packets with
scheduling discipline policy.
The PoE Web Smart Switch supports
eight priority level
queues; the queue service rate is based on the
WRR
(
Weight Round
Robin
). The WRR ratio of high
-priority and low-priority can be set to
4:1
or
8:1
or
any.
