Introduction to Quality of Service (QoS)
A Quality of Service (QoS) network policy refers to the network-wide controls available to:
• Ensure uniform and efficient traffic-handling throughout your network, while keeping the most important
traffic moving at an acceptable speed, regardless of current bandwidth usage.
• Exercise control over the priority settings of inbound traffic arriving in and travelling through your
network.
Adding bandwidth can be a good idea, but is not always feasible and does not completely eliminate the
potential for network congestion. There will always be points in the network where multiple traffic streams
merge or where network links change speed and capacity. The impact and number of these congestion
points will increase over time as more applications and devices are added to the network.
When network congestion occurs, it is important to move traffic on the basis of relative importance.
However, without QoS prioritization, less important traffic consumes network bandwidth and slows down or
halts the delivery of more important traffic. Without QoS, most traffic received by the switch is forwarded
with the same priority it had upon entering the switch. In many cases, such traffic is normal priority and
competes for bandwidth with all other normal-priority traffic, regardless of its relative importance to your
organization's mission.
Using QoS to classify and prioritize network traffic
QoS is used to classify and prioritize traffic throughout a network. QoS enables you to establish an end-to-
end traffic-priority policy to improve the control and throughput of important data. You can manage
available bandwidth so that the most important traffic goes first. For example, you can use QoS to:
• Upgrade or downgrade traffic from various servers.
• Control the priority of traffic from dedicated VLANs or applications.
Chapter 8
Quality of Service (QoS): Managing bandwidth effectively
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Aruba 2530 Advanced Traffic Management Guide for
ArubaOS-Switch 16.09
