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Configuring Quality of Service
EdgeSwitch
™
Administration Guide
Ubiquiti Networks, Inc.
Chapter 7: Configuring Quality of Service
This section gives an overview of Quality of Service (QoS) and explains the QoS features available from the
Quality of Service navigation menu. This section contains the following subsections:
•
“Configuring Access Control Lists” on page 230
•
“Configuring Auto VoIP” on page 238
•
“Configuring Class of Service” on page 243
In a typical switch, each physical port consists of one or more queues for transmitting packets on the
attached network. Multiple queues per port are often provided to give preference to certain packets over
others based on user-defined criteria. When a packet is queued for transmission in a port, the rate at which it
is serviced depends on how the queue is configured and possibly the amount of traffic present in the other
queues of the port. If a delay is necessary, packets get held in the queue until the scheduler authorizes the
queue for transmission. As queues become full, packets have no place to be held for transmission and get
dropped by the switch.
QoS is a means of providing consistent, predictable data delivery by distinguishing between packets
that have strict timing requirements from those that are more tolerant of delay. Packets with strict timing
requirements are given “special treatment” in a QoS capable network. With this in mind, all elements of
the network must be QoS-capable. The presence of at least one node which is not QoS-capable creates a
deficiency in the network path and the performance of the entire packet flow is compromised.
