Table of Contents
Advertisement
C
H A P T E R
14.1 Overview
Use the QoS screens to set up your P-794H to use QoS for traffic management.
Quality of Service (QoS) refers to both a network's ability to deliver data with
minimum delay, and the networking methods used to control bandwidth. QoS
allows the P-794H to group and prioritize application traffic and fine-tune network
performance.
Without QoS, all traffic data are equally likely to be dropped when the network is
congested. This can cause a reduction in network performance and make the
network inadequate for time-critical applications such as video-on-demand.
The P-794H assigns each packet a priority and then queues the packet
accordingly. Packets assigned with a high priority are processed more quickly than
those with low priorities if there is congestion, allowing time-sensitive applications
to flow more smoothly. Time-sensitive applications include both those that require
a low level of latency (delay) and a low level of jitter (variations in delay) such as
Voice over IP (VoIP) or Internet gaming, and those for which jitter alone is a
problem such as Internet radio or streaming video.
14.1.1 What You Need to Know
DSCP
DiffServ Code Point (DSCP) is a field used for packet classification on DiffServ
networks. The higher the value, the higher the priority. Lower-priority packets
may be dropped if the total traffic exceeds the capacity of the network.
Tagging and Marking
In a QoS class, you can configure whether to add or change the DiffServ Code
Point (DSCP) value, IEEE 802.1p priority level and VLAN ID number in a matched
packet. When the packet passes through a compatible network, the networking
device, such as a backbone switch, can provide specific treatment or service
based on the tag or marker.
P-794H User's Guide
Quality of Service (QoS)
14
163
Advertisement
Table of Contents
