Cisco ASA 5512-X Configuration Guide

CHAPTER
17-1
Cisco ASA Series Firewall CLI Configuration Guide
17
Quality of Service
Have you ever participated in a long-distance phone call that involved a satellite connection? The
conversation might be interrupted with brief, but perceptible, gaps at odd intervals. Those gaps are the
time, called the latency, between the arrival of packets being transmitted over the network. Some network
traffic, such as voice and video, cannot tolerate long latency times. Quality of service (QoS) is a feature
that lets you give priority to critical traffic, prevent bandwidth hogging, and manage network bottlenecks
to prevent packet drops.
Note For the ASASM, we suggest performing QoS on the switch instead of the ASASM. Switches have more
capability in this area. In general, QoS is best performed on the routers and switches in the network,
which tend to have more extensive capabilities than the ASA.
This chapter describes how to apply QoS policies.
• About QoS, page 17-1
• Guidelines for QoS, page 17-3
• Configure QoS, page 17-4
• Monitor QoS, page 17-9
• Configuration Examples for Priority Queuing and Policing, page 17-11
• History for QoS, page 17-13
About QoS
You should consider that in an ever-changing network environment, QoS is not a one-time deployment,
but an ongoing, essential part of network design.
This section describes the QoS features available on the ASA.
• Supported QoS Features, page 17-2
• What is a Token Bucket?, page 17-2
• Policing, page 17-2
• Priority Queuing, page 17-3
• DSCP (DiffServ) Preservation, page 17-3

Cisco ASA 5512-X Specifications

General

Brand	Cisco
Model	ASA 5512-X
Category	Firewall
Language	English