Cisco Small Business 200 Series Administration Guide

Quality of Service
QoS Features and Components
Cisco Small Business 200 Series Smart Switch Administration Guide 307
23
QoS Features and Components
The QoS feature is used to optimize network performance.
QoS provides the following:
• Classification of incoming traffic to traffic classes, based on attributes, including:
- Device Configuration
- Ingress interface
- Packet content
- Combination of these attributes
QoS includes the following:
• Traffic Classification—Classifies each incoming packet as belonging to a specific traffic flow,
based on the packet contents and/or the port. Assignment to Hardware Queues—Assigns
incoming packets to forwarding queues. Packets are sent to a particular queue for handling as a
function of the traffic class to which they belong. See Configuring QoS Queues.
• Other Traffic Class-Handling Attribute—Applies QoS mechanisms to various classes, including
bandwidth management.
QoS Operation
When using the QoS feature, all traffic of the same class receives the same treatment, which consists of a
single QoS action of determining the egress queue on the egress port, based on the indicated QoS value in
the incoming frame. This is the VLAN Priority Tag (VPT) 802.1p value in Layer 2 and the Differentiated
Service Code Point (DSCP) value for IPv4 or Traffic Class (TC) value for IPv6 in Layer 3. When operating in
Basic Mode, the device trusts this external assigned QoS value. The external assigned QoS value of a
packet determines its traffic class and QoS.
QoS Workflow
To configure general QoS parameters, perform the following:
STEP 1 Enable QoS by using the QoS Properties page to select the trust mode. Then
enable QoS on ports by using the Interface Settings page.
STEP 2 Assign each interface a default CoS or DSCP priority by using the QoS Properties
page.

Cisco Small Business 200 Series Specifications

General

Brand	Cisco
Model	Small Business 200 Series
Category	Switch
Language	English