Quality of Service (QoS): Managing Bandwidth More Effectively
Using QoS Classifiers to Configure Quality of Service for Outbound Traffic
Assigning a DSCP Policy on the Basis of the DSCP in IPv4
Packets Received from Upstream Devices
The preceding section describes how to forward a policy set by an edge (or upstream) switch. This option changes a DSCP policy in an IPv4 packet by changing its IP ToS codepoint and applying the priority associated with the new codepoint. (A DSCP policy consists of a differentiated services codepoint and an associated 802.1p priority.) You can use this option concurrently with the diffserv 802.1p priority option (above), as long as the DSCPs specified in the two options do not match.
To use this option to configure a change in policy:
1.Identify a DSCP used to set a policy in packets received from an upstream or edge switch.
2.Create a new policy by using qos
3.Use qos
(Figure
N o t e | On the switches covered in this guide, DSCP policies (codepoint |
| cannot be applied to outbound IPv4 packets having IP options. (The 802.1p |
| priority in the VLAN tag is applied.) For more information on packet criteria |
| |
| Syntax: qos |
| Enables ToS |
Syntax: qos
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Configures the switch to select an incoming IP packet carrying the
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Syntax: no qos