HP 6120XG HP ProCurve Series 6120 Blade Switches Advanced Traffic Management G - Page 233

Note On Changing a Priority Setting, No-override, Cannot modify DSCP Policy &lt

Page 233 highlights

Quality of Service (QoS): Managing Bandwidth More Effectively Differentiated Services Codepoint (DSCP) Mapping Effect of "No-override". In the QoS Type-of-Service differentiated services mode, a No-override assignment for the codepoint of an outbound packet means that QoS is effectively disabled for such packets. That is, QoS does not affect the packet queuing priority or VLAN tagging. In this case, the packets are handled as follows (as long as no other QoS feature creates priority assignments for them): 802.1Q Status Received and Forwarded on a tagged port member of a VLAN. Received on an Untagged port member of a VLAN; Forwarded on a tagged port member of a VLAN. Forwarded on an Untagged port member of a VLAN. Outbound 802.1p Priority Unchanged 0 (zero)-"normal" None Note On Changing a Priority Setting If a QoS classifier is using a policy (codepoint and associated priority) in the DSCP Policy table, you must delete or change this usage before you can change the priority setting on the codepoint. Otherwise the switch blocks the change and displays this message: Cannot modify DSCP Policy < codepoint > - in use by other qos rules. In this case, use show qos < classifier > to identify the specific classifiers using the policy you want to change; that is: show qos device-priority show qos port-priority show qos tcp-udp-port-priority show qos vlan-priority show qos type-of-service For example, suppose that the 000001 (dscp 1) codepoint has a priority of 6, and several classifiers use the 000001 codepoint to assign a priority to their respective types of traffic. If you wanted to change the priority of codepoint 000001 you would do the following: 1. Identify which QoS classifiers use the codepoint. 2. Change the classifier configurations by assigning them to a different DSCP policy, or to an 802.1p priority, or to No-override. 3. Reconfigure the desired priority for the 000001 (dscp 1) codepoint. 4. Either reassign the classifiers to the 00001 (dscp 1) codepoint policy or leave them as they were after step 2, above. 5-57

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5-57
Quality of Service (QoS): Managing Bandwidth More Effectively
Differentiated Services Codepoint (DSCP) Mapping
Effect of “
No-override
”.
In the QoS Type-of-Service differentiated services
mode, a
No-override
assignment for the codepoint of an outbound packet
means that QoS is effectively disabled for such packets. That is, QoS does not
affect the packet queuing priority or VLAN tagging. In this case, the packets
are handled as follows (as long as no other QoS feature creates priority
assignments for them):
Note On Changing a Priority Setting
If a QoS classifier is using a policy (codepoint and associated priority) in the
DSCP Policy table, you must delete or change this usage before you can
change the priority setting on the codepoint. Otherwise the switch blocks the
change and displays this message:
Cannot modify DSCP Policy <
codepoint
> - in use by other qos rules.
In this case, use
show
qos <
classifier
>
to identify the specific classifiers using
the policy you want to change; that is:
show qos device-priority
show qos port-priority
show qos tcp-udp-port-priority
show qos vlan-priority
show qos type-of-service
For example, suppose that the 000001 (dscp 1) codepoint has a priority of 6,
and several classifiers use the 000001 codepoint to assign a priority to their
respective types of traffic. If you wanted to change the priority of codepoint
000001 you would do the following:
1.
Identify which QoS classifiers use the codepoint.
2.
Change the classifier configurations by assigning them to a different DSCP
policy, or to an 802.1p priority, or to
No-override
.
3.
Reconfigure the desired priority for the 000001 (dscp 1) codepoint.
4.
Either reassign the classifiers to the 00001 (dscp 1) codepoint policy or
leave them as they were after step 2, above.
802.1Q Status
Outbound 802.1p
Priority
Received and Forwarded on a tagged port member of a VLAN.
Unchanged
Received on an Untagged port member of a VLAN; Forwarded on a
tagged port member of a VLAN.
0 (zero)—”normal”
Forwarded on an Untagged port member of a VLAN.
None