HP ProCurve Switch 6120G/XG Management Manual page 183

Quality of Service (QoS): Managing Bandwidth More Effectively
Preparation for Configuring QoS
5-12
2. Select the QoS option you want to use. Table 5-6 lists the traffic types (QoS
classifiers) and the QoS options you can use for prioritizing or setting a
policy on these traffic types:
Table 5-6. Applying QoS Options to Traffic Types Defined by QoS Classifiers
QoS Options for Prioritizing Outbound Traffic
Option 1: Prioritize traffic by sending specific packet
Configure80 types (determined by QoS classifier) to
2.1p Priority
different outbound port queues on the
Rules Only switch.
Rely on VLAN-tagged ports to carry packet
priority as an 802.1p value to downstream
devices.
Option 2: Prioritize traffic by sending specific packet
Configure types (determined by QoS classifier) to
ToS DSCP different outbound port queues on the
Policies switch.
with 802.1p
Propagate a service policy by reconfiguring
Priorities
the DSCP in outbound IP packets according
to packet type. The packet is placed in an
outbound port queue according to the
802.1p priority configured for that DSCP
policy. (The policy assumes that
downstream devices can be configured to
recognize the DSCP in IP packets and
implement the service policy it indicates.)
Use VLAN-tagged ports to include packet
priority as an 802.1p value to downstream
devices.
1
In this mode the configuration is fixed. You cannot change the automatic priority assignment
when using IP-ToS Precedence as a QoS classifier.
3. If you want 802.1p priority settings to be included in outbound packets,
ensure that tagged VLANs are configured on the appropriate downstream
links.
4. Determine the actual QoS configuration changes you will need to make
on each QoS-capable device in your network in order to implement the
desired policy. Also, if you want downstream devices to read and use
DSCPs in IP packets from the switch, configure them to do so by enabling
ToS Differentiated Service mode and making sure the same DSCP policies
are configured.
QoS Classifiers
IP-ToS IP- Source
Precedence DiffServ -Port
1
Yes Yes
No Yes
Yes
Yes