HP ProCurve 5300xl Series Management Manual page 295

Figure 8-6. Example of Rule Usage When a Configuration Includes DSCP-Map and Type-of-Service Options
Demonstrating How the Switch Uses Resources in DSCP
Configurations. In the default configuration, the DSCP map is configured
with one DSCP policy (Expedited Forwarding; 101110 with a "7" priority) but,
because no ToS Diff-Services options are configured, no rules are used. If ToS
Diff-Services mode is enabled, then one rule is immediately used for this
codepoint. Adding a new DSCP policy (for example, 001111 with a "5" priority)
and then configuring ToS Diff-Services to assign inbound packets with a
codepoint of 001010 to the 001111 policy implements all policies configured
in the DSCP map and, in this case, uses three rules; one for each codepoint
invoked in the switch's current DSCP configuration (101110-the default,
001111, and 001010). Adding another Diff-Services assignment, such as assign­
ing inbound packets with a codepoint of 000111 to the Expedited Forwarding
policy (101110), would use one more rule on all ports.
Figure 8-5. Example of Rule Resources in the Default Configuration
Quality of Service (QoS): Managing Bandwidth More Effectively
Assigning inbound packets with 001010 in the
ToS byte to the newly created 001111 policy
enables ToS Diff-Services mode. Because the
default DSCP map already includes the
Expedited Delivery (101110) policy, enabling
ToS Diff- Services uses three rules on each
port; one for each configured codepoint
(101110, 001010, and 001111). As a result, the
available rule count drops by 3 to 117.
Preparation for Configuring QoS
8-21