Edge-Core ES4524M-PoE, Management Manual, Page: 236 / 560

Configuring the Switch
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Layer 3/4 Priority Settings
Mapping Layer 3/4 Priorities to CoS Values
This switch supports one method of prioritizing layer 3/4 traffic to meet application
requirements. Traffic priorities can be specified in the IP header of a frame, using the
priority bits in the Type of Service (ToS) octet. If priority bits are used, the ToS octet
may contain six bits for Differentiated Services Code Point (DSCP) service. When
these service is enabled, the priorities are mapped to a Class of Service value by the
switch, and the traffic then sent to the corresponding output queue.
Because different priority information may be contained in the traffic, this switch
maps priority values to the output queues in the following manner:
• The precedence for priority mapping is IP DSCP Priority, and then Default Port
Priority.
Selecting IP DSCP Priority
The switch allows you to enable or disable IP DSCP priority.
Command Attributes
• Disabled – Disables IP DSCP priority service. (This is the default setting.)
• IP DSCP – Maps layer 3/4 priorities using Differentiated Services Code Point
Mapping.
Web – Click Priority, IP DSCP Priority Status. Select IP DSCP, then click Apply.
Figure 3-96 IP DSCP Priority Status
Mapping DSCP Priority
The DSCP is six bits wide, allowing coding for up to 64 different forwarding
behaviors. The DSCP replaces the ToS bits, but it retains backward compatibility
with the three precedence bits so that non-DSCP compliant, ToS-enabled devices,
will not conflict with the DSCP mapping. Based on network policies, different kinds of
traffic can be marked for different kinds of forwarding. The DSCP default values are
defined in the following table. Note that all the DSCP values that are not specified
are mapped to CoS value 0.