ECS4660-28F_Management Guide-R03

C HAPTER 10 | Class of Service
Layer 3/4 Priority Settings
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To show the DSCP to CoS egress map in the web interface:
1. Click Traffic, Priority, DSCP to CoS.
1. Select Show from the Action list.
2. Select a port.
Figure 145: Showing DSCP to CoS Egress Mapping
MAPPING IP
PRECEDENCE VALUES
TO INTERNAL DSCP
VALUES
Use the Traffic > Priority > IP Precedence to DSCP page to map IP
precedence values in incoming packets to per-hop behavior and drop
precedence values for priority processing.
The Type of Service (ToS) octet in the IPv4 header includes three
precedence bits defining eight different priority levels ranging from highest
priority for network control packets to lowest priority for routine traffic. The
default IP Precedence values map one-to-one to the Class of Service values
(that is, Precedence value 0 maps to PHB value 0, and so forth). Bits 6 and
7 are used for network control, and the other bits for various application
types. The ToS bits are defined in Table 2 0 .
Table 20: Mapping IP Precedence
Priority Level Traffic Type
7Network Control
6 Internetwork Control
5Critical
4Flash Override
3Flash
2 Immediate
1Priority
0Routine