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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 37 Configuring Quality of Service
Configuring QoS on Supervisor Engines II-Plus, II+10GE, IV, V, V-10GE, 4924, 4948, and 4948-10GE
Configuring the Trust State of Interfaces, page 37-48
Configuring the CoS Value for an Interface, page 37-49
Configuring DSCP Values for an Interface, page 37-49
Configuring Transmit Queues, page 37-50
Configuring DSCP Maps, page 37-53
Default QoS Configuration
Table 37-2 shows the QoS default configuration.
Table 37-2 QoS Default Configuration
Feature Default Value
Global QoS configuration Disabled
Interface QoS configuration (port based) Enabled when QoS is globally enabled
Interface CoS value 0
Interface DSCP value 0
CoS to DSCP map
(DSCP set from CoS values) CoS 0 = DSCP 0
CoS 1 = DSCP 8
CoS 2 = DSCP 16
CoS 3 = DSCP 24
CoS 4 = DSCP 32
CoS 5 = DSCP 40
CoS 6 = DSCP 48
CoS 7 = DSCP 56
DSCP to CoS map
(CoS set from DSCP values) DSCP 0–7 = CoS 0
DSCP 8–15 = CoS 1
DSCP 16–23 = CoS 2
DSCP 24–31 = CoS 3
DSCP 32–39 = CoS 4
DSCP 40–47 = CoS 5
DSCP 48–55 = CoS 6
DSCP 56–63 = CoS 7
Marked-down DSCP from DSCP map
(Policed-DSCP) Marked-down DSCP value equals original DSCP value (no markdown)
Policers None
Policy maps None
Transmit queue sharing 1/4 of the link bandwidth
Transmit queue size 1/4 of the transmit queue entries for the port. The transmit queue size of a
port depends on the type of port, ranging from 240 packets per transmit
queue to 1920 packets per transmit queue.
Transmit queue shaping None