Configuring The Qos Mappings; Default Dscp To Internal Forwarding Priority Mappings - Dell PowerConnect B-FCXs Configuration Manual

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Configuring the QoS mappings

PowerConnect stackable devices
PowerConnect B-Series FCX devices support DSCP-based QoS on a per-port basis. DSCP-based
QoS is not automatically honored for switched traffic. The default is 802.1p to CoS mapping. To
honor DSCP-based QoS, enter the following command at the interface level of the CLI.
PowerConnect(config-if-e1000-11)#trust dscp
Syntax: trust dscp
When trust dscp is enabled, the interface honors the Layer 3 DSCP value. By default, the interface
honors the Layer 2 CoS value.
NOTE
This feature is not supported together with 802.1p priority override.
Configuring the QoS mappings
You can optionally change the following QoS mappings:
•
•
The mappings are globally configurable and apply to all interfaces.

Default DSCP to internal forwarding priority mappings

The DSCP values are described in RFCs 2474 and 2475.
DSCP values to internal forwarding priority values.
TABLE 99
Internal forwarding priority
0 (lowest priority queue)
1
2
3
4
5
6
7 (highest priority queue)
Notice that DSCP values range from 0 through 63, whereas the internal forwarding priority values
range from 0 through 7. Any DSCP value within a given range is mapped to the same internal
forwarding priority value. For example, any DSCP value from 8 through 15 maps to priority 1.
After performing this mapping, the device maps the internal forwarding priority value to one of the
hardware forwarding queues.
Table 100
forwarding queues.
600
DSCP to internal forwarding priority
VLAN priority (802.1p) to hardware forwarding queue
Default DSCP to internal forwarding priority mappings
lists the default mappings of internal forwarding priority values to the hardware
Table 99
DSCP value
0 – 7
8 – 15
16 – 23
24 – 31
32 – 39
40 – 47
48 – 55
56 – 63
PowerConnect B-Series FCX Configuration Guide
lists the default mappings of
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