Brocade Network OS Administrator’s Guide v4.1.1 User Manual
Page 487
Understanding default user-priority mappings for untrusted interfaces
When Layer 2 QoS trust is set to untrusted , then the default is to map all Layer 2 switched traffic to the
port default user priority value of 0 (best effort), unless the user priority is configured to a different value.
The following table presents the Layer 2 QoS untrusted user-priority generation table.
Default priority value of untrusted interfaces
TABLE 82
Incoming CoS
User Priority
0
port
1
port
2
port
3
port
4
port
5
port
6
port
7
port
NOTE
Nontagged Ethernet frames are interpreted as having an incoming CoS value of 0 (zero).
You can override the default user-priority mapping by applying explicit user-priority mappings.
When neighboring devices are trusted and able to properly set QoS, then Layer 2 QoS trust can be set
to CoS and the IEEE 802.1Q default-priority mapping is applied.
The following table presents the Layer 2 CoS user-priority generation table conforming to 802.1Q
default mapping. You can override this default user-priority table per port if you want to change (mutate)
the CoS value.
IEEE 802.1Q default priority mapping
TABLE 83
Incoming CoS
User Priority
0
0
1
1
2
2
3
3
4
4
5
5
Understanding default user-priority mappings for untrusted interfaces
Network OS Administrator’s Guide
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