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Honor dot1p Priorities on Ingress Traffic
By default FTOS does not honor dot1p priorities on ingress traffic. Use the command service-class
dynamic dot1p
from INTERFACE mode to honor dot1p priorities on ingress traffic, as shown in
Figure 41-3. You can configure this feature on physical interfaces and port-channels, but you cannot
configure it on individual interfaces in a port channel.
On the C-Series and S-Series you can configure
service-class dynamic dot1p from CONFIGURATION
mode, which applies the configuration to all interfaces. A CONFIGURATION mode
service-class dynamic
dot1p
entry supersedes any INTERFACE entries. See Mapping dot1p values to service queues on
page 867.
Figure 41-3. service-class dynamic dot1p Command Example
Priority-tagged Frames on the Default VLAN
Priority-tagged Frames on the Default VLAN is available only on platforms: e
x
c s
Priority-tagged frames are 802.1Q tagged frames with VLAN ID 0. For VLAN classification these packets
are treated as untagged. However, the dot1p value is still honored when
service-class dynamic dot1p or
trust dot1p is configured.
When priority-tagged frames ingress an untagged port or hybrid port the frames are classified to the default
VLAN of the port, and to a queue according to their dot1p priority if
service-class dynamic dotp or trust
dot1p
are configured. When priority-tagged frames ingress a tagged port, the frames are dropped because
for a tagged port the default VLAN is 0.
Note: You cannot configure service-policy input and service-class dynamic dot1p on the same interface.
FTOS Behavior: Hybrid ports can receive untagged, tagged, and priority tagged frames. The rate
metering calculation might be inaccurate for untagged ports, since an internal assumption is made that
all frames are treated as tagged. Internally the ASIC adds a 4-bytes tag to received untagged frames.
Though these 4-bytes are not part of the untagged frame received on the wire, they are included in the
rate metering calculation resulting in metering inaccuracy.
FTOS#config t
FTOS(conf)#interface gigabitethernet 1/0
FTOS(conf-if)#service-class dynamic dot1p
FTOS(conf-if)#end
FTOS#