Administrator Guide

Honoring dot1p Priorities on Ingress Traffic
By default, Dell EMC Networking OS does not honor dot1p priorities on ingress traffic.
You can configure this feature on physical interfaces and port-channels, but you cannot configure it on individual interfaces in a port
channel.
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. For more information, refer to Mapping
dot1p Values to Service Queues.
NOTE: You cannot configure service-policy input and service-class dynamic dot1p on the same interface.
• Honor dot1p priorities on ingress traffic.
INTERFACE mode
service-class dynamic dot1p
DellEMC#configure terminal
DellEMC(conf)#interface tengigabitethernet 1/1
DellEMC(conf-if-te-1/1)#service-class dynamic dot1p
DellEMC(conf-if-te-1/1)#end
Priority-Tagged Frames on the Default VLAN
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 you configure service-class dynamic dot1p or trust dot1p.
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 you configure service-class dynamic dotp or trust dot1p. When priority-tagged
frames ingress a tagged port, the frames are dropped because, for a tagged port, the default VLAN is 0.
Dell EMC Networking OS Behavior: Hybrid ports can receive untagged, tagged, and priority tagged frames. The rate metering
calculation might be inaccurate for untagged ports because 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.
Configuring Port-Based Rate Policing
If the interface is a member of a VLAN, you may specify the VLAN for which ingress packets are policed.
• Rate policing ingress traffic on an interface.
INTERFACE mode
rate police
The following example shows configuring rate policing.
DellEMC#configure terminal
DellEMC(conf)#interface tengigabitethernet 1/1
DellEMC(conf-if-te-1/1)#rate police 100 40 peak 150 50
DellEMC(conf-if-te-1/1)#end
Configuring Port-Based Rate Shaping
Rate shaping buffers, rather than drops, traffic exceeding the specified rate until the buffer is exhausted. If any stream exceeds the
configured bandwidth on a continuous basis, it can consume all of the buffer space that is allocated to the port.
Dell EMC Networking OS Behavior: Rate shaping is effectively rate limiting because of its smaller buffer size. Rate shaping on tagged
ports is slightly greater than the configured rate and rate shaping on untagged ports is slightly less than configured rate.
Rate shaping buffers, rather than drops, traffic exceeding the specified rate until the buffer is exhausted. If any stream exceeds the
configured bandwidth on a continuous basis, it can consume all of the buffer space that is allocated to the port.
• Apply rate shaping to outgoing traffic on a port.
INTERFACE mode
rate shape
Quality of Service (QoS)
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