DEI based Classification on 7210 SAS-D
Page 90 7210 SAS D, E, K OS Quality of Service Guide
DEI based Classification on 7210 SAS-D
DEI based classification is supported on Access ports, Access-uplink ports, Network ports and
Hybrid ports as applicable on 7210 SAS platforms. DEI bit in the received packet is used to
determine the ingress profile for the packet. If in the received packet, DEI = 0, then the packet is
considered to be GREEN or in-profile and if DEI = 1, then the packet is considered to be
YELLOW or out-of-profile. The profile assigned at the ingress can be used to enable color-aware
metering with SAP ingress policing, network port ingress policing and access-uplink port ingress
policing. The profile of the packet can be reassigned by ingress meters/policers, when policing is
used on SAP ingress, the final profile of the packet is determined by the meter/policers, based on
the configured CIR/PIR rates. If a packet is below CIR rate, it is assigned green/in-profile and if it
exceeds the CIR rate and is below the PIR rate, it is assigned yellow/out-of-profile.
The final profile assigned at ingress is used by egress to determine the WRED slope to use. The
WRED slope determines whether the packet is eligible to be assigned a buffer and can be queued
up on egress queue for transmission.
The following support is available for DEI classification:
• Under the port configuration, a command is provided to enable DEI based classification,
allowing user an option to enable/disable use of DEI for ingress classification on a per port
basis. Initial profile (also known as color) is based on DEI/CFI bit. If in the received
packet, DEI = 0, then packet can be considered to be GREEN or in-profile and if DEI = 1,
then packet can be considered to be YELLOW or out-of-profile by the subsequent
processing flow in hardware.
• All the SAPs configured on the port (access or hybrid) can use DEI classification for
color-aware metering if user so desires. The user has an option to use color-blind metering
for some SAPs and color-aware metering for some other SAPs configured on the same
port when DEI classification is enabled on the port. When using color-blind mode, the
ingress profile assigned to the packet based on the DEI bit is ignored.
• The user is provided with an option in the sap-ingress policy, to configure a policer as
color aware or color-blind. In color-aware mode, the DEI bit in the packet determines the
ingress profile of the packet. If user configures meter/policer mode as color-aware, then
incoming packet DEI bit is used by the policer as the ingress profile.
• When using policing, the final profile of the packet is assigned by the ingress meter (based
on configured CIR/PIR rate) in both color-aware and color-blind mode.
• For Network Port policy, DEI based classification is supported only when dot1p
classification criteria is in use. In other words, it cannot be used when DSCP based
classification is used.
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