Concept Guide

The following combination of marking actions to be specified match sequence of the class-map command:
● set a new DSCP for the packet
● set the packet color as ‘yellow’
● set the packet color as ‘yellow’ and set a new DSCP for the packet
This marking action to set the color of the packet is allowed only on the ‘match-any’ logical operator of the class-map.
This marking-action can be configured for all of the below L3 match sequence types:
● match ip access-group
● match ip dscp
● match ip precedence
● match ip vlan
Guidelines for Configuring ECN for Classifying and
Color-Marking Packets
Keep the following points in mind while configuring the marking and mapping of incoming packets using ECN fields in IPv4
headers:
● Currently Dell EMC Networking OS supports matching only the following TCP flags:
○ ACK
○ FIN
○ SYN
○ PSH
○ RST
○ URG
In the existing software, ECE/CWR TCP flag qualifiers are not supported.
● Because this functionality forcibly marks all the packets matching the specific match criteria as ‘yellow’, Dell EMC
Networking OS does not support Policer based coloring and this feature concurrently.
● If single rate two color policer is configured along with this feature, then by default all packets less than PIR would be
considered as “Green” But ‘Green’ packets matching the specific match criteria for which ‘color-marking’ is configured will
be over-written and marked as “Yellow”.
● If two rate three color policer is configured along with this feature then,
○ x < CIR – will be marked as “Green”
○ CIR < x< PIR – will be marked as “Yellow”
○ PIR < x – will be marked as “Red”
But ‘Green’ packets matching the specific match criteria for which ‘color-marking’ is configured will be over-written and marked
as “Yellow”.
Quality of Service (QoS)
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