Concept Guide

Similar to ‘dscp’ qualier in the existing L3 ACL command, the ‘ecn’ qualier can be used along with all other supported ACL match
qualiers such as SIP/DIP/TCP/UDP/SRC PORT/DST PORT/ ICMP.
Until Release 9.3(0.0), ACL supports classication based on the below TCP ags:
• ACK
• FIN
• SYN
• PSH
• RST
• URG
You can now use the ‘ecn’ match qualier along with the above TCP ag for classication.
The following combination of match qualiers is acceptable to be congured for the Dell EMC Networking OS software through L3 ACL
command:
• Classication based on DSCP only
• Classication based on ECN only
• Classication based on ECN and DSCP concurrently
You can now use the set-color yellow keyword with the match ip access-group command to mark the color of the trac as ‘yellow’ would
be added in the ‘match ip’ sequence of the class-map conguration.
By default, all packets are considered as ‘green’ (without the rate-policer and trust-diserve conguration) and hence support would be
provided to mark the packets as ‘yellow’ alone will be provided.
By default Dell EMC Networking OS drops all the ‘RED’ or ‘violate’ packets.
The following combination of marking actions to be specied 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 congured for all of the below L3 match sequence types:
• match ip access-group
• match ip dscp
• match ip precedence
• match ip vlan
Guidelines for Conguring ECN for Classifying and
Color-Marking Packets
Keep the following points in mind while conguring the marking and mapping of incoming packets using ECN elds in IPv4 headers:
• Currently Dell EMC Networking OS supports matching only the following TCP ags:
– ACK
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Quality of Service (QoS)