Setup Guide
Guidelines for Conguring ECN for Classifying and
Color-Marking Packets
Keep the following points in mind while conguring 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
– FIN
– SYN
– PSH
– RST
– URG
In the existing software, ECE/CWR TCP ag qualiers are not supported.
• Because this functionality forcibly marks all the packets matching the specic 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 congured along with this feature, then by default all packets less than PIR would be considered as
“Green” But ‘Green’ packets matching the specic match criteria for which ‘color-marking’ is congured will be over-written and
marked as “Yellow”.
• If two rate three color policer is congured 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 specic match criteria for which ‘color-marking’ is congured will be over-written and marked as “Yellow”.
Sample conguration to mark non-ecn packets as “yellow”
with Multiple trac class
Consider the example where there are no dierent trac classes that is all the packets are egressing on the default ‘queue0’.
Dell EMC Networking OS can be congured as below to mark the non-ecn packets as yellow packets.
!
ip access-list standard ecn_0
seq 5 permit any ecn 0
class-map match-any ecn_0_cmap
match ip access-group ecn_0 set-color yellow
!
policy-map-input ecn_0_pmap
service-queue 0 class-map ecn_0_cmap
Applying this policy-map “ecn_0_pmap” will mark all the packets with ‘ecn == 0’ as yellow packets on queue0 (default queue).
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Quality of Service (QoS)