Dell EMC Configuration Guide for the S4048T–ON System 9.14.2.4

Example of the order Keyword to Determine ACL Sequence

ACLs acl1 and acl2 have overlapping rules because the address range 20.1.1.0/24 is within 20.0.0.0/8. Therefore (without the keyword order), packets within the range 20.1.1.0/24 match positive against cmap1 and are buffered in queue 7, though you intended for these packets to match positive against cmap2 and be buffered in queue 4.

In cases where class-maps with overlapping ACL rules are applied to different queues, use the order keyword to specify the order in which you want to apply ACL rules. The order can range from 0 to 254. Dell EMC Networking OS writes to the CAM ACL rules with lower-order numbers (order numbers closer to 0) before rules with higher-order numbers so that packets are matched as you intended. By default, all ACL rules have an order of 255.

DellEMC(conf)#ip access-list standard acl1
DellEMC(config-std-nacl)#permit 20.0.0.0/8
DellEMC(config-std-nacl)#exit
DellEMC(conf)#ip access-list standard acl2
DellEMC(config-std-nacl)#permit 20.1.1.0/24 order 0
DellEMC(config-std-nacl)#exit
DellEMC(conf)#class-map match-all cmap1
DellEMC(conf-class-map)#match ip access-group acl1
DellEMC(conf-class-map)#exit
DellEMC(conf)#class-map match-all cmap2
DellEMC(conf-class-map)#match ip access-group acl2
DellEMC(conf-class-map)#exit
DellEMC(conf)#policy-map-input pmap
DellEMC(conf-policy-map-in)#service-queue 7 class-map cmap1
DellEMC(conf-policy-map-in)#service-queue 4 class-map cmap2
DellEMC(conf-policy-map-in)#exit
DellEMC(conf)#interface te 10/1
DellEMC(conf-if-te-10/1)#service-policy input pmap