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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 47 Configuring Network Security with ACLs
TCAM Programming and ACLs for Supervisor Engine II-Plus, Supervisor Engine IV, Supervisor Engine V, and Supervisor
Note access-list hardware entries packed is the default and does not appear in the output of the show
running-config command. If you configure scattered mode, access-list hardware entries scattered
appears in the output. If you configure packed mode, nothing appears in the output.
Note The default TCAM programming algorithm is packed.
The following output was collected from a switch running in packed mode. Observe that 89 percent of
the masks are required to program only 49 percent of the ACL entries.
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# access-list hardware entries packed
Switch(config)# end
Switch#
01:15:34: %SYS-5-CONFIG_I: Configured from console by console
Switch#
Switch# show platform hardware acl statistics utilization brief
Entries/Total(%) Masks/Total(%)
----------------- ---------------
Input Acl(PortAndVlan) 2016 / 4096 ( 49) 460 / 512 ( 89)
Input Acl(PortOrVlan) 6 / 4096 ( 0) 4 / 512 ( 0)
Input Qos(PortAndVlan) 0 / 4096 ( 0) 0 / 512 ( 0)
Input Qos(PortOrVlan) 0 / 4096 ( 0) 0 / 512 ( 0)
Output Acl(PortAndVlan) 0 / 4096 ( 0) 0 / 512 ( 0)
Output Acl(PortOrVlan) 0 / 4096 ( 0) 0 / 512 ( 0)
Output Qos(PortAndVlan) 0 / 4096 ( 0) 0 / 512 ( 0)
Output Qos(PortOrVlan) 0 / 4096 ( 0) 0 / 512 ( 0)
L4Ops: used 2 out of 64
The following output was collected after the algorithm was switched to scattered. Observe that the
number of masks required to program 49 percent of the entries has decreased to 49 percent.
Note When you enable DHCP snooping and IP Source Guard on all ports on a chassis, you must use the
scattered keyword.
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# access-list hardware entries scattered
Switch(config)# end
Switch#
01:39:37: %SYS-5-CONFIG_I: Configured from console by console
Switch#
Switch# show platform hardware acl statistics utilization brief
Entries/Total(%) Masks/Total(%)
----------------- ---------------
Input Acl(PortAndVlan) 2016 / 4096 ( 49) 252 / 512 ( 49)
Input Acl(PortOrVlan) 6 / 4096 ( 0) 5 / 512 ( 0)
Input Qos(PortAndVlan) 0 / 4096 ( 0) 0 / 512 ( 0)
Input Qos(PortOrVlan) 0 / 4096 ( 0) 0 / 512 ( 0)
Output Acl(PortAndVlan) 0 / 4096 ( 0) 0 / 512 ( 0)