47-12
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 You can only shift entries between the PortAndVlan region and the PortOrVlan region for a specific
TCAM type (for example, from the Input ACL TCAM PortOrVlan region to the Input ACL TCAM
PortAndVlan region). You cannot shift entries between TCAM types.
To determine whether region resizing would be beneficial, enter the following command:
Switch# show platform hardware acl statistics utilization brief
Input Acl(PortAndVlan) 2346 / 8112 ( 29) 1014 / 1014 (100)
Input Acl(PortOrVlan) 0 / 8112 ( 0) 0 / 1014 ( 0)
Input Qos(PortOrVlan) 0 / 8128 ( 0) 0 / 1016 ( 0)
Input Qos(PortOrVlan) 0 / 8128 ( 0) 0 / 1016 ( 0)
Output Acl(PortOrVlan) 0 / 8112 ( 0) 0 / 1014 ( 0)
Output Acl(PortOrVlan) 0 / 8112 ( 0) 0 / 1014 ( 0)
Output Qos(PortOrVlan) 0 / 8128 ( 0) 0 / 1016 ( 0)
Output Qos(PortOrVlan) 0 / 8128 ( 0) 0 / 1016 ( 0)
L4Ops: used 2 out of 64
The above output indicates that the Input ACL PortAndVlan region is out of masks, but there is free
space in the Input ACL PortOrVlan region that could be repurposed.
The following example shows how to change the region balance of the Input ACL TCAM so that 75
percent of the entries are allocated to the PortAndVlan region and only 25 percent to the PortOrVlan
region.
Switch# configure terminal
Switch(config)# access-list hardware region feature input balance 75
After adjusting the region balance, the PortAndVlan region has more resources allocated to it, and the
PortOrVlan region has fewer resources.
Switch# show platform hardware acl statistics utilization brief
Input Acl(PortAndVlan) 2346 / 12160 ( 19) 1014 / 1520 ( 67)
Input Acl(PortOrVlan) 0 / 4064 ( 0) 0 / 508 ( 0)
Input Qos(PortOrVlan) 0 / 8128 ( 0) 0 / 1016 ( 0)
Input Qos(PortOrVlan) 0 / 8128 ( 0) 0 / 1016 ( 0)
Output Acl(PortOrVlan) 0 / 8112 ( 0) 0 / 1014 ( 0)
Output Acl(PortOrVlan) 0 / 8112 ( 0) 0 / 1014 ( 0)
Output Qos(PortOrVlan) 0 / 8128 ( 0) 0 / 1016 ( 0)
Output Qos(PortOrVlan) 0 / 8128 ( 0) 0 / 1016 ( 0)
L4Ops: used 2 out of 64
Switch#
Note Both the no access-list hardware region {feature | qos} {input | output} balance command and a
balance of 50 force the configuration to the default values. A similar configuration can also be performed
for QoS.
Troubleshooting High CPU Due to ACLs
Packets that match entries in fully programmed ACLs are processed in hardware. However, large ACL
and IPSG configurations may exhaust TCAM masks on Supervisor Engines II-Plus-TS, IV, V, and the
Catalyst 4948 switch before the ACLs are fully programmed.