Guidelines And Restrictions - Cisco Catalyst 4500 series Administration Manual

TCAM Programming and ACLs
TCAM Programming and ACLs
You apply three types of hardware resources when you program ACLs and ACL-based features: mapping
table entries (MTEs), profiles, and TCAM value/mask entries. If any of these resources are exhausted,
packets are sent to the CPU for software-based processing.
Supervisor Engine 6-E, Supervisor Engine 6L-E, Supervisor Engine 7-E, Supervisor Engine 7L-E, and
Note
Supervisor Engine 8-E automatically manage the available resources. Because masks are not shared on
the supervisor engines, only one programming algorithm exists. No regions exist so region resizing is
not needed.
If you exhaust resources on the supervisor engine, you should consider reducing the complexity of your
configuration.
When an interface is in down state, TCAMs are not consumed for RACLs, but are for PACLs.
Note
Layer 4 Operators in ACLs
The following sections provide guidelines and restrictions for configuring ACLs that include Layer 4
port operations:
•
•
•
Restrictions for Layer 4 Operations
Cisco IOS XE Release 3.60E and Cisco IOS Release 15.2(2)E do not support the configuration of named
Note
ACLs for noncontiguous ports on an ACE.
You can specify these operator types, each of which uses one Layer 4 operation in the hardware:
•
•
•
•
The limits on the number of Layer 4 operations differ for each type of ACL, and can also vary based on
other factors: whether an ACL is applied to incoming or outgoing traffic, whether the ACL is a security
ACL or is used as a match condition for a QoS policy, and whether IPv6 ACLs are being programmed
using the compressed flow label format.
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
54-10
Restrictions for Layer 4 Operations, page 54-10
Configuration Guidelines for Layer 4 Operations, page 54-11
How ACL Processing Impacts CPU, page 54-12
gt (greater than)
lt (less than)
neq (not equal)
range (inclusive range)
Chapter 54 Configuring Network Security with ACLs
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