Administrator Guide

Table Of Contents
Access Control List (ACL) VLAN Groups and
Content Addressable Memory (CAM)
This chapter describes the access control list (ACL) VLAN group and content addressable memory (CAM) enhancements.
Topics:
Optimizing CAM Utilization During the Attachment of ACLs to VLANs
Guidelines for Configuring ACL VLAN groups
Configuring ACL VLAN Groups and Configuring FP Blocks for VLAN Parameters
Viewing CAM Usage
Allocating FP Blocks for VLAN Processes
Optimizing CAM Utilization During the Attachment of
ACLs to VLANs
This functionality is supported on the Z9000 platform.
You can enable and configure the ACL CAM optimization functionality to minimize the number of entries in CAM while ACLs are
applied on a VLAN or a set of VLANs, and also while ACLs are applied on a set of ports. This capability enables the effective
usage of the CAM space when Layer 3 ACLs are applied to a set of VLANs and when Layer 2 or Layer 3 ACLs are applied on a
set of ports.
In releases of Dell Networking OS that do not support the CAM optimization functionality, when an ACL is applied on a VLAN,
the ACL rules are configured with the rule-specific parameters and the VLAN as additional attributes in the ACL region. When
the ACL is applied on multiple VLAN interfaces, the consumption of the CAM space increases proportionally. For example, when
an ACL with n number of rules is applied on m number of VLAN interfaces, a total of n*m entries are configured in the CAM
region that is allocated for ACLs. Similarly, when an L2 or L3 ACL is applied on a set of ports, a large portion of the CAM space
gets used because a port is saved as a parameter in CAM.
To avoid excessive consumption of the CAM space, configure ACL VLAN groups, which combine all the VLANs that are applied
with the same ACL, into a single group. A class identifier (Class ID) is assigned for each of the ACLs attached to the VLAN and
this Class ID is used as an identifier or locator in the CAM space instead of the VLAN ID. This method of processing reduces
the number of entries in the CAM area significantly and saves memory space by using the class ID as a filtering criterion in CAM
instead of the VLAN ID.
You can create an ACL VLAN group and attach the ACL with the VLAN members. The optimization is applicable only when you
create an ACL VLAN group. If you apply an ACL separately on the VLAN interface, each ACL has a mapping with the VLAN and
increased CAM space utilization occurs. Attaching an ACL individually to VLAN interfaces is similar to the behavior of ACL-VLAN
mapping storage in CAM prior to the implementation of the ACL VLAN group functionality.
The ACL manager application on router processor (RP1) contains all the state information about all the ACL VLAN groups that
are present. The ACL handler on control processor (CP) and the ACL agent on line cards do not contain any stateful information
about the group. The ACL manager application performs the validation after you enter the acl-vlan-group command. If the
command is valid, it is processed and sent to the agent, if required. If a configuration error is found or if the maximum limit
has exceeded for the ACL VLAN groups present on the system, an appropriate error message is displayed. The ACL manager
application verifies the following parameters when you enter the acl-vlan-group command:
Whether the CAM profile is set in VFP
Whether the maximum number of groups in the system has exceeded
Whether the maximum number of VLAN numbers permitted per ACL group has exceeded
When a VLAN member that is being added is already a part of another ACL group
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106 Access Control List (ACL) VLAN Groups and Content Addressable Memory (CAM)