Setup Guide

Table Of Contents

CAM Optimization

When you enable this command, if a policy map containing classification rules (ACL and/or dscp/ ip-precedence rules) is applied

to more than one physical interface on the same port-pipe, only a single copy of the policy is written (only one FP entry is used).

When you disable this command, the system behaves as described in this chapter.

Test CAM Usage

This command applies to both IPv4 and IPv6 CAM profiles, but is best used when verifying QoS optimization for IPv6 ACLs.

To determine whether sufficient ACL CAM space is available to enable a service-policy, use this command. To verify the actual

CAM space required, create a class map with all the required ACL rules, then execute the test cam-usage command in

Privilege mode. The following example shows the output when executing this command. The status column indicates whether

you can enable the policy.

Example of the test cam-usage Command

DellEMC#test cam-usage service-policy input asd stack-unit 1 port-set 0

--------------------------------------------------------------------------

1| 1| IPv4Flow| 232| 0|Allowed

DellEMC#

Implementing ACLs on Dell EMC Networking OS

You can assign one IP ACL per interface. If you do not assign an IP ACL to an interface, it is not used by the software.

The number of entries allowed per ACL is hardware-dependent.

If counters are enabled on ACL rules that are already configured, those counters are reset when a new rule which is inserted

or prepended or appended requires a hardware shift in the flow table. Resetting the counters to 0 is transient as the proginal

counter values are retained after a few seconds. If there is no need to shift the flow in the hardware, the counters are not

affected. This is applicable to the following features:

● L2 Ingress Access list

● L2 Egress Access list

In the Dell EMC Networking OS versions prior to 9.13(0.0), the system does not install any of your ACL rules if the available

CAM space is lesser than what is required for your set of ACL rules. Effective with the Dell EMC Networking OS version

9.13(0.0), the system installs your ACL rules until all the allocated CAM memory is used. If there is no implicit permit in your rule,

the Dell EMC Networking OS ensures that an implicit deny is installed at the end of your rule. This behavior is applicable for IPv4

and IPv6 ingress and egress ACLs.

NOTE:

System access lists (system-flow entries) are pre-programmed in the system for lifting the control-plane packets

destined for the local device which the CPU needs to process. The system access lists always override the user configured

access lists. Even if you configure ACL to block certain hosts, control plane protocols such as, ARP, BGP, LACP, VLT, VRRP

and so on, associated with such hosts cannot be blocked.

Assigning ACLs to VLANs

When you apply an ACL to a VLAN using single port-pipe, a copy of the ACL entries gets installed in the ACL CAM on the

port-pipe. The entry looks for the incoming VLAN in the packet. When you apply an ACL on individual ports of a VLAN, separate

copies of the ACL entries are installed for each port belonging to a port-pipe.

You can use the log keyword to log the details about the packets that match. The control processor becomes busy based on

the number of packets that match the log entry and the rate at which the details are logged in. However, the route processor

(RP) is unaffected. You can use this option for debugging issues related to control traffic.

Access Control Lists (ACLs)