300-620 Exam Dumps : Implementing Cisco Application Centric Infrastructure (300-620 DCACI)

When a bridge domain is configured with the hardware-proxy option for Layer 2 unknown unicast traffic, if the spine switch is unable to find the MAC address in the proxy database, it will drop the Layer 2 unknown unicast packet4. This behavior is controlled by the hardware proxy option associated with a bridge domain4.

To configure a Cisco ACI system to detect network loops for both untagged and tagged traffic and to stop the loop by disabling an interface within 4 seconds, the following configuration must be used:

Enable Mis-Cabling Protocol (MCP): MCP detects loops from external sources and will err-disable the interface on which Cisco ACI receives its own packet. This is crucial for preventing loops in the network1.

Configure MCP Transmit Frequency: Set the MCP transmit frequency to a value that allows for quick loop detection. The Cisco ACI fabric provides faster loop detection with transmit frequencies from 100 milliseconds to 300 seconds. To meet the requirement of detecting and stopping a loop within 4 seconds, you would set the transmit frequency to a value less than 4 seconds2.

Set Action on Loop Detection: Configure the MCP policies to identify loops and decide how to act upon them. You can set the policy to generate a syslog message or disable the port upon loop detection2.

Implement Error Disabled Recovery Policy: Configure an error disabled recovery policy to automatically re-enable ports that were disabled due to loop detection after a configurable interval2.

By implementing these configurations, the Cisco ACI system will be able to detect and stop network loops quickly and efficiently, ensuring network stability and preventing potential disruptions.

References :=

Cisco APIC Online Help - Loop Detection2

Cisco ACI Best Practices Quick Summary

When configuring an L3Out in Cisco ACI and encountering a QoS-related error, creating a custom QoS policy is often necessary to clear the fault. This involves defining a QoS policy that meets the specific requirements of the L3Out configuration and applying it to the relevant interfaces or globally within the fabric. The custom QoS policy should be designed to prioritize traffic appropriately and ensure that the necessary QoS settings are in place for the L3Out connections1.

References :=

Cisco ACI L3Out Configuration Examples1