The XML configuration snippet provided in the exhibit results in the creation of two objects within the Cisco ACI environment:

Bridge Domain (Option C) : This is indicated by the XML element  < fvBD name= " bd1 " > , which defines a bridge domain with the name “bd1”.

VRF (Option E) : This is shown by the XML element  < fvCtx name= " pvn1 " / > , which defines a Virtual Routing and Forwarding instance named “pvn1”.

These objects are essential for network segmentation and routing within the ACI fabric, where the bridge domain represents a Layer 2 broadcast domain and the VRF is used for Layer 3 routing separation.

To detect and prevent Layer 2 loops in a Cisco ACI fabric, the engineer must configure the Mis-Cabling Protocol (MCP) and related policies. MCP is designed to detect loops in Layer 2 network segments connected to ACI access ports and operates in conjunction with Spanning Tree Protocol (STP) running on external Layer 2 networks. The steps to accomplish these goals include:

Enable MCP Globally : Ensure that MCP is enabled globally on all access ports, virtual ports, and virtual port channels (VPCs) unless they are disabled at the individual port level 1 .

Configure MCP Transmit Frequency : Set the transmit frequency to a value that allows for quick loop detection.  Starting with the 3.2(1) release, the Cisco ACI fabric provides faster loop detection with transmit frequencies from 100 milliseconds to 300 seconds 1 .

Set Action on Loop Detection : Decide how the MCP policies will act upon loop detection.  Options include generating a syslog message or disabling the port upon detection of a loop 1 .

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 interval 1 .

By following these steps, the engineer can ensure that the Cisco ACI fabric will detect and prevent Layer 2 loops, thereby maintaining a stable and efficient network environment.

References  :=

Cisco APIC Online Help - Loop Detection 1

ACI Layer 2 loop detection and Mitigation - Cisco Video Portal 2

To set up a Cisco ACI fabric to send Syslog messages related to hardware events to a dedicated Syslog server, the policy should be configured at  uni/fabric/monfab-default 4 .  This location in the Cisco APIC allows for the configuration of Syslog policies that can be applied to the entire fabric 4 .

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/4-x/aci -fundamentals/Cisco-ACI-Fundamentals-401/Cisco-ACI-Fundamentals-401_chapter _01100.html

When the default gateway for endpoints is on an external device instead of a Cisco ACI bridge domain Switched Virtual Interface (SVI), the unicast routing feature should be disabled on the bridge domain. This prevents the ACI fabric from attempting to route traffic for the endpoints, which should instead be directed to the external default gateway.

To advertise a bridge domain subnet out of the ACI fabric to an OSPF neighbor, the following configuration steps are required:

Configure Subnet scope to Advertised Externally : This step involves setting the scope of the subnet within the bridge domain to be advertised externally, which allows the subnet to be propagated to external routing entities 3 .

Add L30ut profile to the bridge domain using Associated L30uts section : This step involves associating the bridge domain with an L3Out profile, which is necessary for the bridge domain subnet to be advertised to OSPF neighbors 4 .

To ensure that application EPGs communicate only with their respective database EPGs, the app-to-db contract should be configured with a scope set to the Application Profile. This scope ensures that the contract is applied only within the specific application profile, allowing for granular control over the communication between the application and database tiers.  By setting the scope to Application Profile, the contract will not apply to other application profiles, thus preventing unwanted traffic between EPGs of different applications 1 .

References  :=

Cisco ACI Contract Guide White Paper 1

To ensure that servers supporting only Cisco Discovery Protocol are discovered automatically by the Cisco ACI fabric when connected, the action that must be taken is to Create an override policy that enables Cisco Discovery Protocol after LLDP is enabled in the default policy group

To ensure that only events related to leaf and spine environmental information are logged without including specific customer data, the configuration should be applied to the fabric policy.  The fabric policy in Cisco ACI is used to define global settings that apply to the entire fabric, such as syslog settings, which can be configured to filter and forward only the desired types of system messages 1 2 .

 The two true statements regarding ACI Multi-Site are:

ACI Multi-Site is a solution that supports a dedicated APIC cluster per site 1 .

ACI Multi-Site is a solution that allows one APIC cluster to manage multiple ACI sites 1 .