Cisco 300-630 Implementing Cisco Application Centric Infrastructure - Advanced (DCACIA) Exam Practice Test

To create an exit point from all the tenants using the common tenant after removing RT-2 and RT-3 devices, the following two configuration tasks must be completed:

Update L3Out ExtEPG Subnet: The L3Out ExtEPG subnet in the common tenant should be updated with the flag “Shared Route Control Subnet” and “Aggregate Shared Routes” (Option C). This configuration allows for the sharing of routes between different tenants through a common exit point.

Mark Subnets and Attach Contract: All subnets should be marked with the flag “Shared between VRFs,” and contract Ctr-3 should be attached as a provider to all the EPGs (Option D). This ensures that all EPGs can provide services under contract Ctr-3 across different VRFs, facilitating inter-tenant communication via shared routes. References := (Implementing Cisco Application Centric Infrastructure Official Cert Guide)

To allow only the return traffic to be redirected to the service node when the load balancer does not perform source NAT, we need to configure a Policy-Based Redirect (PBR). Here’s how it can be achieved:

Create a Contract:

Create a contract linked to the common/default filter. This contract will define the communication rules between the client endpoint and the server endpoint.

Configure L4-L7 Device:

Create an L4-L7 device with the function type set to “GoThrough.” This device will be used to redirect traffic to the service node.

Create a Policy-Based Redirect Policy:

Set up a Policy-Based Redirect (PBR) policy.

Specify the L3 Destination as the load balancer’s inside IP/MAC address.

Ensure that the L4-L7 Policy-Based Redirect Policy has the “GoThrough” function type.

Create a Service Graph Template:

Define a service graph template that references the previously created contract and L4-L7 device.

Apply the service graph template to the relevant connectors.

Connector Configuration:

On the consumer connector, reference the L4-L7 Policy-Based Redirect Policy.

On the provider connector, also reference the L4-L7 Policy-Based Redirect Policy.

By following this configuration, only the return traffic (from the server to the client) will be redirected to the service node, ensuring proper load balancing and traffic management.

References:

Implementing Cisco Application Centric Infrastructure Official Cert Guide

 In Cisco ACI, the spines suppress STP BPDUs to prevent them from being forwarded to other pods. This behavior ensures that the ACI fabric operates efficiently without relying on STP for loop prevention.

References := Cisco APIC Layer 2 Networking Configuration Guide, Release 5.2(x)

 For unrestricted communication between multiple EPGs within a VRF, setting them as preferred group members is essential for scalability. Option B, “Enable Preferred Group Member under the EPG Collection for VRF section,” allows all EPGs within this collection to communicate without restrictions by default. Option D, “Set the EPGs that require unrestricted communication between each other as preferred group members,” designates these groups for unrestricted intercommunication. References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

Using an application-centric approach in Cisco ACI means that multiple VLANs and/or multiple EPGs can be grouped under one bridge domain. This approach aligns network constructs with application requirements, enabling more efficient and flexible network configurations.

References := Network Centric to ACI Centric Migration - Cisco

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 The output shows details of tunnel 6 within a Cisco ACI fabric. The transport protocol is listed as “isvlan,” which is typically associated with the GRE protocol in Cisco ACIterminology. GRE, a tunneling protocol developed by Cisco, encapsulates various network layer protocols inside virtual point-to-point links over an IP internetwork. References: Implementing Cisco Application Centric Infrastructure Official Cert Guide

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 In Cisco ACI fabric, when a Layer 2 unknown unicast packet is encountered, the fabric does not drop the packet. Instead, it uses a flooding mechanism to ensure that the packet reaches its potential destination. This is achieved by utilizing the VRF (Virtual Routing and Forwarding) Outer Multicast Group ID associated with the Bridge Domain (BD) to which the unknown destination MAC address belongs. By doing so, Cisco ACI ensures that all endpoints within the BD have an opportunity to receive and process the packet if they are indeed the intended recipient. References: Implementing Cisco Application Centric Infrastructure Official Cert Guide

Protocol Independent Multicast sparse mode (PIM-SM) is designed for efficient routing to multiple receivers in a multicast group across an inter-pod network (IPN). PIM sparse mode is best suited for environments where receivers are dispersed because it allows for explicit join messages to control the flow of traffic. This makes it ideal for scenarios where broadcast, unknown unicast, and multicast flooding between Cisco ACI pods is required. References := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

For fabric discovery to be successful for the nodes in Pod 2, the engineer should configure POD 2 Data Plane TEP under the Pod Connection Profile. This action establishes the necessary data plane tunnel endpoint for communication between the pods. References := Troubleshoot ACI Fabric Discovery - Multi-Pod Discovery - Cisco, Which action should be taken for fabric discovery to be successful for…

 In a Cisco ACI Multi-Site setup, it’s important to configure the ISN interfaces to handle the encapsulation overhead introduced by the multi-site architecture. Option C is typically the correct choice because it includes:

A subinterface with a specific VLAN ID for traffic segregation.

An increased MTU size to accommodate the extra bytes added by encapsulation.

The correct VRF for inter-site communication.

OSPF configuration for dynamic routing between sites.

References: = Implementing Cisco Application Centric Infrastructure Official Cert Guide

To support an application that is sensitive to latency and jitter, it is crucial to ensure that the Quality of Service (QoS) levels within the ACI fabric and the Inter-Pod Network (IPN) QoS policies are aligned. This alignment will help in maintaining consistent handling of the DSCP values set by the application (AF31 and CS6) as the packets traverse across the two ACI pods. By aligning the QoS levels and policies, the application’s packets are less likely to experience delays or drops, thus preserving the required performance levels for the application’s optimal functionality.

To address resource overconsumption on a border leaf switch, migrating L3Outs to another switch can help distribute the load and reduce strain on the affected switch.

References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

 Deploying a new Cisco ACI Multi-Pod setup involves configuring the TEP pool of the new pod to be routable across the IPN (B) and increasing the interface MTU on all IPN routers to support VXLAN traffic (D). Configuring anycast RP (A) and MP-BGP on IPN routers © are not specific actions for deploying a Multi-Pod setup. Connecting all spines to the IPN (E) is not a required action for deployment3. References := (ACI Multi-Pod White Paper

To limit IP address learning in BD1 when VM1 is incorrectly attached to a PortGroup, enabling the Enforce Subnet Check is the correct action. This feature ensures that only IP addresses belonging to the defined subnets under the bridge domain are learned, preventing incorrect IP data from being disseminated across the network. References := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

 In Cisco ACI fabric, STP BPDUs are flooded in the bridge domain VLAN. This allows the BPDUs to be propagated throughout the fabric, maintaining the STP topology2.

References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

To redirect HTTP traffic between an EPG client and EPG server through a Cisco ASA firewall in a Cisco ACI environment, a contract filter must be configured to allow both ARP and HTTP. ARP is essential for IP to MAC address resolution, which is necessary for layer 2 communications within the same subnet or across subnets when routing is involved. The HTTP filter ensures that only HTTP traffic is redirected to the firewall for inspection or policy enforcement. References: Implementing Cisco Application Centric Infrastructure Official Cert Guide

In Cisco ACI Multi-Pod, when ARP flooding is enabled, broadcast traffic within a bridge domain is managed by associating a multicast address to the bridge domain. The broadcast frames are then forwarded within the pod and across the Inter-Pod Network (IPN) using this multicast address.

References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

In the given scenario where CDP is disabled, LLDP is enabled, and LACP is in Active mode between Cisco UCS FIs and Cisco ACI leaf switches for the DVS setup, the compatible discovery protocol would be LLDP since it’s already enabled. As for load-balancing mechanisms with this setup: MAC Pinning can be used without relying on any link discovery protocol like CDP or LACP; hence option B is valid. Option F suggests usingLACP in Passivemode, whichcould complement the existing Active mode on other devicesto establishan LACP negotiation successfully. References: =Implementing Cisco Application Centric Infrastructure Official Cert Guide

 To advertise the 172.16.2.0/24 network learned from L3Out OSPF out of the fabric via EBGP, a subnet must be created within the L3Out’s External EPG and marked as “Shared Route Control Subnet.” This setting allows the route to be advertised to external routers through EBGP.

References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

 When Leaf 1002 receives a packet from a host attached to Leaf 1001, it learns the MAC address of the source from Leaf 1001. Additionally, Leaf 1002 learns the IP address of the source.

References := Cisco APIC Layer 2 Networking Configuration Guide, Release 5.2(x)

The topology change notification (TCN) in Spanning Tree Protocol (STP) triggers a flush of the MAC address table. When a leaf node receives a TCN, it flushes the MAC address entries associated with the VLANs affected by the topology change. In this case, since the TCN is related to VLAN 101, the ACI fabric will flush all endpoints associated with VLAN 101 in bridge domain BD10123 on the leaf node.

The Endpoint Group (EPG) scope is the correct choice to meet the requirements for the e-commerce software in a Cisco ACI fabric. By selecting the EPG scope, contracts can be reused within the same Virtual Routing and Forwarding (VRF) context, reducing the overall number of contracts. Additionally, it ensures that the e-commerce software communicates only with software EPGs that are part of the same Application Network Profile (ANP), while preventing communication with applications in different ANPs. References := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

To facilitate communication between EPG1 in VRF1 and External EPG in VRF2, the following actions are necessary:

Enable Shared Route Control Subnet: This allows subnets to be shared across different VRFs, which is essential for inter-VRF communication.

Enable External Subnets for External EPG: Activating this makes the subnets within the External EPG routable to external networks.

Enable Import Route Control Subnet: This enables the importation of routes from L3Out into the VRF, permitting connectivity between different VRFs.

These steps ensure that routing and security policies are correctly implemented to permit traffic flow between EPG1 and External EPG across distinct VRFs.

References: Implementing Cisco Application Centric Infrastructure Official Cert Guide

ARP flooding should be disabled on a bridge domain when the default gateway for endpoints is on an external device instead of a Cisco ACI bridge domain SVI. This is because ARP flooding allows for the resolution of IP addresses to MAC addresses within the bridge domain. When the default gateway is external, enabling ARP flooding can lead to unnecessary broadcast traffic on the network, as the ARP requests will not be contained within the ACI fabric. Disabling ARP flooding ensures that ARP requests are handled by the external device serving as the default gateway1234.

References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

When traffic to certain endpoints is dropped in a Cisco ACI fabric configured with hardware proxy, setting the L2 Unknown Unicast option to Flood for Layer 2 switched traffic can prevent this problem. This mode allows unknown unicast traffic to be flooded within the bridge domain, rather than being sent to the spine proxy and potentially discarded if the destination is unknown5.

References := Solved: Unknown Unicast in ACI Fabric - Cisco Community

The best practices for configuring NIC teaming load balancing for Cisco UCS B-Series blades connected to Cisco ACI leaf switches involve enabling LACP (Link Aggregation Control Protocol) in active mode and enabling MAC pinning.

LACP active mode (option B) allows for the automatic bundling of several physical links into a single logical link, providing redundancy and increased bandwidth. This mode actively tests the link to ensure its functionality, which is essential for maintaining a stable connection.

MAC pinning (option E) is a method that assigns a virtual machine’s MAC address to a specific uplink. This ensures consistent forwarding paths for traffic within the same session, which is crucial for avoiding potential traffic distribution issues that could arise from dynamic changes in the network topology.

Creating vPC+ (option A) and vPC (option D) are not recommended as they are related to virtual port channels, which are not applicable in this scenario.PAgP (Port Aggregation Protocol) (option C) is Cisco’s proprietary protocol similar to LACP, but it is not the recommended practice in this context.

References :=

Implementing Cisco Application Centric Infrastructure Official Cert Guide

Cisco’s documentation on UCS B-Series Teaming Bonding Options

Enabling ARP flooding is necessary when VMs are migrated from a pre-existing network to Cisco ACI and their gateways remain in the legacy setup. This allows the ACI fabric to learn about silent hosts that do not initiate communication, ensuring that the migrated VMs can communicate with all hosts in the network, including those that are silent.

Cisco ACI handles MSTP TCN frames by flushing local endpoints in the affected EPG to prevent stale entries. For MST BPDUs to traverse the ACI fabric, a dedicated EPG for the native VLAN with static bindings is required for MSTP-enabled external switches. References := (Implementing Cisco Application Centric Infrastructure Official Cert Guide)

Removing pre-existing Fibre Channel over Ethernet (FCoE) configurations from Nexus devices is necessary to ensure compatibility with Cisco ACI mode. FCoE configurations are not supported in ACI mode, and their presence can hinder the migration process2.

When a host connected to a Cisco ACI fabric leaf switch sends an ARP request, the ingress leaf switch uses a broadcast transmission method to send the ARP requests. This is because ARP requests are meant to discover the MAC address associated with a specific IP address within the same network broadcast domain. The ingress leaf switch does not know the destination MAC address, so it broadcasts the ARP request to all devices within the broadcast domain1.

References := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

 To enable communication between the subnets 192.168.1.0/24 and 172.18.1.0/24 using Cisco ACI fabric, it is necessary to configure the subnets appropriately. For option B, setting 172.18.1.0/24 as an External subnet for an external EPG under L3out_A allows it to be recognized as part of an external network, facilitating communication with other networks within the ACI environment. Similarly, for option D, configuring 172.18.1.0/24 with the Export Route Control scope under L3out_B ensures that this route is advertised out of L3out_B, allowing it to reach other network segments, including those connected via L3out_A where the subnet 192.168.1.0/24 resides. These configurations are crucial for proper routing between these two distinct subnets across the Cisco ACI fabric.

References := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

In a Cisco ACI Multi-Pod deployment, the spine switches within a pod should not be directly connected to the spine switches in another pod. Instead, they should be connected to an IPN (Inter-Pod Network) device that provides Layer 3 IP connectivity between the pods. This setup allows for the extension of the ACI fabric across multiple locations while maintaining a single logical fabric. The IPN device can be a router or a switch with Layer 3 capabilities that can handle the necessary routing protocols and encapsulation methods required for Multi-Pod communication. References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

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