300-630 Implementing Cisco Application Centric Infrastructure - Advanced (DCACIA) Questions and Answers

 To limit both local and remote endpoint learning to instances where the source IP address belongs to a bridge-domain subnet in the VRF instance, the action that should be taken inside the Cisco APIC is to enable the “Enforce Subnet Check” feature. This configuration ensures that IP addresses outside the configured subnets for the bridge domain are not learned, preventing mis-learning of IP addresses that do not belong to the fabric12.

 The correct configuration to prefer the local Policy-Based Routing (PBR) node and redirect traffic to the remote pod PBR node in case of catastrophic failure is option D: location-based PBR, host route advertisement, and node tracking. Location-based PBR allows for the selection of a preferred path based on the location of the traffic source or destination. Host route advertisement enables specific routing information to be propagated throughout the network, which can be used to influence traffic flow. Node tracking provides a mechanism to monitor node status and reroute traffic if a node becomes unavailable due to failure. References := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

 To set up the link between the spine and the IPN device in a Cisco ACI Multi-Pod, the following actions should be taken: A. Enable MP-BGP routing to facilitate the exchange of routing information. B. Enable BIDIR-PIM protocol to support efficient multicast traffic forwarding. D. Enable OSPF routing to ensure dynamic routing between the spine and IPN devices.

When a packet is routed between two endpoints on different Cisco ACI leaf switches, the VXLAN VNID applied to the packet is the VRF (Virtual Routing and Forwarding) VNID. This VNID enables forwarding of the packet through tenant virtual routing and forwarding domains within the fabric34.

References := Cisco APIC Layer 3 Networking Configuration Guide, Release 3.x and later

To prevent MAC flapping on Cisco UCS Fabric Interconnects and ACI leaf switches, MAC Pinning should be selected for the VMM vSwitch Port Channel policy. This ensures consistent uplink usage for each virtual machine’s traffic, avoiding MAC address movement across multiple uplinks.

References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

Implementing an active-active firewall cluster stretched across separate pods with anycast services configured offers several advantages, one of which is that it allows for optimized routing within the Cisco ACI fabric. When anycast services are used, each pod can have its own anycast node (firewall instance), and due to routing preferences set within ACI’s spine switches, they will prefer their local pod’s anycast node for routing decisions. This preference enhances efficiency by reducing cross-pod traffic and improving response times since local spines direct traffic to their respective local pod’s anycast nodes. References: Implementing Cisco Application Centric Infrastructure Official Cert Guide

 Enabling endpoint loop protection is the action that prevents frequent MAC and IP address moves between different leaf switch ports. This feature helps to identify and mitigate loops within the network, which can cause these frequent address moves. By detecting and blocking the looped interfaces, it stabilizes the network and stops the address flapping.

 To allow communication between two application profiles that are configured in the same tenant but different VRFs, the contract scope must be set to ‘tenant.’ This is because the contract scope defines the level at which the contract is enforced. A ‘tenant’ scope means the contract applies to all application profiles within the same tenant, regardless of the VRFs they are in. This allows for the necessary route-leaking between the provider and consumer VRFs to enable communication between the application profiles.

Before associating a schema with a newly configured site in Cisco ACI Multi-Site Orchestrator, it’s essential to configure a provider. This establishes a communication link between the orchestrator and the sites, enabling proper deployment and management of objects across multiple sites.

 To prevent connectivity issues for EP1 when accessing an external L3Out network, it’s essential to enable IP data plane learning for the VRF and unicast routing in BD-BD2. IPdata plane learning allows dynamic endpoint learning within a VRF, ensuring accurate forwarding information for EP1. Unicast routing enables packet routing based on destination IP, facilitating proper traffic routing through the gateway.

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 Cisco ACI, to reassign a unique globally scoped pcTag to an Endpoint Group (EPG) that provides a global contract, one should configure subnets that are shared between VRFs (Virtual Routing and Forwarding instances) (Option C). This action allows subnets associated with an EPG to be shared across different VRFs while maintaining unique identifiers for application endpoint groups within the global scope of the fabric.

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

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)

To allow reachability to services outside of the Cisco ACI fabric while conserving TCAM resources, an engineer should use a contract insertion method where L30ut external EPGsact as providers and vzAny inside VRF acts as consumers. This configuration allows for communication from all EPGs within a VRF (represented by vzAny) to access external services through L30ut without having to create individual contracts for each service EPG, thus saving TCAM resources. References: Implementing Cisco Application Centric Infrastructure Official Cert Guide

 Migrating from Cisco NX-OS VXLAN to Cisco ACI fabric involves several considerations to minimize impact on workloads. Disabling bridge domain unicast routing while the default gateway remains in the VXLAN infrastructure ensures that the migration does not disrupt the existing traffic flow. This approach allows for a smoother transition by maintaining the current routing paths until the migration is complete123.

References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

The VXLAN source port adds entropy to the overlay packet forwarding by using a hash of the inner packet’s Layer 2, Layer 3, and Layer 4 headers. This entropy enables Equal-Cost Multi-Path (ECMP) routing, allowing for multiple parallel paths in the network, which increases bandwidth and redundancy2.

References := VXLAN Traffic Forwarding | VXLAN Packet Flow

For a new Cisco ACI Multi-Site Orchestrator (MSO) node to join an MSO cluster and ensure IP connectivity, it requires connectivity to the Cisco Application Policy Infrastructure Controllers (APICs) over the Out-of-Band (OOB) management network and the management IP of ESXi hosts where the controllers are deployed. The OOB management network allows the MSO node to communicate with the APICs for centralized management and policy control, while the management IP of the ESXi hosts provides the necessary connectivity for the virtual machine infrastructure where the MSO node is deployed123.

References := Cisco ACI Multi-Site Architecture White Paper, Cisco Multi-Site Deployment Guide for ACI Fabrics, ACI Multi-Site Architecture and Deployment - Cisco.

An application-centric design in Cisco ACI focuses on the application requirements and interactions between different application components. In this design, EPGs (Endpoint Groups) represent different application tiers, such as web, application, and database tiers. This approach allows for a more flexible and scalable network configuration that aligns with the application architecture, enabling policies to be applied based on the application’s needs rather than the network topology. References := Implementing Cisco Application Centric Infrastructure Official Cert Guide

 In a Cisco ACI Multi-Pod environment that is expanding, spine headend replication should be configured to ensure efficient forwarding of BUM (Broadcast, Unknown unicast, Multicast) traffic across the IPN (Inter-Pod Network). This configuration optimizes the control plane scaling and ensures that BUM traffic is handled effectively, maintaining network performance and stability.

References: Implementing Cisco Application Centric Infrastructure Official Cert Guide

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 establish intra-VRF communication between two EPGs deployed across different sites with different bridge domains, stretching the bridge domain and EPG components is necessary. Option D, “bridge domain,” and Option E, “EPG,” must be configured as stretched to facilitate communication across different sites within the same VRF. References:= Implementing Cisco Application Centric Infrastructure Official Cert Guide

When extending a Cisco ACI Multi-Pod setup to a Multi-Site implementation, configuring BIDIR-PIM in both the IPN (Inter-Pod Network) and ISN (Inter-Site Network) is necessary. This allows for efficient multicast traffic routing between multiple pods and sites.

References: = Implementing Cisco Application Centric Infrastructure Official Cert Guide

 To address loops detected from endpoints in a Cisco ACI fabric, the engineer should enable the rogue endpoint feature and set the Error Disabled Recovery Policy. This will allow the system to detect rogue endpoints causing loops and automatically recover the port if it was disabled due to the loop detection2.

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

The outer destination IP address in the VXLAN encapsulated packet for Layer 2 Broadcast, Unknown-unicast, and Multicast (BUM) traffic sent between two Cisco ACI sites is the Overlay Multicast TEP (Tunnel Endpoint). This address ensures efficient replication of BUM traffic across different sites in the ACI fabric.

References := Cisco APIC Layer 2 Networking Configuration Guide

 To advertise routes from border leaf switches to compute leaf switches in a shared services scenario, the shared L3Out should be defined in the common tenant. This allows all tenants to access the shared services provided by the L3Out. By configuring the L3Out in the common tenant, routes can be advertised to the compute leaf switches, ensuring that the services are available across the ACI fabric.

References: Implementing Cisco Application Centric Infrastructure Official Cert Guide

 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

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.

The integration of service nodes in transparent mode with a Cisco ACI Multi-Pod setup is achieved by using an active-standby firewall mode stretched across pods. This configuration ensures that the standby node takes over if the active node fails, providing high availability and seamless operation. References := Cisco ACI Multi-Pod and Service Node Integration White Paper

In the Cisco ACI fabric, to ensure that the IP address of Server S1 is learned and the IP addresses of BC1 and BC2 are not learned, one must limit IP learning to a specific subnet and suppress ARP responses from BC1 and BC2. By checking the “Limit IP learning to subnet” box (Option A), it ensures that only IPs within a defined subnet are learned, which would include Server S1’s IP but exclude BC1 and BC2 if they are outside of this subnet.Suppressing ARP response on BC1 and BC2 (Option D) prevents these devices from responding to ARP requests, which in turn prevents their IPs from being learned by other devices in the network. References := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

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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

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