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

When allowing routes learned from one L3Out to be advertised out another L3Out, the Export Route Control Subnet should be enabled, and Aggregate Export should also be enabled. This configuration allows the necessary routes within the specified CIDR block to be aggregated and advertised out, facilitating efficient route advertisement without the need for an explicit list of all routes.

References : Implementing Cisco Application Centric Infrastructure Official Cert Guide

PBR Node Tracking :

Purpose : It is used to monitor the health and availability of endpoints within an Endpoint Group (EPG).

Functionality : When configured, it allows for real-time health checks and traffic redirection based on endpoint status and network conditions.

Benefits : Ensures traffic is directed to healthy endpoints, maintaining application performance and availability.

 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 complete 1 2 3 .

References  := Implementing Cisco Application Centric Infrastructure Official Cert Guide

In a Cisco ACI Multi-Pod deployment, configuring the subnet as shared is crucial to prevent duplicate IP/MAC entries across pods. This allows endpoints in different pods to be part of the same subnet without causing IP/MAC duplication issues, ensuring policy enforcement by the firewall cluster.  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 process 2 .

 For new nodes in a Cisco ACI Multi-Pod environment to be discoverable by existing APICs, DHCP relay needs to be enabled on the IPN devices’ links connected to the ACI spines. This allows the new nodes to obtain an IP address and be recognized by the APICs for integration into the fabric.

References  := Implementing Cisco Application Centric Infrastructure Official Cert Guide

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 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 detection 2 .

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

 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

In a Cisco ACI environment, STP BPDUs are not forwarded across the fabric. The ACI fabric is designed to operate without STP, using a policy-driven, multi-path Ethernet model for loop prevention. Thus, STP BPDUs from external switches are dropped by the ACI leaf switches.  References  := (Implementing Cisco Application Centric Infrastructure Official Cert Guide)

 In a Cisco ACI Multi-Site setup, the ISN (Inter-Site Network) connects different ACI sites. For efficient multicast traffic routing,  BIDIR-PIM  (Bidirectional Protocol Independent Multicast) is configured throughout the ISN, which is why option B is correct. Increasing the  ISN MTU  (Maximum Transmission Unit) to support the maximum MTU sent by endpoints is crucial to prevent packet fragmentation or loss, making option C correct.

Options A, D, and E are not typically required for an ACI Multi-Site setup. Direct connectivity between Spine switches and ISN routers, as mentioned in options A and D, is usually established through leaf switches. Option E, enabling IGMPv3 on ISN routers, is more relevant for managing multicast subscriptions within a single site.

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

 For a full mesh Cisco ACI Multi-Site architecture, configuring the BGP-EVPN Router-ID on each spine is essential.  This configuration ensures unique identification and proper routing of traffic within the overlay network 1

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)

 For the ISN implementation between Cisco ACI data centers using Multi-Site, OSPF must be configured on subinterfaces for dynamic routing, and BIDIR-PIM must be set up on all ISN routers for efficient bidirectional multicast traffic routing.  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.

Within Cisco ACI, when a Topology Change Notification (TCN) BPDU is received in a VLAN, the system flushes the endpoints for the associated encapsulation to ensure network stability.  Additionally, BPDU filter and BPDU guard can be configured on Cisco ACI leaf edge ports to protect against potential STP issues 2 .

To connect two nonsilient servers in active/standby mode to two ACI leaves, you should implement a virtual PortChannel (vPC) on the ACI leaves. vPC provides high availability and load balancing for server connections.

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

 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.

 In a scenario where an organization deploys active-active data centers with active-standby firewalls in each data center within a Cisco ACI Multi-Pod environment, maintaining traffic symmetry through firewalls is crucial for consistent security policy enforcement and avoiding asymmetric routing issues. Enabling Pod ID Aware Redirection allows for intelligent redirection of traffic based on pod identification numbers so that return traffic can be directed back through the same path it originated from, thus maintaining symmetry even in complex multi-pod deployments.  References : Implementing Cisco Application Centric Infrastructure Official Cert Guide

 When EPGs (Endpoint Groups) are stretched across sites, Layer 2 flooding is available across these sites. This allows for the extension of the Layer 2 domain and the sharing of broadcast, unknown unicast, and multicast traffic between EPGs at different locations.

References : = Implementing Cisco Application Centric Infrastructure Official Cert Guide

In an application-centric design, the creation of additional EPGs under one bridge domain is possible. This allows for greater flexibility in managing and segmenting network traffic for different applications or services within the same bridge domain.

References  :=  Network Centric to ACI Centric Migration - Cisco

 In a stretched bridge domain solution between Cisco ACI sites with Layer 2 flood enabled, spine head-end replication is utilized to forward Broadcast, Unknown unicast, and Multicast (BUM) traffic between the sites. This method leverages the spine switches at each site to replicate BUM traffic to other sites, ensuring that all endpoints within the stretched bridge domain can receive such traffic. This approach is chosen over ISN multicast replication because it simplifies the overall design and reduces bandwidth consumption on inter-site links by avoiding unnecessary duplication of BUM traffic.  References  := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

 To meet the requirements specified, two actions must be taken: B. Create a standard contract between EPG 51 and EPG 10 to explicitly allow communication between these two EPGs. A contract in Cisco ACI defines the communication policy between EPGs, and by creating a standard contract, specific communication can be permitted. E. Enable the Preferred Group option on EPGs 1 to 50 to allow communication within this group of EPGs. The Preferred Group feature in ACI allows all EPGs within the group to communicate with each other without the need for explicit contracts, while still enforcing contracts for communication with EPGs outside the group.  References  := Implementing Cisco Application Centric Infrastructure Official Cert Guide

 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 )

 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)

 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. IP data 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

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…

The protocol used for exchanging MAC/IP address information for endpoints between spine switches in different pods within a Cisco Multi-Pod solution is MP-BGPEVPN (Multiprotocol BGP Ethernet VPN). This protocol facilitates scalable communication between separate locations by allowing MAC/IP address information sharing across pods.  References  := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide )

Bidirectional Protocol Independent Multicast (Bidirectional PIM) is used between the inter-pod network (IPN) and spines within each pod in a Cisco ACI environment to allow broadcast traffic replication between pods. This protocol is designed to efficiently route multicast traffic in scenarios where the same data is being sent to multiple receivers, which aligns with the need for broadcast traffic replication in an interconnected multi-pod ACI architecture.  References  := ( Implementing Cisco Application Centric Infrastructure Official Cert 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