300-630 Practice Questions

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. Reference := ( 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.

Reference := Network Centric to ACI Centric Migration - 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. Reference := 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.

Reference: = 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.

Reference := Implementing Cisco Application Centric Infrastructure Official Cert Guide

The configuration set that accomplishes the goals of allowing communication between the external

subnet and internal EPG1, as well as leaking L30ut traffic into VRF named “VF1”, is option D: Export

Route Control Subnet Import Route Control Subnet Aggregate Shared Routes. This configuration

ensures that routes are properly exported from one entity and imported into another while

aggregating shared routes for efficient routing within the VRF “VF1”. It allows for controlled route

leaking which is necessary for communication across different entities within a Cisco ACI

environment. Reference := ( Implementing Cisco Application Centric Infrastructure Official Cert Guide

)

Enabling GARP EP Move Detection allows the Cisco ACI fabric to dynamically update the IP address

to use the MAC address of NIC2 when NIC1 goes offline. This feature is crucial for maintaining

network connectivity and ensuring that traffic continues to flow seamlessly through the standby

interface1.

To prevent inter-tenant communication while reusing the same contract, the contract should be

created in the user tenant with the scope set to VRF and then exported to other tenants. This

approach allows the contract to be shared across tenants while maintaining the isolation of each

tenant’s VRF. By setting the scope to VRF, the contract’s policies apply only within the context of the

specified VRF, thus preventing communication between tenants5678.

Reference := 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. Reference := (Implementing Cisco

Application Centric Infrastructure Official Cert Guide)

In a Cisco ACI environment, when an ARP request is initiated by VM1 for VM2 and VM2 is not known

within the ACI fabric, the leaf switch (Leaf 101) will forward the ARP request to a spine switch that

acts as a proxy VTEP. The spine switch will either respond to the ARP request if it knows VM2’s

location through the COOP database or will flood the ARP request within the fabric if VM2’s location

is unknown. Reference: Implementing Cisco Application Centric Infrastructure Official Cert Guide