300-630 Exam Dumps : Implementing Cisco Application Centric Infrastructure - Advanced (DCACIA)

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.

To ensure the Cisco ACI fabric adheres to strict security protocols and only learns endpoints from configured subnets on a bridge domain, the “Enforce Subnet Check” feature must be enabled. This feature restricts endpoint learning to IP addresses belonging to the subnets defined in the bridge domain associated with the endpoint’s VLAN, enhancing security by preventing learning of endpoints from unconfigured subnets. 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