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

 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 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

The L2 Stretch feature allows for the extension of a Layer 2 network across multiple sites without changing the IP addressing scheme, which satisfies the requirement for starting an application at a DR site without re-IPing servers. Disabling inter-site BUM (Broadcast, Unknown unicast, and Multicast) traffic prevents broadcast storms between sites while still allowing IP mobility, meeting both specified criteria. References := (Implementing Cisco Application Centric Infrastructure Official Cert Guide)