The exhibit shows a network topology where Switch-1 and Switch-2 are part of a Virtual Switching Extension (VSX) fabric, and the router runs OSPF on LAG 100, which is a Layer 3 LAG. The question asks how to control how core-to-access traffic is forwarded, which means how the router chooses between the two links to Switch-1 and Switch-2. To force the router to use both links, ensuring that active gateway is enabled on LAG 100 on both Switch-1 and Switch-2 is not the correct solution. Active gateway is a feature that allows both VSX members to act as the default gateway for downstream devices, using a common virtual MAC address. Active gateway does not affect how upstream devices, such as the router, forward traffic to the VSX members1. To force the router to use both links, the correct solution is to configure equal-cost multi-path (ECMP) in OSPF on the router. ECMP is a feature that allows a router to load balance traffic across multiple paths with the same cost. ECMP can be configured using the maximum-paths command and specifying how many equal-cost paths the router should use2. Therefore, this does not correctly explain how to control how core-to-access traffic is forwarded.

Deploy Aruba CX 6300 switches as data center spine switches is not a best practice when positioning ArubaOS-CX switches in data center networks. The Aruba CX 6300 switches are designed for data center leaf roles, and they provide high density, low latency, and advanced features such as VSX and EVPN. The Aruba CX 83xx switches are more suitable for data center spine roles, and they provide high performance, scalability, and resiliency1.

Virtual Extensible LAN (VXLAN) provides millions of IDs to scale for the needs of a multi-tenant environment is a way that a data center technology can help meet requirements for multi-tenancy. Multi-tenancy is the ability to provide logical separation and isolation of network resources for different tenants or customers on a shared physical infrastructure. VXLAN is a feature that provides Layer 2 extension over Layer

Priority Flow Control (PFC) is a feature of ArubaOS-CX that eliminates packet loss due to congestion on a network link1. PFC uses IEEE 802.1Qbb standard to pause traffic on a per-priority basis1. PFC can be configured to operate in symmetric or asymmetric mode1. Symmetric mode applies PFC to both the receiving and sending of pause frames1. Asymmetric mode applies PFC to either the receiving or sending of pause frames1. To configure PFC on an interface, you need to enable flow control with a priority value and configure a DCBX application priority on the interface1. A DCBX application priority maps a traffic class to a priority group and enables the switch to negotiate PFC parameters with the peer device1. Therefore, this is a requirement for implementing PFC on an ArubaOS-CX switch interface, and the correct answer is yes. For more information on PFC and DCBX, refer to the Aruba Data Center Network Specialist (ADCNS) certification datasheet2 and the QoS Guide for your switch model1.