300-420 Exam Dumps : Designing Cisco Enterprise Networks

L2VPN is the correct solution because the customer requires point-to-point connectivity while preserving existing VLAN infrastructure. Cisco describes Layer 2 VPN services as emulating Layer 2 connectivity across a provider IP or MPLS backbone, commonly through Ethernet pseudowires or VPWS. This allows sites such as dispersed data centers and a colocation facility to exchange Ethernet frames as if they were directly connected at Layer 2. The design is especially useful when data center synchronization, backup workflows, or application dependencies require VLAN continuity or minimal changes to existing addressing and routing. L3VPN would provide routed connectivity and VRF separation, but it would not preserve the VLAN-based service model. GRE would add an overlay tunnel but would not natively provide provider-managed Layer 2 service. DMVPN is designed for scalable Layer 3 IPsec/GRE overlays between branches, not for VLAN extension or point-to-point data center interconnect. Reference topics: L2VPN, VPWS, Ethernet pseudowire, VLAN extension, data center interconnect, WAN service design.

The selected command is correct because the port is already restricted to one manually learned MAC address, and the requirement is to let the switch dynamically learn the connected endpoint while retaining port-security control. In Cisco Catalyst port security, a static secure MAC address is manually configured, while a sticky secure MAC address is dynamically learned and then added to the running configuration. This design is useful on access ports where the administrator wants the operational convenience of dynamic learning but still wants the switch to enforce the maximum secure-address limit. Once the endpoint MAC is learned, subsequent frames from different source MAC addresses can trigger the configured violation action, such as protect, restrict, or shutdown. The command must therefore enable sticky learning on the secured interface rather than simply changing the maximum, disabling port security, or configuring a normal switching feature. This is an access-layer security function, not a routing or QoS function. Reference topics: Catalyst port security, secure MAC addresses, sticky learning, access port hardening, Layer 2 campus design.

The primary capability of IaaS in this question is elastic scaling: the ability to increase or decrease infrastructure resources based on demand. In Infrastructure as a Service, the provider offers compute, storage, and network resources as an on-demand service, while the customer deploys operating systems and applications on top of that infrastructure. Cisco cloud material describes this model as providing scalable IT capacity without requiring the organization to own all physical assets. Option C is the best answer because dynamic capacity adjustment is a fundamental cloud capability and a major reason enterprises choose IaaS for variable workloads. Option B is a valid business benefit because consumption-based billing can reduce cost, but the question asks for a primary capability, not the pricing model. Option D describes automation and orchestration, which support cloud operations but are not the specific capability being tested. Option A is closer to hybrid-cloud workload mobility and is not guaranteed by IaaS alone. Reference topics: cloud service models, IaaS, elasticity, scalable compute, on-demand resource provisioning.