300-540 Dumps With Exact Questions and Answers

In a cloud-scale or data center–scale environment,Virtual Extensible LAN (VXLAN)is used as anoverlay technologyto transportLayer 2 segments over a Layer 3 underlay network. VXLAN encapsulates Layer 2 Ethernet frames inside UDP/IP packets, allowing broadcast, unknown unicast, and multicast (BUM) traffic and tenant Layer 2 domains to be extended across a routed IP fabric.

Key points aligned with Cisco Service Provider Cloud Infrastructure design principles:

VXLAN creates aLayer 2 overlay on top of a Layer 3 underlay.

TheVXLAN Network Identifier (VNI)provides a much larger segmentation space than traditional VLANs, enabling multi-tenancy at cloud scale.

Because the underlay is pure Layer 3 (IP routed fabric), VXLAN allows you tointerconnect Layer 2 segments between leaf switches or data centers over an IP/MPLS backbonewithout relying on large Layer 2 domains in the physical network.

Why the options evaluate as follows:

Option A: extends Layer 2 segments across the underlying Layer 3 infrastructure✅This is the core benefit of VXLAN in cloud-scale designs. VXLAN encapsulates Layer 2 frames intoIP/UDP headers, allowing isolated Layer 2 segments (per VNI) to be stretched across a routed IP network. This enables:

Multi-tenant Layer 2 connectivity across a distributed cloud fabric

Mobility of virtual machines or containers while keeping same IP/MAC addressing

Use of an IP-based leaf–spine or service provider underlay for scalability and resiliency

Option B: extends Layer 3 segments across the underlying Layer 2 infrastructure❌This is the opposite of what VXLAN does. VXLAN is explicitlyL2-over-L3, not L3-over-L2. Extending pure Layer 3 segments over Layer 2 is not the VXLAN use case.

Option C: reduces spanning-tree complexity across the Layer 2 infrastructure⚠️(Partially related but not the primary or direct benefit)In modern designs, the underlay isLayer 3 routed, and VXLAN overlays provide logical Layer 2 segments. This designavoids dependence on spanning tree in the fabric, whichindirectlyreduces STP complexity. However, the fundamental, exam-relevant benefit isL2 extension over L3, so C is not the best or most accurate answer compared to A.

Option D: eliminates the need for a Layer 3 underlay in the service provider infrastructure❌VXLAN absolutelyrequiresan IP (Layer 3) underlay for transport. VXLAN tunnels are built over a routed infrastructure (leaf–spine, MPLS/IP core, etc.). It does not remove the need for Layer 3; it depends on it.

Comprehensive and Detailed Explanation

Cisco NFVIS logging levels (from lowest to highest):

critical

error

warning

info

debug←highest verbosity

To capture maximum diagnostic detail, engineers must enabledebuglogging on theoperational log type, which records system activity and runtime behavior.

Thus the correct command is:

system set-log logtype operational level debug

This provides the deepest troubleshooting visibility.

In an NFV environment following Cisco NFV Infrastructure and ETSI MANO architecture, the onboarding workflow for VNF deployment follows this high-level order:

Define VNF descriptors (VNFD and NSD)– Includes implementation details and service definitions.

Prepare virtual machine resources– Flavor, image, CPU/memory/storage, and placement.

Define the NFV network– This step builds the underlay/overlay connectivity needed for the VNF.– It includes virtual network creation, interfaces, VLs (Virtual Links), connection points, and mapping into OpenStack (Neutron networks, subnets, ports).– No VNF can be deployed until the NFV service networks (management, control, data, HA) are defined.

Apply Day-0 configuration– Bootstrapping/initial config.

Apply Day-1 operational characteristics– Routing, services, policies.

Configure operational monitoring (KPIs)– Performance and fault measurements.

Since the question states“after the VM resources are prepared”, the next mandatory stage is defining the virtual network connectivity on which the VNFs will operate.