Drag and Drop Question Match the topics with the underlying technologies (Options may be used more than once or not at all.) Answer:

Question

Exhibit

Options

• 1EVPN-VXLAN
• 2User Based Tunneling (UBT)
• 3Centralized Overlay
• 4Distributed Overlay
• 5Encapsulated in UDP
• 6Generic Routing Encapsulation (GRE)

Explanation

Drag-and-Drop Explanation: Networking Overlay Technologies

Note: The question text doesn't include the actual wording of items 1–6 (the draggable descriptions), only the correct target mappings. The explanation below is based on the defining technical characteristics of each target technology, which is what the items would describe.

Item 1 → EVPN-VXLAN

EVPN-VXLAN (Ethernet VPN over Virtual Extensible LAN) is a modern overlay fabric technology that uses:

• BGP as its control plane (EVPN) to distribute MAC/IP reachability
• VXLAN as its data plane encapsulation

Why here: Item 1 likely describes a technology that uses a BGP control plane for MAC/IP distribution across a campus or data center fabric. EVPN-VXLAN is the industry standard for scalable, distributed overlays with full BGP route advertisement.

Common misconception: Students confuse EVPN (the control plane) with VXLAN (the encapsulation method). They are paired but distinct - EVPN can theoretically run over other encapsulations, but VXLAN is the overwhelmingly standard pairing.

Item 2 → User Based Tunneling (UBT)

UBT is an Aruba-specific feature where client/user traffic is tunneled from an access switch to an Aruba gateway/controller based on user identity or role.

Why here: Item 2 likely describes a mechanism that redirects user traffic based on identity (role, VLAN, authentication state) through a tunnel to a central enforcement point - that's precisely what UBT does. It is not a general-purpose tunnel; it's user/role-aware.

Common misconception: UBT is often confused with standard GRE or VXLAN tunneling. The key differentiator is that UBT is user/policy-driven and Aruba-proprietary, not a generic L2/L3 encapsulation standard.

Item 3 → Centralized Overlay

Centralized Overlay means all user/client traffic is forwarded through a central controller or gateway, which handles routing, policy enforcement, and security.

Why here: Item 3 likely describes a deployment model where the overlay terminates at a single central point (e.g., an Aruba mobility controller). UBT and traditional tunnel-mode APs both implement centralized overlays.

Common misconception: Students assume "centralized" means physically co-located hardware. It actually refers to the traffic forwarding model - all data plane traffic is pulled to a central node regardless of physical location.

Item 4 → Distributed Overlay

Distributed Overlay means traffic is processed and forwarded at the edge (access layer), not tunneled to a central point. Each node (switch, AP) handles its own routing and forwarding locally.

Why here: Item 4 likely describes local switching, fabric-based forwarding, or edge routing without requiring a central controller in the data path. EVPN-VXLAN is the primary technology enabling distributed overlays in modern campus designs.

Common misconception: "Distributed" does not mean "unmanaged." Distributed overlays still have centralized management/control (e.g., via a controller or orchestrator), but the data plane is local. This is the key distinction from centralized overlay.

Item 5 → Encapsulated in UDP

VXLAN encapsulates Layer 2 Ethernet frames inside UDP packets (destination port 4789). This is VXLAN's defining transport characteristic.

Why here: Item 5 likely states something like "uses UDP as its transport encapsulation" - which is specifically true of VXLAN (and by extension EVPN-VXLAN). UDP was chosen for VXLAN to allow load balancing via ECMP using standard hashing on 5-tuple fields.

Common misconception: GRE (Item 6) is sometimes assumed to also use UDP. It does not - GRE uses IP protocol number 47 directly (no TCP/UDP). This is a frequent exam trap.

Item 6 → Generic Routing Encapsulation (GRE)

GRE is a point-to-point tunneling protocol (IP protocol 47) that wraps packets of one protocol inside another. It's stateless, simple, and widely used for tunnel connectivity between network devices.

Why here: Item 6 likely describes a tunneling protocol used for point-to-point connectivity, carrying multicast or routing protocol traffic, or providing a simple encapsulation layer without encryption. GRE is the classic answer for these use cases.

Common misconception: GRE is often confused with IPsec. GRE provides encapsulation only - no encryption or authentication. IPsec provides security. They are often combined (GRE over IPsec), but are separate protocols.

Summary Table

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