What is an overlay solution that expands the Layer 2 network space across the WAN?

Question

Options

• AEVPN-VXLAN
• BIPsec
• CGRE
• DMC-LAG

• A
  76% (29)
• B
  5% (2)
• C
  16% (6)
• D
  3% (1)

Explanation

EVPN-VXLAN (A) is correct because it is specifically designed as an overlay technology that encapsulates Layer 2 frames within UDP packets, enabling L2 network segments to stretch across Layer 3 WAN infrastructure - effectively expanding the VLAN space far beyond the 4,094 limit by using a 24-bit VNI (Virtual Network Identifier) supporting ~16 million segments.

IPsec (B) is a security protocol for encrypting traffic over IP networks - it protects data in transit but does not extend Layer 2 domains or provide overlay tunneling for L2 expansion.

GRE (C) is a tunneling protocol that can carry various payloads across IP networks, but it lacks the scalability, control-plane intelligence (via BGP), and L2 MAC/ARP distribution capabilities that EVPN-VXLAN provides for modern data center and WAN use cases.

MC-LAG (D) is a Multi-Chassis Link Aggregation Group - a redundancy/bonding technology for combining links across two switches for high availability. It operates at L2 but is a local topology feature, not a WAN overlay solution.

Memory tip: Think "VXLAN = Virtual eXtensible LAN" - the word eXtensible tells you it extends (expands) the LAN (Layer 2) across distances, and EVPN is the control plane that makes it work at scale across the WAN.

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