Understanding VXLAN (Virtual eXtensible LAN) Technology
VXLAN is aLayer 2 over Layer 3 encapsulation protocoldesigned toextend Layer 2 domains across routed networksusingMAC-in-UDP encapsulation.
????Key VXLAN Components:
VTEP (VXLAN Tunnel Endpoints):These encapsulate and decapsulate VXLAN packets.
Underlay Network:The routed IP network that forwards VXLAN packets (does not require VXLAN awareness).
Overlay Network:The logical Layer 2 segments tunneled over VXLAN.
Analysis of the Answer Choices:
✅A. VXLAN uses MAC-in-UDP encapsulation to encapsulate Ethernet packets into UDP packets and thereby extend Layer 2 networks.
Correct:VXLAN usesMAC-in-UDP encapsulation, meaning that the originalEthernet frame is placed inside a UDP packet, allowing Layer 2 networks to extend over IP-based networks.
❌B. When VXLAN is deployed, in addition to devices at both ends of a VXLAN tunnel, intermediate forwarding devices are also required to support VXLAN. Otherwise, VXLAN packets cannot be forwarded.
Incorrect:VXLAN packets are forwarded asregular UDP trafficin the underlay network.
Intermediate routers or switches DO NOT need to support VXLAN, as theyonly forward UDP packetsbased on theouter IP headers.
Only VTEP devices must support VXLANbecause they handleencapsulation/decapsulation.
✅C. VXLAN packets are forwarded through routes on the underlay network, and the MAC address of the terminal in the inner data frame is not considered during underlay forwarding.
Correct:The underlay network routesVXLAN packetsusingouter IP headers(VTEP IP addresses),not the inner MAC address.
✅D. VXLAN can be deployed on campus networks to implement Layer 2 and Layer 3 communication.
Correct:VXLAN is commonly used incampus networksto provide bothLayer 2 bridgingandLayer 3 routingacross different locations.
Real-World Application:
Data Center Networks:VXLAN is widely used formulti-tenant network segmentationin cloud environments.
Enterprise Campus Networks:Enablesseamless Layer 2 and Layer 3 connectivityacross different buildings or locations.
✅Reference:Huawei HCIE-Datacom Guide – VXLAN Deployment and Forwarding Principles
