Understanding VXLAN (Virtual eXtensible LAN) Technology
VXLAN is a Layer 2 over Layer 3 encapsulation protocol designed to extend Layer 2 domains across routed networks using MAC-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 uses MAC-in-UDP encapsulation, meaning that the original Ethernet 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 as regular UDP traffic in the underlay network.
* Intermediate routers or switches DO NOT need to support VXLAN, as they only forward UDP packets based on the outer IP headers.
* Only VTEP devices must support VXLAN because they handle encapsulation/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 routes VXLAN packets using outer 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 in campus networks to provide both Layer 2 bridging and Layer 3 routing across different locations.
Real-World Application:
* Data Center Networks: VXLAN is widely used for multi-tenant network segmentation in cloud environments.
* Enterprise Campus Networks: Enables seamless Layer 2 and Layer 3 connectivity across different buildings or locations.
# Reference: Huawei HCIE-Datacom Guide - VXLAN Deployment and Forwarding Principles