What does VXLAN stand for?
VXLAN stands for Virtual Extensible LAN. Encapsulates Layer 2 frames inside UDP (port 4789) so a virtual segment can stretch across routed data center networks. Its 24-bit identifier allows about 16 million segments, against 4,094 usable 802.1Q VLANs. Common in cloud and virtualized environments.
VXLAN stretches a layer 2 network across a layer 3 network. A device called a VTEP takes an Ethernet frame, wraps it in a UDP packet (destination port 4789) and sends it across the routed network to the VTEP at the other end, which unwraps it. Each virtual network is identified by a 24-bit VXLAN Network Identifier, which allows about 16 million segments where the 12-bit VLAN ID allows 4,094. Data centres use it so that virtual machines in different racks, or at different sites, can sit in the same subnet, and so that many tenants can be kept apart.
VXLAN in practice: an example
A cloud provider hosts thousands of customers, each expecting private networks of its own. With VLANs it would run out at 4,094. With VXLAN each customer network gets its own identifier, and a virtual machine moved to a host in another row keeps its IP address, because the VTEPs of the two hosts tunnel its segment between them over the routed network.
What VXLAN is confused with
VXLAN vs VLAN: what is the difference?
A VLAN separates traffic inside a switched network with a 12-bit tag and ends at a router. VXLAN carries Ethernet segments inside UDP across routers and uses a 24-bit identifier. At the edge, VXLAN segments are commonly mapped to VLANs. What VLAN stands for
VXLAN vs VPN: what is the difference?
A VPN encrypts traffic between sites or users. VXLAN is an encapsulation, not encryption: it extends a segment but does not by itself protect the data. What VPN stands for
Which exams cover VXLAN?
VXLAN is on the official CompTIA acronym list for one of the four exams covered here.
- Network+ N10-009: 1.0 (Networking Concepts).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. A data centre operator needs more than 4,094 isolated layer 2 segments on a routed spine-and-leaf network. Which technology is designed for this?
- VXLAN
- 802.1Q trunking alone
- Spanning Tree Protocol
- Port mirroring
Show the answer
A. VXLAN. VXLAN's 24-bit identifier allows about 16 million segments, and its UDP encapsulation crosses the routed network. 802.1Q stops at 4,094 VLANs.
2. Which transport and port does VXLAN encapsulation use by default?
- UDP 4789
- TCP 443
- UDP 53
- TCP 22
Show the answer
A. UDP 4789. RFC 7348 gives UDP destination port 4789 for VXLAN. A firewall between tunnel endpoints has to allow it.
Sources: RFC 7348: Virtual eXtensible Local Area Network (VXLAN). The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 12 November 2026.