Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 430)

VXLAN gateway overview
Virtual Extensible Local Area Network (VXLAN) is an overlay technology to create a logical Layer 2
network on top of an Layer 3 IP network.
Addressing the need for overlay networks in Layer 2 and Layer 3 data center networks that support
multi-tenant environments, VXLAN functions as a framework to create a Layer 2 logical network over
the existing Layer 3 infrastructure. In this way, VXLAN addresses the scalability requirements of cloud
computing.
VXLAN extends the VLAN address space by adding a 24-bit segment ID called VXLAN Network
Identifier (VNI) and enables 16 million VXLAN network segments. The VNI in each frame segregates
individual logical networks, allowing millions of individual Layer 2 VXLAN segments to coexist on a
common Layer 3 network. Each {Port, VLAN} pair is mapped to a unique VNI to extend the Layer 2
VLAN segment to a remote location.
FIGURE 96 VXLAN gateway
VXLAN Ethernet frame encapsulation
VXLAN uses a tunneling method to carry the Layer 2 overlay network traffic over the Layer 3
networks. Communication is established between two tunnel endpoints called Virtual Tunnel
Endpoints (VTEPs). VXLAN is a MAC Address-in-User Datagram Protocol (MAC-in-UDP)
encapsulation, which encapsulates MAC frames at Layer 2 into a Layer 3 UDP header with an outer
VXLAN gateway overview
430 FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide
53-1003086-04