VXLAN
VXLAN (Virtual Extensible LAN, RFC 7348) creates an L2 overlay over IP/UDP: an Ethernet frame is encapsulated in UDP with destination port 4789 and a VXLAN header containing the VNI. In Peresvet ST, the VXLAN layer is defined in a Library → Network Tunnels object and applied to traffic from the selected Data Plane plugin.
Table — VXLAN Layer Parameters
| Name | Description | Value |
|---|---|---|
| VNI | VxLAN Network Identifier (24 bits) | 1–16777215 |
| Local IP | Local VTEP IP (source in the outer IP header) | Address or start of a range |
| Remote IP | Remote VTEP IP (destination) | Address or start of a range |
| Source / Destination port | UDP ports for outer encapsulation | Destination is usually 4789 |
| Outer MAC policy | Outer-MAC policy | According to the interface/MAC object policy |
Packet Structure
┌──────────────────────────────────────────────────┐
│ Outer Ethernet Header │
├──────────────────────────────────────────────────┤
│ Outer IP Header │ ← Local VTEP → Remote VTEP
├──────────────────────────────────────────────────┤
│ Outer UDP Header │ ← Dest port: 4789
├──────────────────────────────────────────────────┤
│ VXLAN Header │ ← Flags + VNI
├──────────────────────────────────────────────────┤
│ Inner Ethernet / IP / L4 / L7 │ ← Plugin traffic
└──────────────────────────────────────────────────┘
VXLAN adds approximately 50 bytes of protocol headers. Account for the underlay MTU (1550 or jumbo). The outer UDP source port is normally selected with enough entropy for ECMP.
Relationship to the Control Plane: A separate VxLAN overlay for the control plane (VTEP and inner MAC) can be enabled on an interface in the Control Plane tree. Library profiles for Data Plane user traffic are configured here. Do not combine conflicting VLAN/VXLAN modes on one interface without validating the testbed.