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Static VXLAN with IPv4 and IPv6 Underlay

Juniper Cloud-Native Router supports static VXLAN to extend Layer 2 networks over a Layer 3 IP underlay through manually configured VXLAN tunnels.

Static (Virtual extensible LAN) VXLAN enables organizations to extend Layer 2 networks over a Layer 3 IP underlay through manually configured VXLAN tunnels. The VXLAN Identifier (VNI) and VXLAN Tunnel Endpoint (VTEP) configurations are configured manually, instead of relying on EVPN control plane protocols to dynamically discover MAC-to-VTEP mapping. Static VXLAN is ideal for small-scale environments, air-gapped systems, edge computing nodes, and deployments that require predictable behavior and simpler operational model. Static VXLAN offers key advantages including lower complexity, reduced resource consumption, and easier deployment in minimalistic infrastructures. However, it also requires greater diligence in configuration and operational monitoring to prevent inconsistencies and outages. Since dynamic advertisement and auto-discovery are not available, all failover and redundance mechanisms must be carefully planned. You can read more about static VXLAN in the Junos documentation.

Static VXLANs is often implemented in multiple edge, enterprise, and telecom usecases, such as in 5G networks for slice isolation between DU and CU, to extend enterprise LAN across different geographies, and remote branch deployments.

Configuration

Static VXLAN configuration includes multiple VTEPs, each configured with a set of VNIs and corresponding remote VTEPs. There is no central controller or signaling mechanism. Traffic flows based on static mapping and local MAC learning. You must configure the following elements on the Cloud-Native router to bring up static VXLAN:

  • Configure IP loopback interface or source interface for VXLAN

  • Assign a unique VNI for each logical Layer 2 domain

  • Ensure reachability for all configured remote VTEPs

  • Enable VLAN tagging or bridge domains to map to VNIs

  • Set the MTU in the deployment helm chart to accommodate VXLAN header overhead

    Note: Cloud-Native Router must be deployed in L2 or L2-L3 mode to support bridge domains.

You must perform static VXLAN configuration using a Configlet. Review Customize JCNR Configuration for more details. A sample configlet is provided below:

You can also configure Layer 2 circuit (L2CKT) with static VXLAN, such that the Layer 2 control traffic can tunnel over a VXLAN overlay network by manually configuring the tunnel endpoints. The L2CKT stiching requires lt interface pairing. One lt pair is a part of the bridge domain with encapsulation ethernet-bridge and the other participates in the L2 circuit, with encapsulation ethernet-ccc. A sample configlet is provided below:

Verification

You can verify the static VXLAN configuring using the vRouter CLI:

  • Verify the interface list corresponding to the lt interfaces:

  • Verify the VXLAN table using the vxlan --dump command:

  • Verify the bridge domain table using the bd --dump command:

  • Verify the routes in the vRouter bridge table for VRFs 1 and 2 corresponding to the static-vxlan and vswitch routing instances defined in the configuration: