Workloads attached to overlay segments typically communicate at layer 3 with physical devices outside of the NSX domain, through tier-0 gateways instantiated on NSX Edge. However, there are some scenarios where layer 2 connectivity is required between virtual machines in NSX and physical devices.
- Migration from physical to virtual, or virtual to virtual.
- Integration of a physical appliance that provides services to a segment, like an external load balancer.
- Connection to a database server that requires layer 2 adjacency to its virtual machine clients.
The NSX Edge bridge, like the gateway, is supported for long term deployments, even if it is often used as a temporary solution during migrations.
- Make sure that the NSX Edge is suitable for hosting the bridge service. The bridge adds a few constraints to the deployment of an edge in a VM form factor.
- Identify the NSX Edges that run the bridge service. A bridge profile statically designates the edge responsible for running the active bridge and optionally designates a second edge hosting the standby bridge.
- Lastly associate an overlay segment to a VLAN ID or IDs and a bridge profile. This results in the creation of the appropriate active/standby bridges on the edges specified in the bridge profile, that extend at layer 2 the overlay segment to the VLAN or VLANs identified by the VLAN IDs.