MetalLB is a load-balancer implementation for bare metal Kubernetes clusters, using standard routing protocols. Using MetalLB In BGP mode. Each node in your cluster establishes a BGP peering session with your network and uses it for advertising the IPs of external cluster services.
Netris plugin for MetalLB sits between MetalLB and your Linux distro running on the cluster nodes. Netris helps MetalLB to control BGP advertisements of FRR, which talks to the physical switches, thus controlling L3 anycast load balancer built-in Netris managed network and providing high-performance load balancing service to your Kubernetes cluster nodes.