A cluster that uses alias IP address ranges is considered a VPC-native cluster. A cluster that uses custom static routes in a VPC network is called a routes-based cluster

When using VPC-native, administrators can also take advantage of network endpoint groups (NEG), which represent a group of backends served by a load balancer. NEGs are lists of IP addresses managed by an NEG controller and are used by Google Cloud load balancers. IP addresses in an NEG can be primary or secondary IP addresses of a VM, which means they can be pod IPs. This enables container-native load balancing that sends traffic directly to pods from a Google Cloud load balancer.

VPC-native clusters have several benefits:

• Pod IP addresses are natively routable inside the cluster’s VPC network.
• Pod IP addresses are reserved in network before pod creation.
• Pod IP address ranges are dependent on custom static routes.
• Firewall rules apply to just pod IP address ranges instead of any IP address on the cluster’s nodes.
• GCP cloud network connectivity to on-premise extends to pod IP address ranges.

Here is a list of improvements that NEGs bring to the GKE network:Improved network performance

The container-native load balancer talks directly with the pods, and connections have fewer network hops; both latency and throughput are improved.Increased visibility

With container-native load balancing, you have visibility into the latency from the HTTP load balancer to the pods. The latency from the HTTP load balancer to each pod is visible, which was aggregated with node IP-based container-native load balancing. This increased visibility makes troubleshooting your services at the NEG level easier.Support for advanced load balancing

Container-native load balancing offers native support in GKE for several HTTP load-balancing features, such as integration with Google Cloud services like Google Cloud Armor, Cloud CDN, and Identity-Aware Proxy. It also features load-balancing algorithms for accurate traffic distribution.