The ULB supports the following functions:

• Equal Traffic Distribution and Client IP Preservation:

  • Distributes incoming network traffic equitably across all worker nodes for Layer 4 protocols (UDP, TCP).

  • Maintains the original client IP address when distributing ingress traffic to backend pods.

• Direct Server Response (DSR) and Service IP Consistency:

  • Enables backend pods to reply directly to clients, bypassing the load balancer to reduce latency and load.

  • Ensures response packets have a consistent source IP address, matching the service IP address exposed for ingress.

• Dynamic Scaling and Real-Time Configuration Updates:

  • Seamlessly adds and removes worker nodes, automatically integrating new nodes into traffic distribution without downtime.

  • Dynamically incorporates new backend pods into the traffic routing scheme as they are deployed.

  • Triggers real-time updates to the load balancer's configuration with any changes to worker nodes or backend pods.

• Service IP Uniqueness and Consistency for Egress Traffic:

  • Maintains a unique service IP address for egress traffic, even when exiting through multiple worker nodes.

  • Uses the same service IP address for both ingress and egress requests, providing a consistent IP address to external systems.

• Response Routing and UDP Handling for Egress Traffic:

  • Accurately routes responses back to the backend pod that initiated the egress request, preserving the original client IP address.

  • Routes UDP protocol responses to backend pods, even if they did not originate the egress request.

For more information on configuring these features, see the ULB features and configuration section in this guide.