Abstract

Modern cloud-based applications demand high-performance, fault-tolerant, and resilient networking architectures that can support millions of requests per second while maintaining extremely low latency. To meet these requirements, Amazon Web Services (AWS) provides the Network Load Balancer (NLB) as part of its Elastic Load Balancing (ELB) family. NLB operates at Layer 4 of the OSI model, focusing on TCP, UDP, and TLS traffic routing with deterministic performance. Unlike Application Load Balancer (ALB), which supports path- and host-based routing at Layer 7, NLB is designed to handle vast volumes of transport-level traffic by using connection-based hashing algorithms. This paper provides a research-driven overview of NLB’s architecture, routing logic, target group configurations, deployment patterns, benefits, challenges, and best practices. By examining the operational principles and architectural trade-offs of NLB, this study highlights its importance for latency-sensitive workloads, hybrid cloud deployments, and highly scalable microservices environments.