In this article, we compare how traffic flows through NetScaler and Google Cloud Load Balancer from an architecture perspective.
In modern application architectures, traffic management plays a critical role in performance, availability, and scalability. Two popular solutions used by organizations are NetScaler (Citrix ADC) and Google Cloud Load Balancer (GCLB)
While both help distribute traffic efficiently, they are designed for different environments and architectures.
What is NetScaler
NetScaler is an Application Delivery Controller (ADC) commonly deployed in:
It provides advanced features like:
One key characteristic of NetScaler is that traffic typically enters through VIP (Virtual IP) and is processed inside the appliance before reaching backend servers
What is Google Cloud Load Balancer
Google Cloud Load Balancer is a globally distributed load balancing service built on Google's infrastructure.
Key characteristics:
Unlike traditional ADC deployments, traffic is distributed across Google's global network before reaching backend services.
Architecture and Traffic Flow
The key difference between NetScaler and Google Load Balancer is where traffic is processed. NetScaler typically sits inside a datacenter and manages traffic using a Virtual IP (VIP) before forwarding requests to backend servers. Google Cloud Load Balancer operates on Google's global edge network. Traffic enters through an Anycast IP and is routed to the nearest Google edge location before reaching backend services. The diagram below shows how traffic flows in both architectures.
Figure: NetScaler-vs-Google-Loadbalancer-flow.png
NetScaler vs Google Cloud Load Balancer Traffic Flow
When to Use NetScaler
Applications run in on-prem datacenters
Advanced ADC features are required
Hybrid deployments are in place
Fine-grained traffic control is needed
When to Use Google Cloud Load Balancer
Google Cloud Load Balancer is ideal when:
Applications run in GCP
Global traffic distribution is required (NetScaler also has feature GSLB)
Auto scaling is important
You want a fully managed service
Real World Deployment Example
In many enterprise environments, NetScaler and Google Cloud Load Balancer work together.
A common architecture looks like this: Users -> Google Cloud Load Balancer -> Hybrid Connectivity(VPN/Interconnect) -> NetScaler -> Backend Applications
In this model:
Google Cloud Load Balancer handles global traffic distribution
NetScaler manages application delivery and traffic optimization
Backend applications may run in on-prem infrastructure
This approach is common during:
Quick Comparison Summary
| Feature |
NetScaler |
Google Cloud Load Balancer |
| Deployment |
On-prem / Hybrid |
Cloud-native |
| Entry Point |
VIP |
Anycast IP |
| Scaling |
Manual/Configured |
Automatic |
| Architecture |
Data Center based (Cloud version) |
Google Edge Network |
| Management |
Self-managed |
Fully managed |
Conclusion
Both NetScaler and Google Cloud Load Balancer are powerful solutions designed for different architectures. NetScaler excels in application delivery within data centers, while Google Cloud Load Balancer is built for global-scale traffic distribution. Understanding how traffic flows through each solution helps engineers design better and more scalable systems.
Series: Application Delivery & Traffic Engineering
NetScaler Packet Flow Explained
