Azure Load Balancing

Comparing Solutions

Load Balancers in Azure

Azure offers several types of load balancers, each tailored to specific use cases:

Azure Load Balancer

Azure Load Balancer operates at layer 4 of the Open Systems Interconnection (OSI) model. It’s the single point of contact for clients. The service distributes inbound flows that arrive at the load balancer’s frontend to backend pool instances.

• Layer: Operates at Layer 4 (Transport Layer) of the OSI model.
• Traffic Type: Supports both inbound and outbound traffic.
• Use Case: Internal or external load balancing of VMs, containers, or other services.
• Key Features:
  • Low latency and high throughput.
  • Health probes to monitor backend resources.
  • Integration with Virtual Network (VNet).
• Scenarios:
  • Distributing web traffic among VMs.
  • Balancing traffic within a virtual network.

Azure Application Gateway

Azure Application Gateway is a web traffic (OSI layer 7) load balancer that enables you to manage traffic to your web applications.

• Layer: Operates at Layer 7 (Application Layer) of the OSI model.
• Traffic Type: Handles HTTP/HTTPS traffic.
• Use Case: Application delivery with advanced routing capabilities.
• Key Features:
  • URL-based routing.
  • SSL termination for secure traffic handling.
  • Web Application Firewall (WAF) integration for security.
• Scenarios:
  • Serving multiple websites from a single gateway using path-based routing.
  • Protecting applications from common web vulnerabilities.

Azure Front Door

Azure Front Door is Microsoft’s advanced cloud Content Delivery Network (CDN) designed to provide fast, reliable, and secure access to your applications’ static and dynamic web content globally.

• Layer: Operates at Layer 7 (Application Layer).
• Traffic Type: Global web traffic distribution.
• Use Case: Modern Content Delivery Network (CDN) with intelligent routing.
• Key Features:
  • SSL termination and custom domains.
  • Application acceleration through caching.
  • Built-in DDoS protection.
• Scenarios:
  • Speeding up global application delivery.
  • Protecting against DDoS attacks while routing traffic.

Azure Traffic Manager

Azure Traffic Manager is a DNS-based traffic load balancer. This service allows you to distribute traffic to your public facing applications across the global Azure regions. Traffic Manager also provides your public endpoints with high availability and quick responsiveness.

• Layer: DNS-based traffic routing (does not operate directly on OSI layers).
• Traffic Type: Global traffic distribution.
• Use Case: Directing user traffic to the nearest or most appropriate Azure region.
• Key Features:
  • Geographic routing.
  • Weighted routing for testing deployments.
  • Latency-based routing.
• Scenarios:
  • Directing traffic to regional Azure services for reduced latency.
  • Disaster recovery with failover between regions.

References

Azure networking documentation

AzureLoad Balancer documentation

Azure Application Gateway documentation

Azure Front Door and CDN documentation

Azure Traffic Manager documentation