Azure Front Door vs Application Gateway: Top Differences

Cloud platforms are an integral part of modern applications. They offer features like reliability, scalability, and security to the apps for reaching millions of users. Many cloud platforms are available in the market, including Microsoft Azure, Google Cloud Platform, Amazon Web Services, etc. The networking services of the cloud play a crucial role in the optimal communication of services with each other. Microsoft Azure provides two services for network management: Azure Front Door and Azure Application Gateway. Learn more about Microsoft Azure Architect technologies and design and implement advanced infrastructure solutions in Azure.

In this article, we will compare Front Door vs. Application Gateway in terms of their features, Security and Compliance Considerations, Availability and Performance Benefits, Cost Comparison, and use cases.

What is an Azure Front Door?

Azure Front Door is a content delivery network solution provided by Microsoft that helps to provide static and dynamic web content to users with higher availability, lower latency, greater scale, and more secure manner across the globe. 

Front Door can store images, videos, or any other files for your application and deliver them to the users at high speed. It uses global and local points of presence (PoPs) distributed worldwide and routes user requests to the closest and healthiest server for a faster experience. Front Door provides security with built-in DDoS protection and a Web Application Firewall.

What is Azure Application Gateway?

Azure Application Gateway is a traffic manager and load balancer that helps route your application's traffic to a suitable destination. Load balancers mainly reduce the load on servers by calculating the amount of traffic that will route on each server. This enhances the availability and scalability of the application.

Application Gateway can also handle traffic based on the additional parameters of an HTTP request. For example, if a specific pool of servers handles the video-related APIs, then the ‘/videos’ incoming URL will route to the servers configured for videos. Load balancers mainly operate at the transport layer (OSI layer 4 - TCP and UDP). 

Comparing Azure Front Door vs Application Gateway

Let’s compare the two services, i.e., front door vs. application gateway,  based on some crucial parameters. This section will be critical in deciding which service to choose for your use case.

Parameters	Front Door	Application Gateway
Features	Secures applications with built-in layer 3-4 DDoS protection, with integrated Web Application Firewall (WAF) and Azure DNS to protect your domains. Health probes and automatic failover. Integrated Certificate Management. Web Application Firewall (WAF) secures your application against Layer 7 DDoS attacks. Spread across 118 edge locations across 100 metro cities. Support for the end-to-end IPv6 connectivity and the HTTP/2 protocol. Seamless integration with DNS, Web Apps, Storage, etc., for domain and origin management Create your own custom domain, which is convenient for your customers and useful for branding purposes. Integrated with Azure Monitor to monitor your Front Door traffic in real-time. Generate security reports and analytics of the web traffic. Allows you to create a Rule Set for multiple routes and specify how to process the routes.	Supports SSL/TLS termination at the gateway to flow the unencrypted data to the servers and reduces decryption overhead. However, an end-to-end encryption option is also available if companies have security concerns. The Standard_v2 offers autoscaling that can scale your resources up or down based on changing traffic load needs and saving you from the manual tuning of resources. Application Gateway spans multiple Zones, reducing the need to install these gateways in each zone separately. WAF protects your application from cyber attacks and vulnerabilities, including SQL Injection, DDOS, and Cross-Site Scripting. WAF deals with the protocols of OWASP (Open Web Application Security Project) core rule sets 3.1 (WAF_v2 only), 3.0, and 2.2.9. Route traffic based on hostname or domain name, which allows you to use a single gateway for multiple web applications. Support for WebSocket and HTTP/2 protocols. Create custom error pages. Session affinity and cookie-based affinity for directing the user to the specific server where the session was created.
Security and Compliance Considerations	When it comes to Azure Front Door, it provides security measures, including Web Application Firewall (WAF), DDoS Protection, SSL/TLS Encryption, and Traffic Analytics to ensure advanced security for the users and comply with industry standards like GDPR, HIPAA, and ISO certifications.	Azure Application Gateway secures users with a Web Application Firewall (WAF), SSL Termination, Authentication and Authorization, Logging, and Monitoring. Besides, It complies with the PCI DSS, OWASP, SOC, and HIPAA industry standards.
Availability and Performance Benefits	Global Load Balancing: Azure Front Door is available at 118 edges locations across 100 metro cities and provides global load balancing to distribute traffic among multiple Azure regions to enhance availability. Content Caching: Fastens content delivery to end-users by caching at edge locations. Automatic Failover: Automatically route traffic away from failed or unhealthy regions or servers. Global Scalability: Scales horizontally to handle high traffic loads and sudden demand rises.	Layer 7 Load Balancing: Efficiently distributes traffic to backend servers based on application content for routing the traffic to a suitable server. SSL Termination: Offloads SSL encryption to reduce the decryption load on the server side. Autoscaling: Dynamically adjusts resources to handle traffic fluctuations, ensuring consistent performance and availability. Session Affinity: Maintains users' sessions by directing users to the same backend server where their session variables are present to improve user experience. Health Probes: Monitors backend server health and automatically routes traffic away from unhealthy servers to ensure availability.
Cost Comparison (Azure Front Door vs. Application Gateway pricing)	Azure Front Door offers two fixed pricing plans: Azure Front Door Standard, which is mainly for optimal content delivery and charges a monthly fee of $35, and Azure Front Door Premium, which adds features including Private Link, WAF, BOT protection, Microsoft Threat Intelligence (MTI), and security analytics to the Standard plan and comes with a monthly fee of $330.	Application Gateway provides variable pricing options for your usage: Fixed Scheme: $0.246 per gateway hour for Application Gateway and  $0.443 for WAF Application Gateway. Capacity Unit Scheme: $0.008 per capacity unit-hour for Application Gateway and  $0.0144 per capacity unit-hour for WAF Application Gateway

Differences Between Azure Front Door and Application Gateway

1. Azure Front Door and Application Gateway: Pros & Cons

Azure Front Door Pros:

• Globally available network of servers for quick access and availability.
• Anycast network and split TCP connections.
• Scalability and High Availability.
• Integrated Web Application Firewall (WAF) with a lot of policies.
• Layer 3-4 DDoS protection to protect your apps.
• Simplified cost plans.
• Request Logging.
• Seamless integration with DevOps-friendly command line tools.

Azure Application Gateway Cons:

• No free trial available.
• Expensive option.
• Limited advanced routing options.
• Complex configurations.

Application Gateway Pros:

• Layer 7 Load Balancing for routing based on request parameters.
• SSL Offloading at the gateway to reduce overhead data.
• Web Application Firewall (WAF) protection.
• Session Affinity to direct the users to the servers containing their session.
• Autoscaling to manage the resources as per the demand without human intervention.
• Centralized Authentication.
• Easy to set up routing rules.
• Quick setup and configuration update.
• Health monitoring Support.

Application Gateway Cons:

• No annotations for WAF rules, making it difficult to manage.
• The learning curve for advanced features.
• Const considerations.

2. Use Cases for Application Gateway vs Front Door

Let's explore various use cases for Application Gateway and Front Door in optimizing web application delivery.

a. Azure Application Gateway

It is usually used when you expect many users in your apps or wish to manage web traffic based on incoming requests. Application Gateway balances the traffic across multiple servers and supports routing to a specific server based on request components. Besides, Application Gateway is also used when you need to host multiple apps with the same gateway patterns. Go for Cloud Computing training courses and build competency in managing cloud storage, databases, networking, security, and analytics.

b. Azure Front Door

It is usually employed where efficient delivery and high availability of the assets to the users. For example, let’s say you have a streaming application that must regularly render videos and images to the users. In this case, go ahead with Front Door as your Content Delivery Network.

Conclusion

This article covered the primary differences between Azure Application Gateway vs. Front Door. Both services act as a middleman between the server and the client. However, Front Door primarily deals with optimal data delivery and global load balancing, while Application Gateway is mainly concerned with application-level traffic management and security. The choice between the two largely depends on the application type and services you deliver to the users. Check out KnowledgeHut Microsoft Azure Architect technologies and learn to manage decisions for functional areas.