Azure Load Balancer (Layer 4) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Azure Load Balancer (Layer 4)?

Azure Load Balancer (Layer 4) is a service that distributes incoming network traffic across multiple virtual machines or services based on transport layer protocols like TCP and UDP, helping to improve availability and scalability.

beginner

Which OSI layer does Azure Load Balancer operate on?

Azure Load Balancer operates on Layer 4, the Transport Layer, which means it routes traffic based on IP address and TCP/UDP ports without inspecting the content of the packets.

intermediate

What are the two types of Azure Load Balancer?

Azure Load Balancer has two types: Basic and Standard. Basic is for small-scale or dev/test workloads, while Standard supports higher scale, availability zones, and more features.

intermediate

How does Azure Load Balancer handle health probes?

Azure Load Balancer uses health probes to check the status of backend instances. If an instance fails the probe, it stops sending traffic to that instance until it becomes healthy again.

intermediate

What is the difference between Public and Internal Azure Load Balancer?

Public Load Balancer routes traffic from the internet to your VMs, while Internal Load Balancer routes traffic within a virtual network or from on-premises networks, keeping traffic private.

Which protocol does Azure Load Balancer use to distribute traffic?

A HTTP and HTTPS

B DNS and DHCP

C FTP and SMTP

D TCP and UDP

Azure Load Balancer works at Layer 4 and distributes traffic based on TCP and UDP protocols.

What happens if a backend VM fails the health probe in Azure Load Balancer?

A Traffic is still sent to the VM

B Traffic is stopped to that VM until it recovers

C The VM is deleted automatically

D The Load Balancer restarts

Azure Load Balancer stops sending traffic to unhealthy VMs until they pass health probes again.

Which Azure Load Balancer type supports availability zones?

A Basic

B Classic

C Standard

D None

Standard Load Balancer supports availability zones for higher availability.

What is the main difference between Public and Internal Azure Load Balancer?

A Public routes internet traffic; Internal routes traffic within a virtual network

B Public is free; Internal is paid

C Public supports TCP; Internal supports UDP

D Public is Layer 7; Internal is Layer 4

Public Load Balancer handles internet traffic, while Internal Load Balancer routes traffic privately inside a virtual network.

Azure Load Balancer operates at which OSI model layer?

A Layer 4 - Transport

B Layer 3 - Network

C Layer 2 - Data Link

D Layer 7 - Application

Azure Load Balancer works at Layer 4, the Transport Layer.

Explain how Azure Load Balancer improves application availability and scalability.

Think about how spreading traffic helps keep apps running smoothly.

Describe the difference between Basic and Standard Azure Load Balancer.

Consider scale, features, and reliability differences.