Regions

• geographical area
• potentially multiple datacenters(nearby and networked)
• low-latency network

Azure availability zones

• Physically separate datacenters
• One or more datacenters with independent power, cooling, and networking

App Service

• HTTP-based service
• • build and host web-based solutions without managing infrastructure
• • Microsoft Azure Marketplace
• Online store
• • Hosts applications that are certified and optimized to run in Azure