AZ-104 Certification Notes

Chapter 8 - Configuring Azure VNet Peering

Network Connectivity
- Default Connectivity
  - While intra-network traffic and outbound internet traffic is allowed, virtual networks are by default isolated
- VNet Peering
  - Bridge together virtual networks to allow connectivity between these networks
Non-Reciprocal
- Connection must be established in both directions
Global Connectivity
- Peerings can be same region or cross-region (global) Something we have to keep in mind with VNet peerings is that they are non-transitive. Say we have a peering connection between VNet-1 and VNet-2, and the one going in the opposite direction to VNet-2 to VNet-1, these virtual networks are peered. Then let's say that VNet-2 is also in a peering relationship with VNet-3 here. And this peering connection allows VNet-2 and VNet-3 to communicate. Just because VNet-2 is able to communicate with VNet-1 and VNet-3, does not mean that VNet-1 and VNet-3 can communicate. Virtual network peerings are non-transitive. We would have to create a separate peering connection between VNet-1 and VNet-3, and we'd have to have that peering connection in order for them to communicate going in both directions.

Types of Peering
- Virtual network peering
- Global virtual network peering
Benefits
- Low-latency, high-bandwidth connections
- Cross-network communications
- Data transfer between/across subscriptions, AAD tenants via Azure roles, and Azure regions
Transitivity
- Peering connections are non-transitive
Reciprocity
- Peering connections are not reciprocal