Active Directory includes functionality called Sites and Subnets that associates domain controllers with one or more locations and defines proximity between domain controllers and domain-joined clients. Each Site is a named collection of a one or more domain controllers and one or more subnets. Domain-joined clients locate the closest domain controller by querying Active Directory for the sites and subnets then selecting a domain controller from with the site where the subnet best matches the IP address on the client.
The Austin Active Directory defines multiple sites and subnets to associate domain controllers with specific physical locations both on-campus and in the cloud. The Austin Active Directory also defines abbreviated site codes to provide a shortened reference to an appropriate site. The site codes are split into two general groups: campus site codes and cloud site codes. Campus site codes are simple abbreviations (aus, atx, pub, etc.) while cloud site codes follow a general rule: first character is the cloud provider, second and third characters are abbreviations for specific regions in the cloud provider (sites in AWS start with 'w' while sites in Azure start with 'z').
Sites in the Austin Active Directory - Current
| Site Name | Site Code | Domain Controllers | Subnets | Notes |
|---|---|---|---|---|
| AWS-US-East-1 | we1 | Cloud DCs in AWS US East 1 region | Subnets in AWS US East 1 region | |
| Azure-West-US-2 | zw2 | Cloud DCs in Azure West US 2 region | Subnets in Azure West US 2 region | |
| Default-First-Site-Name | atx | Public DCs | On-campus subnets not in other sites | |
| Austin-Public | pub | Public DCs | Public DC subnets | to be retired after new DCs are live |
Sites in the Austin Active Directory - Future
| Site Name | Site Code | Domain Controllers | Subnets | Notes |
|---|---|---|---|---|
| Austin-Campus | aus | Campus DCs | On-campus subnets not in other sites | |
| Austin-Services | atx | Service DCs load-balanced by the F5s | Service DC subnets, RODC subnets | RODCs on campus live with the service DCs |
| AWS-US-East-1 | we1 | Cloud DCs in AWS US East 1 region | Subnets in AWS US East 1 region | |
| Azure-South-Central | zsc | Cloud DCs in Azure South Central region | Subnets in Azure South Central region | |
| Azure-West-US-2 | zw2 | Cloud DCs in Azure West US 2 region | Subnets in Azure West US 2 region | |
| Default-First-Site-Name | atx | Public DCs | Public DC subnets and off-campus subnets | provides DNS resolution and AD services to MCDO |