---
description: Idea of Site & Stie-Links
---

# AD Site and Site-Links

## <mark style="background-color:blue;">Active Directory sites</mark>

<figure><img src="https://3849832254-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F0VV5UVf1Opf7lSgalz6c%2Fuploads%2FBK4XfPfGk8JRPJaMO7tl%2Fimage.png?alt=media&#x26;token=de0d9741-d40e-4bfd-baeb-a4f6e7f66b60" alt=""><figcaption><p>Idea of Site and Site Links </p></figcaption></figure>

> 1. <mark style="background-color:blue;">**The Active Directory site defines a physical topology of the network. Sites can be**</mark>>    \ <mark style="background-color:blue;">**separate buildings in a campus network, with the branch office in a separate city**</mark>>    \ <mark style="background-color:blue;">**or even in a separate country.**</mark>
> 2. <mark style="background-color:blue;">**Active Directory Sites are logical groupings of IP subnets that reflect physical network locations, like offices or campuses. They ensure clients connect to nearby domain controllers (DCs) for faster authentication and reduce WAN traffic.**</mark>
> 3. <mark style="background-color:blue;">**AD sites are used for managing organizations that have branches spread across different geographical locations but fall under the same domain. It is a robust solution to geographically manage an AD network without changing any aspect of the logical structure of the environment. AD sites are physical groupings of well-connected IP subnets that are used to replicate information among domain controllers (DC) efficiently**</mark>

## **What are subnets** &#x20;

{% hint style="success" %}
A **subnet** (short for "_<mark style="color:blue;">**subnetwork**</mark>_") is a logical subdivision of an IP network. In Active Directory (AD), subnets are used to **group computers based on their IP addresses** and physical location on the network.\
\
In Active Directory, **a site is made up of one or more subnets** that are well-connected (have fast and reliable network connectivity between them).
{% endhint %}

## <mark style="background-color:blue;">AD Site Links</mark>

> <mark style="background-color:blue;">**Site Links are connections between sites that control how AD data replicates across locations. They have properties like cost (priority for replication) and schedule (when replication happens), helping manage bandwidth usage.**</mark>



## <mark style="background-color:blue;">Active Directory Replication</mark>



> 1. <mark style="background-color:blue;">**Replication**</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">in Active Directory ensures that</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">**all Domain Controllers (DCs)**</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">across different locations have</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">**consistent and up-to-date data**</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">(</mark><mark style="background-color:blue;">**user accounts, group policies, passwords, and more Configuration**</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">) Within the same Domain.</mark>
> 2. <mark style="background-color:blue;">AD is a</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">**multi-master database**</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">– any DC can be updated, and those changes need to be copied (replicated) to all other DCs.</mark>



## <mark style="background-color:blue;">Intra-site Replication Types</mark>&#x20;

### <mark style="color:blue;">**Intra-site Replication**</mark>

> <mark style="background-color:blue;">**Intra-site replication happens within the same site, using high-speed LAN connections. When a change occurs, the domain controller waits 15 seconds by default before notifying others, ensuring quick updates. This process is event-driven, not on a fixed schedule, making it ideal for local networks, That happen Within DCs in the same Domain.\\**</mark>

### <mark style="color:blue;">**Inter-site Replication**</mark>

> <mark style="background-color:blue;">**Inter-site replication connects different sites, often over slower WAN links. It’s scheduled, with a default of every 3 hours, but can be set to as little as 15 minutes. Administrators might schedule it for off-peak times, and data is compressed to save bandwidth, using bridgehead servers for efficiency.**</mark>

