Lesson 9

In this module, we discussed some important topics regarding the physical structure of the Active Directory.
Now that you have completed this module, you should be able to:

1. Define sites and site links
2. List reasons for creating Active Directory sites
3. Recognize the effect of replication traffic on a slow link
4. Define the relationship between sites and subnets
5. Define the replication components and the purpose of each
6. List two ways to create connection objects
7. Define the difference between intra-site and inter site replication
8. List the characteristics of site link costs
9. Monitor replication traffic using the System Monitor (Performance) and the Replication Monitor

Defining sites and site links in Active Directory (AD) when using Windows Server 2019 is a critical task for ensuring efficient network traffic management and optimizing the replication process across different geographical locations. Here's how you can accomplish this:

1. Defining Sites in Active Directory:
   • Initial Preparation: Ensure that you have administrative privileges on the domain controller. Before proceeding, it's important to have a clear understanding of your network topology, including the physical locations of your servers and the IP address ranges used in each location.
   • Open Active Directory Sites and Services: On your Windows Server 2019, navigate to 'Administrative Tools' and open 'Active Directory Sites and Services'. This tool is integral for managing sites and related settings in AD.
   • Create a New Site: Right-click on the 'Sites' container and choose 'New Site'. Name your site to reflect its geographical location or organizational structure, ensuring it is easily identifiable.
   • Associate a Subnet with the Site: To ensure that AD can correctly identify which site a computer belongs to, you need to link each site to one or more subnets. Right-click on the 'Subnets' container, select 'New Subnet', and enter the subnet address and mask. Then, associate this subnet with the correct site.
2. Defining Site Links in Active Directory:
   • Understand the Purpose of Site Links: Site links represent the physical or logical network connections between AD sites, used to control replication traffic. They are vital for ensuring that AD data is replicated efficiently and according to the physical network topology.
   • Access the Inter-Site Transports Container: In the 'Active Directory Sites and Services' snap-in, expand the 'Inter-Site Transports' container, where you’ll find protocols like IP and SMTP. Typically, IP is used for site link configuration.
   • Create a New Site Link: Right-click on the 'IP' container and choose 'New Site Link'. Add the sites that should be connected by this link. Name the site link appropriately to reflect the connected sites or the physical link it represents.
   • Configure Site Link Properties: Double-click on the new site link to open its properties. Here, you can set the cost (which influences the replication path choice), replication frequency, and schedule. Lower cost values give the site link higher priority in the replication topology.
   • Review and Adjust as Needed: Regularly review your site and site link configuration, especially when there are changes in your network topology, to ensure optimal AD performance.

By carefully planning and configuring sites and site links in Active Directory on Windows Server 2019, administrators can significantly improve network efficiency and replication performance across different physical locations. This setup is crucial for larger organizations with multiple offices or data centers, ensuring that AD services are both resilient and efficient.

Here is a list of terms used in this module that may have been new to you::

1. Connection object: An object that represents a one-way replication path between two server objects and points to the replication source.
2. Intersite replication: Replication of the Active Directory partition that occurs between different sites.
3. Intra-site replication: Replication of the Active Directory partition that occurs within a site.
4. Knowledge Consistency Checker (KCC): A built-in service that runs on all domain controllers and automatically establishes connections between individual machines in the same site.
5. RPC over IP: Remote Procedure Call is a message-passing facility that is used for remote administration of computers. It can run over the Internet Protocol (IP).
6. Site links: A relationship between two sites that allows replication to occur.
7. Site link cost: A way of comparing the efficiency and desirability of using a particular site link based on speed, impact on the network and other factors.
8. SMTP: Simple Mail Transfer Protocol; a protocol often used for sending Internet mail, which can also be used for replication over site links in Active Directory.