This site link uses the IP protocol to join all the sites in your network. However, simply using the default site link may not be your best option, particularly on networks that have redundant connections. Regardless of your situation, it's almost always more effective to use a custom site link than to use the default. Configure the site link's associated attributes. Create site link bridges.
Configure connection objects.
Designate a preferred bridgehead server. Let's examine each of these steps. As the name implies, IP replication uses the IP protocol to replicate Active Directory information within sites and between them. It's the preferred replication protocol in most situations. By default, IP replication is subject to any replication schedules that you set up, although you can tell it to ignore the schedules.