XADM: Explanation of Replication Inbound and Outbound Sites

This article explains the Inbound Sites and Outbound Sites tabs of the Directory Replication Connector (DRC) property pages. Sites appearing in these two property pages depend on the relation of these sites to the site you are replicating with.

Inbound sites include the site that is directly connected to this particular DRC, plus any other site that we indirectly know of through this directly replicated site. Inbound sites are all sites from which the local site receives directory information through this DRC.

Outbound sites include the current site being looked at in the Administrator program and any other site that is known about through replication from replication connectors to other sites in the Inbound sites page. Outbound sites are those sites that the local bridgehead server sends information to, as specified in the DRC's General property page. The site in the General property page is also known as the directly connected site.

The following example better explains this concept. Suppose you have a 5 site organization: A, B, C, D, and E. Directory Replication is set up so that A replicates with B and C, and A also replicates with D and E. This configuration is shown in the following figure: Examining the Sites tab for the replication connectors on each site will reveal the following: One of the most illustrative examples would be Site D's connector to Site B. Notice that Inbound sites include A, B, and C. This is because site D is directly connected to Site B, and it is through site B that site D gets replication information for sites A and C. For outbound sites we see site D and site E because site D has another replication connector to site E, and Exchange directory replication passes on replication information of all Inbound sites to all Outbound sites.

For more information refer to the Exchange Server Administrator's Guide, Chapter 13.