MS DTC Architecture
In general, each Microsoft SQL Server will have an associated distributed transaction coordinator (MS DTC) on the same machine with it.
The MS DTC allows applications to extend transactions across two or more instances of MS SQL Server and participate in transactions managed by transaction managers that comply with the X/Open DTP XA standard.
The MS DTC will act as the primary coordinator for these distributed transactions. The specific job of the MS DTC is to enlist (include) and coordinate SQL Servers and remote servers (linked servers) that are part of a single distributed transaction.
SQL Server will automatically promote a local transaction to a distributed transaction when it encounters the remote server access in combination ...