Controlling the creation of Active Directory replication connections

The knowledge consistency checker (KCC) is a Microsoft Windows 2000 and Microsoft Windows Server 2003 component that automatically generates and maintains the intra- and inter-site replication topology.

Whilst the KCC generally works well, sometimes it may be necessary to prevent the KCC’s automatic generation of replication connections (a scripted method is also available).

It should be noted that manually creating Active Directory connections to tailor the replication topology increases the administrative workload as the KCC will no longer dynamically alter connections to reflect changes in the network topology or replication failures.

Further information on optimising Active Directory replication is available on the Microsoft website.

Determining costs for Active Directory site links

Whilst reviewing a colleague’s Active Directory design document today, I came across the following model for determining the cost of a site link, depending on the available bandwidth:

Replication cost = 1024 x 1/logbandwidth (in Kbps)

The following table gives some example costs for common bandwidth values:

Bandwidth (Kbps) Replication cost
28 702
56 586
64 567
96 517
128 486
256 425
512 378
1024 340
2048 309
4096 283