By default, the controller polls the reference domain controller once every eight hours and the providers once every two hours to collect FRS topology information from Active Directory and FRS data. The schedule is staggered to minimize peaks in bandwidth use during polling.
You might want to change the polling schedule for several reasons:
When changing the polling schedule, keep in mind that polling begins at the specified time and continues until polling is complete. Avoid doing high-frequency polling during periods when you need low-latency replication. If performance is an issue, schedule polling to occur when the replication schedule closes.