TechNet Event: Tucson, AZ - October 4, 2005

We had the latest TechNet Event in Tucson, AZ on Tuesday, October 4, 2005.  During the course of the event, I had one question come up that I did not have the answer for.  Following is the question that needed a little more research on my end.  Please let me know if there is anything missing from the list.  Thanks!!

1. For Peer to Peer Replication (in SQL Server 2005), what is used to ensure transactions are replicated?  Is it the GUID / Primary Key?

I will get an answer posted as soon as I find the answer.  Thanks for your patience!

Harold