After Exchange generates new OAB files, compresses the files, and places the files on a local share, you can then configure the method by which the address books are distributed. There are two methods by which the OAB is distributed to client computers:

• Web-based distribution
  
• Public folder distribution
  

Public folder distribution is the distribution method by which Outlook 2003 or earlier clients that are working offline or through a dial-up connection access the OAB. With public folder distribution, the OAB generation process places the files directly in one of the public folders, and then Exchange store replication copies the data to other public folder distribution points.

With public folder distribution, every request for a full OAB download is served immediately. Depending on network speed and available bandwidth, this volume of traffic could potentially overload the network for an extended period.

To determine which OAB download method to use, consider the following factors as you plan and implement your OAB strategy:

• Size of each OAB in your organization.
  
• Number of OAB downloads.
  
• Number and frequency of parent distinguished named changes.
  
• Simple Mail Transfer Protocol (SMTP) address mismatches. Overall number of changes made to the directory.
  

For more information about how to determine the distribution method, see Understanding Offline Address Books.