Before you proceed with the installation of an RODC in your network, you have to make sure that it covers certain requirements. Here is a brief overview:
- PDC Emulator – the DC holding the PDC FSMO in the domain where you intend to install RODC must be running Windows Server 2008.
- Global Catalog – you need to have a GC running Windows Server 2008.
- Domain Functional Level must be at least Windows Server 2003
- Forest Functional Level must be at least Windows Server 2003
- Schema modification – you must run once in the forest adprep /rodcprep

In addition, you must have in mind the following:
- Global Catalog – if there are Outlook clients in the branch office, the RODC should be configured as GC.
- Authentication Requests – the RODC forwards authentication requests to a Global Catalog, running Windows Server 2008, in a site that is closest to the site with the RODC.
- Multiple RODCs – RODCs in the same site DO NOT SHARE information with each other. If the connection to a writable DC is down, there could be inconsistent logon experiences for the users

In the following Step-by-Step video tutorial, we demonstrate the installation of RODC:

How to Install Read-Only Domain Controller (RODC)

Ref: www.netometer.com/blog