OpenSolaris CIFS Server: Colour Me Confused

The goal of this project is to provide a native, integrated CIFS implementation to support OpenSolaris as a storage operating system. The OpenSolaris CIFS Server provides support for the CIFS/SMB LM 0.12 protocol and MSRPC services in workgroup and domain mode. Substantial work has already gone into modifying and adapting the existing OpenSolaris file system interfaces, services and commands to accommodate Windows attributes and file sharing semantics. The intent is to provide ubiquitous, cross-protocol file sharing in Windows and/or Solaris environments.

Now, I may be wrong, but this all sounds very similar to Samba. So the question is, how did Sun manage to emulate the protocols? And does the agreement between Microsoft and the EU over interoperability have any bearing on this? Yours, confused of London.