You can use CollabNet roles and resources to control specific users' access to specific paths in your repository.
These roles are the most relevant to version control:
/trunk/www. Cannot read or write any other part of the repository.
You may wish to create your own resources and roles specific to your project. Because Subversion presents all branches and tags in ordinary filesystem space, it's possible to selectively restrict access on branches and tags for particular roles.
For example, you might define Developer roles that allow write access to every part of your repository except the
/tags directory, and then create a special "Release Manager" role with special permission to create new tags. There are limitless possibilities.