A write-up of the IP Tunnel Device Driver has been posted for review in: http://www.opensolaris.org/os/project/clearview/docs
The target audience for this document, and all other write-ups that might be posted later, are system administrators. As such, the document's final version will be integrated into one of the System Administration Guides to be published for a Solaris Express release. Your comments are welcome and much appreciated.
