[Nsi-wg] updated

Attached is a revised strawman for the NSI architecture document. This is to review at the OGF in Chapel Hill May 27-28 2009. This is still a work in progress, though it has come a long way. Some sections are not done and some are still being worked on. The document as a whole needs editing for consistency. Comments and suggestions are encouraged. I am putting together an acknowledgement section, but have not completed it - I will include this in later drafts. The document has had all corrections accepted from earlier versions, but still has some comments. Suggestions and comments may be added by modifying the text with change tracking on, or by sending comments to the list. John