Microsoft on patent raid - and they simply steal ideas from the IETF Working Group on IPv6, which they were once involved in. Also a patent that, under Clements' interpretation - and possibly even that of the BMJ - of the EU Patent Directive draft would also be enforceable here. And this could cause quite a few problems when using IPv6. Of course, due to prior art, one could challenge such a thing - but someone would first have to do that and be able to afford it.