Emile Aben is describing an interesting behavior observed in the Wild West of the global Internet: someone started announcing BGP paths with an unknown attribute, which (regardless of RFC 7606) triggered some BGP session resets.

One would have hoped we learned something from the August 2010 incident (supposedly caused by a friend of mine 😜), but it looks like some things never change. For more details, watch the Network Security Fallacies and Internet Routing Security webinar.