checksums propagating bad data with good checksums, incorrect sequence numbers caused buffers to fill, full buffers caused loss of keepalive packets and nodes took themselves off the network! http://www.faqs.org/rfcs/rfc789.html
an AWS Sydney facility resulting from severe weather in that area lead to disruption to a significant number of instances in an Availability Zone. Due to the signature of the power loss, power isolation breakers did not engage, resulting in backup energy reserves draining into the degraded power grid.