This is fascinating. Despite the persistent reports of related phenomena (Alwin we don't need your unhelpful sarcasm here), this issue, in various forms continues to plague SL. SOME of the issues are almost certainly client-side and may be ISP issues. Some are most definitely NOT.
Following yesterday's Main Server Roll, performance on our homestead was distinctly better until the evening, when my partner and I both suffered silent disconnects simultaneously. That was NOT ISP related,(we use different ISPs) and it had more in common with the sort of phenomenon we used to see at the time of the "Time-Warp" BUG a few years ago. Now I noticed from the release notes that yesterday's roll was to introduce new "safeguards" against capability failure. THAT causes me to wonder if it is related to the issue?