Thanks for the traces. Unfortunately these problems appear to be starting outside of our network. We've gone ahead and passed them to our upstream carrier (Cogent in this case).
The one where China Unicom is handing off to AT&T is particularly bad. More often than not this is some sort of DDoS attack that is saturating China Unicom's peering. China Telecom seems to handle these things a bit better (I think they have larger peering connections that don't saturate as quickly when carrying attack traffic).
The good news is that if it's attack-related then it usually subsides on it's own after a bit (especially if whoever is being attacked chooses to null-route).
That said, where I was seeing 20-30% packet loss back to 61.52.48.1 I'm now seeing 0% loss. So that particular issue may have already been resolved.
