http://us.battle.net/d3/en/forum/topic/8197649754
I didn’t have my more extensive map of network monitoring going today when I encountered a sudden spike in latency while taking on an elite pack at the beginning of Stonefort. I included a screenshot of that on top of the screengrab of the game below.
When only the attack animation was occuring but no effects were being displayed, I just kept on going through my attack routine since I was dealing with a waller affix and I was near the stairs at that point. Fortunately, I came out of the spike after around 10 seconds, and I had managed to almost take out the mob fighting blindly.
Latency indicator noted 722ms by the time I was able to look. Checked the network map I did have up at the time and it hadn’t logged any sort of packet loss during the period I had encountered the spike. One of the only battle.net servers which allows ICMP’s is on a different subnet from the actual gaming servers (but it is still part of the same AT&T enterprise hosting network) also logged no dropped packets during that time. None of this is conclusive (that the lag was server side) without more thorough analysis (including capture of packets to rule out deeper issues that could still be ISP side).
Interestingly, this was around the same time frame that I encountered several short spikes last week which eventually led to the massive one that caused my character de-sync (with regards to movement) from the server:
