Repeated packet loss on AT&T

I have a cage at an AT&T hosting facility in NY. Every few weeks I end up with horrendous VPN problems to another site I have on MCI's network in Maryland, as well as to a partners site, in the same area, also on MCI. mtr -s 800 to either site shows 10% packet loss on the hop from: 12.122.105.45 -> 192.205.34.50 Both of these appear to be AT&T routers (I say appear to be because I am relying on the netblock information from ARIN- reverse DNS for routers seems to be uncool). Does anyone else run into this problem? Smaller pings show far fewer (if any) issues and other traffic is passable- but it kills my VPN's. -Don