We have 5 routers for transit and we are seeing low levels of packet loss on one of these routers.
The cause of this is excess traffic due to our direct interconnect with Amazon being down and Amazon traffic being sent over our transit connections instead of the interconnect.
We have contacted Amazon and hope to have the interconnect working again soon, but we're not yet sure why they have taken it down.
We've made contact with Amazon, and the interconnect traffic looks like its starting to be restored. We're monitoring and will update again shortly...
Traffic levels are back to normal.
This problem was caused by our interconnect to Amazon going down due to maintenance at the Amazon side. Amazon have a policy not to route traffic over exchange points such as LINX and LONAP (where we have a lot of excess capacity) but instead would send traffic over our transit links (which have less excess capacity).
To prevent this from happening again: We are already in the process of increasing our transit capacity anyway, and we will investigate having a second interconnect in to Amazon.
Further update: a second interconnect to Amazon is underway.