We expect to reload a router this evening, which is likely to cause a few seconds of routing issues. This is part of trying to address the blips caused by router upgrades, which are meant to be seamless.
The reload is expected shortly, and will be on two boxes at least. We are monitoring the effect of the changes we have made. They should be a big improvement.
Upgrade was tested only on one router (Maidenhead) and caused some nasty impact on routing to call servers and control systems - general DSL was unaffected. Changes are backed out now, and back to drawing board. Further PEW will be announced as necessary.