Between 3am and 7am CDT on Wednesday, March 11, we plan to switch over to a new router in Chicago. The new router is already physically installed and ready to go, which means that we just need to move over the fiber connections to activate it. We expect for this process to take a few minutes, if everything goes smoothly, during which time your server will be unreachable.
After the cutover, we will be testing the new router to make sure that it works properly. This should generally be non-intrusive, but there is a chance that we may need to switch back to the old router, or that we run into a problem, leading to some further downtime during the maintenance window.
During this window, on-site staff will also be accessing a cabinet to install new servers. This should not cause an impact, but they will have to physically move a power strip while it is live, so there is a slim chance of a power disconnection for some machines. We will encourage them to be as careful as possible with this operation.
Update @ 4:37am CDT: We are still working on this. We have tried the new router twice and it has crashed twice (forcing us to revert back to the original router), but we believe that we may have isolated the cause in software and will be trying once more. If that fails, we will be doing yet more testing in the lab (on top of the dozens of hours done already, which, strangely, showed no problems!).
Update @ 6:06am CDT: The new router is in place and running. We are continuing to monitor, but the maintenance is finished.