Got this from my hosting provider:
Please be advised that on April 11th-12th, 2011 at 11:00pm-05:00am CST, we
will be conducting network upgrades and maintenance which will impact your
server within our San Antonio (SAT) Datacenter. This work is part of our planned
ServerBeach Network Upgrades that will provide you with a more robust and
scalable network and enable us to better server your needs.
This maintenance will last approximately 6 hours, during which 15 minutes of
network downtime will occur as the switch your server is located on is upgraded.
This maintenance will ensure that the networking systems are standardized and
will allow us to use more supported commands for configuring and investigating
issues at the networking level.