Just an FYI that the network here at Illinois will be undergoing an upgrade this weekend. The network may be unavailable between 4am and noon (Central time zone) on June 14 and 15.
While it's not clear which services may be affected, I would expect the llvm.org web server and SVN server to be affected as well as the LLVM and Clang mailing lists. Since our building has multiple links, services may be partially available (in that connections may get disconnected if the link they're using gets pulled for replacement). However, if you are paranoid, just assume that you won't be able to access LLVM services at all during those times.
The IRC server should stay available as it's not on our network, and services should be available outside of those times.
Sorry for the inconvenience,