It has been widely discussed on Mac user forums that there are issues with the Wi-Fi connectivity in the latest version of Mac OS X.
IT have seen reports already of issues with this update on staff and student machines. We do not recommend that you update to this version of Mac OS until an update has been released by Apple. There will be problems with accessing University resources such as Wi-Fi until this has been fixed.
An example set of symptoms of this fault include:
Your network works fine for a while, typically between about 30 seconds and five minutes, and then fairly abruptly begins to suffer almost total traffic loss. While this happens, your network connection appears to be active, yet typically, you cannot connect to anything.
While we do not have a workaround, we will update this information as soon as possible.