The RADIUS authentication server has been responding intermittently or very slowly for the last couple of days, but has got significantly worse during the course of this afternoon and evening. You will experience this as difficulty authenticating devices on the wireless network or connecting to the VPN server.
The problem would appear to be with the underlying disks in the server, and comes from the inability to timeously write log files. Unfortunately, maintaining accurate logs is a requirement of providing eduroam services so we cannot disable this function.
We're currently working on the problem, and expect that it'll be resolved during the course of this evening or early tomorrow morning.