Here are some good RADIUS configuration guides for eduroam SP and IdP ...
- Aruba - https://wiki.geant.org/display/H2eduroam/aruba
- Aruba Clearpass - ???
- Cisco ISE - Cisco Support Forum
- FreeRADIUS - GEANT: SP & IdP
- Microsoft NPS
- Configuration guide from UNINETT
- Configuration guide from Jisc
- Configure Framed-MTU attribute