Advanced Authentication vs Access Manager vs Identity Manager

Hi,

I'm struggling to understand the difference between the Advanced Authentication, Access Manager and Identity Manager. We need to implement MFA into our eDir, GroupWise and other systems, where we can. We have 'Advanced Authentication Limited per User' license and 'Identity Manager Bundle Edition per User' and I'm trying to work out the which solution would suit our needs. Any questions, answers, pointers to articles will be gratefully received.

With Thanks

Ian