requiring 2FA for an SP

[Peter Schober]

* IAM David Bantz <dabantz at alaska.edu> [2016-10-04 21:18]:
> I think it should be possible to configure a relying party to require a 2FA
> authN context or method, presumably in relying-party.xml but perhaps in the
> local copy of metadata for the SP, but I've been unable to locate correct
> syntax.

Is the SP requesting an authentication context class?
If not, why not?
-peter