session inactivity time out

[Joe]

Hello again,

We are running IDP 3.1.2 and SP 2.5.4.

I notice that the inactivity time out is less than I expect.
I expect an hour. I haven't quantified the time.
I plan to do that on Monday. It may be ~15 minutes.

shibboleth2.xml settings:
SessionCache
  cacheAllowance="3660"
  inprocTimeout="900"
  cleanupInterval="900"
Sessions
  lifetime="28800"
  timeout="3600"

IDP settings:
  are there any??
  I can not find a reference entry

Thanks for the help!