It's mentioned in the guide Brahma suggested, but you'll also need to install CA EEM (Embedded Entitlements Manager) for authentication. This can be hosted on a remote server or on one with other CA components. It is mentioned that an existing EEM can be used, but I'd strongly advise against this. It isn't a large installation.
It hasn't been announced officially yet, but SOI 3.1 can use EEM version 12.
In fact I found the following in the release notes for 3.1:
Software Requirements
CA SOI requires the following software:
•
CA EEM r8.4.217, r8.4.402, r8.4.404, r8.4.4xx, and r12
Regards,
Pete