One Network SSO is an integral service built into One Network Platform and provides capabilities known as single sign-on (SSO). SSO is a generic industry term used to describe a mechanism that allows for a central repository for user information including passwords so users of your system need not keep multiple user ids for the many different systems they use as part of their normal work day. Many systems from different vendors can participate in an SSO system such that user's need only one user id and password to access any system they might need. When each system stores this information separately, it becomes difficult to change passwords and manage user's in general.
The SSO mechanism integrated into Platform is an open-source technology called OpenID (https://openid.net/connect/).
One Network servers and One Network SSO use OpenID to communicate. In OpenID terms, Platform is the OpenID relying party (RP) and SSO is the OpenID provider (OP). Using OpenID allows SSO to act as a cross-domain provider that is compatible with other clients.