Overview#OpenID Connect Account Porting defines mechanisms to support a user porting from one OpenID Connect Provider to another, such that Relying parties can automatically recognize and verify the change.
OpenID Connect Account Porting extends OpenID Connect to enable an Relying Party to recognize when a user logging in via a New OpenID Connect Provider is the same user who has previously logged in via an Old OpenID Connect Provider. That is, it enables porting between OpenID Connect Providers to be handled automatically by Relying parties|Relying Party]. The central idea is that the user logs into both Old and New OPs in a single session to establish the link between the user's accounts at each. Subsequently, Relying parties can interact with both OpenID Connect Providers to confirm that link, without needing the user to repeat the dual logins.
As most jurisdictions allow users to port their mobile phone number between Mobile Network Operators, and a reasonable expectation of those users will be that their Mobile Connect account (provided by those same operators) can also be ported at the same time. There is a significant difference between phone number and account porting, however. Other parties are generally unaware when number porting occurs; they simply keep using the same phone number to communicate with the user. In contrast, Relying parties are aware when an OpenID Connect account is ported as they interact with a New OpenID Connect Provider.