All systems in the network are identified by a unique EntityID, which is specified in the SAML metadata.The EntityID has the format urn:etoegang:<ROLE>:<OIN>:entities:<index> where <ROLE> can have the values DV, HM, AD, MR or EB, <OIN> represents the OIN of the participant. The <index> is a number between 0 and 8999 that can be selected by the participant or the service provider to define different endpoints. Numbers between 9000 and 9999 are reserved for test systems.
When changes are made to the participant's system (e.g. when moving to a new version of Elektronische Toegangsdiensten) the participant MAY change a system's EntityID.
Although they look similar, EntityID's are not to be confused with ServiceID's. There is an n:n relationship between EntityID's and ServiceID's. One system may offer more than one service, or the other way around: more systems can offer the same service.