Large infrastructures may require to run redundant servers in different data centers, while smaller infrastructures usually need to build a very cost-effective, yet robust, small scale PKI. In either case, a flexible PKI allows the use of both optional directory servers, OCSP responders, and other optional components that are used in different National ID PKI architectures.

PrimeKey and EJBCA PKI offer:
EJBCA PKI is suitable for issuance of all types of electronic IDs:

Some usages of National eIDs are: