As u know, its possible to develop RTL and verification independently using the same specification. If a company, speciliazing in verification, develops a verification environment with the data generator, monitor, score board and other components, its possible to use this by any other company, which are developing RTL.
This kind of verification environment development which are specific to the standard are called verification IPs.
In a ASIC verification process, these IPs are used.
Its also possible to develop verification environments with the RTL already in place.
Hope i've been clear. If any mistakes are there, comments are welcome