What exactly is "nostrification" of a university diploma? I have been reading a bit about nostrification of a university diploma, but I don't quite understand what it means. I do understand that nostrification is basically validation of your diploma in a foreign country. But, does it only mean that your diploma is recognized in this foreign country (so you can actually take a job there, or you can continue to a higher education there) or it actually means that you can go to a university at this foreign country and require the same degree diploma from that university? 

For example, if you have a civil engineering degree from a university in country A, and you do nostrification in country B, does it also mean that you can go to a university that offers a civil engineering programme in country B, and just require a degree diploma from that university cause you already had one from country A?
Nostrification is verification that Degree X you received in Country A has the same value as Degree Y received in Country B. You do not receive a new diploma for Degree Y in Country B.

Well, actually a university in Country B may decide to give you Degree Y based on your work in Country A, but it's certainly not standard, and usually bond to university-level agreement and cooperated studies, but even then it's often not the degree that's nostrificated, but rather the thesis, its reports etc. and the defense that's considered.

The most common reason for diploma nostrification is (1) job requirements in Country B, often in governmental jobs such as offices, schools etc.; or (2) continuation of study, for instance nostrification of Masters for the admission to PhD studies in Country B. In neither case, it is necessary to have Degree Y in Country B.