so basically, some here are advocating that federal employees are to be the only ones allowed to vote while common people working in the private sector do not vote and exist to serve the government employees ?
No.
Go read the book.
But basically, to earn citizenship, you must volunteer for a term of service in your society. You go in, you volunteer, you swear to serve for the term or (in the case of national emergency) until you're released. You ENLIST in the service of your society.
That's the last choice you make. They find something for you to do that's useful to the society. You do that until your term is up. You get paid. When your term is up (or if you decide to go career, when you retire), you muster out of service, and you're a citizen. You can NOW vote. You don't get to vote while in service. You can QUIT the service at any time, and all that happens is you don't get to be a citizen. Some examples of service:
Military duty
Research
Exploration
Civil work
Basically whatever the society has decided to have it's government do. The government MUST find you something to do - you volunteer, that's your part. You go up and say "I want to serve my society". The society then says "glad to have you" and finds you something to do.
There are a few professions reserved to citizens - police and some other civil functions.
The theory behind this is that before you get to exercise control over your society, you must put yourself in the service of it, and sacrifice your freedom for it (except the freedom to quit).
It's a really good book, in spite of the fact that it was made into a HORRRIBLE movie. In fact, at one point I think it was required reading for aspiring officers in one of the branches of our armed services - because it tries to answer the question about why anybody in their right mind would volunteer to fight and die for an abstract concept like "nation".