The Harriers - book 1 of War & Honor by Gordon R. Dickson 1991
Earth is but a memory—the real action these days is in The Magnicate, a league of all the human worlds in the galaxy.
At the center of the Magnicate is the Hub, a huge artificial world from which control of Human Space flows.
The Hub governs, but even so, control sometimes requires force. Enter the Harriers. They are an elite military force created to guard the Hub and do the job that the effete diplomats of the Hub will not and dare not do.
There are the Grand Harriers, who acts as a large force, and the Petit Harriers, who are sent on special missions—and tend to have a hell of a lot more fun! Novellas by S.N. Lewitt, Steve Perry, and Chelsea Quinn Yarbro.