Blades

This novel is set in the far future when mankind has conquered space. The nations of the Earth have assembled as one and became a federation of nations.
The federation forms a Federation Space Force to travel the stars and set up outposts to the edge of space where man has not ventured beyond.
It becomes apparent an alien race is beyond this edge, but no attempt has been made to contact the aliens.
This edge in space becomes an informal boundary acknowledged between the aliens and the Federation. However, without any communication between the two, accidents can happen, and an accident can start a war.