Why did the Han dynasty establish a military outpost near Koko Nor?

The Han dynasty established a military outpost near Koko Nor in 4 ce primarily to keep the Qiang people out of the Han empire. The Han authorities viewed the tribes residing in the Koko Nor region and beyond as a potential threat and sought to secure the empire's borders against them. While this specific outpost was soon abandoned, the move reflected the broader Han strategy of establishing commanderies and military outposts in outlying regions to consolidate control and protect the empire from nomadic incursions.12