1) Bypass 2) Peripheral 
• (a.) Pertaining to the circumference; encompassing; encircling; circuitous.
Cir·cum`fer·en'tial adjective [ Late Latin circumferentialis .] Pertaining to the circumference; encompassing; encircling; circuitous. Parkhurst. 
[adj] - lying around or just outside the edges or outskirts
circumferential Relating to the formation of a circumference.
adjective lying around or just outside the edges or outskirts; `circumferential highways around cities`
of, at, or near the circumference; surrounding; lying along the outskirts. · lying within the circumference. · circuitous; indirect: a circumferential manner of speech.