Interior lines

Interior lines: When naval and military operations are conducted in such a manner that the nearer the belligerent forces get to the enemy the more they support each other, or the nearer they get to bases of supplies, the operations is said to be conducted on interior lines. In the history of warfare such operations have generally been more favoured than the opposite operation known as working on exterior lines. In the present war [Great War] the operation of the British, Belgian and French forces have been very largely upon interior lines.