H1-----SG1=====R1=====.....=====Rn=====SG2-----INTERNETThis allows a routable IP subnet to appear behind a SG to which that subnet could not previously be routed. This could be used to locate branch offices of an organisation physically distant, but logically next door. It could also be used to loan some routable IP addresses to another site or to conceal the true net-location of machines belonging to certain IP addresses.