“…Single-layer mapping: Past work in Internet mapping mainly focused on individual layers and can be broadly classified as mapping at the (i) the physical layer [52,70,71] where each link represents a physical cable between two locations, (ii) the interface level [44,59,82,83], (iii) the router level [58, 60-63, 73, 77, 84], (iv) the PoP level [53,55,64,68,79,81,86], and (v) the AS level [42,43,48,69,72,76,78].…”