This technique relies on [[traceroute]]-like probing on the IP address space. These probes report back IP forwarding paths to the destination address. By combining these paths one can infer router level topology for a given [[Post Office Protocol|POP]]. Active probing is advantageous in that the paths returned by probes constitute the actual forwarding path that data takes through networks. It is also more likely to find [[peering]] links between [[ISP]]'s. However, active probing requires massive amounts of probes to map the entire Internet. It is more likely to infer false topologies due to load balancing routers and routers with multiple IP address aliases. Decreased global support for enhanced probing mechanisms such as [[source-route probing]], [[Internet Control Message Protocol|ICMP]] Echo Broadcasting, and [[IP Address Resolution]] techniques leaves this type of probing in the realm of network diagnosis.
