Abstract: A method for determining network topology of a provider network includes selecting a first network element, selecting a first port on the first network element, and iteratively performing connectivity validation tests using the first port, wherein each connectivity validation test is associated with a type of network element and yields a result that indicates whether a second port on a second network element of the associated type is connected to the first port. A system for discovering topology of a network, the system comprising a topology discovery engine in operable communication with a near network element and operable to identify a first port of a far network element that is connected to a second port of the near network element by remotely altering operation of the near network element to cause the second network element to respond in a manner that identifies the first port.