1. A method comprising: at a control plane element: augmenting a first control packet with a first interface identifier to form a first augmented control packet, the first interface identifier identifying a first interface at a physical network forwarding element; and transmitting the first augmented control packet having the first interface identifier via a tunnel to the physical network forwarding element; and at the physical network forwarding element: identifying the first interface identifier from the first augmented control packet; removing the first interface identifier from the first augmented control packet to obtain the first control packet; and transmitting the first control packet through the first interface at the physical network forwarding element based on the first interface identifier; and at the control plane element: receiving a second augmented control packet from the physical network forwarding element of a physical network underlay; identifying a second interface identifier from metadata in the second augmented control packet, the second interface identifier identifying a control plane presenting interface at the control plane element removing metadata from the second augmented control packet to generate a second control packet; providing the second control packet to the control plane presenting interface so that the control plane presenting interface views the second control packet as being directly received by the control plane presenting interface at the control plane element; and initializing protocol handling of the second control packet at the control plane element.