Methods and apparatus to control synchronization in voice over internet protocol networks after catastrophes

Example methods and apparatus to control synchronization in voice over Internet protocol (VoIP) networks after catastrophes are disclosed. An example border element comprises a network interface to receive a VoIP network registration request message from a VoIP endpoint, a catastrophe detector to determine whether a catastrophe has been detected, a backoff time module to compute a backoff time using a priority assigned to the VoIP endpoint and an expected number of VoIP network registration request messages, a recovery module to determine whether the VoIP endpoint is currently registered with the VoIP network, and to send a response message having a header representing the backoff time to the VoIP endpoint when the catastrophe has been detected and the VoIP endpoint is not currently registered with a VoIP network, and a signaling processor to process the VoIP network registration request message when the VoIP endpoint is currently registered with the VoIP network.