Transfer of voice transmissions to alternate networks

Automatically transferring transmissions of a data network in which one or more processors receive metrics of active concurrent transmission sessions on a LAN that includes a data network, connected to a WAN, and a threshold level of concurrent transmission sessions of the data network of the LAN. Receiving a request for an additional transmission session, and responsive to determining that the threshold level of concurrent transmission sessions is exceeded, accessing data that maps a communication connection of the data network for a targeted recipient, to a communication connection of an alternate network corresponding to the targeted recipient, and performing a transfer of the additional transmission session from the communication connection of the data network for the targeted recipient, to the alternate network corresponding to the targeted recipient.