A device may receive a message en route to a recipient device. The device may provide the message to a first interworking function device associated with the recipient device. The device may determine that the first interworking function device is unavailable to route the message to the recipient device. The device may identify a second interworking function device that is capable of routing the message to the recipient device based on determining that the first interworking function device is unavailable to route the message to the recipient device. The first interworking function device and the second interworking function device may act as gateways between a circuit-switched network and a packet-switched network. The device may provide the message to the second interworking function device for routing to the recipient device.