An example network system includes network interfaces, a data repository, a forwarding structure, a service element, and a forwarding element. The forwarding element is configured to receive a first packet having header information via a tunnel over the first network with one of the networking interfaces, pass the first packet to the service element, receive a second packet from the service element, and forward the second packet via the network interfaces to the second network, wherein the first packet conforms to the first network-layer protocol, and wherein the second packet conforms to the second network-layer protocol. The service element is configured to transform the first packet from a format conforming with the first network-layer protocol into the second packet having a format conforming with the second network-layer protocol, and direct the second packet to the forwarding element.