Abstract: Systems and methods for gracefully switching to direct connections for devices behind NAT devices are described. One of the methods includes receiving, by a server device logically located behind a first NAT device, a request to establish one or more peer-to-peer connections for providing content from the server device to a client device logically located behind a second NAT device. The method includes providing, by the server device to the client device, a control message for establishing a multiplexed connection under a multiplexed connection protocol, in which the control message is sent to the client device over a first peer-to-peer connection through a first network route including a relay device that is logically located between the first NAT device and the second NAT device. The method includes establishing the multiplexed connection between the client device and the server device, wherein the multiplexed connection includes a plurality of apparently separate and apparently independent connections.

Abstract: Techniques of gracefully switching to direct connections for devices behind NAT devices are described. A server device behind a first NAT device receives a request to establish one or more peer-to-peer connections with a client device behind a second NAT device. The server device can establish a first peer-to-peer connection with the client device through a relay device that is publicly reachable by both the server device and the client device. The server device negotiates a second peer-to-peer connection with the client device, while the client device downloads content from the server device over the first peer-to-peer connection. The second peer-to-peer connection is on a network route that is different from a route of the first peer-to-peer connection. Once the second peer-to-peer connection is established, the server device and the client device can communicate with one another using the second peer-to-peer connection.