Multipath TCP Support for Single-homed End-systems

Multipath TCP relies on the existence of multiple paths between end- systems. These are typically provided by using different IP addresses obtained by different ISPs at the end-systems. While this scenario is certainly becoming increasingly a reality (e.g. mobile devices), currently most end-systems are single-homed (e.g. desktop PCs in an enterprise). It seems also likely that a lot of network sites will insist on having all traffic pass a single network element (e.g. for security reasons) before traffic is split across multiple paths. This memo therefore describes mechanisms to make multiple paths available to multipath TCP-capable end-systems that are not available directly at the end-systems but somewhere within the network.