Olivier Bonaventure writes "The TCP protocol is closely coupled with the underlying IP protocol.
Once a TCP connection has been established through one IP address,
the other packets of the connection must be sent from this address. This
makes mobility and load balancing difficult. Multipath TCP is
a new extension that solves these old problems by decoupling TCP from
the underlying IP. A Multipath TCP connection can send packets over
several interfaces/addresses simultaneously while remaining backward
compatible with existing TCP applications. Multipath TCP has several use
cases including smartphones that can use both WiFi and 3G or servers
that can pool multiple high-speed interfaces. Christoph Paasch, Gregory
Detal and their colleagues who develop the implementation of
Multipath TCP in the Linux kernel have achieved 50 Gbps for a single TCP
connection by pooling together six 10 Gbps interfaces. See here for
technical details and full source code."
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