Trusted Multipath-TCP (MPTCP) extension

Multipath TCP (MPTCP) adds the capability of using multiple paths to a regular TCP session and is being deployed extensively. Source Address Validation (SAV) technologies are proposed to prevent network nodes from spoofing others' IP addresses and thus improve the accountability of networks. This document proposes a trusted MPTCP extension based on SAV, which enables MPTCP to work with SAV and thus improve the accountability of MPTCP connections. This extension doesn't intend to replace the security solutions to resolving IP forged attacks, like Hash-based Message Authentication Code (HMAC), but to improve the accountability of them and the whole connection.