Introduction
TCP / IP communication is currently restricted to a single path per connection, yet multiple paths often exist between peers.The simultaneous use of these multiple paths for a TCP / IP session would improve resource usage within the network and thus, improve user experience through higher throughput and improved resilience to network failure. Multipath TCP (MPTCP) is an ongoing effort of the internet enguneering task force's (IETF)multiple TCP working group, that aimes at allowing a transmission control protocol TCP connection to use multiple paths to maximize resource usage and increase redundancy.
Background / Need /Relevance of the topic
MPTCP operates at the transport layer and aims to be transparent to both higher and lower layers .It is a set of additional features on top of standard TCP.A multipath TCP connection privides a bidirectional bytestream between two hosts communicating like normal TCP and thus does not require any changes to the applications.However multipath TCP enables the hosts to use diffrent paths with diffrent IP addresses to exchange packets belonging to the MPTCP connection.A multipath TCP connection appears like a normal TCP connection to an application.However, to the network layer each MPTCP subflow looks like a regular TCP flow whose segments carry a new TCP option type.Multipath TCP manages the creation, removal and utilization of these subflows to send data. The number of subflows that are managed within a Multipath TCP connection is not fixed and it can fluctuate during the lifetime of the Multipath TCP connection.The redundancy offered by Multipath TCP enables inverse multiplexing of resourses and thus increases TCP throughput to the sum of all available link-level channels instead of using a single one as required by plain TCP.Multipath TCP is backward compatible with plain TCP.