Date Added: Nov 2012
Multipath transport protocols such as Multipath TCP can concurrently use several sub-flows to transmit a TCP flow over potentially different paths. Since more than one sub-flow is used, an efficient multipath scheduling algorithm is needed at the sender. The objective of the scheduler is to identify the sub-flow over which the current data packet should be sent. This paper compares the most important types of schedulers for multipath transfers. The authors model their performance analytically and derive key metrics, most notably the resulting end-to-end delay over heterogeneous paths. Their results show that a scheduler minimizing the packet delivery delay yields the best overall performance, but it is complex to realize.