Optimal Scheduling of Multipath Multicast with In-network Cache for One-to-many Transfer
Ryota FUKUDA, Masahiro Shibata, Masato TSURU · 2023
The need for fast and efficient one-to-many file transfers is growing with the rapid increase in traffic among distributed servers for replicating and distributing large files. Assuming centrally-managed Software Defined Networking (SDN) environments, the authors have been developing a framework of one-to-many file transfers for networks with full-duplex links by which every receiver can fully utilize its own max-flow from the sender throughout the file transfer duration. In our framework, a file is divided into multiple blocks that are transmitted to receivers on a set of multicast trees according to a block transmission schedule designed for a given network topology with the locations of the sender and the receivers (called MPMC). Our previous study proposed an extension of MPMC in which the sender generates additional coded blocks from the original blocks and transmits those blocks, but it may suffer from the processing delays of encoding and decoding at the sender and all the receivers. Therefore, this paper proposes a new extension of MPMC (called Rainbow-MPMC) by incorporating in-network cache at tailored switches, in which a block in transmission can be replaced (overwritten) at a switch on the way by another block previously passing the switch and cached, instead of just being forwarded to downstream. Through a variety of network topology examples, we verify that many different optimal sched-ules of Rainbow-MPMC can be generated in a given network, each of which minimizes every receiver's reception completion time simultaneously while requiring a different number of block replacements. We also showed that the minimum number of block replacements among different optimal schedules varies significantly by network even over similar-sized networks.