  Mobile nodes are typically equipped with multiple radios and can connect to
multiple radio access networks (e.g. WiFi, LTE and 5G). Consequently, it is
important to design mechanisms that efficiently manage multiple network
interfaces for aggregating the capacity, steering of traffic flows or switching
flows among multiple interfaces. While such multi-access solutions have the
potential to increase the overall traffic throughput and communication
reliability, the variable latencies on different access links introduce packet
delay variation which has negative effect on the application quality of service
and user quality of experience. In this paper, we present a new IP-compatible
multipath framework for heterogeneous access networks. The framework uses
Multipath Datagram Congestion Control Protocol (MP-DCCP) - a set of extensions
to regular DCCP - to enable a transport connection to operate across multiple
access networks, simultaneously. We present the design of the new protocol
framework and show simulation and experimental testbed results that (1)
demonstrate the operation of the new framework, and (2) demonstrate the ability
of our solution to manage significant packet delay variation caused by the
asymmetry of network paths, by applying pluggable packet scheduling or
reordering algorithms.
