In the first post (beginning of the GSoC 2017 project) I made a few checkpoints to complete at the end of the summer. Now I don’t copy them here, but the good news is all of them completed successfully. The main goal was a very simple transparent multipath Wi-Fi link bandwidth aggregation. The proof in the video above. And the details below.
After lots of experiments, I figured out the way which enables the transparent MPTCP operation for both the client and the server (with the regular kernel).
I tested the configurations at my virtualized environment, check the video below. For configuration infos, please read the video description. (the post continues)
For more info whats the goal of the project, please visit my first blogpost which is here.
What done yet
I created this simple topology for trying out the technologies. I’m still in experimenting status but have some results as well. This virtualized test enviroment run on my machine. The paths between the MPTCP supported machines are shaped to 10 Mbps. With iperf3 and Wireshark I verified that the MPTCP protocol is working fine: clearly shows 20 Mbps between the two MPTCP supported machine (I use the latest 0.92 MPTCP kernel which is based on the 4.4 kernel version). Tha path between the MPTCP and Endhost machines are not shaped, so the throughput is much higher than 20 Mbps. I configured shadowsocks-libev on MPTCP1 (ss-server) and Endhost1 (ss-redir) machine. Then I tired an iperf3 download between Endhost1 and MPTCP2. This looks like:
Endhost1 <——————]TCP[——————-> MPTCP1 <———————]MPTCP[——————–> MPTCP2
I successfully get the 20 Mbps on Enhost1 which is the aggregated throughput of path1 and path2. (continue)
My name is Ferenc Fejes. I’m MSc CE student at the University of Debrecen, infocommunication networks specialization. I glad to introduce my project which is Add MPTCP support in LEDE/OpenWRT. The main idea is from my mentor, Benjamin Henrion. If we have a Wi-Fi mesh network, there are probably more than one network path between the nodes. The point is, we can gain additional throughput if we use those path simultaneously.
Currently no MPTCP support in GNU/Linux nor Windows systems. So the key is, the user using regular TCP/UDP at his system until the first hop, which is a LEDE box with MPTCP support. At this point, this router operating as an intercepting proxy: read the incoming traffic from the host, and distribute that on multiple interface, using MPTCP. At receiver side, we can do the same but in reverse order: get the data from the MPTCP connection and send is to the sink host in regular TCP (or UDP). With this operation, the whole MPTCP transmission remains hidden for the end hosts, but they will enjoy the gain from it – because MPTCP has a good capability to aggregate the bandwitdh of the different paths. Of course, if the bottleneck between the end host and the first hop, the user did not get any gain from this operation.
The key steps for reach the goal of the project:
1. Set up virtual/real machines with MPTCP support. This is not a problem since kernel patches for MPTCP support available.
2. Make a simple multipath topology: end hosts with no MPTCP support, two machine with MPTCP support, functioning as a router and has two different network path between them
3. Search and configure an efficient and transparent proxy software on them, which can suitable for intercept TCP traffic and work as a tunnel for other protocols (like UDP, SCTP, etc.)
4. Reproduce the working configuration on LEDE supported devices, with two Wi-Fi bridge links between the LEDE boxes.
5. Verify the aggregation with iperf3 measurements.