In my last year of university (5 years ago) I took a networking seminar. Each student took a look at a different technology to utilize multiple links for internet data transfers.
Initially I was amazed by MPTCP and wondered why it had so little adoption. As I looked into the papers I slowly figured out why. With different links (WLAN, LAN, LTE) their real world characteristics are too different for efficient aggregation. It is the head of line blocking problem times ten.
It might be fine as a back up link, but there are other problems like the limit to TCP and middelboxes dropping unknowns packets.
The challenges outnumber the benefits for consumers and in data centers there are other technologies to aggregate links that operate on a level below TCP.
I imagine re-ordering is a big problem. The only application I can think of that would require a single flow is media streaming, but you only need ~4Mbs for a decent quality stream anyway. Other applications like file transfer can be split into multiple concurrent flow, at which point you might as well just let the local router nat each flow to each internet connection in turn.
I hope QUIC with its many advanced features gets better adoption to provide many of the benefits so we can just stop messing with TCP for it's completely screwed up by middleboxes.
Cool, but needs a VPS. A simpler approach is to load balance/ fail over individual TCP/UDP flows, eg using mwan3
I'm hoping that with QUIC, there will be a way to use it's migration feature to load balance more accurately (no need to wait for new flows to start). But, right now there is no way for a middlebox to tell if the server end of an individual flow supports migration, as this is only visible to the client.
Love it, but aggregating different connections (latency, LTE vs Adsl, fiber) is hard. Tried different algos, but always had network hogs or even higher ping that slowest connection.
What made it work best (and rock stable) was using LTE only, or ADSL only connections having same ping to aggregator (VPS) and have the VPS as near as possible. (latency wise)
I did not had the time to set up multiple redundant aggregators, so my SPOF was the VPS some times. Maybe there is a solution out there.
So far my experience a year ago. Our provider then offered a way cheaper managed solution, thats why we stopped using it.
Initially I was amazed by MPTCP and wondered why it had so little adoption. As I looked into the papers I slowly figured out why. With different links (WLAN, LAN, LTE) their real world characteristics are too different for efficient aggregation. It is the head of line blocking problem times ten.
It might be fine as a back up link, but there are other problems like the limit to TCP and middelboxes dropping unknowns packets. The challenges outnumber the benefits for consumers and in data centers there are other technologies to aggregate links that operate on a level below TCP.
reply