138 karma · joined July 24, 2018
$75/mo is not particularly expensive, Braze's starter plan is close to $35k/year
Our software and competitors like Braze are typically used in situations where you can’t have a personal connection, but still need to message users, often when they complete specific actions in your application, or if you want to send one-off promotions for example. E-commerce brands or a banking app might use us for example.
We do support replacement variables like you mentioned and are adding integrations actively.
If you want to self host for free, the easiest way would be to run our docker compose on a compute instance-we're in the process of updating our docs for self hosting and I can email you with more info if you'd like.
We are specifically focusing on rebuilding a congestion control algorithm from the ground up that can better tolerate modern network conditions, including things like high bandwidth, high packet loss, and high latency.
With respect to Grid-FTP, wget2 multi-threading, and other multi-flow approaches: the problem with getting performance increases out of multiple, distinct traffic flows is that you become more and more unfair to other packet traffic as you increase the number of flows you are using. For example, if you use 9 TCP (or any other AIMD) flows to send a file over some link, and a tenth connection is started, you now are taking up to 90% of the available bandwidth (because AIMD flows are designed to be fair amongst themselves).
With respect to QUIC, I believe it was designed specifically to reduce the latency of HTTP connections by using multiple UDP flows and building the reliability/ordering guarantees at the application layer.
The problem with getting performance increases out of multiple, distinct traffic flows is that you become more and more unfair to other packet traffic as you increase the number of flows you are using. For example, if you use 9 TCP (or any other AIMD) flows to send a file over some link, and a tenth connection is started, you now are taking up to 90% of the available bandwidth (because AIMD flows are designed to be fair amongst themselves).
I haven't seen hpn-ssh before, but from a cursory look at the project page it looks like the main improvements are targeted at improving the speed of the encryption using multi-threading, and increasing ssh/scp buffer sizes. These are certainly good improvements over standard ssh/scp (and setting TCP buffers to the value of the bandwidth delay product for a particular network path is a well known way to squeeze some perf out of TCP) but do not address the root cause of slowdown in window-based, loss-based congestion control.
In order to be fair to other flows, exponential back-off is required on detection of congestion, and packet loss as an indicator of congestion is both a lagging indicator of congestion and has a very low signal to noise ratio on high throughput, lossy networks.
1. To give you an idea of the speed improvements, we transferred a 2GB file between Ohio and Singapore on AWS and were able to transfer it in 0:26 (seconds) using our protocol, vs 2:15 for SCP.
2. The basis for improvement is taking into account the changes in round-trip-time for a particular network path; these temporary increases are used as the primary congestion signal.
We are not using error correcting codes, which are good for preventing the retransmission of packets but do not address the underlying problem of avoiding congestion in a network.