Hopping Pluggable Transport
The "Hopping" pluggable transport is one of the options offered by obfsvpn. The idea is quite simple: instead of choosing a fixed bridge endpoint, it will randomly cycle through several bridges that are configured to use the same OpenVPN gateway. By splitting traffic in this way, each particular endpoint receives a lesser amount of data. Additionally, the port used in the endpoint is also rotated.
The Hopping Pluggable transport needs that the protocol being tunneled handles session transparently.
Choice of obfuscation layer
For now, we’re using obfs4 as the obfuscation layer, but the design of the transport is orthogonal to encryption and obfuscation. Passing the right configuration, any combination of obfuscation methods should work for the underlying transports.
Transport status
This is an experimental transport. As such, any bridge that deploys it should set the "experimental" flag for the time being, so that clients can opt-in to include these bridges in their selection.
Tutorial
The second part of the tutorial on setting an obfuscated OpenVPN gateway guides you step by step on setting up a hopping obfs4 bridge.