Let’s incorporate a sequencing/reliability layer into our application-layer circumvention protocols.

Something like QUIC or SCTP that does reordering and retransmission.

Instead of transporting a raw unstructured data stream, transport (encoded, encapsulated) packets of the sequencing/reliability protocol.

A design pattern, not a specific implementation.

Example: protocol layering of meek with Tor

Problem: Censors can terminate long-lived TCP connections.

Create a new “virtual” session independent of the TCP connection.

Problem: meek is half-duplex.

Sequence number reordering lets us send when we want.

Snowflake only uses one proxy at a time

Sequence numbers let us multiplex across multiple proxies.

DNS over HTTPS may make a good tunnel but is an unreliable channel.

Solved by retransmissions in the reliability layer.