TcpFallback

TCP Fallback

This example shows how a client can attempt to connect to a server with QUIC and fallback to TCP when the QUIC connection establishment fails - for example, because a middlebox between the client and server does not let QUIC connections through.

The server program creates a server for QUIC and another server for TCP; both servers share the same dispatch pipeline.

The client program first attempts to establish a QUIC connection; if this connection establishment fails, it falls back to a TCP connection.

This example uses QUIC, IceRPC's default multiplexed transport. On Linux and macOS, QUIC requires extra setup steps; see .NET's QUIC platform dependencies.

You can build the client and server applications with:

dotnet build

First start the Server program:

cd Server
dotnet run

In a separate terminal, start the Client program:

cd Client
dotnet run

In order to see the fallback to TCP, comment out quicServer.Listen(); in the Server program and restart it: the client's QUIC connection attempt fails and the client falls back to a TCP connection.