ALPN
acronymcryptographynetworking
Stands for: Application-Layer Protocol Negotiation
The TLS handshake field that negotiates which application protocol to use.
Application-Layer Protocol Negotiation (RFC 7301) lets client and server agree during the handshake on the protocol that will run over the connection - for example h2 for HTTP/2 - avoiding an extra negotiation round trip.
Also known as: alpn