ZMP Protocol¶

What this chapter answers — it introduces the concept of the wire protocol that exchanges the handshake and message frames between sockets. The exact frame format is owned by ZMP protocol internals.

ZMP is the wire protocol that exchanges the handshake and message frames between zlink raw sockets. An application generally does not implement the protocol directly — it uses the socket API instead.

Frame¶

A ZMP data frame expresses message boundaries and multipart continuation. Socket metadata such as the routing id and subscription is returned separately from the payload by that socket pattern's typed API.

Handshake And Metadata¶

The connection handshake exchanges the socket type, identity, and protocol metadata. When the transport is TLS or WSS, the TLS handshake must complete first before the ZMP handshake proceeds.

Request/Reply Envelope¶

DEALER's and ROUTER's typed request/reply APIs carry the message type and request sequence in a Core-managed control part. The application payload stays after the control part, and the receive API returns the payload with the control part stripped, along with the request metadata.

See ZMP internals for the wire format's implementation detail. The application topology protocol is owned by the Framework packages and is outside the scope of the Core ZMP guide.