In general, techniques are described for delegating responsibility for performing a connectivity protocol from one or more endpoint devices to network infrastructure situated along a network forwarding path connecting the endpoint devices. In some examples, an intermediate network device includes a connectivity protocol module of control unit that operates a connectivity protocol session on behalf of a server, wherein the server exchanges application data with the client using an application-layer communication session with the client. The connectivity protocol module monitors connectivity for the application-layer communication session with the connectivity protocol session by exchanging connectivity protocol messages for the connectivity protocol session with the client to determine a connectivity status for the communication session. The connectivity protocol module updates the server with the connectivity status for the communication session by sending a summary report message that includes the connectivity status for the communication session to the server.