# nw_connection_t A bidirectional data connection between a local endpoint and a remote endpoint. ``` typealias nw_connection_t = any OS_nw_connection ``` ## Topics ### Creating Connections [`nw_connection_create(_:_:)`](/documentation/Network/nw_connection_create(_:_:)) Initializes a new connection to a remote endpoint. [`nw_connection_set_queue(_:_:)`](/documentation/Network/nw_connection_set_queue(_:_:)) Sets the queue on which all connection events are delivered. [`nw_connection_start(_:)`](/documentation/Network/nw_connection_start(_:)) Starts establishing a connection. [`nw_connection_restart(_:)`](/documentation/Network/nw_connection_restart(_:)) Restarts a connection that is in the waiting state. ### Handling State Updates [`nw_connection_state_t`](/documentation/Network/nw_connection_state_t) States indicating whether a connection can be used to send and receive data. [`nw_connection_set_state_changed_handler(_:_:)`](/documentation/Network/nw_connection_set_state_changed_handler(_:_:)) Sets a handler to receive connection state updates. [`nw_connection_state_changed_handler_t`](/documentation/Network/nw_connection_state_changed_handler_t) A handler that delivers connection state updates with associated errors. ### Sending and Receiving Data [`nw_connection_send(_:_:_:_:_:)`](/documentation/Network/nw_connection_send(_:_:_:_:_:)) Sends data on a connection. [`nw_connection_send_completion_t`](/documentation/Network/nw_connection_send_completion_t) A completion handler that indicates when the connection has finished processing sent content. [`nw_content_context_t`](/documentation/Network/nw_content_context_t) A representation of a message to send or receive, containing protocol metadata and send properties. [`nw_connection_receive(_:_:_:_:)`](/documentation/Network/nw_connection_receive(_:_:_:_:)) Schedules a single receive completion handler, with a range indicating how many bytes the handler can receive at one time. [`nw_connection_receive_completion_t`](/documentation/Network/nw_connection_receive_completion_t) A completion handler that indicates when content has been received by the connection, or that an error was encountered. [`nw_connection_receive_message(_:_:)`](/documentation/Network/nw_connection_receive_message(_:_:)) Schedules a single receive completion handler for a complete message, as opposed to a range of bytes. [`nw_connection_batch(_:_:)`](/documentation/Network/nw_connection_batch(_:_:)) Defines a block in which calls to send and receive are processed as a batch to improve performance. [`nw_connection_get_maximum_datagram_size(_:)`](/documentation/Network/nw_connection_get_maximum_datagram_size(_:)) Accesses the maximum size of a datagram message that can be sent on a connection. ### Canceling Connections [`nw_connection_cancel(_:)`](/documentation/Network/nw_connection_cancel(_:)) Cancels the connection and gracefully disconnects any established network protocols. [`nw_connection_force_cancel(_:)`](/documentation/Network/nw_connection_force_cancel(_:)) Cancels the connection and immediately disconnects any established network protocols. [`nw_connection_cancel_current_endpoint(_:)`](/documentation/Network/nw_connection_cancel_current_endpoint(_:)) Causes the current endpoint to be rejected, allowing the connection to try another resolved address. ### Handling Path Updates [`nw_connection_copy_current_path(_:)`](/documentation/Network/nw_connection_copy_current_path(_:)) Accesses the network path the connection is using. [`nw_connection_set_path_changed_handler(_:_:)`](/documentation/Network/nw_connection_set_path_changed_handler(_:_:)) Sets a handler that receives network path updates. [`nw_connection_path_event_handler_t`](/documentation/Network/nw_connection_path_event_handler_t) A handler that delivers network path updates. [`nw_connection_set_viability_changed_handler(_:_:)`](/documentation/Network/nw_connection_set_viability_changed_handler(_:_:)) Sets a handler that receives updates when data can be sent and received. [`nw_connection_set_better_path_available_handler(_:_:)`](/documentation/Network/nw_connection_set_better_path_available_handler(_:_:)) Sets a handler that receives updates when an alternative network path is preferred over the current path. [`nw_connection_boolean_event_handler_t`](/documentation/Network/nw_connection_boolean_event_handler_t) A handler that receives Boolean state updates from a connection, such as viability and better path state. ### Collecting Connection Metrics [`nw_establishment_report_t`](/documentation/Network/nw_establishment_report_t) A report that provides metrics about how a connection was established. [`nw_connection_access_establishment_report(_:_:_:)`](/documentation/Network/nw_connection_access_establishment_report(_:_:_:)) Requests a copy of the connection’s establishment report once the connection is in the ready state. [`nw_establishment_report_access_block_t`](/documentation/Network/nw_establishment_report_access_block_t) A block that delivers a connection’s establishment report when it’s in the ready state. [`nw_data_transfer_report_t`](/documentation/Network/nw_data_transfer_report_t) A report that provides metrics about data being sent and received on a connection. [`nw_connection_create_new_data_transfer_report(_:)`](/documentation/Network/nw_connection_create_new_data_transfer_report(_:)) Begins a new data transfer report, which can later be collected. ### Copying Connection State [`nw_connection_copy_protocol_metadata(_:_:)`](/documentation/Network/nw_connection_copy_protocol_metadata(_:_:)) Retrieves the connection-wide metadata for a specific protocol. [`nw_connection_copy_endpoint(_:)`](/documentation/Network/nw_connection_copy_endpoint(_:)) Accesses the endpoint with which the connection was created. [`nw_connection_copy_parameters(_:)`](/documentation/Network/nw_connection_copy_parameters(_:)) Accesses the parameters with which the connection was created. [`nw_connection_copy_description(_:)`](/documentation/Network/nw_connection_copy_description(_:)) Copies the description of the connection as a string. --- Copyright © 2026 Apple Inc. 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