Notification of Network Events

One of the most important responsibilities of a data transport service provider is that of providing indications to the client when certain network events have occurred. The list of defined network events consists of the following:

• FD_CONNECT— A connection to a remote host or to a multicast session has been completed.
• FD_ACCEPT— A remote host is making a connection request.
• FD_READ— Network data has arrived which is available to be read.
• FD_WRITE— Space has become available in the service provider's buffers so that additional data may now be sent.
• FD_OOB— Out of band data is available to be read.
• FD_CLOSE— The remote host has closed down the connection.
• FD_QOS— A change has occurred in negotiated QoS levels.
• FD_GROUP_QOS— Reserved.
• FD_ROUTING_INTERFACE_CHANGE— A local interface that should be used to reach the destination specified in SIO_ROUTING_INTERFACE_CHANGE IOCTL has changed.
• FD_ADDRESS_LIST_CHANGE— The list of local addresses to which application can bind has changed.

The set of network events enumerated above is sometimes referred to as the FD_XXX events. Indication of the occurrence of one or more of such network events may be given in a number of ways depending on how the client requests notification.