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networking/network_task_structure.rst

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+Network Task Structure and Data Flow
+####################################
+
+A schematic diagram of the tasks and message *mbuf* queues in a
+simple RTEMS networking application is shown in the following
+figure:
+
+.. image:: images/networkflow.jpg
+
+
+The transmit task  for each network interface is normally blocked waiting
+for a packet to arrive in the transmit queue.  Once a packet arrives, the
+transmit task may block waiting for an event from the transmit interrupt
+handler.  The transmit interrupt handler sends an RTEMS event to the transmit
+task to indicate that transmit hardware resources have become available.
+
+The receive task for each network interface is normally blocked waiting
+for an event from the receive interrupt handler.  When this event is received
+the receive task reads the packet and forwards it to the network stack
+for subsequent processing by the network task.
+
+The network task processes incoming packets and takes care of
+timed operations such as handling TCP timeouts and
+aging and removing routing table entries.
+
+The ‘Network code’ contains routines which may run in the context of
+the user application tasks, the interface receive task or the network task.
+A network semaphore ensures that
+the data structures manipulated by the network code remain consistent.
+
+.. COMMENT: Written by Eric Norum
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+