Memory management system and method for network controller

For a fiber distributed digital interface (FDDI) network including host and node processors having respectively first and second memories for storing data arranged in frames, a network controller, comprising:

• means for establishing a plurality of buffers at arbitrary locations in said first and second memories;
• and
• means for establishing arbitrarily in said first and second memories descriptors at contiguous locations forming descriptor rings pointing to said buffers;
• wherein each frame has a frame control field;
• and
• means for selected a ring corresponding to a buffer for storing a receive frame in accordance with the content of the frame control field of said receive frame.

For a network including a plurality of processors and memory means for storing packets of receive data arranged in frames and including information identifying a frame characteristic, a network controller, comprising:

• a FIFO memory;
• a receive data path comprising said FIFO memory and said memory means;
• means for establishing a plurality of receive buffers at arbitrary locations in said memory means and for establishing at contiguous locations in said memory means descriptors forming descriptor rings pointing to said receive buffers;
• means for storing receive frames incoming on said receive data path to a descriptor ring corresponding to said frame characteristic;
• and
• means for detecting a blocked receive ring and in response discarding subsequent frames incoming to said blocked descriptor ring.

For a network including a buffer memory, a plurality of processors and memory means for storing packets of data arranged in frames, a network controller, comprising:

• means for establishing a plurality of receive buffers at arbitrary locations in said memory means and for establishing at contiguous locations therein descriptors forming descriptor rings pointing to said buffers;
• means for receiving incoming data packets, each packet including data designating a descriptor pointing to a corresponding buffer and for passing said packets through said buffer memory to said memory means;
• means for storing the incoming data packet in the buffer pointed to by the designated descriptor;
• means for detecting a blocked ring;
• first means responsive to a detected blocked ring and a normal control mode of said network controller for storing subsequent packets incoming thereto in said buffer memory;
• and
• second means responsive to the detected blocked ring and a discard control mode of said network controller for discarding subsequent packets incoming thereto.

For a network adapter operative selectively in normal and discard modes including a plurality of processors and memory means for storing packets of receive data arranged in frames and including information identifying a frame characteristic, a FIFO memory and a receive data flow path through said FIFO memory to said memory means, means for establishing a plurality of receive buffers at arbitrary locations in said memory means and for establishing at contiguous locations in said memory means descriptors forming descriptor rings pointing to said receive buffers, and means for supplying receive frames incoming on said receive data path to a descriptor ring corresponding to said frame characteristic, a method of controlling receive data flow, comprising the steps of:

• detecting a blocked descriptor ring in the receive data flow path;
• in response to a detected blocked ring and the normal mode of operation of said adapter, storing subsequent packets incoming to said adapter in said buffer memory;
• and
• in response to a detected blocked ring and the discard mode of operation of said adapter, discarding subsequent packets incoming to said adapter.

For a fiber distributed digital interface (FDDI) network including host and node processors having respectively first and second memories for storing data arranged in frames each including a frame control field, a method of processing receive frames, comprising the steps of:

• establishing a plurality of buffers at arbitrary locations in said first and second memories;
• and
• establishing arbitrarily in said first and second memories descriptors at contiguous locations forming descriptor rings pointing to said buffers;
• and
• selecting a ring for storing a receive frame in accordance with the content of the frame control field of said receive frame.

For a network adapter including a plurality of processors and at least first and second memories for storing data arranged in frames, a method of processing frames of receive data, comprising the steps of:

• establishing a plurality of buffers at arbitrary locations in said first and second memories;
• and
• establishing arbitrarily in said first and second memories descriptors at contiguous locations forming a plurality of descriptor rings pointing to said buffers;
• the descriptors of each ring each having an indicium pointing to one or the other of said first and second memories;
• detecting information code signals in incoming frames of receive data;
• correlating each said information code signal with a particular one of said descriptor rings;
• and
• storing each incoming frame of receive data in a buffer pointed to by said particular descriptor ring.

For a fiber distributed digital interface (FDDI) network including host and node processors having respectively first and second memories for storing data arranged in frames each including a frame control field, a method of processing frames of receive data, comprising the steps of:

• establishing a plurality of buffers at arbitrary locations in said first and second memories;
• and
• establishing arbitrarily in said first and second memories descriptors at contiguous locations forming descriptor rings pointing to said buffers;
• and
• selecting a ring for storing a receive frame in accordance with the content of the frame control field of said receive frame.