Communication controller and communication control method

A communication controller connected to a host through an input/output bus for controlling network media on the basis of a descriptor indicated from said host to communicate a packet, said communication controller comprising:

• a MAC controller which controls the network media to send and receive a packet;
• an input/output bus controller which controls transmission between an input/output bus and the communication controller;
• a DMA controller which performs data transfer to and from a host memory through said input/output bus controller;
• a descriptor cache memory in which descriptors in a descriptor chain in the host memory are cached as a portion of a virtual descriptor gather list;
• a descriptor cache controller which makes a virtual descriptor gather list by following and analyzing a descriptor chain in the host memory from said descriptor indicted from said host, and which allows a portion of said virtual descriptor gather list to be referred to in a descriptor cache window;
• and
• a network processor element which transfers a received packet to said host memory through said input/output bus controller by obtaining the address of a location in said host memory, in which the received packet is to be stored, from a receive descriptor provided by said descriptor cache controller and by indicating said address to said DMA controller to activate a DMA write operation, and which sends a send packet by obtaining the address of said send packet in the host memory, in which the send packet is stored, from a send descriptor provided by said descriptor cache controller and by indicating said address to said DMA controller.

A communication controller connected between a network and a host which performs communication over said network, comprising:

• a plurality of first processors which perform communication processes between said network and said host;
• and
• a second processor which allocates said communication processes to said first processors,
• wherein said second processor allocates any communication process related with a first communication unit of said communication processes to the first one of said first processors and any communication process related with a second communication unit of said communication processes to the second one of said first processors.

A communication controller connected between a network and a host which performs communication over said network, comprising:

• a plurality of first processors which performs communication processes for packets between said network and said host;
• a second processor which allocates said communication processes to said first processors;
• and
• a first memory which is associated with the corresponding one of said first processors and which stores control information, said control information being generated in said host for each communication unit of said packets and used for said communication processes;
• wherein said first memory includes a first area accessed by the associated one of said first processors to refer to said control information and a second area which stores said control information during said access.