NETWORK INTERFACE HAVING SUPPORT FOR MESSAGE PROCESSING AND AN INTERFACE TO A MESSAGE COPROCESSOR

A network interface for a connection-based communication network has support for message processing, including an interface for communication with an optional message coprocessor that performs a variety of message processing operations. Message processing is low level processing of messages between the host computer and the network. Such processing is performed on transmission in response to control information provided by the host and is performed on reception in response to control information included in incoming messages. Message processing includes low latency remote read and remote write operations, message filtering, and message demultiplexing. Such a network interface provides support for a variety of message processing operations using the coprocessor, while the complexity and cost of the network interface due to this support is minimal. The network interface provides control information for a message to the message coprocessor. The control information indicates an operation to be performed by the message coprocessor, and possibly operands. The message coprocessor responds with one of a small set of commands to be executed by the network interface. The command from the message coprocessor may include additional data, such as a location in memory in which data should be deposited at the host or at a remote destination. Using this kind of interface, the control information provided to the message coprocessor can be completely arbitrary, limited only by the capabilities of the message coprocessor. Since the message coprocessor can be arbitrarily selected so long as it conforms to the protocol used by the network interface, experimentation with new communication protocols in connection with the network interface is simplified.