Abstract: Provided is a signal processing apparatus including upper, intermediate and lower layer processing sections. The lower layer processing section includes a first storage unit having a first memory capacity of a limited size for transfer data. The intermediate layer processing section includes a second storage unit having a second memory capacity larger than the limited size. The upper layer processing section transmits the transfer data of a size, larger than the first memory capacity and not larger than the second memory capacity, to the intermediate layer processing section. The intermediate layer processing section receives the transfer data, divides the data into plural divided data each having a size not larger than the limited size, and transmits the data to the lower layer processing section. Being untransmitted divided data, the intermediate layer processing section transmits this data to the lower layer processing section without transmitting any response signal.

Abstract: A packet communication apparatus is provided for transmitting a packet with a label for distinguishing each packet to each destination apparatus, and receiving a response packet with the same label transmitted from each destination apparatus. A plurality of application units respectively provide a plurality of functions which are independent of each other, and each application unit requests for issuing a label in accordance with start of a process of the function, and returns the issued label upon completion of the same process of the function. One common memory is provided in common for a plurality of application units, and stores a plurality of labels added to a header of each packet to distinguish a plurality of packets whose destination apparatus is identical.

Abstract: A communication apparatus is provided for communicating with further communication apparatuses which are connected with the communication apparatus, and for allowing one of a plurality of function units to execute a predetermined process in accordance with a request signal from a further apparatus. In the case where one of the further communication apparatuses is permitted to communicate with the communication apparatus, when a request signal of start of communication is sent from another one of the further communication apparatuses different from the one of the further communication apparatuses which has been already permitted to communicate with the communication apparatus, a manager unit returns response information including the designation information stored in the memory to another one of the further communication apparatuses so as to permit another one of the further communication apparatuses to communicate with.