A communication method and digital multi-customer data interface for interconnecting a number of customer terminals to a main packet switching network of a local area data transport system that provides data communication services such as interactive video text service between data service vendors and customers. The digital multi-customer interface utilizes a main processor, control circuit, and multi-customer protocol controller to implement the protocol functions for the communication of packets and control information over individual serial transmission paths. The multi-customer protocol controller comprises a control processor and a formatter circuit for synchronously communicating packets for a plurality of customer terminals via customer line units and customer lines. The control circuit handles communication of all control and status information between the main processor and the customer line units. The control processor includes a shared memory and first-in first-out memories that are used to communicate messages with the main processor. Both processors address the shared memory with logical addresses, and the control processor's logical address space is structured so as to facilitate the use of relative addressing.
The present invention includes a data transfer system (28) which includes a first bus (32) and a second bus (34) wherein both buses are bidirectionally connected to a first memory (30). Similarly, a third bus (42) and a fourth bus (44) are bidirectionally connected to a second memory (40). A plurality of data cells (50a through 50h) are provided for intermediate storage when units of information are transferred between first and second memories (30 and 40). A first pointer (37) is under control of first pointer circuit (36) and first control circuit (38) such that buses (32 and 34) may have access to selected ones of the plurality of data cells (50a through 50h). Similarly, a second pointer (47) is under control of second pointer circuit (46) and second control circuit (48) such that third and fourth buses (42 and 44) may have access to the plurality of data cells (50a through 50h).
A communications controller is provided that allows transfer of a large number of frames to each of the channels of an S.sub.0 -type link to be handled simultaneously at a data transfer rate matched to that of the link. The communications controller is connected between a bus associated with at least one host computer and the terminals of a network connected by a time-multiplexed digital link. The communications controller includes a base unit connected to the bus for managing and effecting the transfer of frames for the link, and a peripheral unit connected to the base unit and to the network. The base unit has a first processor of commands for transferring frames from the host to the network and vice versa, the first processor being associated with a frame storage memory; a peripheral part comprising a coupler controlled by second processor for ensuring multiplexing or demultiplexing of the data; and a second processor, in communication with the first, for transferring frames from the frame storage memory to the peripheral part and vice versa.
A data packet switching and server load balancing device is provided by a general-purpose multiprocessor computer system. The general-purpose multiprocessor computer system comprises a plurality of symmetrical processors coupled together by a common data bus, a main memory shared by the processors, and a plurality of network interfaces each adapted to be coupled to respective external networks for receiving and sending data packets via a particular communication protocol, such as Transmission Control Protocol/Internet Protocol (TCP/IP). A first one of the processors is adapted to serve as a control processor and remaining ones of the processors are adapted to serve as data packet switching processors. The data packet switching processors are each coupled to at least one of the plurality of network interfaces. The control processor receives raw load status data from the external networks and generates load distribution configuration data therefrom. The load distribution configuration data is stored in the main memory for access by the data packet switching processors. The switching processors route received ones of the data packets to a selected one of the external networks in accordance with information included in a header portion of the data packets and the load distribution configuration data. The switching processors perform periodic polling of corresponding ones of the network interfaces to detect a received one of the data packets therein. In addition, the switching processors re-write the routing information included in the header portion of the data packets to reflect the selected one of the external networks.
A real time data processing system in which each of a series of processing nodes is provided with its own data store partitioned into a first section reserved for the storage of data local to the respective node and a second section reserved for the storage of data to be shared between nodes. The nodes are interconnected by a data link and whenever a node writes to an address in the second section of a data store the written data is communicated to all of the nodes via the data link. The data in each address of the second sections of the data stores can be changed only by one respective processing node which acts as a master for that address. As each address containing shared data can only be written to by one node collisions between different nodes attempting to change a common item of data cannot occur.
Apparatus and a method for providing real estate agents, persons relocating to another home or acquiring an interest in a property, and providers of home insurance, with an audio-visual presentation of a property supplied over existing cable, telephone, ISDN or other types of broadband network facilities. The audio-visual presentation is mode on a computer monitor from a database containing a visual walkthrough and a textual description of the property and surrounding areas.
