Patents by Inventor Kenneth N. Schaff

Kenneth N. Schaff has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5388238
    Abstract: A system and method are described for enforcing the validity of circulating pointers stored in a pointer FIFO (first-in-first-out) memory. One or more target pointers are generated and compared to circulating pointers. If a pointer does not circulate through the system within a pre-specified time, then a pointer has been lost and an error is reported. If a circulating pointer matches a target pointer, it is suppressed by being removed from the set of circulating pointers. Another timer is then set to determine whether further circulating pointers match a target pointer. If so, then multiple pointers to the same location are present and all duplicate pointers are suppressed. After expiration of the second time, the target pointers are added to the set of circulation pointers. This process repeats with new target pointers, so that the validity of the set of circulating pointers is verified.
    Type: Grant
    Filed: July 24, 1992
    Date of Patent: February 7, 1995
    Assignee: AT&T Corp.
    Inventors: Christopher G. McHarg, Kenneth N. Schaff
  • Patent number: 5291482
    Abstract: A fast packet switch comprising one buffer directly connected between a plurality of input ports and a plurality of output ports to effect rapid throughput of data packets. A pointer to a location in the buffer is allocated by a buffer manager upon receipt of notification of an incoming packet at the receiving input port and the input port delivers the packet as it is received to the location designated by the pointer. After the data packet is received, the input port delivers the pointer and a destination address for the packet to a router, which selects one of the plurality of output ports based on the destination address. The router queues the pointer in a queue for the selected output port. The output port then retrieves the data packet from the buffer using the pointer to determine the location, and transmits the data packet. After the transmission is complete, the output port returns the pointer to the buffer manager.
    Type: Grant
    Filed: July 24, 1992
    Date of Patent: March 1, 1994
    Assignee: AT&T Bell Laboratories
    Inventors: Christopher G. McHarg, Thomas E. Newman, Kenneth N. Schaff, Kenneth E. Wendland