Abstract: A data transmission method quickly and reliably transfers data (e.g., a computer file) from a source to recipients. While the frames are being transmitted, negative acknowledgments from recipients are received by the source. These acknowledgments indicate which frames require retransmission. After all frames have been transmitted out, a retransmission is performed by the source for only those frames which the acknowledgments indicate require retransmission. Additional retransmissions can occur. This multi-pass data transfer technique requires only negative acknowledgements to be sent by the recipients. Features include the ability to set the transmission rate and to define multicast groups. Also, it is possible to determine the capacity of links of unknown capacity using a "multicast network probe" feature of the invention, and to determine the frame error rates of known-capacity links by utilizing the same feature.

Abstract: The transmission of data (e.g., a computer file) from one or more content sources over a network to one or more replicated servers is scheduled and performed according to the schedule. The content sources request the schedule from a network resource scheduler. The scheduler receives the requests and determines if and how the various requests can be accommodated. The scheduler determines at least a start time and a transfer rate for each of the content sources that can be accommodated.

Abstract: A data transmission method quickly and reliably transfers data (e.g., a computer file) from a source to recipients. While the frames are being transmitted, negative acknowledgments from recipients are received by the source. These acknowledgments indicate which frames require retransmission. After all frames have been transmitted out, a retransmission is performed by the source for only those frames which the acknowledgments indicate require retransmission. Additional retransmissions can occur. This multi-pass data transfer technique requires only negative acknowledgements to be sent by the recipients. Features include the ability to set the transmission rate and to define multicast groups. Also, it is possible to determine the capacity of links of unknown capacity using a "multicast network probe" feature of the invention, and to determine the frame error rates of known-capacity links by utilizing the same feature.

Abstract: A data transmission method quickly and reliably transmits data (e.g., a file) from a source to one or more recipients over a communications link. The method includes transmitting the data, which are in the form of a plurality of frames, from the source over the link to one or more of the recipients until all of the plurality of frames have been transmitted over the link. While the data are being transmitted by the source, acknowledgments from one or more of the recipients are received by the source. The acknowledgments indicate which frames require retransmission. After all of the frames have been transmitted over the link, a retransmission is performed by the source for only those frames which the acknowledgments indicate as requiring retransmission.