Abstract: The benefits of a multicast-enabled network are realized by a flexible, easy to deploy, software-based solution that does not require reconfiguring of network routers. Systems and methods that implement this solution can perform as follows. A packet is received that was sent by a sender to at least one receiver, and the packet includes a parameter relating to a multicast announce address. A forwarding rules set is associated with the packet if the parameter has a defined value. This forwarding rules set is used to determine whether any of the at least one destination addresses included in the packet corresponds to one of the receivers that has a receiver format that must be converted. In addition, the forwarding rules set defines when a packet should be converted from a sender format to a receiver format before forwarding the packet.

Abstract: The benefits of a multicast-enabled network are realized by a flexible, easy to deploy, software-based solution that does not require reconfiguring of network routers. Systems and methods that implement this solution can perform as follows. A packet is received that was sent by a sender to at least one receiver, and the packet includes a parameter relating to a multicast announce address. A forwarding rules set is associated with the packet if the parameter has a defined value. This forwarding rules set is used to determine whether any of the at least one destination addresses included in the packet corresponds to one of the receivers that has a receiver format that must be converted. In addition, the forwarding rules set defines when a packet should be converted from a sender format to a receiver format before forwarding the packet.

Abstract: The benefits of a multicast-enabled network are realized by a flexible, easy to deploy, software-based solution that does not require reconfiguring of network routers. Systems and methods that implement this solution can perform as follows. A packet is received that was sent by a sender to at least one receiver, and the packet includes a parameter relating to a multicast announce address. A forwarding rules set is associated with the packet if the parameter has a defined value. This forwarding rules set is used to determine whether any of the at least one destination addresses included in the packet corresponds to one of the receivers that has a receiver format that must be converted. In addition, the forwarding rules set defines when a packet should be converted from a sender format to a receiver format before forwarding the packet.

Abstract: The benefits of a multicast-enabled network are realized by a flexible, easy to deploy, software-based solution that does not require reconfiguring of network routers. Systems and methods that implement this solution can perform as follows. A packet is received that was sent by a sender to at least one receiver, and the packet includes a parameter relating to a multicast announce address. A forwarding rules set is associated with the packet if the parameter has a defined value. This forwarding rules set is used to determine whether any of the at least one destination addresses included in the packet corresponds to one of the receivers that has a receiver format that must be converted. In addition, the forwarding rules set defines when a packet should be converted from a sender format to a receiver format before forwarding the packet.

Abstract: To make registration and confirmation of groups and confirmation of data transmission more scaleable, particularly for large groups, the size of a host list pruned in subsequent transmission. This host list management can be achieved by (a) creating a message that includes a list of one or more receivers;(b) sending the message over a network; (c) receiving over the network one or more replies from one or more of the receivers; (d) identifying each receiver for which one of the replies was received and establishing another message that includes the list with the identified receivers; (e) sending the message established in step (d) over the network; (f) creating a modified list by removing the identified receivers from the list; and (g) if there are one or more receivers on the modified list, repeating steps (c), (d), (e), (f), and (g) using the modified list as the list.

Abstract: This invention relates to a system and method for managing a session during which data is sent to receivers, wherein retransmission of the data to the receivers can be automatically rescheduled if the receiver did not receive some or all of the data. An object of the invention is to send content to receivers that did not or could not receive data during a multicast data transmission session. In accordance with this and other objects of the invention, one aspect of the invention relates to a method of managing a session during which data is sent to receivers. A first message is sent over a network a message to a list comprising at least one receiver, the first message relating to receiving data during a first session. Replies are received over the network from the receivers on the list. Based on the replies received, each receiver on the list that will not be receiving data during the first session is identified.

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.

Abstract: A modem fault detector and corrector system including: a first modem including a first transmitter and first receiver and a second modem including a second transmitter and second receiver; switch means for selectively switching the first and second transmitters on and off of a transmission line; and the first and second receivers on and off of a receiver line; and for connecting one of the receivers with the output of either of the first and second transmitters; means for monitoring the status of each of the modems; means for correlating transmit data with receive data; means for sequencing the switch means to enable the means for correlating to compare transmit data selectively with the output of the first transmitter and the second transmitter; and means, responsive to the means for monitoring, the means for correlating, and the means for sequencing for detecting a malfunction in one of the first modem, second modem and transmission-receiver lines and directing the switch means to replace a malfunctioning o