A system and method are disclosed for the repair of IP multicast sessions. A repair server polls multiple transmit servers to accumulate as many of the packets missing from the multicast session as possible. A network includes a source of multicast packets in a multicast session and a plurality of multicast recipients in that session. A repair server in the network provides the packets it receives to the recipients. The repair server includes a missing packet detector. There is a plurality of retransmit servers in the network buffering portions of the packets they respectively receive during the session. The repair server maintains an ordered list of the retransmit servers that are most likely to have buffered copies of packets missing from the session. When the repair server detects that there are packets missing from the session it has received, it uses the ordered list to sequentially request the missing packets from respective ones of the plurality of retransmit servers.
The invention relates to a method for data repair in a system capable of one-to-many transmission. The method comprises transmitting data from a sender to at least one receiver and provides for various sender driven or receiver driven repair methods of missing data.
To ensure the polling of a server 11 will reach clients 12 from which an ACK/NACK has not been received despite the change of IP addresses of clients 12 in a network system where an ACK/NACK is to be sent back from each client 12 to the server 11 after file data is transmitted from the server 11 to multiple clients 12 by means of broadcast.Clients 12 in a group are granted identification IDs that are mutually identifiable and permanent. Server 11 send the polling by means of multicast that contains information about permanent IDs of the clients 12 from which it has not received an ACK/NACK. Each of the clients 12 replies with an ACK/NACK if its own permanent ID is contained in the polling, otherwise makes no reply.
In one embodiment the invention is a method. The method includes receiving data from a first party into a multiplexing device or a plurality of multiplexing devices. The method also includes receiving from a second party into a first jitter buffer, processing the data from the second party, and sending output data from the first jitter buffer to a multiplexing device or a plurality of multiplexing device. The method also includes receiving data from a third party into a second jitter buffer, processing the data from the third party, and sending output data from the second jitter buffer to a multiplexing device or a plurality of multiplexing devices. The method further includes sending data from one or a plurality of the multiplexing devices to a first output device. The method further includes sending data from one or a plurality of the multiplexing devices to a second output device. Moreover, data is further sent from one or a plurality of the multiplexing devices to a third output device. In one embodiment the data received from the first party, second party, and third party is packetized voice data.
When a transport rate Rs is updated, in the case where the updated transport rate Rs is within a variable range (Rc<Rs<U.times.Rc, and U>1) defined by a current encoding rate Rc, FEC (Forward Error Correction) data sending rate Rf is updated (Rf=Rs-Rc) without updating the current encoding rate Rc. On the other hand, in the case where an Rc update timer set to three seconds, for example, is timed out, the encoding rate Rc is updated using a minimum value Rs_min of the transport rate up to that time (Rc=V.times.Rs_min, and 0<V<1). Even when the transport rate Rs greatly varies to be out of the variable range, the encoding rate Rc is updated in the same manner.
The disclosed embodiments relate generally to monitoring and correcting failure conditions in networked computer systems and, more particularly, to improving the usefulness of stored video data retrieved for playback from a managed server. The disclosed embodiments include a method and apparatus for storing captured video data for retrieval and replay in a temporally accurate manner at a later time. The video data replayed in this manner is useful for identifying potential problems in the managed server.
