ATOMIC CHANNEL CHANGES IN A SWITCHED DIGITAL VIDEO SYSTEM
Atomic channel change in a switched digital video (SDV) system. A set-top box (STB) sends join and leave message commands to a SDV device when requesting a channel change. If one of the IGMP message commands does not reach the SDV device, oversubscription can occur. A combined join and leave message ensures that a join command is performed only when a leave command is also performed. If the single message does not reach the SDV device, the STB resends the command.
1 . A method for implementing IGMP-based channel changes in a broadcast system to prevent oversubscription, said method comprising the steps of:
transmitting a message to a switched digital video (SDV) device to implement a channel change; and
in response to transmitting said message, terminating a current channel transmission from said SDV device and transmitting a requested channel transmission from said SDV device.
2 . The method of claim 1 , further comprising the step of retransmitting said message to said SDV device in response to no channel change occurring.
3 . The method of claim 1 , further comprising the step of identifying bandwidth of said current channel and identifying bandwidth of said requested channel.
4 . A method for implementing IGMP-based channel changes in a broadcast system to prevent oversubscription, said method comprising the steps of:
transmitting a message to a switched digital video (SDV) device to implement a channel change;
dropping said message to said SDV device; and
retransmitting said message to said SDV device in response to no channel change occurring.
5 . The method of claim 4 , further comprising the steps of terminating a current channel transmission from said SDV device and transmitting a requested channel transmission from said SDV device.
6 . The method of claim 4 , further comprising the step of identifying bandwidth of said current channel and identifying bandwidth of said requested channel.
7 . An IGMP message comprising a request to implement a channel change by leaving a current channel and joining a requested channel, said message to be received at a switched digital video (SDV) device to terminate said current channel transaction and to initiate transmission of said requested channel transmission.
8 . The message of claim 7 , wherein said SDV device transmits said current channel transaction and initiates said transmission if said requested transmission substantially simultaneously.
9 . An IGMP message comprising a request to implement a channel change by leaving a current channel and joining a requested channel,
said message identifying bandwidth of said requested channel, and
said message to be received at a switched digital video (SDV) device to terminate said current channel transaction and to initiate transmitting of said requested channel transmission if said bandwidth of said requested channel is available.
10 . The message of claim 9 , wherein said SDV device transmits said current channel transaction and initiates said transmission if said requested channel transmission substantially simultaneously.