Failure Recovery - Providing continuous playback

In P2Cast, the departure of a client can disrupt both the delivery of a patch stream and the transmission of the base stream over the base tree. The ability to provide continuous playback in the face of these disruptions is essential to the success of P2Cast. In the following, we examine this issue from the following two aspects: (1) the disruption effect on the continuous playback of the patch stream; and (2) the disruption effect on continuous playback of the base stream. We find that the patch stream is relatively immune to the disruption because of its short duration. For the base stream, we proposed the shifted forwarding technique to conceal the disruption. Finally, the threshold in P2Cast serves as a knob that can adjust the balance between the scalability and the clients' viewing quality.