Initial Offset Placement in p2p Live Streaming Systems
  Initial offset placement in p2p streaming systems is studied in this paper. Proportional placement (PP) scheme is proposed. In this scheme, peer places the initial offset as the offset reported by other reference peer with a shift proportional to the buffer width or offset lag of this reference peer. This will introduce a stable placement that supports larger buffer width for peers and small buffer width for tracker. Real deployed placement method in PPLive is studied through measurement. It shows that, instead of based on offset lag, the placement is based on buffer width of the reference peer to facilitate the initial chunk fetching. We will prove that, such a PP scheme may not be stable under arbitrary buffer occupation in the reference peer. The required average buffer width then is derived. A simple good peer selection mechanism to check the buffer occupation of reference peer is proposed for a stable PP scheme based on buffer width 
Chunxi Li and Changjia Chen