Since P2P applications generate large amount of traffic on the network without considering the physical network topology, it is an urgent issue for Internet service providers to solve the problem. In recent years, content delivery services have been introducing P2P mechanisms and started delivering video contents same as TV programs, in partnership with broadcasting stations, mainly in Europe. It is concerned that the traffic might rapidly increase due to frequent channel switching, i.e., zapping like on TV. In this paper, we analyzed the traffic characteristics of a P2P video content delivery service, PPStream, when a peer zapped channels. The results show that both the receiving throughput and the number of connected peers significantly increase while zapping especially on long video contents.