P2P video streaming is receiving enormous attention, and when video is involved, the efficient use of the network becomes a very important issue, specially if live applications are addressed. In this work we study properties of Push/Pull protocols for the exchange of video chunks in non-structured systems. Push/Pull protocols are a broad class of chunk exchange mechanisms where peers alternate phases where they actively send chunks to other peers, with phases where they seek for missing chunks from other peers. We focus on the properties of the protocol, trying to gain insight on the distributed exchange mechanism itself. Then, we explore how performances can be improved if peers, in selecting the peers to exchange information with, also consider network level parameters, namely the round trip delay.