In our practice of the IPTV test system construction

many technical problems related directly to subscriber quality of experience

networking cost and the scale of operation are encountered.Two key problems among them

i.e.

the CDN node storage problem and the live broadcasting QoS problem

are investigated in this paper.Through performance and cost comparison between several popular CDN storage schemes

the superiority of SAN becomes clear.Channel switch and multicast packet loss

the two critical points involved in QoS of live broadcasting service

are discussed in detail

and practical measures to improve the associated QoS are then obtained based on the analysis.