Application Layer Traffic Optimization (ALTO) allows operators to guide the peer selection of P2P applications. Using ALTO, operators can reduce inter-domain transmissioncosts while at the same time P2P applications can improve their performance. Essentially, an ALTO server is a dedicated service (operated by a network operator or ISP) which can guide applications by providing network layer information about resource providers which applications cannot measure themselves. In this work, we study the effect of ALTO-guidance for P2P live streaming applications. In earlier work, we studied to what extent the amount of costly inter-ISP traffic can be reduced with ALTO while still fulfilling the stringent requirements of P2P live streaming. In this work we focus on how ALTO can be beneficial from an application/user perspective. We investigate in which scenarios and to what extent ALTO can reduce application-layer delay and chunk loss, thereby improving the perceived Quality-of-Experience (QoE) for users. Based on data sets that model the Internet’sAS-level routing topology with high accuracy, we investigate different peer selection strategies to assess the effectiveness of ALTO-guidance in decreasing delay and chunk loss in P2P live streaming applications.