End users are often frustrated by unexpected problems while using networked software, leading to frustrated calls to the help desk seeking solutions. However, trying to locate the cause of these unexpected behaviors is not a simple task. The key to many network monitoring and diagnosis approaches is using cross-layer information, but the complex interaction between network layers and usually large amount of collected data prevent IT support personnel from determining the root of errors and bottlenecks. There is a need for the tools that reduce the amount of data to be processed, offer a systematic exploration of the data, and assist wholestack performance analysis. In this paper, we present Visty, a network stack visualization tool that allows IT support personnel to systematically explore network activities at end hosts. Visty can provide an overview picture of the network stack at any specified time, showing how errors in one layer affect the performance of others. Visty was desi...