In this paper we present the AFDX (Avionics Full-DupleX switched Ethernet) extension for the open-source networking tool Net2Plan [1][2]. The Net2Plan-AFDX extension is also open-source, with no cost. This software will provide integrators, researchers and students with a set of tools to calculate, given an AFDX network design, an exhaustive set of AFDX parameters and performance merits. Net2Plan-AFDX can also be used for developing additional tools to evaluate and research alternatives related to AFDX. The implemented AFDX modules offer a Network Calculus and a Trajectory Approach algorithms' implementation for the theoretical worst-case delay calculation, given a configuration table. It also implements a simulation tool that produces realistic end-to-end latency values expected in an operational environment, as well as other performance merits. Avionics System Integrators can improve their designs using the obtained results.