All ports are assigned a number at the time they are created in the project editor. There is no limit on the number of ports and the number of ports has a minimal impact on the analysis time needed for de-embedding. By default, the ports are numbered by the order in which they are created (i.e. first port created is assigned the number 1, second port created is assigned the number 2, etc.). With this default method, all ports are positive and unique. However, there are some applications that require the ports to have duplicate, and even negative, numbers. Ports may also be assigned multiple port numbers. There is also a special case of Port 0 which is used for a ground connection.