Introduction With the evolution of wire speed switch-routers from enterprise networks to the core public carrier data networks, Packet over SONET/SDH (POS) has emerged as the dominant Layer-2 protocol for high-speed IP public data network connectivity. The POS Analysis Test Software application assists: •Carrier-class Gigabit router manufacturers to test and verify 40Gb/s POS designs and accelerate time-to-market and •Service providers to select the best routing devices for a service network and maintain its operation with a powerful test and evaluation tool.