I have a Nortel CS 2100 that will be connected to 5 Avaya G3R R11 CM1. What is the best way to intergrate CS 2100 to G3R's, DS1 or IP Trunks. What are the benefits of DS1 or IP Trunks. AS you know the CS 2100 is a IP Switch and the G3R's are TDM Switch but IP enable.