The E320 is a high-performance router optimized for small to medium-size PoPs and central offices. The E120 has a 120G switch fabric and hosts up to six line modules that support OC3/STM1 through OC48c/STM16 and 10 Gigabit Ethernet rates. The E320 also supports both full height and half-height IOAs that permit flexible and efficient physical network connectivity.