We have to replace one of EoL router. That router has VWIC2-2MFT-T1/E1 card and serial link ( E1 and ppp encapsulation ) . We have bought new ISR 4331 router to replace this router. Does the Gigabit ethernet port on this router can be used for WAN connection or what do we need to do to make it work. Any information is much appreciated.