Juniper Networks EX Series EX4550 Virtual Chassis - network stacking module

The Virtual Chassis Module is a hot-insertable and hot-removable field replaceable unit (FRU). The Virtual Chassis Module has two dedicated Virtual Chassis ports (VCPs), using which you can interconnect the EX4550 switch to an EX4200, EX4500, or EX4550 switch in a Virtual Chassis configuration.