... extension functions, including VLAN Stacking/Trunk, etc.Support flexible DBA, uplink/downlink service rate-limited, minimum ... swappable fans module4Power module1Hot-swappable power supply module supports 220Vac power in, builds dual power redundant hot backup with -48Vdc ... VLAN extension functions, support VLAN Stacking/Trunk and flexible QinQ, etc.RSTPSupport STP, RSTPIGMPSupport IGMPv1/v2 protocol ...