Poe switch rackmount switch switching ports 28 gigabit ethernet ports 4 x sfp 26 x rj 45 switch type standalone management managed layer 3 network standards power over ethernet poe quality of services qos vlan access control list acl address resolution protocol arp energy efficient ethernet flow control igmp snooping link aggregation lag link aggregation control protocol lacp link layer discovery protocol lldp spanning tree protocol stp backplan