ports : 24 x 10/100/1000base-t ports; 4 x combo sfp 1 x rs-232 console port power over ethernet : 802.3af poe support per 10/100/1000base-t port 15.4w x power provision per port (max.); 370w system poe power budget stacking : 2 x hdmi stacking ports ; 6 x number of unit per stack (max) bandwidth/topology : up to 10gbps (linear topology) up to 20gbps (bi-directional redundant ring topology) switch capacity: 68 gbps 64-byte packet forwarding rate: 50.6mpps mac address table size : 8k packet buffer: 768kb jumbo frame : 10,240bytes power input : 100 to 240 vac, 50 to 60 hz internal universal power supply dimensions : 440mm x 210mm x 44mm 19-inch standard rack-mount width, 1u height mtbf : 212,377 hrs * security - port security, acl, 802.1x port-based/mac-based access control guest vlan, traffic segmentation, 256 vlan groups, d-link safeguard engine * traffic monitoring/bandwidth, control, port mirroring,granular bandwidth control (down to 64kbps per port), broadcast storm control * resiliency/performance 802.1d, 802.1w and 802.1s spanning tree, 802.3ad link aggregation (port trunks), jumbo frame * configuration/management web-based gui , command line interface (cli)