20 auto-sensing 10/100/1000 ports(IEEE 802.3 Type 10Base-T, IEEE 802.3u Type 100Base-TX, IEEE 802.3ab Type 1000Base-T), Media Type: Auto-MDIX, Duplex: 10Base-T/100Base-TX: half or full; 1000Base-T: full only; 4 dual-personality ports, each port can be used as either an RJ-45 10/100/1000 port or an open mini-GBIC slot (for use with mini-GBIC transceivers)