The 10/100-Mbps Fast Ethernet switching module (10/100Base TX 12 port) provides 12 switched, 10/100-Mbps (10/100BaseTX Category 5 UTP), full- or half-duplex Fast Ethernet ports using 12 RJ-45 connectors.The WS-X5203 module supports Fast EtherChannel. On all Fast EtherChannel-capable hardware, port groups determine which ports can form a channel. Channels must be composed of contiguous ports from the same port group. A channel cannot have some ports from one group and some ports from another. However, you can configure multiple channels within a single group. On the WS-X5203, the ports form three groups of four ports each (ports 1-4, 5-8, and 9-12).