Dell PowerConnect 3048 User Manual page 41

Port Trunking
In the Port Trunking page, you can create multiple links between switches that work as one virtual, aggregate link. You can create four trunks at a time, with
each trunk containing up to eight ports. Only ports of the same speed can belong to a single trunk: 10/100 Fast Ethernet ports and Gigabit Ethernet ports
cannot be in the same trunk.
NOTICE: Fast Ethernet trunks can only include ports from a single eight-port cluster: Ports 1 to 8, ports 9 to 16, ports 17 to 24, ports 25 to 32, ports 33
to 40, or ports 41 to 48.
NOTICE: Built-in 10/100/1000BASE-T ports cannot be trunked with GBIC ports.
To add a port to a trunk, click the toggle button below the port number until the correct trunk number appears.
Use the arrow keys to navigate to the port and trunk intersection that you want to edit. Press the spacebar to enable or disable trunking.
NOTICE: All ports participating in a trunk must be operating in Full Duplex mode.
NOTICE: All ports participating in a trunk should have the same VLAN and CoS settings.