Port Trunking
Port trunking is a feature that allows multiple links between switches to function as one virtual link or aggregate link. Trunks can be defined for similar port types only. For example, 1 10/100 port cannot form a Port Trunk with a gigabit port.
Trunks can only be formed within the same cluster. A cluster is a set of 8 ports. Four trunks can be created at the same time.
Spanning Tree will treat trunked ports as a single virtual network.
A trunk cannot have both Fast Ethernet and Gigabit Ethernet member. A Fast Ethernet trunk cannot span multiple Fast Ethernet port groups. Fast Ethernet port groups are 1-8, 9-16 and 17-24.