Trunking

About trunking

Trunking is a mechanism that groups together multiple network interfaces (links) into one logical interface (trunk). Different vendors refer to trunks by the following terms:

Virtual aggregations
Link aggregations
Virtual interfaces (the term Network Appliance uses)
EtherChannel

The appliance implementation closely follows the IEEE 802-3ad specification.

Advantages of trunking

Trunks provide several advantages over individual interfaces, such as the following:

Higher throughput because of multiple interfaces working as one interface.
Fault tolerance. If one interface in a trunk goes down, the appliance can still stay connected to the network using the other interfaces.
Protection against a switch becoming a single point of failure.

Appliance interfaces before trunking

The following illustration shows four separate appliance interfaces, e3a, e3b, e3c, and e3d, before trunking.

Appliance interfaces after trunking

The following illustration shows the four appliance interfaces joined after trunking into a single trunk called Trunk1.