Link aggregation (LAG) is used to describe various methods for using multiple parallel network connections to increase throughput beyond the limit that one link (one connection) can achieve. For link aggregation, physical ports must reside on a single switch. Split Multi-Link Trunking (SMLT) and Routed-SMLT (RSMLT) remove this limitation and physical ports are allowed to connect/split between two switches.

Link aggregation is a technique used in a high-speed-backbone network to enable the fast and inexpensive transmission of bulk data. The best feature of link aggregation is its ability to enhance or increase the network capacity while maintaining a fast transmission speed and not changing any hardware devices, thus reducing cost.