LA (Link Aggregation) is a method of combining physical network links into a single logical link for increased bandwidth. LA increases the capacity and availability of the communications channel between devices (both switches and end stations) using existing Fast Ethernet and Gigabit Ethernet technology. LA also provides load balancing where the processing and communication activity is distributed across several links in a trunk, so that no single link is overwhelmed. By taking multiple LAN connections and treating them as a unified, aggregated link, practical benefits in many applications can be achieved.
Improvements are obtained using existing hardware (no upgrading to higher-capacity link technology is necessary)
The Link Aggregation Control Protocol (LACP), described by IEEE 802.3ad, defines a method for two switches to automatically establish and maintain link aggregation groups ( LAG)s, or also called port channels or channel-groups. Port channels combine the bandwidth of multiple Ethernet ports into a single logical link, and management functions treat an LAG as if it were a single physical port.
When LACP is not enabled, a port channel might attempt to transmit packets to a remote single interface, which causes the communication to fail.
When LACP is enabled, a local LAG cannot transmit packets unless an LAG with LACP is also configured on the remote end of the link.
A channel group is a collection of Ethernet interfaces on a single switch. A port channel interface is a virtual interface that serves a corresponding channel group and connects to a compatible interface on another switch to form a port channel. Port channel interfaces can be configured and used in a manner similar to Ethernet interfaces. Port channel interfaces are configurable as Layer 2 interfaces, Layer 3 (routable) interfaces, and VLAN members.
The switch supports up to 8 link aggregation groups, with a maximum of up to 8 ports per group.