Link aggreg ation is the bundling of several links. It plays an important role in the scaling of networks and is controlled in Multi Link Trunks( MLT) according to IEEE 802.3ad via the Link Aggregation Control Protocol (LACP).
The LACP protocol can be used to form a single Ethernet link with a cummulated data rate from multiple Ethernet links. It ensures that the link formation functionally matches the aggregation groups and new links are added only when their functionality matches. For the operation of the Multi Link Trunk (MLT), both link endpoints are enabled.
If the LACP protocol is not available, 802.3ad provides the option of manual aggregation. This only requires that both link ends are functional. In any case, 802.3ad ensures that no frame is lost or duplicated when a link is added or removed.
Virtual switches support two LACP modes of operation: active operation (Active) and inactive operation (Inactive). In active mode, the LACP protocol negotiates between two virtual switches; in inactive mode, no agreements take place and received LACP packets are ignored.