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Link Aggregation Group

Instead of having redundant links and allowing STP to put one of the links in blocked mode, a user can bundle the links and create a logical aggregation so that the multiple links will then appear as a single one. The redundancy provided will be same as that of STP.

The Link Aggregation Control Protocol (LACP) follows the IEEE 802.3ad standard.

The Ethernet interfaces at the physical layer form a single link layer interface by using IEEE 802.3ad link aggregation, also known as a link aggregation group (LAG) or bundle.

It helps in reducing the expense as a single Fast Ethernet can provide bandwidth of a higher-speed Gigabit Ethernet link. It provides increased bandwidth and port density at a lower cost by using IEEE 802.3ad link aggregation. For example, if you need 650 Mbps of bandwidth to transmit data and have only a 100-Mbps Fast Ethernet link, creating a LAG bundle containing seven 100-Mbps Fast Ethernet links is more cheaper than purchasing a single Gigabit Ethernet link.

• The Link Aggregation Control Protocol (LACP) is used to create and maintain LAG bundles, exchanging port and system information, the Link Aggregation Control Protocol (LACP) is used. Across the link layer interface, the LAG bundle distributes the MAC clients. Then traffic is collected from the links to present to the MAC clients of the LAG bundle.
• You can add one or more Ethernet physical interfaces to create the links in the LAG bundles. The LACP protocol detects Ethernet interfaces as links if they are configured on the same line card and have the same physical layer characteristics. The MAC address of the Ethernet link with the highest port priority is assigned to the LAG bundle.
• The exchange of LACP protocol data units (PDUs) between the Ethernet links in the LAG bundle is also controlled by LACP. The LAG bundle is maintained as PDU contain information about each link.
• The PDUs that contain information about the state of the link are not exchanged by the Ethernet links by default. The Ethernet link are often configured actively or passively to transmit PDUs by sending out LACP PDUs only when it receives the PDUs from another link. The receiving link is understood as the Partner and the transmitting link is called as the Actor.

The above mentioned features are offered and supported by VCL-MX-50xx family of IP/MPLS Routers.