Dell Force10 S4820T S4820T Configuration Guide - Page 569

27 Link Aggregation Control Protocol (LACP) e c s Link Aggregation Control Protocol (LACP) is supported on platforms: S4820T The major sections in the chapter are: • Introduction to Dynamic LAGs and LACP • LACP Configuration Tasks • Shared LAG State Tracking • Configure LACP as Hitless • LACP Basic Configuration Example Introduction to Dynamic LAGs and LACP A Link Aggregation Group (LAG), referred to as a port channel by FTOS, can provide both load-sharing and port redundancy across line cards. LAGs can be enabled as static or dynamic. The benefits and constraints are basically the same, as described in Port Channel Interfaces in the Interfaces chapter. The unique benefit of a dynamic LAG is that its ports can toggle between participating in the LAG or acting as dedicated ports, whereas ports in a static LAG must be specifically removed from the LAG in order to act alone. FTOS uses LACP to create dynamic LAGs. LACP provides a standardized means of exchanging information between two systems (also called Partner Systems) and automatically establishes the LAG between the systems. LACP permits the exchange of messages on a link to allow their LACP instances to: • Reach agreement on the identity of the LAG to which the link belongs. • Move the link to that LAG. • Enable the transmission and reception functions in an orderly manner. The FTOS implementation of LACP is based on the standards specified in the IEEE 802.3: "Carrier sense multiple access with collision detection (CSMA/CD) access method and physical layer specifications." LACP functions by constantly exchanging custom MAC PDUs across LAN Ethernet links. The protocol packets are only exchanged between ports that are configured as LACP capable. Link Aggregation Control Protocol (LACP) | 569