M A G N U M 6 K S W I T C H E S , M N S - 6 K U S E R G U I D EChapter1515 – Dual-HomingFault tolerance options for edge devicesesigning and implementing high-availability Ethernet LAN topologies innetworks can be challenging. Traditionally, the choices for redundancy foredge of the network devices were too limited, too expensive, and toocomplicated to be considered in most networks. Redundancy at the edge ofthe network is greatly simplified by the using dual-homing.D.DInreual-Homing conceptsEthernet LANs, dual-homing is a network topology that addsliability by allowing a device to be connected to the network byway of two independent connection points (points of attachment).One connection point is the operating connection, and the other is a standby or back-upconnection that is activated in the event of a failure of the operating connection. A dual-homing switch (such as EDS42) offers two attachments into the network or twoindependent media paths and two upstream switch connections. In the case of theMagnum 6K family of switches, any two ports can be defined as dual-home ports toprovide this level of redundancy. Loss of the Link signal on the operating port connectedupstream indicates a fault in that path, and traffic is quickly moved to the standbyconnection to accomplish a fault recovery.j187
