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 EChapter1212 – Spanning Tree Protocol (STP)Create and manage alternate paths to the networkpanning Tree Protocol was designed to avoid loops in an Ethernet network. An Ethernetnetwork using switches can have redundant paths – this may however cause loops and toprevent the loops MNS-6K software uses spanning tree protocol. As a manager of the MNS-6Ksoftware, controlling n which span the traffic traverses is necessary. It is also necessary to specifythe parameters of STP. STP is available as the IEEE 802.1d protocol and is a standard of the IEEE.S STSTP features and operationhe switch uses the IEEE 802.1d Spanning Tree Protocol (STP). WhenTP is enabled, it ensures that only one path at a time is active betweenany two nodes on the network. In networks where more than one physicalpath exists between two nodes, STP ensures only a single path is active by blocking allredundant paths. Enabling STP is necessary to avoid loops and duplicate messages. Thisduplication leads to a “broadcast storm” or other erratic behavior that can bring down thenetwork.jAs recommended in the IEEE 802.1Q VLAN standard, the Magnum 6K family ofswitches uses single-instance STP. This means a single spanning tree is created to makesure there are no network loops associated with any of the connections to the switch.This works regardless of whether VLANs are configured on the switch. Thus, theseswitches do not distinguish between VLANs when identifying redundant physical links.The switch automatically senses port identity and type, and automatically defines port costand priority for each type. The MNS-6K software allows a manager to adjust the cost,priority, the mode for each port as well as the global STP parameter values for the switch.While allowing only one active path through a network at any time, STP retains anyredundant physical path to serve as a backup (blocked) path in case the existing active pathfails. Thus, if an active path fails, STP automatically activates (unblocks) an availablebackup to serve as the new active path for as long as the original active path is down.The table below lists the default values of the STP variables.147
