Cabletron Systems 9A128-01 manual Bridge Spanning Tree

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Bridging

2.Type in the new Ageing Time (allowable range is 10 to 1,000,000 seconds; the default is 300 seconds).

3.Click to accept the new Ageing Time, or click to exit the window without making changes.

NOTE

Note that the Source Addresses Ageing Time is the same as the Ageing Time displayed (and conﬁgured) via the Filtering Database window; setting the Ageing Time in the Source Addresses window also changes the time in the Filtering Database window, and vice versa.

Bridge Spanning Tree

The Bridge Spanning Tree window allows you to display and modify the selected module’s bridge port information and protocol parameters relating to the Spanning Tree Algorithm.

In a network design with multiple bridges placed in parallel (i.e., attached to the same LAN), data loops must be prevented. The Spanning Tree Algorithm (STA) is the method that bridges use to communicate with each other to ensure that only a single data route exists between any two end stations. On a LAN interconnected by multiple bridges, Spanning Tree selects a controlling Root Bridge and Port for the entire bridged LAN, and a Designated Bridge and Port for each individual LAN segment. A Designated Port/Bridge for a LAN segment forwards frames from that LAN towards the Root Bridge, or from the Root Bridge onto the LAN. All other bridge ports attached to that LAN are conﬁgured to ﬁlter (block) frames. When data passes from one end station to another across a bridged LAN, it is forwarded through the Designated Bridge/Port for each LAN segment towards the Root Bridge, which in turn forwards frames towards Designated Bridges/Ports on its opposite side.

During the Root Bridge Selection process, all bridges on the network communicate STA information via Bridge Protocol Data Units (BPDUs). With BPDUs, all network bridges collectively determine the current network topology and communicate with each other to ensure that the topology information is kept current.

To access the Bridge Spanning Tree window:

1.From the Bridge Status window, click on to display the Bridge menu. or

From the Module View window, click on the Bridge label in the module display; the bridge menu will appear.

2.Drag down to Spanning Tree..., and release. The Bridge Spanning Tree window, Figure 5-9, will appear.

5-14	Bridge Spanning Tree

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Contents Cabletron Systems Virus Disclaimer Page Restricted Rights Notice Page Contents Chapter Bridging Chapter Fddi ManagementIndex Introduction Using This GuideRelated Reading IP Address Software ConventionsCommon Window Fields Device NameLocation Using ButtonsUsing On-line Help Getting HelpFTP Getting Help from the Cabletron Systems Global Call CenterFirmware Versions Supported 9A128-01 Module View Front Panel Information Viewing Module InformationPort Status Boot PromConnection Status UpTimeTime Menu StructureDate Device Menu A128-01 Module View Menu StructurePort Status Menu Board Menus Fddi MenuUtilities Menu Help MenuPort Menus Port Status DisplaysBridge Port Status Displays Selecting a Port Status ViewFddi Port Status Displays Bridge Port StateBridge Mapping Bridge Port Status Color CodesLER Estimate Connection StateFddi Port Status Color Codes Chassis Manager WindowDevice Type Viewing Hardware TypesModule Type Module Type Window Viewing I/F Summary InformationInterface Performance Statistics/Bar Graphs IndexDescription StaLoad Raw CountsInterface Statistics Window RateNon-Unicast ErrorAddress UnicastPackets Transmitted Transmit only Using the Find Source Address FeaturePackets Received Received only Transmit Queue Size Transmit onlyManaging the Hub Setting the Device Date and TimeBridge Ports Enabling and Disabling PortsModule Ports ATM Conﬁguration Accessing the ATM Connections WindowConnection Data ATM ConﬁgurationVPI SettingsAdding a New Connection Conﬁguring ConnectionsDeleting a Connection ATM Conﬁguration Conﬁguring Connections Fddi Management Fddi Management ConﬁgurationMAC State Req. Requested Target Token Rotation Time SMT VersionNeg. Negotiated MAC Path Concentrator M PortsConcentrator Non-M Ports Number of MACsConnection Policy 15 32,768 a permanently set value for this bit Station List Address ModeNumber of Nodes Upstream Neighbor Stations PanelNode Class TopologyPerformance Lost Frames Frame ErrorsTransmit Frames Receive FramesFddi Management Performance Bridging Bridging Bridge Status WindowBridge Address Up TimeBridge State on Interface Interface TypeConﬁguring Duplex Modes Enabling and Disabling Bridging Performance Graphs Bridge StatisticsForwarded Green Conﬁguring the Bridge Performance Graphs Total Errors RedFiltered Magenta Xmitted BlueXmitted ErrorsForwarded FilteredForwarded to Interface Statistics WindowForwarded from Description Using Source Addressing Port Source Addresses Window Setting the Ageing TimeBridge Spanning Tree Bridge Priority Conﬁguring the Bridge Spanning Tree WindowProtocol Root BridgeRoot Cost Root PortHold Time Forwarding DelayHello Time Max AgeChanging Bridge Spanning Tree Parameters Changing the Spanning Tree Algorithm Protocol Type Changing Bridge PriorityChanging Hello Time Changing Max Age Time Changing Forwarding Delay TimeChanging Port Priority Changing Path Cost Filtering DatabaseBridging Bridging Ageing Time ListNumber CapacityReceive Port Conﬁguring the Filtering DatabasePort Filtering Changing the Port Filtering Action Altering the Ageing TimeChanging the Type of Entry Changing the Receive PortClearing All Permanent, Static, or Dynamic Entries Bridging Filtering Database Index Index-2 Index-3 Index Index-4