Cabletron Systems 9A128-01 manual Root Bridge, Root Cost, Root Port, Protocol

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Bridging

Part of a bridge’s Identifier is based on its MAC address. In most network installations,

TIP the difference between bridge performance may be negligible. You may, however, find your data bottle-necked in installations where both a low-performance bridge and a high-performance bridge are attached to the same LAN segment and the two (or more) bridges have the same Priority component set (e.g., at the default 8000 Hex). In such a scenario you may want to alter the Priority component of the higher performance bridge to ensure that it becomes root for the segment (or overall root). Remember, if Priority components are equal the bridge on the segment with the lowest Hex value of MAC address would have a better chance of being selected as the root bridge — as it would have a lower Bridge Identifier. If your bridges come from multiple vendors, they will have different MAC address values (e.g., Cabletron devices have a lower MAC address than 3Com devices); if they come from the same vendor, the bridge with the earlier manufacture date will be likely to have the lower MAC address value.

Root Bridge

Displays the MAC address of the bridge that is currently functioning as the Root Bridge.

Root Cost

Indicates the cost of the data path from this bridge to the Root Bridge. Each port on each bridge adds a “cost” to a particular path that a frame must travel. For example, if each port in a particular path has a Path Cost of 1, the Root Cost would be a count of the number of bridges along the path. (You can edit the Path Cost of bridge ports as described later.) The Root Bridge’s Root Cost is 0.

Root Port

This field displays the identifier (the physical index number) of the selected module’s bridge port that has the lowest cost path to the Root Bridge on the network. If the selected module is currently the Root Bridge, this field will read 0.

Protocol

Displays the Spanning Tree Algorithm Protocol type the selected module is currently using. The choices are:

•802.1

•DEC (DEC Lanbridge 100)

•None

The following four fields display values used for various Spanning Tree timers that are set at the Root Bridge and this bridge. In Spanning Tree operations, the value used for the tree is the one set at the Root Bridge (with the exception of Hold Time, which is a fixed value); but you can change the value for each bridge on your network in the event that it becomes Root.

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Bridge Spanning Tree

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Contents Cabletron Systems Virus Disclaimer Page Restricted Rights Notice Page Contents Chapter Fddi Management Chapter BridgingIndex Introduction Using This GuideRelated Reading Common Window Fields Software ConventionsDevice Name IP AddressUsing On-line Help Using ButtonsGetting Help LocationFTP Getting Help from the Cabletron Systems Global Call CenterFirmware Versions Supported 9A128-01 Module View Front Panel Information Viewing Module InformationConnection Status Boot PromUpTime Port StatusMenu Structure TimeDate Device Menu A128-01 Module View Menu StructurePort Status Menu Utilities Menu Fddi MenuHelp Menu Board MenusPort Menus Port Status DisplaysBridge Port Status Displays Selecting a Port Status ViewBridge Mapping Bridge Port StateBridge Port Status Color Codes Fddi Port Status DisplaysLER Estimate Connection StateFddi Port Status Color Codes Chassis Manager WindowViewing Hardware Types Device TypeModule Type Module Type Window Viewing I/F Summary InformationDescription IndexSta Interface Performance Statistics/Bar GraphsLoad Raw CountsInterface Statistics Window RateAddress ErrorUnicast Non-UnicastPackets Received Received only Using the Find Source Address FeatureTransmit Queue Size Transmit only Packets Transmitted 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 SMT Version Req. Requested Target Token Rotation TimeNeg. Negotiated Concentrator Non-M Ports Concentrator M PortsNumber of MACs MAC PathConnection Policy 15 32,768 a permanently set value for this bit Address Mode Station ListNumber of Nodes Node Class Stations PanelTopology Upstream NeighborPerformance Transmit Frames Frame ErrorsReceive Frames Lost FramesFddi Management Performance Bridging Bridging Bridge Status WindowBridge State on Interface Up TimeInterface Type Bridge AddressConfiguring Duplex Modes Enabling and Disabling Bridging Performance Graphs Bridge StatisticsForwarded Green Filtered Magenta Total Errors RedXmitted Blue Configuring the Bridge Performance GraphsForwarded ErrorsFiltered XmittedInterface Statistics Window Forwarded toForwarded from Description Using Source Addressing Port Source Addresses Window Setting the Ageing TimeBridge Spanning Tree Bridge Priority Configuring the Bridge Spanning Tree WindowRoot Cost Root BridgeRoot Port ProtocolHello Time Forwarding DelayMax Age Hold TimeChanging Bridge Spanning Tree Parameters Changing Bridge Priority Changing the Spanning Tree Algorithm Protocol TypeChanging Hello Time Changing Forwarding Delay Time Changing Max Age TimeChanging Port Priority Changing Path Cost Filtering DatabaseBridging Bridging Number ListCapacity Ageing TimeConfiguring the Filtering Database Receive PortPort Filtering Changing the Type of Entry Altering the Ageing TimeChanging the Receive Port Changing the Port Filtering ActionClearing All Permanent, Static, or Dynamic Entries Bridging Filtering Database Index Index-2 Index-3 Index Index-4
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