Cabletron Systems 9E312, 9E423 manual Root Bridge, Root Cost, Root Port, Protocol

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9E312/9E423 Module 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 9E312/9E423 Module bridge port that has the lowest cost path to the Root Bridge on the network. If the 9E312/9E423 Module is currently the Root Bridge, this field will read 0.

Protocol

Displays the Spanning Tree Algorithm Protocol type the 9E312/9E423 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 Page Virus Disclaimer Page Restricted Rights Notice Page Contents 9E312/9E423 Module Bridging IndexIntroduction Introduction Using the 9E312 and 9E423 User’s GuideRelated Manuals Common 9E312 and 9E423 Window Fields Software ConventionsUsing Buttons and Menus Getting Help Using On-line HelpGetting Help from Cabletron Systems Technical Support FTP 9E312 and 9E423 FirmwareIntroduction 9E312 and 9E423 Firmware 9E312/9E423 Module View 9E312/9E423 Module View Viewing Module InformationConnection Status Front Panel InformationMenu Structure Device Menu E312/9E423 Module View Menu StructureHelp Menu Utilities MenuBridge Menu Bridge Port Menu 9E312/9E423 Module Port Status DisplayChassis Manager Window Managing the Module Setting the Device Date and TimeViewing the Device Type Edit Time Window Enabling and Disabling Bridge Ports Using the Find Source Address FeatureFind Source Address Window Summary InformationIndex Interface Description FieldsType DescriptionRaw Counts Interface Performance Statistics/Bar GraphsLoad Interface Detail WindowRate Unicast Interface Detail Window StatisticsMulticast ErrorDiscarded Unknown ProtocolPackets Received Testing and Disabling the Current InterfacePackets Transmitted Making Sense of Interface StatisticsUsing the Applications Pull-down menu 9E312/9E423 Module View Summary Information Bridging Basics 9E312/9E423 Module BridgingMore on Transparent Bridging An Overview of Remote Bridge ManagementBridge Status Window Bridge State on Interface Bridge Status Window Information FieldsInterface Address Interface TypeInterface Speed Bridge Statistics Enabling and Disabling BridgingPerformance Graphs Bridge Performance Graph Window Fields Errors RedFrames Forwarded Green Filtered MagentaConfiguring the Bridge Performance Graphs Interface Statistics WindowAddress Interface Statistics Window FieldsNon-Unicast Bridge Spanning Tree9E312/9E423 Module Bridging Bridge Level Fields Configuring the Bridge Spanning Tree WindowBridge Priority Root Cost Root BridgeRoot Port ProtocolBridge Port Level Fields Designated Cost Path CostDesignated Root Designated BridgeChanging Bridge Priority Changing Bridge Spanning Tree ParametersChanging the Spanning Tree Algorithm Protocol Type Changing Hello Time Changing Forwarding Delay TimeChanging Max Age Time Changing Port Priority Filtering DatabaseChanging Path Cost 9E312/9E423 Module Bridging Filtering Database Window List Filtering Database Window FieldsNumber CapacitySource Port Configuring the Filtering DatabaseReceive Port Port FilteringChanging the Type of Entry Altering the Ageing TimeChanging the Receive Port Adding or Deleting Individual Entries Changing the Port Filtering ActionClearing All Permanent, Static, or Dynamic Entries Using Port Source AddressingDevice Ageing Time Window Setting the Ageing TimeDuplex Modes Window Duplex ModesInterface Duplex Modes Window FieldsFull Duplex Setting the Duplex Mode Index Index-2
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