Cabletron Systems 9A128-01 manual Filtering Database, Changing Path Cost

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Bridging

Changing Path Cost

To change the Path Cost:

1.If necessary, select the desired port by clicking the mouse to highlight the port in the lower right quadrant of the window. The lower left quadrant of the window will now allow you to edit parameters for the selected port.

2.Highlight the Path Cost field, and type in a new value from 1 to 65535 decimal (default is 100 decimal).

3.Click on Set.

The new path cost will be applied to the port.

Filtering Database

The Filtering Database, which makes up the IEEE 802.1 Source Address Table, is used to determine which frames will be forwarded or filtered between the selected module’s bridging ports.

Transparent bridges like the 9A128-01 use the Filtering Database to determine a packet’s route through the bridge. During initialization, the bridge copies the contents of its Permanent Database to the Filtering Database. Next, the bridge learns network addresses by entering the source address and port association of each received packet into the Filtering Database. When in the Forwarding state, the bridge examines each received packet and checks it against the contents of the Filtering Database. If the destination address is located on the network from which the packet was received, the bridge filters (does not forward) the packet. If the destination address is located on a different network, the bridge forwards the packet to the appropriate network. If the destination address is not found in the Filtering Database, the bridge forwards the packet to all networks. To keep Filtering Database entries current, older entries are purged after a period of time, which is called the Dynamic Ageing Time.

The Filtering Database consists of two separate databases: the Static and the

Learned Databases.

The Static Database contains addresses that are entered by a network administrator. You add these addresses directly to the database while the bridge is powered up, or to the selected module’s battery-backed RAM so that they are stored on shutdown till the next power-up.

The Learned Database consists of addresses that accumulate as part of the bridge’s learning process as it is up and running. These do not remain in the Source Address Table when the system is shut down. The Learned Database also contains the addresses that are in the Static Database upon start-up of the bridge.

Entries to the Source Address Table are one of four types: Permanent, Static,

Dynamic, or Learned.

Filtering Database

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Contents Cabletron Systems Virus Disclaimer Page Restricted Rights Notice Page Contents Index Chapter Fddi ManagementChapter Bridging Using This Guide IntroductionRelated Reading Device Name Software ConventionsCommon Window Fields IP AddressGetting Help Using ButtonsUsing On-line Help LocationGetting Help from the Cabletron Systems Global Call Center FTPFirmware Versions Supported 9A128-01 Module View Viewing Module Information Front Panel InformationUpTime Boot PromConnection Status Port StatusDate Menu StructureTime A128-01 Module View Menu Structure Device MenuPort Status Menu Help Menu Fddi MenuUtilities Menu Board MenusPort Status Displays Port MenusSelecting a Port Status View Bridge Port Status DisplaysBridge Port Status Color Codes Bridge Port StateBridge Mapping Fddi Port Status DisplaysConnection State LER EstimateChassis Manager Window Fddi Port Status Color CodesModule Type Viewing Hardware TypesDevice Type Viewing I/F Summary Information Module Type WindowSta IndexDescription Interface Performance Statistics/Bar GraphsRaw Counts LoadRate Interface Statistics WindowUnicast ErrorAddress Non-UnicastTransmit Queue Size Transmit only Using the Find Source Address FeaturePackets Received Received only Packets Transmitted Transmit onlySetting the Device Date and Time Managing the HubEnabling and Disabling Ports Bridge PortsModule Ports Accessing the ATM Connections Window ATM ConfigurationATM Configuration Connection DataSettings VPIConfiguring Connections Adding a New ConnectionDeleting a Connection ATM Configuration Configuring Connections Fddi Management Configuration Fddi ManagementMAC State Neg. Negotiated SMT VersionReq. Requested Target Token Rotation Time Number of MACs Concentrator M PortsConcentrator Non-M Ports MAC PathConnection Policy 15 32,768 a permanently set value for this bit Number of Nodes Address ModeStation List Topology Stations PanelNode Class Upstream NeighborPerformance Receive Frames Frame ErrorsTransmit Frames Lost FramesFddi Management Performance Bridging Bridge Status Window BridgingInterface Type Up TimeBridge State on Interface Bridge AddressConfiguring Duplex Modes Enabling and Disabling Bridging Bridge Statistics Performance GraphsForwarded Green Xmitted Blue Total Errors RedFiltered Magenta Configuring the Bridge Performance GraphsFiltered ErrorsForwarded XmittedForwarded from Interface Statistics WindowForwarded to Description Using Source Addressing Setting the Ageing Time Port Source Addresses WindowBridge Spanning Tree Configuring the Bridge Spanning Tree Window Bridge PriorityRoot Port Root BridgeRoot Cost ProtocolMax Age Forwarding DelayHello Time Hold TimeChanging Bridge Spanning Tree Parameters Changing Hello Time Changing Bridge PriorityChanging the Spanning Tree Algorithm Protocol Type Changing Port Priority Changing Forwarding Delay TimeChanging Max Age Time Filtering Database Changing Path CostBridging Bridging Capacity ListNumber Ageing TimePort Filtering Configuring the Filtering DatabaseReceive Port Changing the Receive Port Altering the Ageing TimeChanging the Type of Entry 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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