IBM NH2025-10 manual Topology Change Notification Bpdu, Using STP to Manage Redundant Links

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Configuring, Modifying, and Monitoring the Unit

Topology Change Notification BPDU

A non-Root interface sends a Topology Change Notification BPDU (TCN BPDU) over its Root interface any time it believes that the network topology has changed.

The following circumstances can cause this to happen:

∙A Root interface gives up its Root status and the topology state is changing.

∙A switch receives a TCN BPDU from another unit via a non-Root interface.

∙An interface's state changes (it enters the Forwarding state). When a Root interface receives a TCN BPDU, it sets a Topology Changing flag in its Hello BPDU for an interval that is twice the length of the Forward Timer. When a non-Root interface receives a Hello BPDU with this flag set, it quickly ages its dynamic filter s so that it can relearn its filters based on the new topology.

Using STP to Manage Redundant Links

Multiple switches can be connected to form a larger switched network, without using STP the connections between the switches would form a loop. STP should be used to block one of the connections. If the primary connection fails for some reason, STP reconfigures the topology and direct all inter-switches traffic on the redundant link.

Spanning Tree and VLAN restrictions

If you want to use STP and VLAN you should know how the implementation of STP in our products operates. One instance of STP runs in the management VLAN. So the consequence is that STP does not resolve loop in VLAN to which it does not belong. If you want to use the redundancy facility you should use Trunking/EtherChannel feature instead.

Spanning Tree Commands

To view the Spanning Tree commands, enter sp-tree at the CLI prompt. The following are the available port commands.

Enabling/Disabling STP

set-stp enable

Enabling or disabling Spanning Tree does not take effect until the SNMP agent is reset, via warm-reset, cold-resetor a power cycle. The default is disabled.

get-stp

The get-stpcommand retrieves the current state of Spanning Tree.

Example

SYS_console> get-stp

Running spanning tree engine is disable

Next session of the Spanning Tree engine will be disabled.

SYS_console>

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Contents Page Page FCC Notice Standards ComplianceCE Mark Page Contents Configuring, Modifying, and Monitoring the Unit Iii Statistics General View OverviewNetwork Management Systems ApplicationsPerformance/Configuration Feature SummaryManagement Page Front Panel Installing and Setting Up the UnitInstalling the Unit Rack MountingRear Panel Installing Modules in the UnitEM2003-1GE Modules for NHEM2003-2FO Em2003-2GE Connecting Power to the UnitInput Supply EM2003-8TPConnecting Your Network Connecting Ethernet DevicesGrounding Page Getting Started Connecting to the Management PortLogging Into the Command Line Interface Setting the IP AddressSYSconsole ping 192.1.1.1 Verifying the InstallationAccessing the Command Line Interface Remotely SYSconsole set-ipGetting Command Parameter Help Using the Command Line InterfaceCommand Conventions Command Line HelpUsing Command Wildcards Getting Command Group HelpSYSconsole ping 129.1.1.7 ? Connectivity matrix Retrieving Command HistorySYSconsoleget-co Incorrect Number of Parameters Command Line ErrorsNonexistent Command SYSconsole pin Command ‘pin’ not foundHelp-kbd Configuring, Modifying, and Monitoring the UnitConsole Commands Completes commandLogout LoginBanner ClearSet-passwd Sys-stat System CommandsSet-stst-level Warm-resetCold-reset Get-stst-levelGet-tftp-mode Get-tftp-srvrSet-tftp-srvr Set-tftp-modeGet-ip-cfg IP CommandsIP Configuration Get-ipIP broadcast SYSconsole Setting an IP addressSet-ip Set-ip-cfgConfiguring a Gateway Erasing an IP ConfigurationBootp Configuration Add-arp-entry Address Resolution Protocol ARPGet-arp-tbl Del-arp-entryGet-port-cfg dport pipe all Port configurationDisplaying the Port Configuration Get-arp-statsSet-port-cfg Setting the port configurationSet-port-state Get-fctrl Setting the flow controlSet-fctrl Get-ec-tbl Getting the EtherChannel ConfigurationSetting the EtherChannel Configuration EtherChannelPort Priority Deleting the EtherChannel Configuration del-ecSet Port Priority Get-priority-port-cfg Modifying the Switch Policy Get Port Priority Vlan PriorityHow the STP Topology Stabilizes Spanning Tree Protocol STPManually Designating a Root Bridge Selecting a Designated Switch/BridgeSpanning Tree Parameters Root BridgeSpanning Tree and Vlan restrictions Using STP to Manage Redundant LinksSpanning Tree Commands Topology Change Notification BpduMax Age set-br-maxage Configuring the BridgeViewing Bridge Parameters Get-st-bcfgGet-st-pcfg Viewing the Port ConfigurationSetting Port Configuration Hello Time set-br-hellotSet-prt-prio 4 Priority was changed for port SYSconsole Set-prt-enb port-number enabledisableSet-prt-pcost dport pathcost Get-lt-age Switching CommandsAging Configuration Learning TableGet-lt-16 Get-lt-entryFind-lt-addr Adding Static Entries Deleting EntriesCreating VBC Domains Viewing the VBC ModeSetting the VBC mode Virtual Broadcast DomainGet-vbc-tbl Viewing VBC MatrixGet-vbc-matrix Del-vbc-domain runnvram domainid Virtual NetworkingDeleting a VBC Del-vbc-domainImportant Considerations Viewing the Vlan ModeSetting the Vlan Mode SYSconsoleset-vlan-mode run tag Set run Vlan mode tag OKPrinciples of Isvlan Inter-Switch Vlan or IsvlanViewing the Isvlan Mode Tag Field FormatCreating a Server Port Setting a Tagged PortServer Port Removing a Tagged PortRemoving a Server Port Viewing Vlan ConfigurationCreating a Vlan Get-vlan-entry Deleting a VlanDel-vlan Deleting the Management from a Vlan Vlan ManagementViewing the Management Tag Modifying the Management TagCreating a Vlan with Port Management VLAN, Server-port, Example of ConfigurationPhysical configuration schema Vlan Server Port ConfigurationApplicationChecking the Configuration Vlan ConfigurationPayroll Vlan Configuration Finance Vlan ConfigurationPing Utilities CommandsPing Commands Port mirroringStopping Monitoring Setting the Monitoring PortSaving the Configuration Monitoring with monitorFrame Generator Viewing the Nvram ConfigurationErasing the Nvram configuration Setting the Frame GeneratorNBase-Xyplex Snmp Support Snmp basic configurationStopping the Frame Generation Get-comm Snmp Community String CommandsSetting the Read or Write Community Viewing the Community StringSnmp Traps Setting Authentication TrapsViewing the Authentication Trap Status Setting the Authentication TrapGet-traps Example Configuring the Trap StationsAdd-trap Clr-cnt Clearing the Switch CountersStatistics Getting Collisions on a PortGetting Rmon Statistics Group for a Port Rmon StatisticsGetting the Packet Size Distribution Getting the Management Counters Page Trouble Shooting Mailservice@mrv.com Commands Quick Reference Snmp Commands Ping CommandsARP Commands EtherChannel CommandsVirtual LAN Commands Switching Database CommandsSwitching Statistics Commands Port Configuration CommandsPort Monitoring Spanning Tree Commands Page Snmp System Default ValuesPage Download Procedure Client Mode Appendix B Firmware Download Using TftpDownload Procedure Server mode ∙ set-tftp-mode client Tftp Recovery Breaking into the BootROMCompatibility Appendix C Technical SpecificationsStandards Compliance