D-Link DES-5024 Spanning Tree Algorithm, Bridge Priority, Root Cost, Hello Time, Max Age Time

Page 68

Fast Ethernet Switching System User’s Guide

Spanning Tree Algorithm

Spanning Tree Algorithm can be enabled or disabled. Use Spanning Tree to prevent network loops.

Bridge Priority

The Bridge Priority can be from 0 to 65535. Zero is the highest Bridge Priority. The higher the Bridge Priority the greater the chance that the DES-5024 will be selected as the Root Bridge. The DES-5024 with the highest Bridge Priority is the Root Bridge.

Root Cost

The Root Cost is the number of times a packet is regenerated before reaching its destination. A source sends a packet to the first device (switch or hub) on the network. When the packet reaches the next hub or switch and is sent out again, the Path Cost becomes two. Each switch and active hub regenerates the packet. To determine the Root Path Cost, count the number of times the packet is regenerated.

The switch with the lowest Path Cost is the Root Bridge. Make the Root Bridge the best switch on the network.

Hello Time

Is the interval between two transmissions of packets sent by the Root Bridge to tell all other switches that it is the Root Bridge. The Hello Time can be set manually, with a range in seconds from 1 to 10. If the Hello Time is set for the switch and the switch is not the Root Bridge then the Hello Time will not take effect until the switch becomes the Root Bridge.

Forward Delay Time

This is the time any port on the DES-5024 spends in the listening state while moving from the listening state to the forwarding state. It can be set from 4 to 30 seconds.

Use the following formula when setting the Hello Time and the Forward Delay Time:

2 x (Forward Delay minus 1 second) > Max Age

2 x (Hello Time plus 1 second) < Max Age

Max Age Time

Is the time a non-root bridge waits for a packet to be sent. At the end of the Max Age, if a packet has not been received from the Root Bridge, the DES-5024 will start sending its own packets and request permission to become the Root Bridge. If it turns out that the DES-5024 has the lowest Bridge Identifier it will become the Root Bridge.

Managing the DES-5024

60

Image 68

Contents DES-5024 Fast Ethernet Switching System User’s Guide Link Limited Warranty Hardware North, Central, and South America Copyright Statement Wichtige Sicherheitshinweise Table of Contents Page Page Organization About This GuideAudience Features IntroductionPage Front Panel DES-5024 Front PanelRear Panel DES-5024 Rear PanelManagement Methods Updating FirmwareLocal Console Management Telnet ManagementInstalling the DES-5024 Unpacking the DES-5024Installation Options Desktop/ Shelf Installation Install Feet on BottomAttach Feet Rack Installation Attach Mounting Brackets Insert into Rack Installing Modules Remove Blank Bracket Insert Optional Module Power On Copper Cable Connecting the DES-5024 to the NetworkCable Specifications Cable Diagram Fiber Optic Cable Ports MDI-X PortsFiber Optic Ports RS-232 PortConnecting the DES-5024 to other Switches and Hubs DES-5024 to DES-5024 ConnectionLEDs DES-5024 LEDsPower CPU ModuleLED Port 10/100-TX Module LinkPort 100BASE-FX Module ColLit Dark Port 1000BASE-SX Module ActManaging the DES-5024 Local Console Management ∙ Data bits ∙ Parity None ∙ Stop bits ∙ Flow Control NoneTelnet ∙ Default User Name D-Link ∙ Default Password D-Link LogHelp Message Help MessagePanel Conventions SpacebarUser Account Management System ConfigurationConsole Program 100BASE-FX/ 1000BASE-SX Switch Port Module Spanning Tree ConfigurationSnmp Management Configuration Vlan Port ManagementSystem Configuration Menu System ResetFactory Reset to Default Config Values System InformationSoftware Update Boot Prom Firmware VersionSystem Information Menu Hardware RevisionLAN Default Gateway MAC AddressSystem Description System NameSystem Reset System ResetFactory Reset Factory ResetFactory Reset confirmation Disadvantages of Store and Forward System Rate ControlAdvantages of Store and Forward Advantages of Cut-Through Disadvantages of Cut-ThroughSoftware Update Menu Software Update menuTransfer Firmware Xmodem User Account Management User Account Change MenuPassword Confirm PasswordAccess Level Create New UserPage Delete Delete UsersStatus Page New Password Change PasswordOld Password Page Switch Port Configuration Physical Switch Port Configuration MenuState Flow Control Port StatePriority STA Operation Levels Spanning Tree ConfigurationSpanning Tree Configuration Menu Forward Delay Time Spanning Tree AlgorithmBridge Priority Root CostRoot Bridge Root PortSnmp Management Configuration Snmp Management Configuration Menu Snmp Manager SettingAccess Right Snmp Community StringSnmp Trap Manager Setting Authentication FailureCold Start Link Change EventPage Vlan Port Management Vlan Port Management Menu Vlan Port Management menuCreate New Vlan New Vlan NamePort # TrunkGroupPage Delete Vlan Menu Vlan NameModify Vlan Menu Virtual LAN NameTrunking Port Management Menu Trunking Port Management menuName Create New Trunking PortNew Trunking Group Name Page Modify Trunking Port Delete Trunking PortTrunking Port Trunking Port Name Modify Trunking PortTroubleshooting ProblemSolutionPage Diagnostic LED Port Specifications Appendix a DES-5024 Technical SpecificationsSwitch Specifications 10BASE-T EMI Fast Ethernet Switching System User’s Guide Performance Access Level IndexUser Name 50, 52